The ISCAR
Reference Guide for

Machining Titanium

www.iscar.com

THE STANDARDS INSTITUTION OF ISRAEL

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CERTIFIEDEN

CERT
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C

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THE STANDARDS INSTITUTION OF ISRAEL

SI
OHSAS
18001:2007

GYMANAGEM
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SI
ISO
50001

SYSTEM
ENT

THE STANDARDS INSTITUTION OF ISRAELD OHS SY
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THE STANDARDS INSTITUTION OF ISRAELTIFIED EM
ERSI
ISO 14001:
2004

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AS 9100

TIFIED QM
ERSIISO 9001:
2008

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TIFIED QM
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THE STANDARDS INSTITUTION OF ISRAELSymbols and units................................................................................................................................... 3
Abbreviation list....................................................................................................................................... 4
TITANIUM GRADES.............................................................................................................. 5
MACHINABILITY OF TITANIUM............................................................................................. 7
MILLING TITANIUM.............................................................................................................. 9
CEMENTED CARBIDE GRADES FOR MILLING TITANIUM.................................................................. 9
HOW TO CHOOSE THE CORRECT CARBIDE GRADE?..................................................................... 11
GENERAL GUIDELINES FOR MILLING TITANIUM............................................................................. 13
INITIAL CUTTING DATA IN MILLING................................................................................................... 16
TOOLS FOR MILLING TITANIUM EFFICIENTLY.................................................................................. 33

TOOLS FOR MACHINING TITANIUM

A word to the reader................................................................................................................................ 2

Indexable extended flute cutters for milling shoulders and wide edges................................ 33
Milling with high pressure coolant (HPC)............................................................................. 35
Fast feed milling titanium.................................................................................................... 38
High speed milling titanium................................................................................................. 43
DRILLING TITANIUM.......................................................................................................... 47
DRILLING SHALLOW HOLES.............................................................................................................. 49
CENTER DRILLING............................................................................................................................... 50
SELECTING A DRILL............................................................................................................................ 51
INITIAL CUTTING DATA IN DRILLING................................................................................................. 52
REAMING TITANIUM.......................................................................................................... 54
INITIAL CUTTING DATA IN REAMING................................................................................................. 56

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TOOLS FOR MACHINING TITANIUM

A WORD TO THE READER
Titanium and its alloys are widely used in modern industry. Today, due to exceptional strengthto-weight ratio, high corrosion resistance and performance over a wide temperature range,these lightweight metals are essential elements in the designs of aerospace, shipbuilding,chemistry and medicine. Aircraft frame components, stressed skins, fasteners, compressor
disks and blades, casings, marine screw propellers, and orthopedic implants - theseare some typical examples of parts and units made from titanium and its alloys.
In spite of these indisputable advantages, titanium and titanium alloys are characterized by certain
disadvantages; and poor machinability is one of them. Indeed, the Titans were also imperfect– themythical giants after whom a new lightweight metal, discovered in the late 18th century, was named.
Manufacturers of cutting tools make great efforts to improve their products intended for machining
titanium. At ISCAR, we consider the issue of high-performance cutting tools for machining
titanium as a primary-importance direction of our work. Our ongoing research and development
aim to provide the industry with effective and reliable cutting tools for productive machining oftitanium. A guide on how to choose and operate the tools intelligently also contributes to theeffectiveness of machining; we hope that this quick reference guide in milling titanium will act
as a useful reference tool and a real help in machining titanium with modern ISCAR tools.
The main aim of the guide is to assist in selecting the most suitable rotating tool
for machining titanium, and to quickly find initial cutting data required for operating
the tool. The guide contains additional data about titanium machinability, tool
materials, coolant supply, shop talk, and even some historical anecdotes.
With compliments,
ISCAR team,Your partner in intelligent machining

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The guide utilizes metric units and their equivalent US customary units as well.
As a rule, the latter are put in brackets and follow metric measurements.
AE
a
ae
ap
apmax
c
d
de
f
fz
fzo
fzmin
fzmax
fzav
hm
hmax
Ke
Kf
Kh
Km
Ks
n
Q
Vo
Vc
Vf
VHP
αr
χ

angle of engagement,machining allowance (stock to be removed) per pass, mm (in)width (radial depth) of cut, mm (in)axial depth of cut, mm (in)maximum axial depth of cut, mm (in)ratio of width of cut ae to nominal tool diameter dnominal tool diameter, mm (in)effective diameter, mm (in)feed, mm/rev (IPR, ipr, inches per revolution)
feed per tooth (chip load), mm/tooth (IPT, ipt, inches per tooth)basic (initial) feed, (chip load), mm/tooth (IPT, ipt, inches per tooth)minimum feed per tooth (chip load), mm/tooth (IPT, ipt, inches per tooth)maximum feed per tooth (chip load), mm/tooth (IPT, ipt, inches per tooth)arithmetic average feed per tooth (chip load), mm/tooth (IPT, ipt, inches per tooth)average chip thickness, mm (in)maximum chip thickness, mm (in)engagement factor
tooth strength factor
overhang factor
machinability factor
stability factor
rotational velocity (spindle speed), rpm (rpm)metal removal rate (MRR), cm³/min (in³/min)basic cutting speed, m/min (SFM, sfm)
cutting speed, m/min (SFM, sfm)
feed speed (feed rate), mm/min (IPM, ipm, inch per minute)cutting speed in machining with high pressure coolant, m/min (SFM, sfm)
ramping angle
cutting edge (entering) angle

TOOLS FOR MACHINING TITANIUM

SYMBOLS AND UNITS** in metric system (US customary units are given in brackets)

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TOOLS FOR MACHINING TITANIUM

ABBREVIATION LIST
A
ASTM
AM
BASCA
Bling
Blisk
BlotorBlum
BUE
CAD/CAM
CBN
CNC
CVD
DA
Dia.
DOC
ELI
FF
HFM
HPC
HSM
HSS
IBR
ISO
MTB
MRR
PCD
PVD
R
SCEM
STA
UHPC
WOC

annealing (annealed)
American Society for Testing and Materials
additive manufacturingbeta annealing followed by slow cooling and aging(beta annealed, slow cooled and aged)
bladed ring
bladed disk
bladed rotor
bladed drumbuild-up edge
computer-aided design and manufacturing
cubic boron nitride
computer numerical control
chemical vapor deposition
duplex annealing (duplex annealed)diameterdepth of cut
extra low interstitials
fast feed*high feed millinghigh pressure coolant
high speed milling, high speed machining
high-speed steel
integrally bladed rotors (IBR)
International Organization for Standardization
machine tool builder (builders)
metal removal rate
polycrystalline diamond
physical vapor deposition
rolling (rolled)
solid carbide endmills
solution treatment and annealing (solution treated and annealed)ultra high pressure coolant
width of cut* fast feed is synonymic with high feed

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The common term “titanium” usually implies not only pure titanium, but also
its alloys. For the most part, industry consumes just alloys. Alloying titanium isoriented to receiving grades with different properties and allows heat treatment
for some of them. Typical alloying elements for titanium are Aluminum,
Vanadium, Molybdenum, Ferrum, Chrome and others. Even small amountsof these elements can drastically change the properties of the alloys.
Pure titanium can exist in two crystalline forms: the low-temperature α-phase withhexagonal close-packed lattice and the higher-temperature β-phase with bodycentered cubic lattice. The alloying elements in titanium alloys lead to an increasein α-phase or β-phase. Elements that strengthen, or stabilize a phase are calledstabilizers: α-stabilizers or β-stabilizers. For example, Aluminum, Nitrogen andPlumbum are α-stabilizers, and Vanadium and Molybdenum are β-stabilizers. Someelements added to titanium alloys do not strengthen either the α- or β-phase, but
are important as “neutral” elements that give certain properties to the alloy.

TITANIUM GRADES

TITANIUM GRADES

Based on its metallurgical characteristics, titanium is divided into the following groups:• Commercially pure titanium (unalloyed), featuring a good
corrosion resistance but low strength.
• α-alloys (alpha-alloys), consisting of only α-phase and having a lot of
α-stabilizers, which feature strength retention at relatively high temperatures.
• Near-α-alloys (near-alpha-alloys), which are α-alloys with a small addition of β-stabilizers
and have good resistance to creep for working temperatures 450°C -550°C.
• α-β-alloys (alpha-beta-alloys), perhaps the most common group, which is a typeof mixture of both phases and contains α- and β-stabilizers. The alloys of thisgroup are suitable for heat treatment and aging for strength improvement.
• β-alloys (beta-alloys) include a sufficiently large number of β-stabilizers to obtain
β-phase structure after treatment or even cooling in some cases. The group ischaracterized by high hardenability and, therefore, high strength. However, increasing
the amount of the alloying elements leads to higher density. In addition, increasing
strength by solution treating and aging causes a reduction in ductility.
The family of near-β-alloys (near-beta-alloys) is sometimes separated from thegroup because it does not retain a fully β-phase structure after treatment.
Generally, the α-alloys have better ductility and the β-alloys have higher strength.
The α-β-alloys lay between the mentioned two (Fig. 1).
There are different code systems for designating titanium. The American
Society for Testing and Materials (ASTM), for instance, uses a grade
numbering method: Grade 1, Grade 2, … , Grade 12,…
This guide utilizes the chemical composition system, where the designation shows thepercentage of main alloying elements in an alloy. For example: “Ti6Al4V” or“Ti-6Al-4V” means that the titanium alloy contains 6% Aluminum (Al) and 4% Vanadium(V). The amount of the other alloying elements is small and, if necessary, can befound in detailed specification of the grade. The remaining component is titanium.

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TITANIUM GRADES

Table 1 shows some typical titanium grades and their use in industry.

Table 1 - Application Of Selected Titanium GradesGroup

Designation

Conditions Application examples

Commerciallypuretitanium

ASTM
Grades1-4Aα-titanium
alloysTi-5Al-2.5Sn

A

Aircrafts (compressor blades, pipelines),
steam turbine blades

Ti-8Al-1Mo-1V
near-αtitanium alloys Ti-6Al-1Mo-2Cb-1Ta

DA
R

Airframes
Welded corrosion-resistance parts

α-β-titanium
alloysTi-6Al-4V
Ti-7Al-4Mo

A; STA
STA

Turbine and compressor blades,disks, fasteners, rocket parts
Airframes, rocket parts

β- andnear
β-titanium
alloys

Ti-13V-11Cr-3Al
Ti-10V-2Fe-3Al
Ti-5Al-5Mo-5V-1Cr-1Fe
Ti-5Al-5Mo-5V-3Cr

A; STASTA
A; STASTA

Fasteners, stressed structure elements, rocket parts
High-strength parts, airframes, landing gears
High-strength parts, airframes, landing gears
High-strength parts, airframes, landing gears

Medical equipment, implants, chemical
equipment, marine and aircraft parts

A- annealed, DA - duplex annealed, R - rolled, STA - solution treated and aged

Titanium received its name from Martin Klaproth, a German chemist, one of the discoverers oftitanium in the end of 18th century. Klaproth, who found the oxide of a new metal in an ore, gaveit the name of the mythical giants – the Titans. However, there is another and more exotic version,according to which the source of the name “titanium” is Titania, the Queen of the Fairies and thewife of King Oberon in William Shakespeare’s “A Midsummer Night’s Dream” . With the combinationof an ability to withstand titanic stress and its fairylike lightness, titanium fully justifies its name.

α−Τi

α−β−Τi

Ductility

Fig. 1 Ductility-strength properties of titanium alloys

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β−Τi

StrengthThere a widespread belief that titanium is like austenitic stainless steel interms of its machinability. This may be true when relating to commercially puretitanium and also, with some assumption, α- or even α-β-alloys; however, it isfundamentally wrong with respect to the treated β- and near-β- alloys.
In general, titanium alloys (which we will refer to as titanium and specify their composition, gradeand properties separately where necessary) are hard-to-machine materials and their machinability
depends on various factors: chemical composition, hardness, method of treatment.
The main difficulties in cutting titanium are the following:• Intensive heat generation leads to excessive adhesive wear of cutting edge.
• Low heat conductivity results in poor heat transfer and slowing heat dissipation
down. Therefore, cutting edge experiences considerable thermal loading.
• “Springiness” of titanium due to low modulus of elasticity contributes tovibrations and worsens machining accuracy and surface finish.
The mentioned factors significantly reduce tool life and affect performance.
The averaged data in Table 2 allows estimating machinability of titanium
compared with other groups of basic engineering materials.

MACHINABILITY OF TITANIUM

MACHINABILITY OF TITANIUM

Table 2 - Machinability Of Titanium Vs. TypicalEngineering Materials (Averaged Data)
Material

ISO group

Machinability, %100

Non-alloy free cutting steelP

Low alloy steel, annealed

60

High alloy steel, annealed

50

Austenitic stainless steel, annealedM

40

Commercially pure titanium

S

43

Titanium Ti-6Al-4V, annealed25

At the same time, as already mentioned, titanium machinability varies depending on the titaniumgroups and the grades within the groups.
Table 3 provides a comparison of machinability for different titanium representatives;and Fig. 2 shows an appropriate graphic expression.

Titanium is a difficult-to-cut-material and its machining is challenging.

Table 3 - Machinability Rating Of Titanium Grades (Averaged Data)Group

Designation

Pure titanium

Grade 2α- and nearα-titanium

Ti-5Al-2.5Sn
Ti-8Al-1Mo-1V

α-β-titanium
β- and nearβ-titanium

Condition*

Hardness

Machinability %HB 150-200

170

A

HRC 31-34

115

DA

HRC 34-36

110

Ti-6Al-4VA

HRC 32-36

100

Ti-8V-5Fe-1AlA

HRC 34-38

97

Ti-6Al-4V

STA

HRC 39-41

90

Ti-10V-2Fe-3Al

STA

HRC 35-42

56

Ti-13V-11Cr-3AlA

HRC 39-41

53

Ti-5Al-5Mo-5V-3Cr

STA

HRC 36-44

51* A - annealed, DA - duplex annealed, STA - solution treated and aged

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MACHINABILITY OF TITANIUM

Machinability Rating
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Pure

α- andnear-α-α- ββ- and near-β-

Fig. 2 Machinability of titanium groups (averaged data)β-stabilizers, which contribute to higher strength, increase specific cutting force.
As a rule, the β-phase structure reduces machinability and machining β- titanium is more difficult.

Extensive use of titanium in industry, particularly in the aerospace sector, led to in-depth study ofmachining titanium and caused serious changes in technology. As a result, manufacturers built
reliable metal cutting processes and took titanium machining productivity to a new level.
This reduced production costs and caused added momentum to a wide penetration of titanium in
new designs. Today, for example, machining Ti-6Al-4V, the most commonly used titanium grade,is considered already as a closed chapter, although 15-20 years ago it was not a cakewalk.
Success has boosted interest in a wider application of other titanium grades featuring better
strength but with poorer machinability. These grades focused the attention of designers as agood alternative to steel and stainless steel for weight saving but the low productivity presented
a barrier. Following new demands, industry faced a problem with productive machining titanium
alloys such as Ti-10V-2Fe-3Al and Ti-5Al-5Mo-5V-3Cr (VST 5553) that had a strong presence
as key elements in different structural components. On the one hand, machine tool builders(MTB) achieve an impressive success in high-efficiency machine tools specifically dedicatedto cutting titanium. These latest-generation multi-axis machines are intended for high volume
production capability and feature high-torque main drive, advanced CNC software and adaptive
control units, and high-pressure coolant supply. On the other hand, far slower progress in the
cutting tools field has presented an obstacle in taking full advantage of the new machines.
Finding a way how to close the produced gap dictates strict requirements for cutting
tools intended for machining titanium. The cutting tool, which often seems to be aminor link in a whole technological chain, actually plays a role of the prime factor,
which can boost productivity of titanium and firstly its difficult-to-cut grades.
There are few options for substantial improvement of cutting tools. The main directions for thedevelopment of advanced tools relate to cutting tool materials and cutting tool design (geometry).

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Cemented Carbide Grades for Milling Titanium
In indexable milling, ISCAR proposes several grades that were designed especiallyfor machining ISO S materials including titanium. Some of the grades are themain grades; the others are considered as complementary. Fig. 3 characterizes
the application field of the grades in accordance with ISO 513.

