Cutting insert and clamping arrangement therefor

A cutting insert with improved chip control and metal cutting capabilities and a toolholder with an improved clamping arrangement for use in combination therewith. The insert includes a first notch disposed in the insert body extending from the cutting end to the mounting end thereof. A top wall of the insert body has a forward section with a cutting edge, a middle section with a second notch extending across substantially the entire insert body and a rearward section. In one embodiment, the forward section of the insert body includes a chipbreaker. In another embodiment, the forward portion includes an advanced cutting material which defines a cutting edge. In yet another embodiment of the insert, the insert body top wall forward section defines the cutting edge and the insert body does not include a chipbreaker.

FIELD OF THE INVENTION 
The invention is directed to cutting inserts, especially metal cutting 
inserts with chip control and to a holder and clamp arrangement therefor. 
BACKGROUND OF THE INVENTION 
Cutting inserts are well known and a large percentage of them are of the 
throw away design. Such inserts are detachably clamped on a holder and 
then are discarded when they become dull or chipped. 
The inserts must be securely and accurately held in place within an insert 
holder during the cutting operation. This is especially true when the 
inserts are employed with numerically controlled machines which depend for 
accuracy upon an accurately located and firmly supported insert. When the 
inserts are of a substantial area, it is possible to fix the insert both 
accurately and firmly within the pocket of a toolholder by providing the 
insert with a central hole and the toolholder with a pin-type clamping 
device. In other cases, such inserts may be held in place by a top clamp. 
Examples of such holders are found in U.S. Pat. Nos. 3,754,309; 3,399,442 
and 3,762,005 and British Patent Specification No. 1,363,542. 
Several toolholding systems designed to work in cooperation with specific 
insert configurations are available in the metal cutting industry. One 
example of such a system is the TOP NOTCH brand toolholder and insert 
combination which is taught in U.S. Pat. No. 3,754,309 and which is 
manufactured and sold by Kennametal Inc., the assignee of the subject 
invention. This style of insert which is characterized by a diagonal notch 
is retained in a three-sided toolholder pocket by means of a clamp 
arrangement which engages both the notch in the insert and a diagonal 
recess in the toolholder body. 
Another example of a dedicated toolholder-insert system is marketed by the 
Greenleaf Corporation of Saegertown, Pa. This system employs a toolholder 
with a female "V" shaped seat in which an insert with a corresponding male 
"V" bottom is retained by a clamp adjustably held in the toolholder. Iscar 
Tools LTD., markets a similar toolholder with a female "V" shaped seat in 
which an insert with a corresponding male "V" bottom is retained. Iscar 
also a markets a toolholder with an insert-pocket wedge geometry having a 
female "V" shaped seat on the bottom and a male "V" shaped seat on the 
top. An insert with corresponding male and female "V" shaped bottom and 
top portions is passively retained in the pocket. No adjustable clamping 
arrangement is provided in the Iscar toolholder. 
The main object of metal machining is the shaping of the new work surface. 
Much attention is paid to the formation of the chip during the machining 
process, even though the chip is a waste product. This is because the 
consumption of energy occurs mainly in the formation and movement of the 
chip. Also, a chip can turn back into the workpiece and damage the 
machined finish thereof. This represents a significant problem, for 
example, in machining aluminum wheels in the automotive industry or when 
deep grooving, profiling or cutting off any material, including 
synthetics, that produce a continuous chip. Moreover, in certain metal 
cutting operations it has been found that the chips can cause excessive 
wear and/or damage to the clamping arrangement and/or toolholder. Thus an 
essential feature of any metalcutting operation is effective chip control. 
A principal class of chips is the discontinuous chip which has the 
practical advantage of being easily cleared from the cutting area. While 
some metals and alloys generate discontinuous chips during cutting 
operations, many do not. It is therefore very desirable to produce 
discontinuous chips during a cutting operation, regardless of the metal or 
alloy of the workpiece. 
It has been a common practice to place a mechanical chip breaking member 
between the insert and the clamp securing the insert to the tool in order 
to provide at least a degree of chip control during the cutting operation. 
This arrangement presents the obvious drawback of increasing the effective 
area necessary for metal cutting operations with a given tool. 
