JPS6210763B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to cutting tools for processing chip forming materials. More specifically, the present invention includes:
The present invention relates to a cutting insert having a particularly advantageous chip control geometry at relatively high feed rates.

Conventional chip control inserts have exhibited performance problems when used at relatively high feed rates, such as speeds of 0.020 inches per revolution or higher. These problems are caused by chip collisions caused by the cutting process, where the chip collides with one or more of the prior art insert surfaces, resulting in damage to the cutting insert material. This causes excessive friction and wear leading to premature wear and/or failure.

Examples of prior art disclosing chip control cutting inserts with geometries that impede chip flow at higher feed rates include: US Pat. No. 4,288,179 to inventor KRUGER; US Pat. No. 3,395,434 to inventor Wirfelt; and US Pat. No. 3381349 is US Pat. No. 3,213,716 to Inventor Getts.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a cutting tool that utilizes a chip control geometry that is useful at relatively high feed rates and that overcomes the aforementioned problems associated with the prior art.

The invention, in its preferred form, is embodied as an indexable cutting insert for processing chip-forming materials, the insert having improved chip control when used at relatively high feed rates. A land extends around at least one chip breaker or rake face of the insert adjacent the insert cutting edge and cutting corner. Connected to the land is a first sloped surface or tip control surface extending downwardly from the peripheral land of the insert. The first bevel is broken at each cutting corner of the insert at a corner control plateau or surface to prevent damage caused by chip concentration behind the active cutting corner. A second ramp or control surface is adjacent to the first ramp and extends downwardly and inwardly from the first ramp, preferably at an angle less than the slope angle of the first ramp. A third ramp or control surface is formed at each corner area of the insert between the inner boundary of the corner control surface and the second slope.
connect with the slope of

The combination of ramps and control surfaces provides relatively smooth chip flow at relatively high feed rates, thereby reducing cutting forces and wear.

The combined shape of the various insert surface portions also allows for better control of the chip at relatively high feed rates by forming a chip with a convex cross section.

Polygonal inserts designed according to the present invention will exhibit a longer life span as their chip handling capacity will more effectively resist cutting edge cratering and breakage.

These and other objects and features of the invention will become apparent from the detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.

To better point out the advantages of the present invention, reference is first made to FIGS. 1-4, which illustrate various chip control configurations of the prior art. Prior art inserts having the chip control geometries shown in FIGS. Tip on shoulder (number 102 in figure 1, number 20 in figure 2)
4. In Fig. 4, it is curled and directed by number 404). Such inserts are suitable at relatively low feed rates, such as about 0.020 inches per revolution or less. However, such a shoulder becomes undesirable at high feed rates resulting in thick chips. Impaction of the thick chips with these shoulders causes excessive friction (and therefore heat) and wear. Excessive heat is
This causes a chemical reaction between the chip on the work surface and the insert material (such a reaction is also known as a built-up edge). Accordingly, such chip deflecting shoulders wear rapidly under severe feed rate conditions, thereby reducing the life of the insert.

The prior art insert of FIG.
8 and a land 302, and the land 302 is followed by an inclined surface 304 and a flat inner floor surface 306. Although the insert of FIG. 3 is more effective at high feed rates, the insert is placed in a negative attitude (i.e., face 306 Cutting blade 300
Since the chip must be mounted at an angle (upwardly relative to the chip), a friction-generating surface is still present and disturbs the flow of the chips.

A disadvantage of the value of using a tip control insert designed according to FIGS. 2-4 at high feed rates results from the use of an internal cup-shaped recess within the nose radius of the insert. During the material cutting process, the chip is forced into such a recess and at the same time tries to curl at 90 degrees to the feed direction. Due to this compound movement of the tip, the tip control profile of the insert is subjected to excessive forces caused by attempting to bend a relatively thick tip in two different directions at the same time. Such excessive force in the nose radius region makes the trailing edge of the nose radius susceptible to breakage at the effective cutting corners of the insert, thus shortening the life of the insert.

The cutting tools of the present invention, such as the inserts shown in FIGS. 5-7, have rake face geometries that overcome the aforementioned problems of prior art inserts used at relatively high feed rates. Referring to FIGS. 5-7, the cutting insert 10 has, for example, generally square top and bottom chip breaker surfaces which are generally perpendicular to the plane containing the chip breaker surfaces, i.e. side walls 7. are connected. a land area 1 in which four indexable cutting edges extend around the flank face 7 and the chip breaker face;
It is composed of the intersection of As can be seen in Fig. 6, the angle a5 between the land 1 and the flank surface 7
is approximately 90°.