MILLING TITANIUMMILLING TITANIUM

Producers of titanium parts have high hopes for additive manufacturing (AM), that it will be a wind ofserious changes in technology. AM allows forming a nearer-to-net shape part to minimize machining
operations substantially. Removing high-volume material during rough cuts will be cancelled and it
will automatically change the machine tool population of a company: heavy duty machines will simply
disappear. However, despite the great success of AM, experts believe that introducing this innovativeand promising method will take time. Strict safety requirements from the aerospace industry, themain consumer of titanium components, necessitate extreme caution in adoption of the new ideas.

ISO S GRADES

S05
S10

IC808
IC908

S15
S20

IC830

IC840
IC882

S25

IC330
IC328

IC5820

IC830
IC928

S30
Main grade

Complementary grade

IC380- Especially for milling Ti in stable conditions

Post-coating SUMO TEC treatment
Post-coating treatment

Fig. 3 ISCAR carbide grades for indexable milling titanium

The main grades are represented by IC808/IC908 (the hardest grades),IC882 (the toughest grade) and IC840, which is in between.
The complementary grades demonstrate good results in specific applications,such as IC380 with its impressing performance when milling in stable conditions,and, therefore, they can be used in machining titanium as well.

Fig. 4 Bronze “sun tan” carbide inserts

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MILLING TITANIUM

Some facts about carbide grades
A carbide grade is the combination of three elements: a tungsten carbide substrate, which is
produced by powder-metallurgy technology, a wear-resistant coating and a post-coating treatment,
while only although only the substrate is essential. In some cases a specific tungsten carbide
may act as an uncoated grades; while in other cases it will be a substrate of a coated grade.
SUMO TEC is a special post coating treatment of indexable inserts, which provides substantially
improved tool life and better reliability.
It has the effect of making the rake face of an insert even and uniform, minimizing inner stresses,
cracks and droplets in coating that leads to smooth chip flow and extended tool life.
ISCAR PVD coated grades IC840 and IC882 have a bronze chocolate color. The peripheryof inserts, which are made from SUMO TEC CVD coated grade IC 5820, is also a brownshade. Development of these “sun tan” grades was directed exactly towards milling ISO S(titanium and heat-resistant alloys) and ISO M (austenitic and austenitic/ferritic stainless steel)materials. ISCAR believes that the above “sunbathed” cemented carbides (Fig. 4) will bringa real premium-class cutting “assorted chocolate” to the manufacturer of titanium parts.
While the choice of carbide grades for solid carbide endmills (SCEM) and MULTI-MASTER
end milling heads is somewhat limited, it is enough for producing a rich variety of milling toolsthat effectively cut titanium by different techniques, including a high speed machining (HSM)
method. Fig. 5 and 6 show the application field of the grades in concordance with ISO 513.
ISO S GRADES - Solid Carbide Endmills

S05

IC902*

S10
S15

IC903

S20

IC900
IC300

S25
S30
Main grade

Complementary grade* First choice for trochoidal millingFig. 5 ISCAR carbide grades for milling titanium by SCEMISO S GRADES - MULTI-MASTER Heads
S05
S10
IC903*

S15
IC908

S20
IC308
S25
S30
Main grade

Complementary gradeFig. 5 ISCAR carbide grades for milling titanium by SCEM

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* First choice for trochoidal millingAs the people engaged in production like to say, the best carbide grade is the grade that you have inyour stock. This statement (which can be related to the cutting tool as a whole) is probably true if it
is a production situation that requires an operative decision. However, productive process planning,or effective tool stock managing requires more serious applicative analyzing of the pros and consof the proposed carbide grades. Fig. 3-6 with schematic representations of the application
field of the grades, illustrate clearly the conclusions regarding recommended grade selection.

MILLING TITANIUM

How To Choose
The Correct Carbide Grade?

Indexable Milling Cutters
IC840 is the most universal carbide grade, and therefore it should be considered as thefirst-choice grade, especially in the most general cases of process engineering.
Grade IC808 features higher hardness compared to IC840. It is suitable mostly forsemi-finish and finish operations and may be defined as a second-choice grade.
IC882 is the strongest among the main cemented carbide grades for indexable
milling titanium. It is intended primarily for heavy duty milling, machining in
unfavorable conditions, for cases with significant impact load, etc.
With regards to the complementary grades, IC380 has proved itself, in milling when
the rigidity of a technological system is high; and IC5820 shows impressive resultsin machining with high pressure coolant supply (HPC), preferably pin-pointed.
Comparative characteristics of grade performance in specific casesof indexable milling titanium are shown in Table 4.

Table 4 Performance Of Carbide Grades In Specific Milling Applications
Comparative performance

Grade

Heavy duty
Cutting

Fast feed
Milling (FF)

Unfavorable
Conditions

High rigidity
Of system

Finishing at
Small ae**

IC808

♦

◊

♦

♦

♦♦◊

♦♦♦

IC840

♦♦

♦♦

♦♦◊

♦♦

♦♦

♦♦

IC882

♦♦♦

♦♦♦

♦

♦♦♦

♦♦

♦◊

IC380

♦

♦

♦

♦

♦♦♦

♦♦

IC5820

♦◊

♦◊

♦♦♦

♦◊

♦♦◊

♦♦◊

IC830

♦◊

♦♦

♦

♦♦

♦♦

♦◊

IC330

♦♦

♦♦

♦◊

♦♦◊

♦◊

♦

HPC*

* high pressure coolant supply** ae - width of cut

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MILLING TITANIUM

Solid Carbide Endmills (SCEM) and MULTI-MASTER Milling Heads
The choice of carbide grades in SCEM and MULTI-MASTER families is a little lower
compared to indexable milling cutters. The grades available are are more general andall-purpose from a practical standpoint, and feature a wide field of application. Table
5 shows the recommended carbide grades for typical and trochoidal milling.

Table 5 Choosing ISO S Carbide Grades for SCEM and MULTI-MASTER Heads
GradesSolid carbide endmills
MULTI-MASTER heads

Typical milling techniques
1st choice
2nd choice

Trochoidal milling
1st choice
2nd choice

IC300

IC900

IC902

IC903

IC308

IC908

IC903

-

ExampleThe production engineering office of a manufacturer of titanium plant is planningcomparative tests for indexable high feed milling cutters. The operation is milling thelarge-sized open plane surface of a titanium component. Technologists chose ISCARMILL4FEED shell mills carrying inserts FFQ4 SOMT 120516HP. As the catalog
shows, the inserts are available in grades IC882, IC830, IC5820 and IC808. The
office decides to test two different grades. Which of them should be ordered?
High feed (fast feed in ISCAR terminology) milling causes considerable tooth load. In accordancewith grade data (refer to Fig. 3), the available grades IC882, IC830, IC5820 and IC808
feature the following ISO application fields: (S20-S30), (S15-S30), (S15-S25) and (S10-S25)
correspondingly. An increasing number after “S” characterizes growth of a grade toughness,
grades IC882 and IC830 are more suitable for testing and therefore they should be ordered.

ExampleWhich carbide grade is the most effective for indexable milling with high pressure coolant supply?
Table 4 provides a clear answer to this question: IC5820.

Nano layered PVD coating
PVD coatings were introduced during the late 1980’s. With the use of advanced
nanotechnology, PVD coatings performed a gigantic step in overcoming
complex problems that were impeding progress in the field.
Developments in science and technology brought a new class of wear-resistantnano layered coatings. These coatings are a combination of layers having athickness of up to 50 nm (nanometers) and demonstrate significant increases
in the strength of the coating compared to conventional methods.

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When milling titanium, a manufacturer tries to obtain the most effective milling technique and theappropriate tool. Best production practices have already developed general recommendations to
successfully complete these tasks, in order to overcome the main difficulties in cutting titanium
while ensuring acceptable productivity and tool life. Even though the technique and the tool
relate to each other, the recommendation may be considered with respect to each separately.

Milling Technique
Milling technique or milling strategy determines the tool path and the“depth of cut (ap) – width of cut (ae)” relation. In choosing the most suitablemachining strategy, the following points are taken into consideration:

MILLING TITANIUM

General Guidelines for Milling Titanium

A rotating mill contacts a machined workpiece by arc that is measured by angle ofengagement AE (Fig. 7). Decreasing this arc (i.e. width of cut ae) reduces the heatload on a cutting edge of the mill. In addition, it increases the interval during which theedge is involved directly in cutting, and so ensures more time for edge cooling. Less
heat generation diminishes the risk of titanium work hardening during machining.
Due to the above factors, reducing ae allows increasing cutting speed Vc. In milling full slot
directly from solid with cutting speed Vc1, the width of cut is equal to tool diameter d. In
comparison with this case, in milling square shoulder with ae less than 0.1×d (AE≈37°) the
cutting speed may be increased by 150-200% (1.5…2×Vc1). Fig. 8 shows an approximate
plot of Vc against AE and ae in milling slot in a workpiece from Ti-6Al-4V by different methods.

n1

Mill1

n2

Mill2

ae1
ae2
AE1

AE2

vf1

vf2

Fig. 7 Contact arc and angle of engagement

3. An approach cut by arc (“rolling in”) is preferable (Fig. 9). When a milling cutter enters a machinedmaterial by arc, the mechanical and the thermal loads on the cutting edge grow gradually andnot suddenly, which significantly contributes to machining stability and improving tool life.
4. Today with the use of advanced CAD/CAM systems it is possible to plan a tool
path with a practically constant angle of engagement. This can constrain thearc of contact to prevent both overloading and overheating the tool.
5. In cutting, when the temperature in a cutting zone is high, a chemical interaction between
the cutting edge and the material, as well as edge oxidation, results in notch wear. If a milling
cutter machines a deep square shoulder by passes with constant depth of cut ap per pass, anotch is more likely to occur. This notch causes deformation in the material instead of cutting it,
which leads to material work-hardening and scoring the material surface, resulting in abnormal
cutting conditions and poor surface finish. Therefore, varying ap per pass in multi-pass milling
reduces intensive notch wearing in located area and diminishes these negative effects.

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MILLING TITANIUM

6. Titanium alloys, especially their more difficult-to-machine grades, feature significant specific cutting
force, which leads to high mechanical loading of the cutting edge. Titanium’s “springiness” boosts
vibrations, particularly in rough milling with considerable machining allowance. This means that effective
cutting under such conditions stipulates high rigidity of the whole technological system, and stiffnessof a machine tool, proper work- and tool holding, and the tool overhang may be crucial.

7. In process planning, check the possibility of milling titanium while it is in a soft condition.
Heat treatment and age-hardening make titanium much more difficult to machine.
8. High-pressure coolant (HPC) supply can dramatically improve milling efficiency*.
9. Milling deep pockets and cavities requires a high tool overhang. When planningmachining operations, possible alternatives are to use several milling cutters withdifferent overhangs, or several assemblies, in which the same cutters are mounted
in toolholders with various neck lengths, instead of one long-reach tool.
10. High feed milling (HFM, fast feed milling) may be a viable alternative to traditional heavyduty rough milling. HFM titanium is suitable for machining tools with slow table drive dueto the feed speed being considerably lower compared to the values necessary for HFM
steel. However, applying the alternative requires machines with a rigid spindle unit.

Trochoidal milling
Trochoidal milling is a high efficiency milling technique that uses advantages of decreasing
the angle of engagement, machining with thin chip, and approach cut by arc, which result inincreasing cutting speed and feed rate. In trochoidal milling, a fast-rotating tool that operates
at high depth of cut, moves along arc and “slices” a thin but wide layer of material. When thelayer is removed, the cutter advances deeper into the material radially and then repeats theslicing. This method ensures uniform tool engagement and stable average chip thickness.
Therefore, the tool experiences constant load that causes uniform wear and predictable tool
life. The small thickness of sliced material both significantly reduces heat impact on the tooland ensures increasing the number of the tool teeth. As a result, the method ensures very highmetal removal rate with considerably decreased power consumption and improved tool life.
Trochoidal milling is very popular in producing titanium parts, for example in roughand semi-finish machining slots in blisks (bladed disks) and impellers.
ae

d

n
vf
AE

n

n

ae
d

AE

0.02

15°

0.07

30°

0.25

60°

0.5

90°

0.75

120°

1

180°

vf
vf

Vc
Vc1

2×Vc1

Fig. 8 Plot Vc against AE and ae

Fig. 9 Direct entering into material
and entering by arc (“rolling in”)

* HPC benefits are considered in more detail in the following page of the guide

14

ISCAR

Selecting a suitable tool for milling titanium is a very important issue. The following three
features: cutting geometry, tool material, and design configuration, should be examined.
1. It is considered that tools for milling titanium feature positive-rake geometry with appropriateedge preparation. This is quite right with respect to commercially pure and easy-to-machinetitanium grades. However, milling the difficult-to-machine grades requires a reinforced
cutting edge that is ensured by neutral or negative T-land. In many cases of roughing
applications (such as heavy-duty milling by indexable extended flute milling cutters or HFM),
tools with negative-rake geometry, which provide higher feed, are the best choice.
2. Milling titanium dictates increasing relief angle.
3. When indexable milling tools are examined, cutters with one-sided inserts are preferable.
Generally, they demonstrate better performance when compared to tools carrying double-sided
inserts. However, in rough machining wide edges of workpieces (edging), the indexable extended
flute cutters with tangentially clamped double-sided inserts can be a first-choice solution.
4. The tool material and design should ensure a sharp edge during reasonable tool
life. In conditions of intensive heat generation, a dull (“bad”) edge increases buildup edge formation and tool wear, and leads to serious tool damage.
5. Machining titanium features considerable heat build-up and mechanical load,
particularly for difficult to machine grades, and the tool material must maintain acorrect balance between high-temperature strength and impact resistance.
6. Coated cemented carbides are the main tool materials for titanium milling. PVD coating
retains a sharp cutting edge better than CVD. The majority of indexable carbide inserts
intended for milling titanium are PVD-coated. However, CVD-coated inserts, which are usuallyless sharp than PVD-coated inserts, often perform better in heavy-duty rough milling.
7. Cutting ceramics and cubic boron nitride (CBN) are not so suitable for machining titanium,although polycrystalline diamond (PCD) has proved itself in finish milling in several cases.
8. Most machine tools today are usually designed to supply coolant through a spindle. Therefore,
applying cutting tools with internal coolant supply through the tool body is preferable.
9. Vibration strength in end milling can be improved drastically by using solid
carbide endmills (SCEM) with chatter-free cutting geometry.
10.Milling cutter accuracy is an important factor not only for ensuring the required precisionparameters in finishing operations. Low accuracy, especially in case of small-diameter
cutters, affects performance and reduces tool life. For example, excessive run out leads toincreased loading of a tooth and its early wear, which causes overloading the other teeth
and even cutter failure. Poor cylindricity of the tool shank diminishes the effective area ofcontact between the shank and a toolholder that significantly decreases clamping force.

MILLING TITANIUM

Milling Tool

15

MILLING TITANIUM

Initial Cutting Data In Milling
Generally, cutting data relates to finding depth and width of cut (ap and ae correspondingly),
cutting speed Vc and feed per tooth fz. Defining ap and ae is strongly dependent not only ona chosen milling method and process planning but also on tool design characteristics such as
diameter and maximal cutting length. This section of the guide considers Vc and fz estimation.

Cutting Speed
Vc varies within a broad range, depending on the type of machining and machinabilityof a specific titanium grade. Typical Vc values are shown in Table 6.

Table 6 Typical Cutting Speed Vc When Milling Titanium
Type of Machining

ExamplesCutting speed Vc, m/min (sfm)Hard (H)Heavy-duty roughing, milling in
unfavorable conditions

25-60(80-200)

Medium (M)Medium-duty roughing,semifinish milling

40-80(130-260)

Light (L)Finish milling,light-duty cutting

70-120(230-400)

A more accurate estimation of starting speed Vc requires asimple calculation in accordance with equation (1).

Vc=Vo×Km×Ke×Ks		
Where:
		
		
		

(1)

Vo – basic cutting speed
Km – machinability factor
Ke – engagement factor
Ks – stability factor

Basic Cutting Speed Vo
Basic cutting speed Vo depends on a tool material. Table 7 gives Vo values for the
carbide grades that are used in indexable milling cutters, and Table 8 gives Vo values
for the carbide grades intended for SCEM and MULTI-MASTER heads.