Because chip control is an important consideration in metal cutting 
operations, it has been a long standing objective in the art of metal 
cutting to develop improved chip control techniques for use with tools as 
well as improved designs for the cutting inserts. Among the improvements 
to the cutting insert are various chip control geometries which can be 
molded into the insert during manufacture. These geometries include 
various depressions and elevations on the surface of the insert. 
It is an object of the invention to provide an insert with improved chip 
control characteristics. 
It is another object of this invention to provide a method of manufacturing 
an insert incorporating advanced cutting tool materials and having 
improved chip control. 
It is still another object of this invention to provide an insert with 
improved metal cutting capabilities when machining, for example, 
nonferrous and abrasive materials or other materials, including synthetics 
that produce a continuous chip. 
It is yet another object of this invention to provide an improved chip 
control insert configured to cooperate with a clamping element of an 
insert toolholder. 
It is still another object of this invention to provide a toolholder with 
an improved clamping arrangement for use in combination with cutting 
inserts, chip control features and advanced cutting tool materials. 
SUMMARY OF THE INVENTION 
The invention provides both a cutting insert with a unique configuration 
that results in improved chip control and a metal cutting capabilities and 
a toolholder with an improved clamping arrangement for use in combination 
therewith. The improved clamping arrangement substantially eliminates chip 
erosion of the clamp elements and chip congestion about the clamping 
elements. 
The improved cutting insert comprises an insert body with a first and 
second mounting end. A pair of substantially parallel side walls extend 
between the first and second ends. A bottom wall is generally 
perpendicular to the side walls and includes means therein defining a 
first notch. The first notch is disposed in the insert body and 
substantially extends from the first end or cutting end to the second end 
or mounting end of the insert. A top wall of the insert body has a forward 
section, a middle section and a rearward section. The forward section in 
combination with the first or cutting end includes means defining a 
cutting edge disposed at a first elevation relative to the bottom wall of 
the insert body. The middle section includes means defining at least in 
part a second notch extending across substantially the entire insert body 
between the side walls. The bottom or trough of the second notch portion 
is disposed at a second elevation relative to the bottom wall. The 
rearward section is disposed at a third elevation relative to the bottom 
wall. The third elevation is less than the first elevation and greater 
than the second elevation. 
In one embodiment, the top wall forward section of the insert body can also 
include means defining a chipbreaker. The means defining the chipbreaker 
is formed during the manufacture of the insert as an integral portion of 
the insert body and is disposed at a fourth elevation relative to the 
bottom wall. This fourth elevation is greater than the first elevation. In 
another embodiment, the top wall forward portion means which defines the 
chipbreaker can further include means defining a slot adapted to receive 
partially therein an advanced metal cutting material such as, for example, 
a polycrystalline diamond material or a polycrystalline cubic boron 
nitride (CBN) material or a material of similar quality. The 
polycrystalline material is bonded to the top wall forward section of the 
insert body and the means defining the chipbreaker extends at least 
partially over the polycrystalline material. The polycrystalline material 
defines a cutting edge and the means defining the chipbreaker may define 
in part a curvilinear surface. In yet another embodiment of the insert, 
the insert body top wall forward section defines the cutting edge and the 
insert body does not include a chipbreaker. 
A cutting insert toolholder for use with the aforedescribed insert 
comprises a holder means having a first end, a second end, a top surface 
and a longitudinal mounting axis. The first end has a cutting insert 
receiving pocket formed therein. The pocket has one end wall means and a 
bottom wall means and is open on the other four sides. The bottom wall 
means includes means defining a first engaging means for the cutting 
insert. This engaging means extends parallel to the longitudinal mounting 
axis of the holder means. The top surface has a recess therein adjacent 
the insert receiving pocket. The recess is substantially perpendicular to 
the longitudinal mounting axis. A clamp element includes a pair of 
dependent legs. One of the legs defines a second engaging means for 
engaging the cutting insert. The other of the legs of the clamping element 
is adapted to cooperate with the recess in the holder means top surface. 
Means on the holder means engage the clamp element and are adjustable 
relative thereto for urging the clamp element toward the holder means. 
