A N T I - V I B R AT I O N

Reference Guide

www.iscar.com

Table of Contents
Chatter suppression method of ISCAR anti-vibration tools.............................................................................3
User Guide - WHISPERLINE vibration - damping turning tools for lathe machines.......................................6
User Guide - WHISPERLINE vibration - damping turning blades for lathe machines..................................13

A N T I - V I B R AT I O NCutting tool vibration is a well-known problem in machining. The most common
issue is that of self-excited vibrations, also known as "chatter."During machining, a vibrating tool generates undulation on a workpiece surface.
In a subsequent tool pass, the cutting edge would then be machining the previously
generated wavy surface - leaving behind a newly generated wavy pattern, as shownin the figure below. The chip thickness and therefore the cutting forces vary withtime. This phenomenon can greatly amplify vibrations and develop chatter.

Chatter vibrations are detrimental to the safety and quality of machining operations.
They cause a rough surface finish, increase cutting forces, reduce tool andmachine life, decrease productivity, and create irritating high noises.
During internal turning, the tool usually has a large overhang (large L/D). In general, whereL/D>3, chatter vibrations become apparent due to high tool flexibility and low damping.
ISCAR's anti-vibration tools are designed for operations in which large overhangs
are required. These tools include Dynamic Vibration Absorber (DVA) systems toincrease damping and therefore stability during machining – see figure below.
The DVA is a heavy Tungsten mass supported by elastomeric components andlocated in an internal cavity at the furthest available position in the tool.

mass
DVA mass
DVA
physicalmodel

CHATTER SUPPRESSION METHOD OF ISCAR ANTI-VIBRATION TOOLS

Chatter Suppression Method of
ISCAR's Anti-Vibration Tools

3

mass

The tuning procedure is performed by experimental modal analysis as shown in the figure below.
A modal hammer is used for applying and measuring impact forces and an accelerometer is usedfor measuring the resulting acceleration. Using these signals, the Frequency Response Function(FRF) which reflects the tool dynamic flexibility is obtained.
The FRF of ISCAR's anti-vibration tools may be compared to those of conventional ones
without DVA at the same overhang length – see figure below. Due to the high damping,
ISCAR'S anti-vibration tools have relatively a very low FRF peak magnitude.
20

FRF (μm/N)

CHATTER SUPPRESSION METHOD OF ISCAR ANTI-VIBRATION TOOLS
4

A mechanism is designed to preload the elastomers and therefore to modify the stiffness oftheir equivalent spring. Modification of the spring stiffness causes a change of the DVA naturalfrequency. The DVA system is tuned such that its natural frequency is brought close to that ofthe tool without DVA. This is done in order to introduce a phase shift between the tool and theDVA mass vibration, eventually causing attenuation of the oscillation amplitude of the tool.

18Tool without DVA

16Tool with turned DVA

141210864
20200

400600800 1000 1200 1400 1600 1800f (Hz)The border between a stable cut and an unstable one can be demonstrated in the planeof depth of cut (ap) and spindle speed and it is known as the Stability Lobe Diagram (SLD).
The SLD can be used to find the machining parameters that result in the maximum chatter-freematerial removal rate. The SLD can be obtained using a tool FRF and machining conditions.

ISCAR

Tool stiffness and mounting rigidity also affect the FRF and the stability limit of the tool.
Increasing the mentioned stiffness will cause improvement in the FRF and stability limit.

Conventional tool - without DVA

Conventional tool - with DVA

3.0

3.0

Chatter

2.0

2.0

1.5

ap. lim (mm)2.5

ap. lim (mm)ap. lim (mm)

Chatter
2.51.5

1.0

1.0

0.5

0.50500

1000

1500

2000

2500

3000

Spindle speed (rpm)

3500

4000

4500

5000

5000

0Stable
500

1000

1500

2000

2500

3000

Spindle speed (rpm)

3500

4000

4500

5000

CHATTER SUPPRESSION METHOD OF ISCAR ANTI-VIBRATION TOOLS

Decreasing the FRF peak magnitude, via increasing the tool damping, yields anenhancement in its stability limit. The SLD’s of ISCAR's anti-vibration tools and corresponding
conventional tools are compared in the figure below, where ISCAR's anti-vibration
tools show a considerably higher stability limit than that of conventional tools.

5USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES
6User Guide
WHISPERLINE – Vibration Damping
Tools for Lathe Machines
Vibrations are one of the most common problems that limit machining. In more severecases an operation becomes impossible due to excessive vibrations. In other cases,
machining is possible, but at the cost of reduced cutting conditions. Additional effectsof vibration include worse surface quality and a decrease in insert tool life.
Using ISCAR's WHISPERLINE tools can greatly reduce the above problems, leading
to a substantial increase in productivity, surface finish and insert tool life.
Vibration issues occur more drastically at large overhangs where, in many cases, machining
becomes impossible with conventional tools. However, improvements in all machining
parameters can be achieved also at shorter overhangs by implementing WHISPERLINE tools.

Availability of Tools Per Shank Diameter and Machining Depth
14D*
12D*
10D
OVERHANG
7D

4D
16(0.625")20(0.75")25(1")

32(1.25")40(1.5")50(2")

60(2.5")

Diameter
WHISPERLINE (Steel)

ISCARWHISPERLINE (Carbide)*Upon request

80(3.15")

Following all the recommendations below (as closely as possible)
will greatly improve WHISPERLINE tool performance.
1 Bar D-min parameter should be 10%- 20% smaller than themachined bore to allow for chip evacuation and deflection.

Example: For a bore diameter of 80 mm (3") it is recommended to use a 60 mm (2.5")
bar rather than a 80 mm (3") bar. Although the 80 mm bar is stiffer, the lack of spacefor chip evacuation will decrease the surface finish and can cause breakages.
2 Clamping stability is crucial! Please follow the guidelines below as strictly as possible:

a Increase clamping length as much as possible.
The minimum recommended length is 4 X bar diameter.
Clamping length

4XBD

USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES

Basic Considerations

7

USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES
8b Flat-bed lathe with a tool post provides higher rigidity compared to turretclamping. When using larger diameter bars, the moment exerted on theclamping tool (just by the bars weight) is increased dramatically.

Movement Created From Bar Weight
Nm3025151050

AV-D16-7

AV-D25-10

AV-D32-7

AV-D40-10

AV-D60-10

AV-D80-10

c Choose a machine that is in proportion to the tool size and overhang.
Use a flat bed lathe if possible.

Flat Bed Lathe

Turret Lathed You can employ several methods to decrease the negative effect of the moment:• Install a counterweight:

ISCAR• Both methods create forces in opposite direction to the bars weight andthus reduce the moment that is exerted on the tool post.
e Split sleeve vs screw.
Choose a tool post with peripheral and uniform clamping forces

3 Zero Setting:

Use the AV-set device (sold separately) to ensure center height of the cutting edge.

USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES• Work with the bar upside down:

9USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES
104 Shortening the bar:

In case the bar is too long for your machine or application, it is possible to shorten it.
Each bar has a red marking that shows the minimum length to which the bar can be shortened.

Bar Diameter

Maximum Length After Shortening

DCONMS (mm)OAL 7D (mm)OAL 10D (mm)16 (0.625")

100 (3.9")

Not Recommended

20 (0.75")

125 (4.9")

Not Recommended

25 (1")

158 (6.2")

255 (10")32 (1.25")

190 (7.5")

320 (12.5")

40 (1.5")240 (9.5")

410 (16")50 (2")305 (12")520 (20")60 (2.5")

380 (15")630 (25")

ISCARChoosing the correct insert can have a big influence on the overall success of vibration damping.
The main way the insert can improve the machining stability is by minimizing the cuttingforces. Following the guidelines below should be your first step to eliminate vibrations:
1 Choose an entry angle that is as close as possible to 90° to reduce the radial forces to a minimum.
75°