Machinability Factor Km
Machinability factor Km reflects the difference in machinability for titanium grades. It isa derived value of machinability rating (Table 3, Fig. 2). Km is shown in Table 9.

Engagement Factor Ke
Reducing the angle of engagement AE (i.e. width of cut ae) allows increasing the
cutting speed Vc (Fig. 8). Table 10 gives appropriate values Ke for correction.

Stability Factor Ks
Stability factor Ks is defined by the estimate below of milling operation stability:• Ks=1 for normal stability• Ks=0.7-0.8 for unstable operations (high overhang, poor tool- or workholding,milling thin walls, etc.) and milling in unfavorable conditions.

16

ISCAR

MILLING TITANIUM

Cutting in unfavorable or unstable conditions? Heavy or heavy-duty machining?
“Cutting in unfavorable or unstable conditions” – which is correct? The meaning of these two
definitions is confusing sometimes. “Unfavorable conditions” relate to the following cases of
cutting: skinned workpiece, variable machining allowance (material to be removed) that leads
to changing the depth of cut, significant impact load, surfaces with high-abrasive inclusions,chatter. “Unstable conditions” characterize low stability of a complete system (machine tool,
workpiece holding fixture, cutting tool, workpiece) caused by poor tool and/or workpieceholding, non-rigid machine tool, high tool overhang, thin-walled workpiece, etc. Despite thegap in definitions, the conditions are in a cause-and-effect relationship: for example, lowtechnological rigidity contributes to increased vibrations and thus worsens cutting conditions.
Therefore, in some instances the above definitions are considered as synonyms.
Regarding heavy and heavy-duty machining. “Heavy-duty” means significant mechanicaland thermal loading of the technological system and its separate components, including the
cutting tool, due to removing considerable allowance, extreme cutting data, etc. “Heavy” isused with respect to machining large-sized heavy-weight parts on powerful heavy machine
tools. So, “heavy-duty” specifies the mode of machining, a degree of loading the tool;and “heavy” is used more to define dimensions of the machined parts and metal cutting
tools. Note that a small-size cutting tool can work in heavy-duty cycles under extremely
high load and that producing large parts may require applying the small tool as well.
A “golden rule” for manufacturer engineer, process planner and machinist says: “Avoid
heavy-duty machining in unfavorable conditions especially if your technological system isunstable!” This holds for all metalworking branches and among them heavy industry.

Table 7 Basic Cutting Speed Vo for Indexable Milling Cutters
Vo for Carbide Grade of Inserts, m/min (sfm)
Main Grades

Complementary GradesType of Machining

IC808 /
IC908

IC840

IC882

IC5820

IC380

IC830 /
IC928

IC330 /
IC328

Hard (H)43 (141)43 (141)38 (125)

43 (141)40 (131)40 (131)38 (125)

Medium (M)53 (174)

48 (157)

43 (141)48 (157)

45 (147)45 (147)

43 (141)

Light (L)

65 (213)60 (197)

50 (164)60 (197)55 (180)55 (180)50 (164)

Table 8 Basic Cutting Speed Vo for SCEM and MULTI-MASTER Heads
Vo for Carbide Grades, m/min (sfm)
Main Grades

Complementary GradesType of Machining

IC90 / IC908

IC300 / IC308

IC902*

IC903*

Hard (H)43 (141)40 (131)--

Medium (M)53 (174)45 (147)

65 (213)58 (190)

Light (L)

65 (213)55 (180)75 (246)

70 (230)* The grades are recommended mainly for HSM by trochoidal method

17

MILLING TITANIUM

Table 9 Machinability Factor Km for Titanium Grades
Group
Pure Titanium
Α-and near-αTitaniumΑ-β Titanium

Β-and near-βTitanium

Typical representative
Condition*

Designation
Grade 2Hardness
HB 150-200

Machinability
Factor Km
1.70

Ti-5Al-2.5Sn

ELI

HRC 31-34

1.25

Ti-5Al-2.5Sn

A

HRC 31-34

1.15

Ti-8Al-1Mo-1V

DA

HRC 34-36

1.10

Ti-6Al-4V

ELI

HRC 30-35

1.10

Ti-6Al-4v

A

HRC 32-36

1.00

Ti-8V-5Fe-1AlA

HRC 34-38

0.97

Ti-6Al-4V

STA

HRC 39-41

0.90

Ti-5Al-5Mo-5V3Cr

BASCA

HRC 34-36

0.57

Ti-10V-2Fe-4Al

STA

HRC 35-42

0.56

Ti-13V-11Cr-3AlA

HRC 39-41

0.53

Ti-5Al-5Mo-5V-3Cr

STA

HRC 36-44

0.51* A- annealed, BASCA- beta annealed, slow cooled and aged, DA - duplex annealed, ELI - extra low interstitials,
STA - solution treate d and age dTable 10 Engagement Factor Ke
Ae/d
AE
Ke

1.00
180°
0.80

0.93
150°
0.90

0.75
120°
0.95

0.5
90°
1.00

0.37
75°
1.05

0.25
60°
1.20

0.12
40.5°
1.30

0.10
36°
1.50

0.07
30°
1.80

ExampleFind the cutting speed for a face milling operation performed by a DOVEIQMILL indexable milling
cutter carrying inserts, made from carbide grade IC840.
The cutter diameter is 100 mm (4 in), the set width of cut is 70 mm (2.75 in) and thewidth of cut 2.5 mm (0.1 in). The workpiece material is Ti-6Al-4V, annealed.
Assume that operation stability is sufficient (face milling by the cutter of relatively
big diameter, short overhang, good conditions of a machine tool, proper
workpiece clamping) and machining type is medium (ap is 2.5 mm).
1. Rough estimating with the use of Table 6: starting speed Vc=60 m/min (197 sfm)
2. More accurate calculations using equation (1):Vo=48 m/min (157 sfm), Km=1, Ke≈0.96 (Tables 7, 9, 10 correspondingly),
Ks=1.Vc=48×1×0.96×1=46 m/min (151 sfm)

The discrepancies in the received results are significant: roughestimating results in 30% more cutting speed.

ExampleDuring process planning, a technologist examines applying an 80 mm (3 in) Dia. indexable
extended flute shell mill for rough machining deep shoulder. The workpiece material is“triple 5 titanium” (Ti-5Al-5Mo-5V-3Cr), HRC 39-41. Cutting parameters: ap=85 mm(3.35 in), ae=20 mm (0.79 in), wet coolant supply – internal. The carbide grade of inserts
mounted in the shell mill is IC882. The operation will be performed on a new machine tool,
workholding is rigid and, despite a relatively high overhang of the shell mill, which is mounted
on arbor, operational stability is normal. Which Vc should be chosen for further calculation
and analysis? Assuming that machining is hard, with the use of Tables 7, 9 and 10:

Vo=38 m/min (125 sfm), Km=0.51, Ke=1.2 (ae/d=0.25). Ks=1.
Vc=38×0.51×1.2×1=23 m/min (76 sfm)

Rough estimating with the use of Table 6 (the lower speed limit
for heavy roughing) gives 25 m/min (80 sfm).

18

ISCAR

Example
In semi finish trochoidal milling slots in blisk (bladed disc) produced fromannealed Ti-6Al-4V, a 7-flute 10 mm (0.4 in) Dia. solid carbide endmill(SCEM) is applied with the following cutting parameters:

ap=40 mm (1.57 in), ae=0.8 mm (0.031 in).

The SCEM material is carbide grade IC902. Estimate starting Vc.

MILLING TITANIUM

Poor machinability of hard-to cut titanium grades is a serious obstacle for increasing productivity inrough milling. To overcome this problem, industry uses progressive machining methods such as highspeed milling (HSM), high feed milling (HFM) and machining with high pressure coolant (HPC) supply.

The operation can be considered as light-duty cutting.
In accordance with data in Tables 8-10:

Vo=75 m/min (246 sfm), Km=1, Ke≈1.8 (ae/d=0.08).
Ks=1. Vc=75×1×1.8×1=135 m/min (443 sfm)

Feed Per Tooth
Cutting speed Vc, feed per tooth (advance per tooth) fz is a key parameter in milling. In
the USA, it is often called “chip load” – fz reflects largely mechanical and thermal load on
the tooth of a milling cutter. Increasing fz thickens generated chips that affects the abilityof the chips to remove heat from the cutting zone, and causes a growth of cutting forces.
However, seriously reduced fz results in chips that are too thin, worsens cutting action
and dramatically reduces tool life. Therefore, selecting the feed per tooth should ensure
an appropriate chip thickness, and maintaining the same chip thickness during a cutting
process is a formula of good performance. While advanced CAD/CAM systems can program
a tool path that maintains constant chip thickness, operating via feed per tooth is easierto understand and more practical, so metal cutting workers require this information.
In milling, the chip has complicated variable-thickness shape, while the thickness changes fromminimum to maximum. Average chip thickness hm is used for cutting characteristics, engineering
calculations and selecting fz. There is a mathematical relationship between average chip
thickness, feed per tooth, width of cut and tool diameter - hm may be considered as a functionof fz and vice versa. The average chip thickness is a computed value, but this feature does notdiminish its importance: hm characterizes mechanical load on a milling cutter and a machine
tool; in experienced hands it is one of the key parameters for estimating milling performance.
Various sources of technical information recommend the following equation for
approximate calculating hm if the cutting edge angle of a milling cutter is 90°:hm=fz× √ae/d(2)

fz=hm× √d/ae(2a)Equation 2 is simple and easy to use in shop floor conditions, and gives good results that aresuitable for finding hm for peripheral milling (machining by cylindrical or slab mill, 90° endmill –Fig. 11) and one kind of 90° face milling (Fig. 12). Also, it may be accepted for milling slots
and grooves by a disc milling cutter in some cases. In other circumstances, the equations foraverage chip thickness differ. Tables 11 and 12 provide summarized data for finding hm andmaximum chip thickness hmax that are suitable for rapid calculations under factory conditions.

19

MILLING TITANIUM

There are different methods for calculating average chip thickness in milling hm such as arithmetic
mean, weighted mean, or a result based on finding the cross-sectional area of an assumingly
undeformed chip and its substitution by simple rectangular, but the most common method is tocompute average chip thickness in relation to half of an angle of engagement AE (Fig. 10).

Vf

fz
hmax
nn

ae

AE/2
hm
AE/2

Fig. 10 Average (hm) and maximum (hmax) chip thickness in milling

n

Vf

ae
d

Fig. 11 Slab milling and milling deep shoulderaeaeae ≤ 2d
Fig. 12 Face milling with depth of cut no more than the radius of a milling cutter

20

ISCAR

Condition

FigureCutter position

ExampleHm, hmaxfz
aeAE≤90°*(ae≤d/2)AEdhm=fz×√ae/d
hmax=fz×sinAE
hmax=2×fz×√ae×d-ae2/d

hmax
vf
n

Fig. 10AE
aeAE>90°*(ae>d/2)

d
n

hmax
(=fz)

vf

MILLING TITANIUM

Table 11 Calculating Chip Thickness In Peripheral Milling

1st method
hm=fz×sin (AE/2)
hmax=fz
2nd method
hm=fz×[√2/2+cos((AE-90°)/2)]
hmax=fz* also suitable for milling slots by disc milling cutters

ae
d

a)

ae

ae=d

ae
d

b)

c)

ae
d

d

d)

e)

Fig. 13 Possible application of 90° face mills

21

MILLING TITANIUM

Table 12 Calculating Chip Thickness In Face Milling
Cutter position

ExampleAE
aeFig. 13
Case a)Hm, hmax
1st method
hm=fz×sin (AE/2)
hmax=fz

d
n

hmax
(=fz)

2nd method
hm=fz 2×(√2/2+cos(AE-90°)/2)
hmax=fz

vf

vfdFig. 13
Case b)

AE=180ae=dnhm=hmax=fz

hm=hmax
(=fz)

vf

d

AE

Fig. 13
Case c)*ae

hm=hmax=fz

hm=hmax
(=fz)

n

fz
ae

Fig. 13
Case d)AEehm=hmaxdψ

hm=fz×cos (Ψ +AE/2)
hmax=fz×cosΨ

nFig. 13
Case e)ae

1st method
hm=fz×sin (AE/2)
hmax=fz

AE
e
hmax
(=fz)

d
n

2nd method
hm=hmax=fz* Unfavorable milling conditions - this cutter position should be avoided whenever possible

22

ISCAR

According to a manufacturing method, a 90° face mill of 100 mm (4 in) diameter is planned
to machine the open plane surface of a part. The surface width is 75 mm (3 in). What is thevalue of feed per tooth that should be set to ensure average chip thickness 0.1 mm (.004”)?
Referring to Table 12 and Fig. 13, case a), hm=fz×sin(AE/2) fz=hm/sin(AE/2).
Angle of engagement AE=90°+arcsin((ae-r)/r) where r=d/2 – the radius of the face mill.
AE=90°+arcsin((75-50)/50)=120°, AE/2=60° and fz=0.1/sin60°=0.11 (mm/tooth).
For a 4 in. dia. cutter: AE=90°+arcsin((3-2)/2)=120°, fz=.004/sin60°=.0046 (ipt).

MILLING TITANIUM

ExampleExampleA deep square shoulder in a titanium part is roughly machined by an 80 mm (3 in)diameter indexable extended flute cutter that is operated with the following data:
ae=20 mm (.75 in),fz=0.2 mm/tooth (.008 ipt).
Find the chip parameters.
With the use of Table 11 and Fig. 11:- average chip thickness

hm=fz×√(ae/d)=0.2×√(20/80)=0.1 (mm),- maximum chip thickness

hmax=2×fz×√(d×ae-ae2 )/d=2×0.2×√(80×20-20 2 )/80=0.17 (mm).

Accordingly, for the inch-size cutter:

hm=.008×√(.75/3)=.004 (in),- hmax=2×.008×√(3×.75-.75 2 )/3=.007 (in).

Radial chip thinning
The given examples show that the calculated values of both average hm and maximum chip
thickness hmax are lower than feed per tooth (chip load) fz. The examples illustrate one conclusionthat can be made when examining Tables 11 and 12: if width (radial depth) of cut ae in peripheral
milling and face milling (cases a) and d)) is less than the radius of a milling cutter, hmax becomes
lower than fz. Reducing ae leads to decreasing hmax and, accordingly, hm. This effect isknown as “radial chip thinning”, and taking it into account is very important, especially in millingtitanium which features intensive heat generation. Produced chips transfer most of the heat
and, therefore, they should be thick and massive enough to retain the heat and carry it away.
Maintaining the feed per tooth should ensure the required chip thickness and avoid criticalchip thinning. Understanding this effect is a key element for correctly programmed fz.
Tables 13 and 14 give auxiliary data that can help in quickly calculating
chip thickness for more common cases of milling:- Table 13 for peripheral milling when AE<90° (or ae<d/2),- Table 14 for face and peripheral milling when AE>90° (ae>d/2).
The following formulas may be useful for estimating AE in peripheral milling with ae<d/2:

AE=arcsin (2×√c-c2)

(3)

and

AE=arccos (1-2×c )(3a)where c=ae/d – ratio of width of cut ae to nominal tool diameter d.

Table 13 Auxiliary Data for Peripheral Milling When AE<90°
Ae/d
√ae/d
SinAE
AE

0.05
0.224
0.436
25.8°

0.1
0.316
0.6
36°

0.15
0.387
0.714
45.6°

0.2
0.447
0.8
53°

0.25
0.5
0.866
60°

0.3
0.547
0.916
66.4°

0.35
0.591
0.954
72.5°

0.4
0.632
0.98
78.5°

0.45
0.67
0.995
84.3°

23

MILLING TITANIUM

Table 14 Auxiliary Data for Face and Peripheral Milling When AE<90°
Ae/d
AE
AE/2
Sin (AE/2)

0.55
95.7°
47.8°
0.741

0.65
107.5°
53.7°
0.806

0.75
120°
60°
0.866

0.85
134.4°
67.2°
0.921

0.95
154°
77°
0.974

ExampleFind chip thickness for a deep square shoulder in a titanium part is roughly machined by an 80
mm (3 in) diameter indexable extended flute cutter that is operated with the following data:- width of cut ae=60 mm (2.25 in),- feed fz=0.15 mm/tooth (.006 ipt).
Basing on Fig. 13, case a), and Table 12, average chip thickness hm=fz×sin(AE/2) and hmax=fz.
Due to ae/d=60/80=0.75, from Table 14 AE=120° and sin(AE/2)=0.866.
So, hm=0.15×0.866=0.13 (mm) and hmax=0.15 mm.
Note. Estimating hm with the use of 2nd method (Table 12) gives the result as below:
hm=fz/2×[√2/2+cos((AE-90°) /2)]
=0.15/2×(√2/2+cos15°)=0.125 (mm)

Similarly, for 3 in. Dia. milling cutter:ae/d=2.25/3=0.75, sin(AE/2)=0.866, hm=.006×0.866=.005 (in), hmax=.006 in.