When so urged, the clamp element presses one of the legs into the recess 
and the other of the legs into engagement with the cutting insert for 
fixedly clamping the cutting insert in the pocket. The first engaging 
means in the bottom wall of the insert pocket inhibits lateral movement of 
the cutting insert relative to the longitudinal mounting axis. The second 
engaging means inhibits axial movement of the cutting insert relative to 
the longitudinal mounting axis. 
Preferably, the means defining the first engaging means for the cutting 
insert which extend parallel to the longitudinal mounting axis comprises a 
seat having an inverted V-shaped portion on which the cutting insert is 
mounted. When the insert is mounted in the toolholder pocket, the insert 
toolholder is dimensioned so that the first end thereof is of a 
predetermined width which is less than the remaining portion of the 
toolholder. Preferably, this predetermined width of the first end of the 
toolholder is less than the width of the cutting insert cutting edge in 
order to facilitate presentation of the insert cutting edge to a 
workpiece. The clamp element and its pair of dependent legs is preferably 
dimensioned so as to have a limited elevational profile. This limited 
profile minimizes the possibility of damage being inflicted on the clamp 
element by the chips coming from the workpiece. Additionally, this limited 
profile minimizes the damage which can be inflicted on the workpiece 
finish by chips curling back against it by permitting the unobstructed 
flow of chips away from the workpiece and across the top of the insert and 
clamp combination of this invention. Moreover, the limited profile of the 
clamp element substantially eliminates chip congestion at and about the 
clamp element.

DETAILED DESCRIPTION OF THE INVENTION 
A cutting insert with improved chip control features and metal cutting 
capabilities is isometrically shown in FIG. 1 and generally indicated by 
the reference character 10. The insert incorporates a hard cemented 
carbide substrate and a cutting edge formed from an advanced cutting tool 
material. The insert 10 comprises an insert body 12 having a first end 14 
and a second end 16. The first end 14 is generally referred to as the 
cutting end and the second end 16 as the mounting end. A pair of 
substantially parallel walls 18 and 20 extend between the first and second 
ends. It will be noted, however, that the cutting end 14 has a slightly 
cylindrical shape on whole. However, while the cutting edge can be a 
curvilinear edge which is presented to a workpiece, the cutting edge can 
be of a geometry appropriate for deep grooving, profiling, parting or 
cutting operations. It should be appreciated that the specific cutting 
application for which the insert is to be used dictates the geometry of 
the cutting edge and the cutting end 14 of the insert body. A bottom wall 
22 is generally perpendicular to the side walls 18 and 20. The bottom wall 
22 includes therein means 24 defining a first notch disposed in the insert 
body 12. The notch means 24 extends from the first end 14 to the second 
end 16 of the insert body. The notch 24 defines an inverted V-shaped 
trough along the bottom wall 22 of the insert body. The insert body 12 
includes a top wall portion 26 having a forward section 28, a central or 
middle section 30 and a rearward section 32. The forward section 28, in 
combination with the first end 14 of the insert body, define a cutting 
edge 34. The cutting edge 34 is disposed at a first elevation with respect 
to the bottom 22 of the insert body. The middle section 30 includes means 
36 defining at least in part a second notch extending substantially across 
the insert body from first side 18 to the second side 20. The bottom or 
trough portion of the notch 36 is at a second elevation relative to the 
bottom wall 22 of the insert body. The rearward section 32 of the top wall 
26 of the insert body is disposed at a third elevation relative to the 
bottom wall 22. The rearward section 32 is generally planar and 
perpendicular to the sides 18 and 20 of the insert body. The rearward 
section 32 of the top wall 26 is at a third elevation which is less than 
the first elevation and greater than the second elevation. 
The insert body itself is manufactured according to techniques well known 
in the art of metalcutting insert manufacture. The insert body is 
preferably a hard cemented carbide such as tungsten or titanium carbide or 
tungsten titanium carbide, or a cermet or a sialon material, for example. 
In the embodiment of FIGS. 1 through 5, the top wall 26 forward section 28 
of the insert body 12 includes means 38 defining a chipbreaker. The 
chipbreaker means is disposed at a fourth elevation relative to the bottom 
22 of the insert body, which elevation is greater than the first elevation 
defined between the cutting edge 34 and the bottom 22 of the insert body. 