90°

45°

2 Choose the smallest insert head angle possible. This will reduceoverall cutting forces and increase the clearance.

55˚35˚80˚
60˚V

D

80˚TW

CS

R

3 Choose a small nose radius to reduce the cutting forces and to enable machining

in a lower depth of cut. (Depth of cut should be larger than the nose radius)

0.2(0.008)

1.2(0.047)

0.4(0.016)

4 Machining depth (ap) should be larger than the nose radius.

84USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES

Choosing the Correct Insert

11

USER GUIDE - WHISPERLINE VIBRATION DAMPING TOOLS FOR LATHE MACHINES
125 Use an insert with an overall positive geometry to reduce the cutting forces:

15º

13º

DO

11º

7ºPC

5ºB

6 Choose a positive top rake geometry:

7 Use an insert with a small honing size. This can usually be achieved bychoosing ground inserts and /or inserts with thin coating.

Small Honing

Big Honing

8 Avoid using wiper inserts. These types of inserts improve surface finish but

this is achieved at the expense of increasing the cutting forces

Each one of these steps reduces the cutting forces. You can use all or a combinationof some of them depending on the limitations of your application.

ISCAR0ºN

While many anti-vibration tools exist in the market for internal machining applications, ISCAR
is the only company that offers anti-vibration blades for external applications. The company’s
vast experience and unmatched designing skills have enabled ISCAR to produce an ingenious
damping mechanism that is small enough to be assembled onto blades and created theoptimal blade for a large range of overhangs. This unique ISCAR damping mechanism
consists of two plates connected by a screw and fixed to the blade by an O-ring.

Distance
between plates

DampingplatesO-RingCalibration screw

USER GUIDE - WHISPERLINE VIBRATION - DAMPING TURNING BLADES FOR LATHE MACHINES

Vibration Damping Turning Bladesfor Lathe Machines13

USER GUIDE - WHISPERLINE VIBRATION - DAMPING TURNING BLADES FOR LATHE MACHINES
14User Guide• RPM is one of the most important factors that affect vibrations. To maintain astable and controlled machining process, use constant RPM (G97).
• Each blade is pre-calibrated in laboratory conditions for an overhang of 100mm (3.94").
• Although the pre-calibration is suitable for a wide range of overhangs, sometimes fine-tuning
calibration is necessary, depending on the overhang and clamping rigidity of the machine.
• Before making fine tuning calibration, try to optimize the cutting conditions.

Fine Tuning Calibration• For shorter overhangs / more rigid clamping conditions, it is recommended toincrease the compression of the O-ring by rotating the calibration screw clockwise(make sure the distance between the damping plates increases).
• For longer overhangs / less rigid clamping conditions, it is recommended todecrease the compression of the O-ring by rotating the calibration screw counterclockwise (make sure the distance between the damping plates decreases).

• The fine-tuning resolution should be about a half-turn foreach 30mm (1.18") difference in the overhang.
• To restore the initial setup, use the distance between the damping plates imprinted on the blade.

For Longer Overhangs / Less
Rigid Clamping Conditions

Reduce distance

ISCAR

For Shorter Overhangs / More
Rigid Clamping Conditions

Increase distanceTHE STANDARDS INSTITUTION OF ISRAELCERTIFIEDEN

CERT
ICCC

THE STANDARDS INSTITUTION OF ISRAEL

SI
OHSAS
18001:2007

GYMANAGEM
ER

SIISO
50001

SYSTEM
ENT

THE STANDARDS INSTITUTION OF ISRAELD OHS SYFIEMSTE

THE STANDARDS INSTITUTION OF ISRAELTIFIED EMER
SIISO 14001:
2004

SAS 9100

TIFIED QM
ERSIISO 9001:
2008

S

S

TIFIED QM
ERTHE STANDARDS INSTITUTION OF ISRAEL

Quality Standard
ISCAR has been certified by the prestigious Standards Institution, as being in full complianceto ensure delivery of the finest quality goods. Quality control facilities include the metallurgicallaboratory, raw metal testing, an online testing procedure and a machining center for tool
performance testing and final product inspection.
Only the finest products are packaged for entry into ISCAR’s inventory.

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Reference Guide