Note. Estimating in accordance with the 2nd method (Table 12) will give
hm=.006/2×(√2/2+cos15°)=.005 (in)Unfavorable, unstable, heavy and heavy-duty examples
The above terms may be simply explained with everyday life analogies:
Imagine that you are driving along a road. If your road is horseshoe and undivided,
covered with stones or pitted – you are driving in unfavorable conditions.
If you are driving in a car carrying two bicycles on an upright mounton the car roof – you are driving in unstable conditions.
A large-size truck transporting a caterpillar excavator is a typical heavy vehicle.
If the driver of a light pickup car, which is loaded to maximal capacity, decides toovertake the truck, the pickup car motor will work in heavy-duty conditions.

If the cutting edge angle of a milling tool is not 90° (Fig. 14), the equations (2) and (2a)change tohm=fz×√(ae/d) ×sinχ (4)and

fz=hm×√(d/ae)×1 /sinχ (4a)correspondingly
Here χ – cutting edge (entering) angle
In the same manner, the cutting edge angle should be taken into account incalculating hm and hmax with the use of the equations in Tables 11 and 12.

24

ISCAR

A planner of the process department that works under improving technology,
examines applying face mill IQ845 FSY D125-09-40-R07 carrying inserts
IQ845 SYHU 0704ADN-MM 808 to machining the top surface of a titanium component.
The catalog specifies the insert feed range as 0.15-0.3 mm/tooth (.006-.012 ipt) and the cutting
tool angle of the mill as 50°. The mill diameter is 125 mm (4.92 in).
At which feed should the mill be operated to ensure average chip thickness 0.12-0.15 mm(.005-.006 ipt), if the depth of cut and the width of cut are 3.5 and 100 mm correspondingly?
With a use of equation (4a) the feed per tooth for ae=100 mm (4 in) will be

MILLING TITANIUM

Example0.12×√125/100×1/sin 50° =0.18 (mm/tooth) (.007 ipt) and 0.15×√125/100×1/sin 50°=0.22(mm/tooth) (.0087 ipt) for average chip thickness 0.12 and 0.15 mm correspondingly.
Hence, the programmed feed can be recommended of 0.2 mm/tooth (.008 ipt) witha possible increase of up to 0.22 mm/tooth (.0087 ipt) for maximal productivity.
Note. In brief calculations that are made without taking chip thickness as an important factor
in setting correct cutting data, the feed per tooth is found in the following manner:
the required hm is (0.12+0.15)/2=0.135 (mm) (.0053 in) in average,
if consider the found value as hmax,
fz=hmax/sin 50°=0.135/ sin 50°=0.176≈0.18 (mm/tooth) (.007 ipt).
Alternatively, fz can be calculated, if 0.15 mm will be referred as hmax:
fz=0.15/sin 50°=0.195≈0.2 (mm/tooth) (.008 ipt).
Comparing these results with the values found previously shows that considering chip thickness
as a function of ae gives more precise data and ensures better productivity.
Another simplified way for setting the feed is simply to take the average value from a declared feed range as the
programmed data. In our example it will be(0.15+0.3)/2=0.22 (mm/tooth) (.0087 ipt). In our case it is equal to fz, which was found for hm=0.15 mm (.006 in), if
ae=100 mm. However, if ae=80 mm (3.15 in),for 0.15 mm (.006 in) chip thickness the feed should be already 0.24 mm/tooth(.0094 ipt) that is approximately 10% more than the average value from the feed range.

Alternatively, instead of the feed values as a function of chip thickness, cutting tool producers
often provide the data about the recommended feeds organized as a chart, which specifies abounded area of application graphically (Fig. 14). The chart shows a range of possible feed fromminimum (fzmin) to a limiting value depending on a cutting data parameter (usually depth of widthof cut). If, as in Fig. 14, the parameter is the ratio of working depth of cut ap to maximum depthof cut apmax, the starting feed in feed milling with ae=(0.6…0.8)×d may be simply found with theuse of a thumb rule: the feed is the maximum feed that corresponds to the ratio in the chart.

ap
apmax
1
3
4
1
2
1
4

fzmin
fzav =

fzav
fzmin + fzmax

fzmax

fz

2

Fig. 14 A typical field of feeds in face milling for ae=(0.6…0.8)×d

25

MILLING TITANIUM

ExampleFind the feed for the example, which was discussed previously, if the range of usable feeds is
specified by Fig. 14 where fzmin=0.15 mm/tooth (.006 ipt) and fzmax=0.3 mm/tooth (.012 ipt).
apmax=4.6 mm (0.18 in) – the catalog data, ap/apmax=3.5/4.6=0.76.
According to Fig. 14, arithmetic average feed fzav may be consideredas the limiting value that corresponds to the above ratio.
Hence, following our rule of thumb, the starting feed, which was chosen
as the arithmetic average, will be 0.225 mm/tooth (.009 ipt).
In the shown example, applying the rule of thumb method gave a result that can be
accepted with some reserve. The received value is about 10% more than the starting
feed, which was found with the use of chip thickness calculations previously.

In finding starting feeds, empirical rules led to acceptable results in relatively
limited cases. However, calculating the feeds using required chip thickness is moreaccurate and therefore preferable, particularly as this calculation is simple.
Starting feed fz can be determined by several ways. For rough estimates, setting fz as theaverage value in the feed range from a catalog (a technical brochure), using rules of thumb suchas in the outlined above example or own experience may be quite enough. A more accurate
and less complicated method requires taking into consideration the chip thickness factor.



In any case, maximum chip thickness hmax should not exceed maximum feed fzmax
specified for the considered inserts, solid carbide endmills or MULTI-MASTER heads

26

ISCAR

Table 15 gives averaged values of basic feed per tooth fo and corresponding
parameters of chip thickness (hm, hmax) depending on the ratio between
ae and d and a carbide grade for peripheral milling by indexable cutters andTable 16 – by solid carbide endmills and MULTI-MASTER heads.
Starting feed per tooth fz is defined by the following equations:for 90° indexable cutters

fz=fzo×Ks		

(5)

MILLING TITANIUM

Peripheral Milling- for 90° SCEM and MULTI-MASTER heads

fz=fzo×Ks×Kf
Where:(6)

fzo – basic feed per tooth
Ks – stability factor
Kf – tooth-strength factor (Table 17)

The stability factor here is set as below:• Ks=1 for normal stability• Ks=0.8-0.85 for unstable operations (high overhang, poor tool- or workholding,milling thin walls, etc.), and milling in unfavorable conditions.

ExampleA manufacturer considers milling square shoulder by a MULTI-MASTER tool that carries
a 20 mm (0.750 in) Dia. cutting head, made from carbide grade IC308. The shoulder is
9.5 mm (0.375 in) in depth and 5 mm (0.2 in) in width. Operational stability is sufficient.
Which feed per tooth (chip load) fz should be set as starting?
ae/d=5/20=0.25. fzo=0.085 mm/tooth(Table 16), Kf=0.94 (Table 17). Ks is assumed as 1.
fz=0.085×0.94×1=0.08 (mm/tooth) or 0.031 ipt.
The average chip thickness in this case will be 0.042×0.94=0.04 (mm) or 0.15 in,and the maximum chip thickness – 0.073×0.94=0.068 (mm) or 0.026 in.

27

28

ISCAR

25.8°

36°

45.6°

53°

60°

66.4°

78.5°

90°

120°

0.05
(5%)

0.1
(10%)

0.15
(15%)

0.2
(20%)

0.25
(25%)

0.3
(30%)

0.4
(40%)

0.5
(50%)

0.75
(75%)

Parameters
hm
hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo
Hm
Hmax
Fzo

* The table values are given in metric units with their US customary equivalents in italic brackets: fz in mm/tooth (ipt), hm and hmax in mm (in)1
180°
(100%)

AE

Ae/d
(%)

Fzo, mm/tooth (ipt), and hm and hmax, mm (in), for carbide grade of inserts*
Main Grades
Complementary Grades
IC808 IC908
IC840
IC882
IC5820IC380
0.06 (.0023)
0.06 (.0023)
0.07 (.0027)
0.06 (.0023)
0.05 (.002)
0.11 (.004)
0.11 (.004)
0.13 (.005)
0.11 (.004)
0.1 (.0039)
0.26 (.01)
0.26 (.01)
0.3 (.012)
0.26 (.01)
0.22 (.0087)
0.06 (.0023)
0.06 (.0023)
0.07 (.0027)
0.06 (.0023)
0.05 (.002)
0.11 (.004)
0.11 (.004)
0.13 (.005)
0.11 (.004)
0.1 (.0039)
0.19 (.0075)
0.19 (.0075)
0.22 (.0087)
0.19 (.0075)
0.16 (.0063)
0.06 (.0023)
0.06 (.0023)
0.07 (.0027)
0.06 (.0023)
0.05 (.002)
0.09 (.0036)
0.11 (.004)
0.11 (.004)
0.13 (.005)
0.11 (.004)
0.16 (.0063)
0.16 (.0063)
0.18 (.007)
0.16 (.0063)
0.13 (.0051)
0.067 (.0026)
0.067 (.0026)
0.076 (.003)
0.067 (.0026)
0.056 (.0022)
0.12 (.0047)
0.12 (.0047)
0.13 (.005)
0.12 (.0047)
0.09 (.0036)
0.15 (.0063)
0.15 (.0063)
0.17 (.0067)
0.15 (.0063)
0.125 (.005)
0.07 (.0027)
0.07 (.0027)
0.08 (.0031)
0.07 (.0027)
0.06 (.0023)
0.12 (.0047)
0.12 (.0047)
0.14 (.0055)
0.12 (.0047)
0.1 (.004)
0.14 (.0055)
0.14 (.0055)
0.16 (.0063)
0.14 (.0055)
0.12 (.0047)
0.07 (.0027)
0.07 (.0027)
0.08 (.0031)
0.07 (.0027)
0.06 (.0023)
0.12 (.0047)
0.1 (.004)
0.12 (.0047)
0.12 (.0047)
0.127 (.005)
0.127 (.005)
0.127 (.005)
0.14 (.0055)
0.127 (.005)
0.11 (.004)
0.07 (.0027)
0.07 (.0027)
0.08 (.0031)
0.07 (.0027)
0.06 (.0023)
0.108 (.0042)
0.108 (.0042)
0.122 (.0048)
0.108 (.0042)
0.098 (.0038)
0.11 (.0043)
0.11 (.0043)
0.125 (.0049)
0.11 (.0043)
0.1 (.004)
0.075 (.003)
0.075 (.003)
0.088 (.0035)
0.075 (.003)
0.065 (.0025)
0.11 (.0043)
0.11 (.0043)
0.125 (.0049)
0.11 (.0043)
0.09 (.0035)
0.11 (.0043)
0.11 (.0043)
0.125 (.0049)
0.11 (.0043)
0.09 (.0035)
0.095 (.0037)
0.095 (.0037)
0.11 (.0043)
0.095 (.0037)
0.078 (.0031)
0.125 (.0049)
0.11 (.0043)
0.09 (.0035)
0.11 (.0043)
0.11 (.0043)
0.11 (.0043)
0.11 (.0043)
0.125 (.0049)
0.11 (.0043)
0.09 (.0035)
0.1 (.004)
0.1 (.004)
0.11 (.0043)
0.1 (.004)
0.09 (.0035)
0.1 (.004)
0.1 (.004)
0.11 (.0043)
0.1 (.004)
0.09 (.0035)
0.1 (.004)
0.1 (.004)
0.11 (.0043)
0.1 (.004)
0.09 (.0035)
IC830 IC928
0.07 (.0027)
0.13 (.005)
0.3 (.012)
0.07 (.0027)
0.13 (.005)
0.22 (.0087)
0.07 (.0027)
0.13 (.005)
0.18 (.007)
0.076 (.003)
0.13 (.005)
0.17 (.0067)
0.08 (.0031)
0.14 (.0055)
0.16 (.0063)
0.08 (.0031)
0.127 (.005)
0.14 (.0055)
0.08 (.0031)
0.122 (.0048)
0.125 (.0049)
0.088 (.0035)
0.125 (.0049)
0.125 (.0049)
0.11 (.0043)
0.125 (.0049)
0.125 (.0049)
0.11 (.0043)
0.11 (.0043)
0.11 (.0043)

IC330 IC328
0.07 (.0027)
0.13 (.005)
0.3 (.012)
0.07 (.0027)
0.13 (.005)
0.22 (.0087)
0.07 (.0027)
0.13 (.005)
0.18 (.007)
0.076 (.003)
0.13 (.005)
0.17 (.0067)
0.08 (.0031)
0.14 (.0055)
0.16 (.0063)
0.08 (.0031)
0.127 (.005)
0.14 (.0055)
0.08 (.0031)
0.122 (.0048)
0.125 (.0049)
0.088 (.0035)
0.125 (.0049)
0.125 (.0049)
0.11 (.0043)
0.125 (.0049)
0.125 (.0049)
0.11 (.0043)
0.11 (.0043)
0.11 (.0043)

MILLING TITANIUM

Table 15 Basic Feed per Tooth fzo and Chip Thickness
Data for Peripheral Milling by Indexable Cutters

Table 16 Basic Feed per Tooth fzo and Chip Thickness Datafor peripheral Milling by SCEM and MULTI-MASTER Heads
Fzo, mm/tooth (ipt), and hm and hmax, mm (in),For carbide grade of SCEM and heads*
Main grades
Ae/d
(%)

AE

0.03
(3%)

19.9°

0.05
(5%)

25.8°

0.1
(10%)

36°

0.15
(15%)

45.6°

0.2
(20%)

53°

0.25
(25%)

60°

0.3
(30%)

66.4°

0.4
(40%)

78.5°

0.5
(50%)

90°

0.75
(75%)

120°

1
(100%)

180°

Parameters
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo
hm
hmax
fzo

IC900
IC908
0.04 (.0016)
0.078 (.0031)
0.23 (.009)
0.04 (.0016)
0.078 (.0031)
0.18 (.0071)
0.041 (.0016)
0.076 (.003)
0.13 (.0051)
0.04 (.0016)
0.075 (.0029)
0.105 (.004)
0.04 (.0016)
0.07 (.0027)
0.09 (.0035)
0.04 (.0016)
0.07 (.0027)
0.081 (.0032)
0.04 (.0016)
0.068 (.0027)
0.073 (.0029)
0.04 (.0016)
0.063 (.0025)
0.064 (.0043)
0.04 (.0016)
0.057 (.0022)
0.057 (.0022)
0.049 (.0019)
0.057 (.0022)
0.057 (.0022)
0.057 (.0022)
0.057 (.0022)
0.057 (.0022)

Complementary grades
IC300
IC308
0.042 (.0016)
0.083 (.0032)
0.245 (.0096)
0.041 (.0016)
0.08 (.0031)
0.185 (.0073)
0.042 (.0016)
0.078 (.0031)
0.133 (.0052)
0.043 (.0017)
0.078 (.0031)
0.11 (.0043)
0.041 (.0016)
0.074 (.0029)
0.093 (.0037)
0.042 (.0016)
0.073 (.0028)
0.085 (.0033)
0.043 (.0016)
0.071 (.0028)
0.078 (.0031)
0.043 (.0016)
0.067 (.0026)
0.068 (.0027)
0.042 (.0016)
0.06 (.0024)
0.06 (.0024)
0.052 (.002)
0.06 (.0024)
0.06 (.0024)
0.06 (.0024)
0.06 (.0024)
0.06 (.0024)

IC902**
0.035 (.0013)
0.068 (.0027)
0.2 (.0079)
0.035 (.0013)
0.067 (.0026)
0.155 (.0061)
0.036 (.0014)
0.067 (.0026)
0.115 (.0045)
0.035 (.0013)
0.065 (.0026)
0.091 (.0036)
0.036 (.0014)
0.064 (.0025)
0.08 (.0031)
0.036 (.0014)
0.063 (.0025)
0.073 (.0029)
0.036 (.0014)
0.06 (.0024)
0.065 (.0026)

MILLING TITANIUM

Avoid misunderstanding: titanium beta (β)
An incorrect interpretation of shop talk may cause serious misunderstandings and evenwrong decisions. In many cases, “titanium-beta”, so freely used in manufacturing, does notmean β-alloys but β-(beta-) annealed α-β-alloys, in particular for the “universal” Ti-6Al-4V.