The chipbreaker means 38 further includes means 40 defining a slot 
therein. In this embodiment of the insert of this invention, a 
polycrystalline diamond material or a polycrystalline cubic boron nitride 
(CBN) material or a material of similar quality (hereinafter referred to 
as polycrystalline material) is bonded to the top wall forward section 28 
of the insert body. When used in combination with the chipbreaker as 
shown, the slot 40 of the chipbreaker 38 is dimensioned so as to receive 
therein the rearward portion of the polycrystalline material which is 
bonded to the top surface 28 of the insert body. This polycrystalline 
material 42 is manufactured separately from the insert body and later 
bonded thereto by, for example a brazing technique. In FIG. 1, both the 
cutting edge 34, defined by the polycrystalline material 42, as well as 
the chipbreaker means 38, are shown to have curvilinear edges or faces 
which are presented to a workpiece. It should be appreciated that the 
specific cutting application for which the insert is to be used dictates 
the geometry of both the cutting edge 34 and the chipbreaker means 38. 
The rear wall 16 of the insert body 12 can be made so as to have a 
clearance angle which facilitates mounting of the insert and retention 
thereof in the toolholder. Additionally, the intersecting edge of the 
insert body bottom portion 22 side walls 18 and 20 and rear end 16 can be 
beveled as at 44. This bevel 44 also enhances the ease of mounting and 
securing the insert within the toolholder. 
A toolholder for use with the insert described above is generally indicated 
by the reference character 50. The toolholder 50 is in the form of a 
bar-like steel member 52 adapted for being clamped in a tool support of 
any suitable type. The holder means 50 has a first end 54, a second end 
56, a top surface 58 and a longitudinal mounting axis shown at 60. The 
first end 54 has a cutting insert receiving pocket 62. The receiving 
pocket has one end wall means 64 and a bottom wall means 66. The receiving 
pocket 62 is open on the other four sides. The bottom wall means 66 
includes means 68 defining a first engaging means. The engaging means 68 
extends parallel to the longitudinal mounting axis along substantially the 
entire bottom wall 66 of the insert pocket 62. The engaging means 68 on 
which the cutting insert 10 is mounted is preferably an inverted V-shaped 
portion. The inverted V-shaped portion, or male V, 68 mates with the 
female V-shaped portion 24 on the bottom wall 22 of the insert body 12. 
The combined mating means 68 and 24 cooperate to insure axial alignment 
along the longitudinal mounting axis 60 of the toolholder 50. The end wall 
64 of the pocket 62 is dimensioned so as to cooperate with the clearance 
angle of the end wall 16 of the insert body 12. 
The top surface 58 of the holder 50 includes a recess 70 therein. The 
recess 70 is adjacent the insert receiving pocket 62 and is substantially 
perpendicular to the longitudinal mounting axis 60. 
A clamp element 72 has a pair of dependent legs 74 and 76. One of the legs 
76 defines a second engaging means which cooperates with the notch 36 in 
the top wall 26 of the insert body 12. The other of the legs 74 is adapted 
to cooperate with the recess 70 in the top surface 58 of the holder 50. 
Means are provided on the holder 50 to engage the clamp element and urge 
the clamp element toward the holder means. This holding and engaging means 
comprise a clamp screw 78 which extends through a hole 80 in the clamping 
element 72 which is between the legs thereof and into a threaded hole 82 
in the top surface 58 of the toolholder 50. When the insert is placed in 
the pocket, the clamp member is put in position, and screw 78 is tightened 
up, and the insert is pressed firmly against the bottom wall 66 of the 
insert pocket 62 while simultaneously being drawn toward end wall 64. The 
insert is thus fixedly clamped in the pocket in the holder and is 
accurately located therein by being urged against the walls of the pocket. 
As indicated above, alignment of the insert relative to the toolholder is 
effected by a combination of the engaging means 68 on the bottom wall of 
the pocket 62 and the means 24 defining the notch in the bottom wall of 
the insert body. The configuration of the toolholder's insert receiving 
pocket in combination with the configuration of the insert body results in 
a stable and repeatable insert location for presentation of the insert's 
cutting edge to the workpiece. Further, the infinitely variable changes in 
the resultant forces acting on the cutting insert do not adversely effect 
the location of the insert's cutting edge during metal cutting operations. 
Turning now to FIGS. 6 and 7, there is shown a plan view and a side view 
respectively of a first alternative embodiment of the cutting insert of 
this invention. Basically, the alternative embodiment does not incorporate 
the chipbreaker 38 shown in the embodiment of FIGS. 1 through 5. The 
insert 110 comprises an insert body 112 having a first end 114 and a 
second end 116. The first end 114 is generally referred to as the cutting 
end and the second end 116 as the mounting end. A pair of substantially 
parallel walls 118 and 120 extend between the first and second ends. It 
will be noted, however, that the cutting end 114 has a slightly 
cylindrical shape on whole. However, while the cutting edge can be a 
curvilinear edge which is presented to a workpiece, the cutting edge can 
be of a geometry appropriate for deep grooving, profiling, parting or 
cutting operations. It should be appreciated that the specific cutting 
application for which the insert is to be used dictates the geometry of 
the cutting edge and the cutting end 114 of the insert body. A bottom wall 
122 is generally perpendicular to the side walls 118 and 120. The bottom 
wall 122 includes therein means 124 defining a first notch disposed in the 
insert body 112. The notch means 124 extends from the first end 114 to the 
second end 116 of the insert body. The notch 124 defines an inverted 
V-shaped trough along the bottom wall 122 of the insert body. The insert 
body 112 includes a top wall portion 126 having a forward section 128, a 
central or middle section 130 and a rearward section 132. The forward 
section 128, in combination with the first end 114 of the insert body, 
define a cutting edge 134. The cutting edge 134 is disposed at a first 
elevation with respect to the bottom 122 of the insert body. The middle 
section 130 includes means 136 defining at least in part a second notch 
extending substantially across the insert body from first side 118 to the 
second side 120. The bottom or trough portion of the notch 136 is at a 
second elevation relative to the bottom wall 122 of the insert body. The 
rearward section 132 of the top wall 126 of the insert body is disposed at 
a third elevation relative to the bottom wall 122. The rearward section 
132 is generally planar and perpendicular to the sides 118 and 120 of the 
insert body. The rearward section 132 of the top wall 126 is at a third 
elevation which is less than the first elevation and greater than the 
second elevation. 
In this embodiment of the insert of this invention, a polycrystalline 
diamond material is bonded to the top wall forward section 128 of the 
insert body. This polycrystalline material 142 is manufactured separately 
from the insert body and later bonded thereto by, for example a brazing 
technique. The cutting edge 134, defined by the polycrystalline material 
142 has a curvilinear edge which is presented to a workpiece. It should be 
appreciated that the specific cutting application for which the insert is 
to be used dictates the geometry of the cutting edge 134. 
The rear wall 116 of the insert body 112 can be made so as to have a 
clearance angle which facilitates mounting of the insert and retention 
thereof in the toolholder. Additionally, the intersecting edge of the 
insert body bottom portion 122 side walls 118 and 120 and rear end 116 can 
be beveled as at 144. This bevel 144 also enhances the ease of mounting 
and securing the insert within the toolholder. 