IC903**
0.037 (.0014)
0.073 (.0029)
0.215 (.0085)
0.037 (.0014)
0.072 (.0028)
0.165 (.0065)
0.038 (.0015)
0.07 (.0027)
0.12 (.0047)
0.037 (.0014)
0.068 (.0027)
0.095 (.0037)
0.038 (.0015)
0.067 (.0026)
0.084 (.0033)
0.038 (.0015)
0.066 (.0026)
0.076 (.003)
0.038 (.0015)
0.063 (.0025)
0.069 (.0027)* The table values are given in metric units with their US customary equivalents in italic brackets: fz in mm/tooth (ipt),
hm and hmax in mm (in)** The grades are recommended mainly for HSM by trochoidal milling and finish operations

Table 17 Tooth-Strength Factor Kf for SCEM and MULTI-MASTER Heads
Nom. diameter
D
Kf

Mm

24<d≤32

19<d≤24

14<d≤19(in)(.945<d≤1.250)(.750<d≤.945) (.551<d≤.750) (.354<d≤.551) (d≤.354)

1

0.94

0.88

9<d≤14

0.78

d≤9

0.65

29

MILLING TITANIUM

ExampleA producer of jet engines plans to apply ISCAR’s 12 mm dia. 7 flute solid carbide endmills formachining slots in titanium integrally bladed rotors (blisks) by trochoidal milling technique. The
titanium grade is Ti-6Al-4V, HRC 33-35. In milling slots, the width of cut is 1-1.2 mm, and thedepth of cut is variable. The selected endmills are made from cemented carbide IC902. The
machine tools intended for this operation are in good condition and clamping rotor rigidity is high.
Estimate cutting data for calculating cycle time.
According to equation (1) cutting speed Vc=Vo×Km×Ke×Ks.
Vo=75 m/min (246 sfm) from Table 8,
Km=1 (Table 9),
Ke=1.5 (Table 10),
Ks=1 (operational stability is sufficient),
Vc=75 ×1×1.5×1=112 (m/min) (370 sfm),
n=2971 rpm.
fz=fzo×Ks×Kf (equation (6)),
fzo=0.115 mm/tooth (0.0045 ipt) from
Table 16,
Kf=0.78 (Table 17),fz=0.115×1×0.78=0.09 (mm/tooth) (.0035 ipt).
Feed speed Vf=0.015×7×2971=312 (mm/min) (12.3 ipm).

ExampleFind cutting data for edging operation to be performed by a 63 mm (2.5 in) dia. extended fluteendmills with DIN69871 tapered shanks carrying T490 LNMT/LNHT 13... tangentially clamped
inserts. The endmill has 4 flutes (effective teeth). The workpiece material is titanium alloy “triple
5” VST 5553 (Ti-5Al-5Mo-5V-3Cr). The width of cut varies from 6 to 8 mm (0.236…0.315in), the depth of cut is around 50 mm (2 in). The inserts are made from carbide grade IC882.
Cutting conditions are estimated as stable. Ratio ae/d is accepted as 0.12 in average.
Usually, edging relates to removing a skinned material. As a rule, the extended
flute tools with integral shank feature high overhang. Based on these
conditions, the type of machining is assumed as hard (Table 6).
Vo=38 m/min (125 sfm) (Table 7), Km=0.51 (Table 9), Ke=1.3 (Table 10), Ks=1.
Vc=38 ×0.51×1.3×1=25 (m/min) (83 sfm) (equation (1)),
N=126 rpm.
fzo≈0.2 mm/tooth (.0079 ipt) (Table 15, a value that lays between
data corresponding to ae/d=0.15 and ae/d=0.1).
fz=0.2×1=0.2 mm/tooth (.0079 ipt).
Vf=0.2×4×126=100.8 (mm/min) (3.97 ipm).
The average chip thickness and the maximum chip thickness are
0.07 mm and 0.13 mm correspondingly (Table 15).

30

ISCAR

In face milling, starting feed per tooth fz is calculated by equation (7):fz=fzo×1/sinχ ×Ks		

(7)

Here:
fzo – basic feed per tooth (Table 18),
		 χ – cutting edge (entering) angle,		Ks – stability factor.
Face milling features considerable width of cut: normally ae=(0.6…0.8)×d. Therefore, for quick
estimation fzo may be set as the basic feed per tooth from Tables 15 and 16 that corresponds
ae/d=0.75. The appropriate values of fzo for indexable milling cutters are shown in Table 18.

MILLING TITANIUM

Face Milling

Table 19 gives already calculated values of 1/sinχ for typical cutting edge angles of face mills.

Table 18 Basic Feed per Tooth fzo and Chip Thickness Datafor Indexable Face Milling
Fzo, mm/tooth (ipt), and hm and hmax, mm (in), for carbide grade of inserts*
Main grades
IC808
Parameters IC908
0.095
Hm(.0037)0.11
Hmax(.0043)0.11
Fzo(.0043)Complementary grades
IC840
0.095
(.0037)0.11(.0043)0.11(.0043)IC882
0.11(.0043)0.125(.0049)0.125(.0049)IC58200.095(.0037)0.11(.0043)0.11(.0043)

IC380
0.078
(.0031)
0.09(.0035)0.09(.0035)

IC830
IC928
0.11
0043)
0.125
(.0049)0.125(.0049)

IC330
IC328
0.11
(.0043)0.125(.0049)0.125(.0049)* The table values are given in metric units with their US customary equivalents in italic brackets:
fz in mm/tooth (ipt), hm and hmax in mm (in)Table 19 Calculated Values Of (1/Sinχ) for Typical Cutting Edge Angles
Χ

90°

75°

65°

60°

45°

30°

1/sinχ

1

1.03

1.1

1.15

1.4

2

Cutting edge angle and lead angle are not synonyms!
The “cutting edge angle” is the angle between the main cutting edge of a milling cutter andthe plane containing the direction of feed motion. "Lead angle" (or “approach angle”) is theangle complementary to the cutting edge angle, i.e. the sum of both these angles is 90°. For atypical face milling cutter, the cutting angle is the angle between the cutting edge and the plane,
which the cutter generates. If this angle is 60°, then the lead angle will be 30°. The cutting edge
angle and the lead angle are equal only for 45° milling cutters. The term "lead angle" is morecommonly employed in the U.S., while "approach angle" is often used in Europe and Japan.
Solid carbide endmills and the majority of MULTI-MASTER tools are not intended for face
milling. However, there are MULTI-MASTER replaceable heads (for example, MM FM, Fig. 15)
and special solid carbide cutters that were designed especially for face milling applications.

31

MILLING TITANIUM

Fig. 15 MULTI-MASTER face milling head MM FM

In this case starting feed per tooth fz can be found with the use of equation (7a):fz=fzo×Kf×1/sinχ ×Ks
Here:
		
		

(7a)

fzo – basic feed per tooth (Table 20),
Kf – tooth-strength factor (Table 17)χ – cutting edge (entering) angle.

ExampleA producer of titanium components needs to machine a plane surface of a large-size part, which ismade from Ti-6Al-4V. 200 mm dia. milling cutter SOF45 8/16-D200-14-60R carrying inserts
ONHU 050500-PL IC830 is intended for applying in finish milling the surface. The depth of cut and thewidth of cut are 1.5 mm and 160 mm correspondingly. Which cutting speed and feed should be set?
Cutting edge angle χ=45°, ae/d=0.8, the type of machining is considered as light (Table 6),
and operational stability is assumed as sufficient.
For carbide grade IC830 Vo=55 m/min or 180 sfm (Table 7), Km=1 (Table 9),Ke≈0.92 (Table10), Ks=1.
Hence, from equation (1) Vc=55×1×0.92×1=50.6 (mm/min) ≈51 m/min (167 sfm).
n=1000×51/π/200=81 (rpm).
Table 18 gives fzo=0.125 mm/tooth (.0049 ipt), 1/sin45°=1.4 (Table 19); and using equation (7)fz=0.125×1.4×1=0.175 (mm/tooth) (.0069 ipt).
Vf=0.175×14×81=198 (mm/min) (7.82 ipm).

Table 20 Basic Feed per Tooth fzo and Chip Thickness Data for
Face Milling by Solid Carbide and MULTI-MASTER Tools
Fzo, hm and hmax for carbide grade
Main grades
Parameters
hm
hmax
fzo

IC900
IC908
0.049 (.0019)
0.057 (.0022)
0.057 (.0022)* The table values are given in metric units with their US customary equivalents
in italic brackets: fz in mm/tooth (ipt), hm and hmax in mm (in)

32

ISCAR

IC300
IC308
0.052 (.002)
0.06 (.0024)
0.06 (.0024)

ISCAR provides a rich variety of tools that are specifically designed for millingtitanium. This section is intended for quickly selecting a suitable tool family for themost typical milling operations that require machining titanium components.

Indexable Extended Flute Cutters
for Milling Deep Shoulders and Wide Edges
A considerable part of milling titanium, especially in producing large-size parts, relates toremoving a high volume of material during rough machining of various cavities and pockets. A
common way to do this is by applying indexable extended flute (long-edge) cutters. These mainly
have a cutting edge angle of 90° and perform peripheral milling of deep shoulders. In addition,these cutters are the first-choice tools for machining wide edges of workpieces (edging).

MILLING TITANIUM

Tools for Milling Titanium Efficiently

Referring to the most popular ISCAR families of extended flute cutters, Table 21 andTable 22 prioritize the families and Table 23 specifies their general design features.

Table 21 Indexable Tool Families for Milling Deep Shoulders
MILLINGDEEPSHOULDERS

1st choice

2nd choice

Possible

Rough

XQUAD
EXTENDED FLUTEHELITANG
T490 LINEMILLSHREDP290 LINE

Semifinish

HELITANGFIN LNKXQUAD
EXTENDED FLUTEMILLSHREDP290 LINE

Table 22 Indexable Tool Families for Milling Wide Edges (Edging)
MILLING
WIDE EDGES(EDGING)

1st choice

2nd choice

Possible

Rough

HELITANG
T490 LINEXQUAD
EXTENDED FLUTEMILLSHREDP290 LINE

Semifinish

HELITANGFIN LNKXQUAD
EXTENDED FLUTEMILLSHREDP290 LINE

Chip splitting and chip chopping in milling titanium
The desire to improve performance and increase the dynamic behavior of extended flute
cutters led to the use of inserts with a chip splitting action. The cutting edges of theseadvanced inserts feature specially designed chip splitting grooves. Further developments
have resulted in the introduction of inserts with chip crushing ability, that literally chop chips
into small segments. Advances in powder metallurgy allow the production of tough, sinteredchip crushing inserts with high-strength shredded cutting edges, such as ISCAR’s indexable
MILLSHRED P290 - a family of extended flute cutters that adheres to the more common
concept of clamping inserts radially. The main distinctive feature of this family is the serrated
cutting edge of the inserts, which chops or shreds the chips. Unlike many chip splitting insertsthat are currently available, the P290 one-sided inserts, which possess two indexable serrated
cutting edges, do not require special instructions for mounting in the MILLSHRED extended
flute cutters, and are simply secured in any pocket. This operator-friendly feature simplifies
tool assembly and eliminates errors in insert indexing, which may cause tool destruction.

33

MILLING TITANIUM

Table 23 Indexable Extended Flute Cutter Families: General Data*
Diameter range
FamilyMm

XQUAD

50-100 2.0-4.0

HELITANG
T490 LINE

32-80

HELITANGFIN LNK

50-80 1.97-3.15

In

1.0-4.0

MILLSHRED
25-100 1.0-4.0
P290 LINE

Design configuration
InsertEndmills with
Flex.
Cut, edge formshank**
tooling
No. ofType
InsertShell And
Cut.
Cylindrical Tapered mills heads Clamping (O/D***) edges Smooth Chipslitted
●

●

●

●

●

●

●

●

●

●

radialO

4●tangential

D

4

●

tangential

O

2

●

radial

O

2

●

●

●

* at the time of writing** The type of the shank is indicated in the columns*** O-one sided, D-double-sided

Radial or tangential?
Generally, the concept of a tool carrying one-sided radially clamped inserts is more common in
the design of the indexable extended flute cutters for milling titanium. A one-sided radially clamped(laydown) insert provides more options for varying cutting geometry and ensuring necessary
relief angles. Cutters carrying these inserts usually feature greater chip gullet than tools with
tangential inserts and, therefore, better chip evacuation when milling with high metal removal
rate, especially in machining deep cavities and pockets. Also, they usually have higher ramping
abilities. This explains why the radial concept prevails in extended flute cutters for milling titanium.
ISCAR’s family of HELITANG T490 extended flute cutters, primarily tools with size 13 inserts,
is an exception to this general rule. The principle of tangential clamping contributes to improving
the cutter rigidity and optimal loading of a screw to secure the inserts while usually ensuring
a higher insert density that results in increased feed rate. HELITANG T490 extended flute
cutters show their worth in edging – rough milling the wide edges of titanium workpieces,where the depth of cut is considerable, but the width of cut is not too large. Under these
conditions there is no problem with chip evacuation, and the extended flute cutter carrying
tangentially clamped inserts wholly meets the requirements of high-efficiency roughing.



Chip splitting geometry may be a good solution for rough milling in unstableconditions (high overhang, poor workholding etc.). In many such cases, chip splitting
cutters demonstrates better dynamic behavior that results in better performance.

“Raking by fraze”
Chip chopping is the main principle of the ISCARMILLSHRED P290 family. The cutting actionof a shredded P290 mill can be compared witha fraze or a rotary rake (Fig. 16). If you need toloosen soil, the fraze will require less effort thana hoe. In our case, if you overlap the teeth ofyour “fraze”, this will reduce the production ofcusps and will improve surface quality. The hand
movements in Fig. 16 illustrate this action.

Fig. 16 A “fraze”

34

ISCAR

There are no strict definitions of high and ultra high pressure coolant (HPC and UHPC
correspondingly). Traditionally, machine tools feature coolant supply at 10-15 bar(145-217 psi) pressure. This level is now considered as low pressure. Some CNC machine tool
equipment producers manufacture what are known as “medium pressure” pumps; these have valuesof up to 50 bar (725 psi). Various modern machining centers have the option to supply coolant at
rates of 70-80 bar (1000-1200 psi), which is considered as high pressure coolant. High pressure
coolant features coolant flow pinpointed to its target. Today the industry adopts machining with ultrahigh pressure coolant that relates to pressure values of 100-200 bar (1450-2900 psi) and even higher.

MILLING TITANIUM

Milling With High Pressure Coolant (HPC)

There is growing interest in cutting with HPC due to the ultimate performance of this method,especially when heat generation rate during machining is high. As milling titanium relates to processes
with intensive heat emission, it is no wonder that HPC has focused titanium manufacturers’ attention.
Heat generation is a permanent feature of machining. If heat generation is intensive,the conventional low pressure coolant forms a vapor layer on the surfaces of a tool
and a workpiece. This layer acts as heat sealing, producing an insulating barrier
and making heat transfer harder, which significantly shortens tool life.
Pinpointed high pressure coolant penetrates the barrier and helps to overcome the problem.
• HPC improves tool life of a cutting edge due to reducing oxidation and adhesion wear
and increasing crack strength.
• HPC chills chips quickly, making them hard and brittle. The chips become thinner and smaller,
and they break away from the workpiece more easily. High-speed coolant flow removes
the chips. This significantly improves chip evacuation and prevents chip re-cutting.
• HPC improves chip evacuation because the chips diminish in size, and the high-velocity
coolant flow takes them away easily. It allows the design of cutters with smaller chip gullet,
leading to a higher number of cutter teeth. Effective cooling reduces the temperature in the
cutting zone, ensuring an increased angle of engagement AE (i.e. width of cut ae).