A second alternative embodiment of the invention is shown in FIGS. 10 and 
11. Basically, the alternative embodiment does not incorporate the 
chipbreaker or the polycrystalline material shown in the embodiments of 
FIGS. 1 through 7. The insert 210 comprises an insert body 212 having a 
first end 214 and a second end 216. A pair of substantially parallel walls 
218 and 220 extend between the first and second ends. It will be noted, 
however, that the cutting end 214 has a slightly cylindrical shape on 
whole. A bottom wall 222 is generally perpendicular to the side walls 218 
and 220. The bottom wall 222 includes therein means 224 defining a first 
notch disposed in the insert body 212. The notch means 224 extends from 
the first end 214 to the second end 216 of the insert body. The notch 224 
defines an inverted V-shaped trough along the bottom wall 222 of the 
insert body. The insert body 212 includes a top wall portion 226 having a 
forward section 228, a central or middle section 230 and a rearward 
section 232. The forward section 228, in combination with the first end 
214 of the insert body, define a cutting edge 234. The cutting edge 234 is 
disposed at a first elevation with respect to the bottom 222 of the insert 
body. The middle section 230 includes means 236 defining at least in part 
a second notch extending substantially across the insert body from first 
side 218 to the second side 220. The bottom or trough portion of the notch 
236 is at a second elevation relative to the bottom wall 222 of the insert 
body. The rearward section 232 of the top wall 226 of the insert body is 
disposed at a third elevation relative to the bottom wall 222. The 
rearward section 232 is generally planar and perpendicular to the sides 
218 and 220 of the insert body. The rearward section 232 of the top wall 
226 is at a third elevation which is less than the first elevation and 
greater than the second elevation. 
As indicated above, in this embodiment of the insert, a polycrystalline 
material is not bonded to the top wall forward section 228 of the insert 
body. Rather, in this embodiment, the cutting edge 234 is defined by the 
forward section 228 of the insert body. The cutting edge can be a 
curvilinear edge which is presented to a workpiece or the cutting edge can 
be of a geometry appropriate for deep grooving, profiling or cutting 
operations. It should be appreciated that the specific cutting application 
for which the insert is to be used dictates the geometry of the cutting 
edge 234. 
The rear wall 216 of the insert body 212 can be made so as to have a 
clearance angle which facilitates mounting of the insert and retention 
thereof in the toolholder. Additionally, the intersecting edge of the 
insert body bottom portion 222 side walls 218 and 220 and rear end 216 can 
be beveled as at 244. 
A third alternative embodiment of the invention provides a modification of 
the cutting insert shown in FIGS. 1 through 4 wherein the insert does not 
include the polycrystalline material. In this embodiment which is not 
illustrated herein, but which can be readily appreciated in view of the 
second alternative embodiment as shown in FIGS. 10 and 11, the insert body 
is of the configuration described in association with FIGS. 1 through 5 
with the exception that the means 40 defining the slot in which the 
polycrystalline material is mounted as well as the polycrystalline 
material are not present. In this embodiment, the cutting edge is defined 
by the forward section 28 of the insert body. The cutting edge can be a 
curvilinear edge which is presented to a workpiece as shown in the Figures 
or, for example, the cutting edge can be of a geometry appropriate for 
deep grooving, profiling or cutting operations. It should be appreciated 
that the specific cutting application for which the insert is to be used 
dictates the geometry of the cutting edge. 
Turning now to FIGS. 8 and 9, a plan view of the toolholder of this 
invention with the alternative embodiment of the cutting insert as shown 
in FIGS. 6 and 7 retained therein is shown in a plan and side view 
respectively. As can be clearly seen in FIGS. 8 and 9, the first end 54 of 
the toolholder 50 is of a dimension which is significantly less in width 
than the remainder of the toolholder body. As can clearly be seen in the 
plan view, the cutting edge of the insert is of a greater width than the 
width of the insert body and the toolholder pocket 62. This configuration 
provides clearance between the toolholder and the workpiece when engaged 
in cutting operations. A particularly unique feature of the combined 
cutting insert and toolholder is the low profile of the clamping element 
with respect to the cutting edge of the insert. When used in combination 
with the chipbreaker design shown in FIGS. 1 through 4, the clamp element 
is substantially protected from chips coming from the workpiece. 
Additionally, the extremely low profile of the clamping element relative 
to the cutting edge of the insert minimizes, if no substantially 
eliminating, the adverse consequence of a chip being forced back onto the 
workpiece by contact with a clamping element. It can be seen that a chip 
is unhampered as it is removed from the workpiece and can travel 
rearwardly away from the cutting edge of the insert. Thus chip congestion 
and chip build up in the clamping area is substantially eliminated. 
It has been found that a metal cutting insert incorporating the features 
described herein when used in combination with the toolholder provided 
therefor renders significantly improved chip control over a wide variety 
of metalcutting conditions. What has been described is an improved cutting 
insert and toolholder clamping arrangement for use therewith.