HPC provides a good solution for increasing cutting speed
andOverall,feed rate for boosting productivity, which is based on:- transforming improved tool life in higher cutting speed,- increasing feed rate by using a tool with more teeth comparing with thetool of same diameter that is intended for low pressure coolant,- milling with greater width of cut.

35

MILLING TITANIUM

In view of this, the up-to-date machining centers, which MTB companies offer to producersof titanium components, are suitable for HPC supply. As practice shows, machining with HPC
can even double cutting speed in comparison with classical As shown in practice, Accurate
value for increasing cutting speed depends on specific factors. To estimate initial cutting
speed in milling with HPC VHP, it is recommended to use the following equation (8):VHP=(1.2…1.3)×Vc,(8)

where Vc – Initial cutting speed, given by equation (1), or determined with the use of (Table 6).
By assuming that the increase in VHP is 25% in average, this equation
after substituting the terms of equation (1) will look as follows:

VHP=1.25×Vo×Km×Ke×Ks (8a)As in case of finding starting speed in milling in general, basic cutting speed Vo, factors: Km(machinability), Ke (engagement) and Ks (stability) are (also) found in Tables 7-10. Stability factor
Ks is assumed as 1 for normal stability, and 0.7…0.8 for milling in unstable conditions.

ExampleFind initial cutting data for rough milling deep square shoulder in a workpiece from titanium Ti6Al-4V ELI. The applied tool is ISCAR’s 80 mm (3 in) dia. indexable extended cutter carrying
inserts made from carbide grade IC5820. The cutting parameters are as below:
depth of cut ap=85 mm (3.35 in), width of cut ae=20 mm (0.79 in).
The machine intended for the milling operation is a vertical machining center with HPC option, and thecutter has inner channels for high pressure coolant supply. Operational stability can be estimated as high.
Vo=43 m/min (141 sfm). (Table 7, hard type of machining)
Km=1.1 (Table 9).
Ke=1.2 (Table 10).
Ks=1.

Vc=43×1.1×1.2×1=52 (m/min) or 170 sfm.

Hence, VHP=(1.2…1.3) ×Vc ≈ 65 m/min=
213 sfm.
From Table 15 for ae/d=0.25 fzo=0.14 mm/tooth (0.0055 ipt) and

fz=fzo×Ks=0.14×1=0.14 (mm/tooth)or 0.0055 ipt.

There are different factors that influence HPC supply through the body of a milling cutter,
which tool engineers take into account when designing the cutter. In indexable milling, fromthe application point of view, attention should be drawn to the coolant outlets. They areformed by nozzles, screwed in appropriate holes that open into chip gullets (Fig. 17, 18).

Fig. 17 A T490 extended flute cutter
Intended for HPC. The cutter design
Enables nozzles to be mounted in the
Coolant supply hole outlets

36

ISCAR

Fig. 18 A nozzle mounted in a coolant
supply hole near a T490 extended
flute cutter face-cutting insert

MILLING TITANIUM

Why nozzles?
There are several reasons for using nozzles as outlets in indexable extended flute cutters.
Firstly, a technological aspect. The required outlet diameter usually lays within 0.6…2 mmrange. Drilling these “pinholes” deep enough in a relatively hard steel body is quite difficult.
It makes sense to increase the diameter, cut a thread near the opening, and screw in an
appropriate nozzle. Secondly, a control reason. Varying outlet diameters by changing thenozzles allows optimizing coolant flow that depends on the characteristics of an HPC pumpand the number of the nozzles in a cutter. Also, if the cutter does not mill to its maximum
depth of cut, the coolant holes near the non-working inserts can be easily plugged.

The nozzle diameter is less than the diameter of the hole. In accordance with the laws of flowmechanics, input and output relations for a fluid velocity exist. The difference in diameters
increases the coolant velocity, and the coolant leaves the nozzle with higher velocity than entersin it. On the other hand, there is a certain relationship between pressure, velocity and flow rate
for fluid, e.g. for coolant in our case. Increasing the nozzle diameter requires higher flow rate toensure a necessary pressure level. A growth of the number of the nozzles has the same effect.
For efficient application of indexable extended flute milling cutters with HPC supply
through the cutter body, the following two points should be considered:
1. If a turning tool has one cutting edge and one nozzle is sufficient for coolant supply, theextended flute cutter features several cutting blades. Each blade is produced by a set of
replaceable inserts, located one after another. A pinpointed jet of coolant to the blade areas
demands at least one nozzle per every insert. It means that the characteristics of an HPCpump should meet the required flow rate that considerably differs from turning cases.
2. If depth of cut is smaller than the length of the cutting blade, there is no need to supply
coolant to the inserts that are not involved in cutting. It is recommended to unscrew thenozzles corresponding to these inserts from the holes, and then close the holes by plugs
or standard set screws. This is a simple and effective way for improving performance.

Standard or special (tailor-made)?
Indexable HPC extended flute cutters are intended for removing a high volume of metal. They
work in hard cutting conditions under heavy load that is usually combined with a substantial tool
overhang. This raises the question as to which is preferable, assembly from a standard cutter
and standard modular toolholding units such as arbors, holders, reducers etc., or a special(tailor-made) integral tool with direct adaptation to the spindle? Although assembly from standard
elements looks reasonable, titanium component manufacturers prefer the integral design inmany cases. This configuration provides maximum rigidity and ensures more productive milling.
Specific tool diameters, cutting lengths, and overhang, as well as adaptations that vary fromone manufacturer to another, increase demands for various tailor-made HPC milling cutters.

37

MILLING TITANIUM

Fast Feed Milling Titanium
Fast feed milling (FF), also referred to as high feed milling (HFM), is usually associatedwith productive rough machining steel and cast iron. However, this effective method ofrough milling may be successfully applied to manufacturing titanium components.
Rather than using a traditional high metal removal technique – milling with considerable depths
and widths of cut – FF proposes machining with similar widths of cut but with a much smaller
depth of cut. FF cutters feature small cutting edge angles that allow significant increasing infeed per tooth fz and therefore feed speed Vf due to the effect of chip thinning (Fig. 19).

90˚

apmax

χ1

fz
hmax=fz

h1<<hmax

apmaxfz1>>fz

apmax

χ1

h2=hmax

Fig. 19 Geometrical relations between feed per tooth, cutting edge angle and chip thickness

Another distinctive feature of fast feed milling is reducing the bending moment, whichan FF tool takes. The small cutting angle leads to minimizing the radial effect of the
cutting force and maximizing its axial influence. The bending moment depends on theforce acting on the tool perpendicular to its axis. This bending force is the resultant of
the radial and the tangential components of the cutting force, substantially decreasing
the bending moment. The axial force acts towards the spindle axis, i.e. the direction of
maximum machine tool rigidity. The result – improved milling stability, reduced vibrationand increased productivity. Decreasing the bending force is especially important inmachining titanium, due to the already mentioned “springiness” of the material.
The classical cutting edge of the FF tool is an arc or large diameter. Today, thisgeometry mainly features solid carbide endmills and replaceable heads. The
cutting edge of the indexable tools is usually one or two chords of the arc.
ISCAR has a rich variety of FF tool families: indexable mills, SCEM and MULTI-MASTER cutters.
Indexable tools carry inserts that differ in type (one- and double sided), shape (trigon, quadrihedral,
hexagonal etc.) and size.
Table 24 provides general guidelines for choosing the most suitable indexable
family for fast feed milling titanium, from ISCAR’s standard product line.

A new birth of FF tools
Originally, FF tools were indexable cutters of relatively large nominal diameters. Advances in
multi-axis grinding machines enabled development of FF geometry in tools of solid design:
SCEM and replaceable heads of considerably less diameters. Further attempts to find a costsaving alternative to more accurate solid tools resulted in a small-size indexable solution.
For high feed milling titanium, ISCAR proposes the recently-introduced MICRO3FEED– a family of multi-flute indexable FF cutters with a 10 mm minimum diameter.

38

ISCAR

Mm 10-16

20-40

50-63

80-100In.315-.625.750-1.500

2.000-2.500

3.000-4.00

MICRO3FEED(T)

HELI6FEED(HP)

TANG4FEED(ER)

MILL4FEED(HP)

2nd choice

MILL4FEED(HP)

MILL4FEED(HP)

TANG4FEED(ER)

Possible

LOGIQ4FEED(HP)

HELI6FEED(HP)

HELI6FEED(HP)

DiameterRange
1st choice

MILLING TITANIUM

Table 24 Indexable Extended Flute Cutter Families: General Data** The recommended type of the insert chipformer id shown in the brackets.

ISCAR’s FF solid carbide endmills and MULTI-MASTER heads are represented
by several families. A general description of the families is given in Table 25.

Table 25 FF SCEM and MULTI-MASTER Heads
Range of diameters
FamilyDesignation

Mm

In

NumberOf teeth

SOLIDFEEDMILL

EFF-S

1-20

.250-.750

2, 4

MULTIFEEDMASTER

MM EFF

8-25.472-1.000

4, 6

MULTIFEEDMASTER

MM FF

10-20

.375-.750

239

MILLING TITANIUM

Applications
The main operations performed by FF tools are rough milling pockets and cavities(“pocketing”), pre-shaping complex surfaces (“profiling”) and plane faces (“facing”). Someof the tools feature side plunge milling capabilities (“side plunging”). Milling pockets andcavities are the most common cutting operations performed in producing titanium parts.
It is worth noting however, that fast feed face milling titanium is still not as
popular as steel. The reason is, again, heat. Thick chips, produced by an
FF tool, makes heat removal from the cutting zone more difficult.
Also, face mills generally feature relatively large diameters that increase thecontact of an insert with the machined material. This results in intensifying
the heat load on the cutting edge and shortening tool life.
By contrast, applying FF tools to pocketing enables decreasing the bending
force in high feed milling and therefore this method is recommended for roughmachining pockets and cavities in thin-walled and low-rigidity parts.

Fast Feed Facing
Initially the FF cutters were considered mainly as tools for productive rough milling of cavities andpunches in die and mold applications. The FF approach was later applied to face milling.
Fast feed face milling ( “fast feed facing” or, simply, “triple F”) with the use of indexable cutters,
opened another application field for FF tools.



An FF tool generates a machined surface with cusps. The cusp height diminishes with reducing
width of cut ae. It is recommended that the width of cut be no more than diameter DC (Fig. 20)
to prevent tooth overloading, because of excess machining allowance in the produced cusps.

Cusp
Stepdown

DCae >DCap>apmax

Fig. 20 Width of cut and cusps in fast feed milling

In CNC programming, an FF tool is often specified as a milling cutter with a corner radius. The
radius is calleda "radius for programming" (R in Fig. 21). It defines the maximum thickness ofa cusp – a mismatch, produced by such specification (correspondingly t in the same figure).

t

R

Fig. 21 Radius for programming

40

ISCAR

HFM demands tough carbide grades. In indexable milling, IC882 is the first choice andIC330, IC328, and IC840 are reasonable options. Solid carbide FF endmills are produced
from grades IC903 and IC902, and FF MULTI-MASTER heads – from IC903 and IC908.

Initial Cutting Data
Initial cutting speed Vc can be found using equation (1), where the basic cutting speed andfactors, which the equation uses, are in Tables 7-10. Basic cutting speed Vo should bechosen from data for medium (M) type of machining. As in the previous cases, stability factor
Ks is defined as 1 for normal stability and 0.-0.8 for unstable machining conditions.

MILLING TITANIUM

Carbide Grades

Note. In milling cavities and pockets, in many cases an FF tool starts from cutting solid material byramping down (with AE=180°) and then continues to machine the shoulder. For a rough calculationof Vc it is enough to simplify equation (1) by setting engagement factor Ke as 1.
Starting feed per tooth fz for indexable FF tools is specified by equation (5):fz=fzo×Ks
Table 26 provides basic feeds depending on carbide grades of inserts,
and Table 27 – for SCEM and MULTI-MASTER heads.

Table 26 Basic Feed fzo for Indexable FF Tools
Cutting
Insert
Edge
Size
angle

Tool
FamilyDesignation
MICRO3FEED FFT3
03
0405
HELI6FEEDFF EWX/FWX 07
08
09
MILL4FEED
FFQ4
12
17
LOGIQ4FEED FFX4
04
TANG4FEED FFV
07

17°

17°
12°
9°
14°
17°
16°

fzo, mm/tooth (ipt), for carbide gradesof FF inserts

IC882, IC330, IC328

IC830, IC840,
IC5820IC808, IC908

0.38 (.015)
0.4 (.016)
0.4 (.016)
0.45 (.0177)
0.45 (.0177)
0.55 (.0217)
0.7 (.0275)
0.47 (.0185)
0.45 (.0177)
0.47 (.0185)

0.35 (.0137)
0.38 (.015)
0.38 (.015)
0.42 (.0165)
0.42(.0165)
0.51 (.02)
0.65 (.0256)
0.44 (.0173)
0.42 (.0165)
0.44 (.0173)

0.33 (.013)
0.36 (.0142)
0.36 (.0142)
0.4 (.016)
0.4 (.016)
0.49 (.0193)
0.62 (.0245)
0.42 (.0165)
0.4 (.016)
0.42 (.0165)* The recommended type of the insert chipformer id shown in the brackets.

ExampleIt is planned to use the HFM method for rough milling the cavity in a titanium part. The titanium
grade is solution treated and aged Ti-6Al-4V. The cavity dimensions(length L × width W × depth H) are 220 × 110 × 70 mm (8.66 × 4.33 × 2.75 in). The technologist of
a company machining division that has LOGIQ4FEED fast feed shell mill FFX4 FD040-6-16-04 on
hand, decided to apply it and machine the cavity by ramping down including ramping by helix. The
mill carries inserts FFX4 XNMU 040310HP IC882. Operational stability is considered as normal.
Which cutting data should be set?
Basic cutting speed Vo=43 m/min (141 sfm) - Table 7, and Km=0.9 – Table 9.
Initial cutting speed Vc=43 × 0.9 × 1 × 1 ≈ 39 (m/min) or 128 sfm.
Spindle speed n=1000 × 39 /(π × 40)=310 (rpm).
Feed fz, which is equal to basic feed fzo in this case, is found from Table 26:
fz=fzo=0.45 mm/tooth (.0177 ipt).

41

MILLING TITANIUM

The mill has 6 teeth, hence feed speed Vf=0.45 × 6 × 310=837 (mm/min) or approx. 33 ipm.

Maximum depth of cut (DOC) apmax (the catalogue data) for the mill is 0.8 mm (.0031 in).
Necessary ramping angle for milling lengthwise
αr≈ tan-1 (apmax/(L-d))=tan-1 ( 0.8/180)=0.25° (Fig. 22), while for milling
widthwise αr≈ tan-1 (apmax/(W-d))=tan-1 (0.8/110)=0.65°.
Due to the maximum 0.9° ramping angle for the mill (the catalogue data), ramping inboth directions with reaching the maximum DOC in the end of the pass is possible.

αr

apmax

L

Fig. 22 Ramp-down milling

Table 27 - fzo for FF SCEM and MULTI-MASTER Heads
FamilyDesignation

SOLIDFEEDMILL and
MULTIFEEDMASTER

EFF-S andMM EFF

MULTIFEEDMASTER

MM FF

FamilyDesignation

SOLIDFEEDMILL and
MULTIFEEDMASTER

EFF-S andMM EFF

MULTIFEEDMASTER

MM FF

1 (.037)0.02(.0008)8 (.315)0.21(.0083)

Basic feed fzo, mm/tooth (ipt)Diameter d, mm (in)2 (.075)
3 (.125)
4 (.160)
0.1
0.16
0.2
(.004)(.0063)(.008)

5 (.200)
0.2(.008)

6 (.250)0.2(.008)

Basic feed fzo, mm/tooth (ipt)Diameter d, mm (in)10 (.375) 12 (.500) 16 (.625) 20 (.750)
0.25
0.25
0.3
0.32
(.01)
(.01)
(.012)(.126)
0.37
0.37
0.45
0.48
(.0146)(.0146)(.018)(.019)

25 (1.000)
0.35(.138)

ExampleFind cutting data for high feed milling a workpiece from titanium Ti-10V-2Fe-3Al, which will bemachined by a reinforced special MULTI-MASTER tool carrying
two-flute head MM FF120R2.0-2T08 908.
On the assumptions that the whole technological system is rigid, from Table 7 basic
cutting speed Vo=53 m/min (174 sfm) Table 7, and from Table 9 Km=0.56.
Initial cutting speed Vc=53 × 0.56 × 1 × 1 ≈ 30 (m/min) or 97 sfm.
Spindle speed n=1000 × 30 / (π × 12)=795 (rpm).
Basic feed fzo is chosen from Table 27: fzo=0.37 mm/tooth (.0146 ipt).
Feed rate Vf=0.37 × 2 × 795=588 (mm/min) or 23 ipm.

Tooth structure and feed per tooth
There are two kinds of MULTI-MASTER fast feed milling heads: four- and six-flute MM EFF
and two-flute MM FF. The recommended feed per tooth fz for MM FF heads is 1.5 times morethan for MM EFF ones. The reason is a tooth structure. If the teeth of the multi-flute heads MM
EFF are produced by grinding cylindrical blanks similarly to solid carbide endmills, the teethof “economy-type” two-flute heads MM FF are pre-shaped by sintering and then are merely
finished by grinding. The high-impact structure of a sintered tooth ensures greater fz.

42

ISCAR

High Speed Milling (HSM) Can Refer To Several Operations:• high cutting speed milling,• high spindle speed milling,• high feed speed milling.
All the mentioned speeds are interrelated. Increasing spindle speed n automatically results inincreasing feed speed Vf as well, and likewise more cutting speed Vc requires more spindle speedn to the same extent. As cutting speed varies in direct proportion to the diameter of a rotating
tool, ensuring the same Vc for mills of different diameters demands different spindle speeds.
In the context of the guide, more correct understanding of HSM relates to high spindle speed.
In milling titanium, cutting speeds are significantly lower than in milling steel.
Although advanced tool materials and new machining techniques have led
to growing a growth in averaged cutting speeds set for milling titanium, highVc and n values for titanium may look like “normal” values for steel.

MILLING TITANIUMHigh Speed Milling Titanium

There are several factors that result in high spindle speed n:• small tool diameter,• small effective diameter,• trochoidal milling as the machining strategy.
The small effective diameter de relates to milling by profiling tools (especially ballnose or lens type) at shallow depth of cut. Table 28 and Fig. 23 show possible
cases for calculating the effective diameter for ball nose milling cutters.
ExampleAn 8 mm (0.315 in) solid carbide ball nose endmill machines the inclined
surface of a titanium workpiece by ramp-up milling. Ramping angle α=12°,
machining allowance per pass a=0.1 mm. The workpiece material is annealed
Ti-6Al-4V, the endmill carbide grade – IC908. Find spindle speed n.
From Table 28 effective diameter

de=(8-2×0.1)×sin12°+2×√((8×0.1-0.1 2 )×cos12°=3.36 (mm) (0.132 in).

Basic cutting speed V0=65 m/min (213 sfm), Table 8.
For simplicity assume that cutting speed is the same (Vc=V0).
Spindle speed n=(1000×65)/(π×3.36)=6158 (rpm).

Effective diameter
A profile milling tool (ball nose cutter, toroidal mill etc.) features a shaped, non-straight cutting profileand the cutting diameter is a function of a depth of cut. In profile milling, the effective diameter is thelargest true cutting diameter.
Generally, it corresponds to the diameter, measured at the axial depth of cut.
A necessary cutting speed should be calculated with respect to the effective diameter.
Ignoring it can cause essential errors in cutting data and result in poor performance.
Note. For the equal cutting speed, which corresponds to nominal tool diameter d=8 mm (0.315in), spindle speed will be 2586 rpm. For the nominal diameter, the found spindle speed provides
the cutting speed 154.8 m/min (507.8 sfm). Using this virtual speed as a characteristic of theconsidered operation is misleading because the real cutting speed is much lower.

43

MILLING TITANIUM

n

n

n

a

Stepdown (ap)

α
+ VF

VF

ap

VF
de

de

ae
de

Fig. 23 Milling by ball nose cutter

Table 28 Calculating Effective Diameter De for Ball Nose Milling Cutters

Cutting path

Case inFig. 23 Effective Diameter de

The cutter axis is normal to a machined surfacea)

2× √(d×ap-ap2)

Ramping, milling inclined surfacesb)(b-2×a)×sinαr+2× √(dxa-a2)×cosαr* ≈d×sinαr**

Milling straight walls

c)

d

Notes

* αr - ramping angle, a - machining allowance (stock to be removed) per pass.
** The simplified equation is often used for estimating effective diameter. In many cases it gives a more or less suitable
result. Nevertheless, this equation should be applied for rough calculation only due to the truncation error that can be aserious of inaccuracy.

Conventional milling of slots or grooves starts from machining solid material directly at fulltool engagement. Milling with full tool engagement requires increased cutting forces and, asa consequence, consumes more power. A high speed trochoidal rough milling technique
can be an effective alternative to the common slot milling strategy. In trochoidal milling, a
rapidly rotated tool machines material by arc motion at a significant depth of cut and verysmall width of cut (usually, 5-15% of tool diameter d). The small angle of engagement AE
both allows multi-flute tool design and ensures substantial increasing cutting speed Vc andfeed per tooth fz. The tool slices thin layers of material with both high speed and high feed
rates and this productive rough milling method features a noticeable reduction in power
consumption. Trochoidal milling has been utilized successfully in manufacturing titanium
parts with various slots and grooves (Fig. 24), and also pockets or cavities¸ especially thosewith relatively thin walls. The metalworking industry adopted this method for producing
different integrally bladed rotors (IBR) such as blisks, blings, impellers, etc. (Fig. 25)

44

ISCAR

MILLING TITANIUM

ExampleAn aircraft engine builder has decided to apply trochoidal milling to rough machining
slots in an integrally bladed rotor. ISCAR’s 10 mm (0.394 in) dia. ECK-H7 7-flutesolid carbide endmill, made from carbide grade IC900, will be used under thefollowing averaged machining parameters: ap=16 mm (0.63 in), ae=1 mm (0.04 in).
Material – Ti-6Al-4V ELI. Operational stability is good. Find initial cutting data.
Assume that Ks=1 (stable cutting).
Basic cutting speed V0=65 m/min (213 sfm) (Table 8).
Km=1.1 (Table 9).
ae/d=1/10=0.1. Angle of engagement AE=36°, Ke=1.5 (Table 10).
From equation (1): initial cutting speed Vc=65×1.1×1.5×1=107 (m/min) or 352 sfm.
Spindle speed n=(1000×107)/(π×10)=
3406 (rpm).
Basic feed per tooth fzo=0.13 mm/tooth (0.0051 ipt) (Table 16).
Kf=0.78 (Table 17).
From equation (6): starting feed fz=0.13×1×0.78=0.1 (mm/tooth) or 0.004 ipt.
Feed rate Vf=0.1×7×3406=2384 (mm/min) (93.86 ipm).
Estimated metal removal rate Q=1.6×0.1×238.4=38.14 (cm³/min) (2.36 in³/min)

Slot
axis

vf

n

Fig. 24 Trochoidal milling

Solid carbide endmills (SCEM), which are used in machining titanium, can be successfully
operated by trochoidal milling techniques and commonly feature 4-5 flutes. A variety of
SCEM with greater number of flutes have been designed specifically for trochoidal milling
applications. Table 29 gives basic data about ISCAR’s families of these solid carbide endmills.

Table 29 SCEM Families for Trochoidal Milling Titanium

FamilyDesignation

Ti-TURBO

ECK-H7/9-CFR 1st choice

CHATTERFREE EC-E7/H7-CF

Priority

Diameters
D, mm (in)

Flute
Numberhelix
Of flutes, Z Angle

Angular Carbide
Pitch
Grade

6-20

7 and 9*Different

Variable IC900

7

for flutes

IC902

2nd choice 2-20 (.125-.750)* 7 teeth for d up to 12 mm, 9 teeth for d more than 12 mm.

Trochoid
A trochoidal curve or, simply, a trochoid, is the general name of the curves that are
generated by a fixed point of a curve rolling along a directing line or curve without slip.

45

MILLING TITANIUM

Fig. 25 Milling blisk

For optimal results of high speed trochoidal milling titanium in specific applications (milling blisk is
the most typical example), manufacturers require many tailor-made (special) tools that differ indiameters, cutting and overall lengths, and a shank type. An excellent solution can be found withthe use of MULTI-MASTER products ensuring numerous design configurations for assembled
tools.
The MULTI-MASTER family features a rich variety of special multi-flute heads, which areintended for trochoidal milling and are produced by request.

Flying bling
A rotor, the rotating part of a turbine, mainly comprises a shaft, a disk and blades. Traditionally, therotor is an assembly in which the blades are mounted in a disk. An alternative design features anintegrally bladed rotor (IBR) - a monoblock part that integrates the blades and the disk.
In comparison with the assembled structure, the alternative reduces the rotor
weight but, at the same time, makes maintenance more difficult. Depending on thespecific configuration, IBR (“bladed rotor” or simply “blotor”) may be considered asa bladed disk (“blisk”), a bladed ring (“bling”) or even a bladed drum (“blum”).

46

ISCAR

ISCAR provides different tools for drilling titanium that can be divided in two main types: solid
carbide drills (Fig. 26) and assembled drills with exchangeable cutting parts. The latter comprise
drills carrying indexable carbide inserts (Fig. 27) and drills with replaceable cutting heads(Fig. 28, 29). Assembled drills are the most common in machining titanium components.
Table 30-34 show general engineering data of ISCAR’s drill families that are mostused in machining titanium. In drilling titanium, inner coolant supply (throughthe tool body) is preferable, and all the drills are suitable for this option.

Table 30 ISCAR’S Drills for Machining Titanium

DRILLING TITANIUMDRILLING TITANIUM

Diameter range
FamilyDR-TWIST

Designation TypeDR
assembled

SUMOCHAM DCN

assembled

SOLIDDRILL SCD ACP

solid

Cutting areaindexable inserts

Z**
1

Hole
Mm
In
Accuracy*
12…60 0.469…2.344 IT12replaceable head

2

6…32

0.236…1.260

IT10-IT92

3…200.180…0.813

IT10-IT9* ISO tolerance grades, provided in average cutting conditions** number of effective cutting edges

Table 31 Cutting Length Series for Indexable Drills DR-TWIST
Diameter d*Cutting length series

Mm

In

2×d

12 to 140.469 to 0.562

14 up to 24

0.562 up to 0.936

over 24 up to 38

over 0.936 up to 1.500

over 38 up to 60

over 1.500 up to 2.344

3×d

4×d

5×d

* the nominal diameter of a drill.

Table 32 Cutting Length Series for Drills With Replaceable Heads SUMOCHAM
Diameter d*Cutting length series

MmIn

1.5×d 3×d

6 to 80.236 to 0.315

8 up to 26

0.315 up to 0.984

5×d

8×d

12×d

over 26 up to 32 over 0.984 up to 1.220
over 1.220 up to 1.260* the nominal diameter of a drill.

Table 32 Cutting Length Series
for Solid Carbide SOLIDDRILL
Inch Line Drills, Metric Line
Diameter d*,
Mm

Cutting
Length series
3×d

5×d

3 to 4.9

8×dTable 33 Cutting Length
Series for Solid Carbide Drills
SOLIDDRILL , Inch Line
Diameter d*,In

Cutting
length series
3×d 5×d0.180 up to 0.343

4.9 to 7.8

over 0.343 up to 0.813

7.8 up to 9.9* the nominal diameter of a drill.

over 9.9 up to 12
over 12 up to 20* the nominal diameter of a drill.

47

DRILLING TITANIUM

Fig. 26 A solid carbide drill from the SOLIDDRILL family, intended for machining titanium

No-setup time
ISCAR’s tools with replaceable heads (for example SUMOCHAM and MULTI-MASTER
families) wholly meet the requirements of the important “no-setup time” principle, as replacing
a worn head does not require additional setup operations. The head can be changed without
removing a tool from a machine, which significantly decreases downtime. The MULTI-MASTER
unified thread connection allows the shank to carry different cutting heads and vice versa,
converting the shank to a universal holder and so reducing both tool inventory and storage.

1.5×d 3×d

Fig. 27 DR drill with indexable inserts

Replaceable
solid carbide
cutting head

5×d

8×d 12×d

Fig. 28 SUMOCHAM drills of different cutting length series

Steel body
Polished speciallyshaped flute

Advancedpocket design

High-strength steel grade
Grooved forclamping
key

Precisecentering
surface

Twisted coolant channel

Axial
stopper
Radial stopper

Flute specifically designed for
effective chip formation

Fig. 29 The structure of a SUMOCHAM drill

48

ISCAR

Frontal coolant

Drilling shallow holes is widely used in processing, for example in short pre-drilling or spotting
a hole, in order to achieve location accuracy and successful further drilling. Any drill of
relatively small diameter may be applied for this operation; however, there is no need for the
tool to have a significant cutting length. A better performance is achieved with the use ofdrills featuring stab cutting length that are intended specifically for producing short holes.
ISCAR provides various solutions for drilling shallow holes and spot drilling (Table 35) in the following
design configurations: replaceable MULTI-MASTER heads and solid carbide drills. In addition to
spot drilling, these simple tools are suitable for countersinking, milling chamfer and removing burrs.

		Fig. 30 MM HCD head				DRILLING TITANIUM

Drilling Shallow Holes

Fig. 31 MM ECD head

Table 35 Spot Drills
FamilyDesignation

MM HCD

MM ECD

ECD-S2

Diameter*,Mm (in)88.3(0.375)
10
10.4
12
12.4
(0.500)(0.625)16
16.5(0.750)
20
6
8
10
12
16
3
4
5
6
8
10

Point angle
60°

80°

90°

120°

Fig**

30

31

32

* the nominal diameter of a drill.
** an illustrative example

Fig. 32 Solid carbide spot drill ECD-S

49

DRILLING TITANIUM

Center Drilling
MULTI-MASTER replaceable MM ECS heads (Fig. 33), produced from solid carbide, are intended
for drilling 60° center holes in accordance with DIN 332 and ANSI B94.11M (metric and inch products
correspondingly). There are two types of heads that ensure drilling the center holes of form A(without protective chamfer, “plain type”) and form B (with conical protective chamfer, “bell type”).
Table 36 specifies the application range for ISCAR's standard line of these heads.

Fig. 33 MM ECS head for drilling center holes

Table 36 - Applicabillity Of MM ECS Center Drilling Heads
Center holeType

Size acc. to ANSI
B94.11M

Designation acc. to DIN 332
1×2.12 1.6×3.35 2×4.25 3.15×6.7 4×8.5

5×10.6 6.3×13.2

4

5

A (“plain”)
B (“bell”)

Drill or countersink?
A center drill is needed for forming a conical hole in workpieces. This hole is used forsupporting the workpieces by the centers of machine tools. One of the methods for forming
conical holes is countersinking - machining by a specially designed cutter, a countersink. In
fact, the center drill performs a combination of two operations simultaneously: drilling andcountersinking. Therefore, the center drill is often referenced as a “combined countersink”.
Other names of the center drill – “Slocombe drill” and “Slocomb drill” – are rarely used.
Sometimes, the center drill is considered as a spot drill; however this specification is notstrictly correct. A spot drill only drills but a center drill performs two operations: drillingand countersinking, therefore “spot a hole” and “drill a center hole” are not the same.

50

ISCAR

6

Selecting a suitable drill is based on the necessary design configuration, cutting geometry, andcutting material of a tool. Hole diameter, accuracy, and required cutting length define the drill
configuration, while a the geometry and the cutting material are defined by the workpiece material.
Fig. 34, which is based on Tables 31-34, shows the application area of ISCAR’s drill families
intended for machining titanium, in coordinates “drill diameter-drill cutting length” in simplified form.

Central drilling: carbide vs. HSS
High-speed steel (HSS) reversible center drill bits are the most popular tools for center drilling.
The bits are simple, always available for purchase, and feature low prices. This may raise thequestion: “Does the MM ECS replaceable solid carbide head offer a real alternative to thebits?”. A seemingly obvious answer may be not so evident, especially in cases of machining
difficult-to-cut material (like titanium). The carbide head ensures noticeable increases in
cutting speed and feed, resulting in higher productivity and reduced machining costs. In
addition, the tool life of the head is much longer. Therefore, the correct answer requires brief
economical calculations, which will show the actual situation for every specific case.

DRILLING TITANIUM

Selecting A Drill

Cutting
Length

12xd
10xd
8xd

4xd
2xd

3
(.112)

6

12(.500)

20(.750)

32(1.250)60(2.344)

Diameter d,
mm(inch)

Fig. 34 Application range of ISCAR’s drilling line (standard delivery)

To select the most suitable ISCAR drill for machining titanium,
note the general recommendations below:



SUMOCHAM drills are the first-choice products and should be used wherever possible.
IC908 is the preferred carbide grade.
MULTI-MASTER tools are most recommended for spot drilling.
Coolant
Coolant supply is a vital factor in drilling titanium. Liquid coolant is not only preferable
but is essential. Although wet cooling by flooding under low pressure is still common,
tool body-through (inner) coolant supply ensures high performance. Advanced drills(both solid and assembled) feature inner coolant channels for delivering coolant
through the drill body, and such drills should be used whenever possible.
Recommended minimal coolant pressure is 12 bars (174 psi). Higher values will improve theresults. Normally, the pressure range is 12…70 bars (174…1015 psi). Higher range values relate tomachining with high pressure coolant (HPC) supply, and they require separate consideration.

51

DRILLING TITANIUM

Initial Cutting Data In Drilling
Cutting Speed
In drilling titanium with coolant pressure up to 70 bar,initial cutting speed Vc is found with the use of equation (9):Vc=Vo×Km×Ks
Where:(9)

Vo – basic cutting speed (Table 37)
Km – machinability factor (Table 9)
Ks – stability factor (1 for normal stability and 0.7-0.8
for unstable drilling and machining in unfavorable conditions)

Table 37 Basic Cutting Speed Vo In Drilling
Vo, m/min (sfm) or drill diameter d, mm (in)FamilyDesignation

Over 6
To 12
(over
0.236
Up to
0.472)

Over 3Up to 3up to 6(up to (over 0.118
0.118)
Up to
0.236)

From 12
up to 20
(over
0.472
Up to
0.787)

DCN

Over 20
Over 32
up to 32
up to 60
(over 0.787 (over 1.260
Up to
Up to
1.260)
2.362)
50 (164)SCD ACP32 (105)

MM HCD,
MM ECD
ECD-S2

45
(148)

38
(125)

32 (105)DR

50 (164)

Chip splitting in drilling
A chip-splitting cutting geometry may be used in drilling
tools. There are different designs of drill cutting edges
with chip splitting grooves, for example, ICG heads
in SUMOCHAM family (Fig. 34). Splitting chips into
small segments improves chip evacuation and provides
increased cutting speed (by an average of 15%). Under
the same cutting conditions, a straight-style edge
ensures better surface finish. Therefore, the chip-splitting
geometry is suitable mainly for rough drilling operations.
Fig. 34 ICG drilling head withchip-splitting cutting edges

Feed
Following equation (10) defines starting feed f (per revolution):

f=fo×Kh(10)

Where:

fo – basic feed (Table 38, 39)
Kh – overhang factor (Tables 40, 41)

Table 38 Basic Feed Fo for DR-TWIST DR Drills
Insert size
Basic feed
fo

52

ISCAR

04

05

06

07

09

10

11

12

14

mm/rev

0.05

0.06

0.06

0.07

0.08

0.08

0.1

0.1

0.12

inch/rev (IPR)

0.002

0.002

0.002

0.003

0.003

0.003

0.004

0.004

0.005

DrillDiameter

Basic feed fo

Mm

Up to 3

Inches

up to
0.118

Mm/rev

0.04

Inch/rev (IPR) 0.002

Over 3 Over 5
up to 5 up to 8
over
over 0.2
0.118 up up to
to 0.2
0.315
0.07
0.09

Over 8 Over 12 Over 16 Over 20 Over 25
up to 12 up to 16 up to 20 up to 25 up to 32
over
over
over 0.63 over 0.78 over
0.315 up 0.472up up to
up to
0.984 up
to 0.472 to 0.63 0.787
0.984
to 1.26
0.12
0.15
0.19
0.21
0.23

0.003

0.005

0.004

0.006

0.008

0.008

0.009

* for tools carrying MM HCD, MM ECD and MM ECS heads

Table 40 Overhang Factor Kh for DR-TWIST DR Drills
Cutting length series
Overhang factor Kh

2×d*
1

3×d
0.93

4×d
0.82

DRILLING TITANIUM

Table 39 Basic Feed Fo for SUMOCHAM DR, SOLIDDRILL SCD ACP,
MULTI-MASTER* and SOLIDMILL ECD S2 Drills

5×d
0.75

* d - drill diameter

Table 41 Overhang Factor Kh for SUMOCHAM DR, SOLIDDRILL SCD
ACP, MULTI-MASTER and SOLIDMILL ECD S2 Drills
Cutting length series*
Overhang factor Kh

up to 3×d**

5×d

8×d

12×d

1

0.87

0.82

0.80

* tool overhang for MULTI-MASTER tools** d - drill diameter

ExampleA machining division technologist plans the process for manufacturing a part, which is produced
from annealed titanium Ti-6Al-4V. One of the machining operations is drilling a series of throughholes in the part base, which have thickness 65 mm (2.56 in). The holes are 24 mm (0.945in) in diameter, the diameter tolerance limits are ±0.065 mm (±0.0026 in). The technologist
decided to use an ISCAR drill for this operation. Recommend the drill and cutting data.
The hole depth/diameter ratio is 65/24≈2.7, so the drill cutting length series should be
3×d. The required accuracy for the diameter relates to ISO IT11 grade. SUMOCHAM
products are recommended as the first-choice drills. We can select the DCN 240-07232A-3D (24 mm Dia., 3×d cutting length series) as it provides IT10-IT9 hole accuracy (Table
29). This drill carries the head ICM 240 IC908 (IC908 – the preferred carbide grade).
Basic cutting speed Vo=38 m/min (125 sfm), Table 37. Machinability factor Km=1 (Table 9).
By assuming that the operational stability is normal (Ks=1), equation (9) gives starting speed Vc as below:
Vc=38×1×1=38 (m/min) or 125 sfm.
Spindle speed n=( 1000×38)⁄(π×24) =504 (rpm)Basic feed fo=0.21 mm/rev (0.0082 IPR), Table 39.
Overhang ratio Kh=1 (Table 41).
Calculating feed f with the use of equation (10) gives the following result:
f=0.21×1=0.21 (mm/rev) or 0.0082 IPR.
Feed speed Vf=0.21×504=105.8 (mm/min) or 4.13 IPM.

Short and deep holes
Cutting length series
Commonly used terms “short” and “deep” holes do not have a strict definition.
It is widely accepted that drilling a hole of diameter d and (10…12)×d or higher in
depth relates to deep drilling, while holes having depth up to 5×d, are short.
In the terminology used by ISCAR, only a drilling depth of 12×d and higher is considered as deep.
Consequently, the holes with shallower depths are short. The drills intended for machining short holes
vary in their cutting length series: short (up to 3×d), long (4×d and 5×d) and extra-long (8×d and 12×d).

53

REAMING TITANIUMREAMING TITANIUM
Reaming is not a very common operation in machining titanium; however, various processes
require it. ISCAR’s line of reaming tools comprises several families of reamers. The families
differ in their design: a solid carbide concept or an assembled one. Reaming titanium featuresa relatively large proportion of required non-standard dimensions for the nominal diameterof a hole and its tolerance limits. It often is caused by “springiness” of titanium and thischaracteristic should be considered during process planning. ISCAR provides tools for reamingtitanium at the customer’s request, as tailor-made products; the most suitable solutions arecustomized high-speed reamers on the base of the BAYO T-REAM family (Fig. 35).
A typical BAYO T-REAM reamer (Fig. 36) is an assembled tool comprising a holder (alsoreferenced as a shank) and an interchangeable multi-flute reaming head, produced from
cemented carbide. The head is mounted in the holder with the use of a unique quick-changebayonet mechanism. The heads feature different connection size (“bayonet number”) thathas designation BN5, BN6, …, BN9. Each size corresponds to a specific area within the
diameter range of the reamers. There are heads with different flute directions dependingon the type of a machined hole: through or blind (Fig. 37). The holder material is usuallysteel but, if necessary, it may be also heavy metal and cemented carbide. The reamers are
suitable for inner coolant supply where the coolant flow is directed on every cutting edge.

Fig. 35 A BAYO T-REAM reamer

The design concept of the family offers the following advantages:
1. Versatility – the holder can carry different heads, and the head is suitable for mounting in different
holders. This feature ensures a wide usage of standard holders, diminishes needs for tailor-madeones, and thus reduces tool stock.
2. "No setup time" principle – replacing a worn head by a new one does not require additional setup
operations and can be done when a reamer is clamped directly in the spindle of a machine tool.
It is an efficient means to cut the machine downtown and reduce production cost.
3. Easy-to-use – the head is replaced in a quick and simple way.

54

ISCAR

REAMING TITANIUM

Table 42 contains general data that characterize the tools for reamingtitanium from thefamilyKey

Reamer
Head

BayonetScrew

HolderFig. 36 Elements of a BAYO T-REAM reamer

Fig. 37 An interchangeable reaming head with straight flutes

Table 42 BAYO T-REAM Tools for Reaming Titanium: General Data
Value in units
Parameter

MetricUS customary

Range of diameters

11.5…32

0.4528…1.26
IT 7

Hole accuracy*, ISO grade
Hole surface finish*, Ra

0.2…0.4

8…16* in average cutting conditions

55

REAMING TITANIUM

Initial Cutting Data In Reaming
Reaming Allowance
When reaming titanium, guide values for the reaming allowance – a material
stock (per diameter) left for reaming – are shown in Table 44.

Table 44 Diametral Reaming Allowance for BAYO T-REAM Tools
Allowance for hole diameter
From 11.5 to 13.5
(from 0.4528 to 05315)
0.15-0.25(0.006-0.01)

From 13.5 to 16(from 0.5315 to 0.63)
0.20-0.30(0.008-0.012)

From 16 to 32(from 0.63 to 1.26)
0.20-0.35(0.008-0.014)* units: mm (in)Cutting Speed
Initial cutting speed Vc is calculated by equation (11):

Vc=Vo×Km (11)Where:

Vo=45 m/min (148 sfm) – basic cutting speed
Km – machinability factor (Table 9)

Feed
Table 43 provides data for setting starting feed per tooth fz.

Table 43 Recommended Feed Values for BAYO T-REAM Tools*
Feed fz, mm/tooth (IPT)
Through hole
Connection
Size

SmoothInterrupted

Blind hole
SmoothInterrupted

BN5…BN6

0.04-0.05-0.07
0.03-0.04-0.06
0.03-0.04-0.06
0.03-0.03-0.05(0.0016-0.002-0.0027) (0.0012-0.0016-0.0024) (0.0012-0.0016-0.0024) (0.0012-0.0012-0.002)

BN7…BN90.05-0.07-0.09
0.04-0.06-0.08
0.04-0.06-0.07
0.04-0.05-0.06(0.002-0.0027-0.0035) (0.0016-0.0024-0.0031) (0.0016-0.0024-0.0027) (0.0016-0.002-0.0024)* recommended feed values are given as: minimal-starting-maximal

When reaming with BAYO T-REAM tools, the best results are reached with coolant pressure
15-20 bars (217-290 psi).

ExampleFind cutting data for reaming a through hole in the process of manufacturing a titanium part. The
titanium grade is Ti-10V-2Fe-3Al, the required hole diameter is specified as Ø25Js8. It is planned
to apply a BAYO T-REAM reamer carrying a specially designed 8-flute head with BN8 connection.
Machinability factor Km=0.56 (Table 9).
According to equation (11), initial cutting speed Vc will be as follows:
Vc=45×0.56=25 (m/min) or 83 sfm.
Spindle speed n=( 1000×25) ⁄ (π×25)=318 (rpm)
From Table 44 starting feed fz=0.07 mm/tooth (0.0027 IPT).
Feed speed Vf=0.07×8×318=178 (mm/min) or 7 IPM.

56

ISCAR

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iscar@iscar.ru
www.iscar.ru
Chelyabinsk
ISCAR RUSSIA EAST LLC
Tel/fax +7 351 277 74 32
info@iscar-east.com
www.iscar-east.ru
SerbiaISCAR TOOLS d.o.o.
Tel +381 11 314 90 38
Fax +381 11 314 91 47
info@iscartools.rs
Singapore
SINO TOOLING SYSTEM
Tel +65 6566 7668
Fax +65 6567 7336
sinotool@singnet.com.sg
Slovakia
ISCAR SR, s.r.o.
Tel +421 (0) 41 5074301
Fax +421 (0) 41 5074311
info@iscar.sk
www.iscar.sk
Slovenia
ISCAR SLOVENIJA d.o.o.
Tel +386 1 580 92 30
Fax +386 1 562 21 84
info@iscar.si
www.iscar.si
South Africa
ISCAR SOUTH AFRICA (PTY) LTD.
ShareCall 08600-47227
Tel +27 11 997 2700
Fax +27 11 388 9750
iscar@iscarsa.co.za
www.iscar.co.za

South Korea
ISCAR KOREA
Tel +82 53 760 7594
Fax +82 53 760 7500
leeyj@taegutec.co.kr
www.iscarkorea.co.kr
Spain
ISCAR IBERICA SA
Tel +34 93 594 6484
Fax +34 93 582 4458
iscar@iscarib.es
www.iscarib.es
SwedenISCAR SVERIGE AB
Tel +46 (0) 18 66 90 60
Fax +46 (0) 18 122 920
info@iscar.se
www.iscar.se
Switzerland
ISCAR HARTMETALL AG
Tel +41 (0) 52 728 0850
Fax +41 (0) 52 728 0855
office@iscar.ch
www.iscar.ch
TaiwanISCAR TAIWAN LTD.
Tel +886 (0)4-24731573
Fax +886 (0)4-24731530
iscar.taiwan@msa.hinet.net
www.iscar.org.tw
Thailand
ISCAR THAILAND LTD.
Tel +66 (2) 7136633-8
Fax +66 (2) 7136632
iscar@iscarthailand.com
www.iscarthailand.com
TurkeyISCAR KESICI TAKIM
TIC. VE. IML. LTD
Tel +90 (262) 751 04 84 (Pbx)
Fax +90 (262) 751 04 85
iscar@iscar.com.tr
www.iscar.com.tr
Ukraine
ISCAR UKRAINE LLC
Tel/fax +38 (044) 503-07-08
iscar_ua@iscar.com
www.iscar.com.ua
United Kingdom
ISCAR TOOLS LTD.
Tel +44 (0) 121 422 8585
Fax +44 (0) 121 423 2789
sales@iscar.co.uk
www.iscar.co.uk
United States
ISCAR METALS INC.
Tel +1 817 258 3200
Tech Tel 1-877-BY-ISCAR
Fax +1 817 258 3221
info@iscarmetals.com
www.iscarmetals.com
Venezuela
FERREINDUSTRIAL ISO-DIN C.A.
Tel +58 2 632 8211/633 4657
Fax +58 2 632 5277
iso-din@cantv.net
Vietnam
ISCAR VIETNAM(Representative Office)Tel +84 8 38 123 519/20
Fax +84 8 38 123 521
iscarvn@hcm.fpt.vn
www.iscarvn.com“© 2013 Iscar Ltd. This document, as well as all
information and other data contained herein and/or derived therefrom, including but not limited to, alltrademarks, logos, trade-names, concepts, pictures,designs and/or devices, as well as any data fromwhich any proprietary and/or intellectual property right
may emanate (“Information”), is the sole and exclusive
property of Iscar Ltd. and is protected by copyrightand other applicable laws. No part of any Information
may be used or otherwise disseminated for any
purpose whatsoever without the express priorwritten consent of Iscar Ltd.
Items appearing in this catalog may be improved,
amended or withdrawn without prior notice.”

Please check ISCAR’s online catalog
www.iscar.com for the most current
technical information regarding
our products.

The ISCAR
Reference Guide forwww.iscar.com

3375110 RAV 05/2019 © ISCAR LTD All rights reserved

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