A first sloped surface or control surface 2a extends downwardly from the land adjacent to the inner boundary of the land 1 at an angle a1 to the plane of the chip breaker face and extends between the cutting corners of the insert and has a narrow portion 2a. continue from the control surface 2a and extend around each rounded cutting corner of the insert 10.

A second ramp, or control surface 3, adjoins the inner boundary of each ramp 2a and extends downwardly from the ramp 2a at an angle a2 to the plane of the chip breaker surface; It ends at a floor surface 6 that is approximately parallel to the plane. Insert 10 may be tightened into a cutting position using central attachment point 11 in a variety of known manners.

At each cutting corner of the insert, bevel 2
a is partially interrupted by a recessed plateau, namely a corner control surface 4, which in this embodiment is approximately parallel to the chip breaker surface. The inner boundary of each corner control surface 4 connects to the control surface 3 via a third slope, or control surface 5, extending downwardly at an angle a3 to the plane of the chip breaker surface.

The width L1 of land 1 is approximately 0.381 mm (0.015 inch)
in the range of 0.889 mm (0.035 inch), preferably about 0.457 mm (0.018 inch) to 0.762 mm (0.030 inch).
inches) to provide sufficient corner size to resist deformation.

Slope 2 and slope 2a range from about 10° to 20°,
It preferably extends downwardly at an angle a1 in the range of about 15 DEG to 20 DEG to provide a smooth, drag-free chip flow path. The majority of the chips resulting from the relatively large depth of cut then proceed down a downwardly extending slope 3 at an angle a2 in the range of about 5° to 15°, preferably in the range of about 5° to 10°. Angle a1 is angle a
It is desirable that it be larger than 2. In such a configuration, the bevel 3 provides little or no resistance to chip flow, unlike the prior art flat bottomed insert of FIG. 3 discussed above. Even if crater wear were to occur on the bevel 3, the bevel 3 is spaced far enough inward of the insert cutting edge that no deleterious consequences affecting the life of the insert would occur.

Although the inserts of FIGS. 5-7 must be installed in a negative rake position, the disclosed configuration allows the chips to flow smoothly with minimal resistance over surfaces 1, 2, and 3, and also allows the chips to flow smoothly over surfaces 1, 2, and 3. curls and breaks due to its inherent thickness and mechanical properties. The configuration of surfaces 1, 2 and 3 thereby overcomes the shoulder and floor friction problems encountered with prior art designs. This result is obtained because, after the chip has passed through the land 1, it encounters slopes 2, 3 which are positively oriented (i.e. inclined downwards from the plane of the feed direction).

The innermost boundary of the slope 2a is at a distance H1 from the plane of the land 1. Distance H1 is approximately 0.101mm (0.004
inch) to 0.254 mm (0.010 inch), preferably approximately 0.101 mm (0.004 inch) to 0.202 mm
(0.008 inch) range. The innermost boundary of the slope 3 is at a distance H2 from the plane of the land 1. Distance H2 ranges from approximately 0.3048 mm (0.012 inch) to a maximum depth limited primarily by the required diameter of the mounting hole 11, preferably approximately 0.3048 mm (0.012 inch).
It ranges from 0.508 mm (0.020 inch). Chips are concentrated near the nose radius of the cutting corner,
To overcome the above-mentioned problem of the resulting high pressures, a pedestal or corner control surface 4 followed by a beveled surface 5 is placed inside each insert cutting corner. The control surface 4 is at a depth H3 from the plane of the land 1. Depth H3 is 1/ of depth H1
It is desirable that it be about 2. The ramp 5 extends downwardly from the inner boundary of the control surface 4 at an angle a3 in the usable range of about 10 DEG to 25 DEG, preferably in the range of about 15 DEG to 20 DEG. With this configuration, stresses are reduced in the area of the cutting corners. Another advantage of corner control surfaces is the ability to provide good chip control at relatively shallow depths of cut. The control surface 4 deflects the chip and breaks it when the depth of cut is mostly directed towards the control surface 4. Beyond this depth of cut, the chips flow freely due to the configuration of the surfaces 2, 3. Such free flow, together with the action of the corner control surfaces 4, creates a barrel-shaped or convex and somewhat brittle chip which facilitates breaking. The length dimension L2 (FIG. 5) is determined by the radius of curvature of the cutting corner, and L2 is preferably in the range of about 1 to 1.5 times such radius.

FIG. 8 shows a modified configuration of the land surface 1' intersecting the flank surface 7 at an obtuse angle a5' (i.e., the land 1' intersects the flank surface 7 at an obtuse angle a5').
4 indicates that the cutting edge is inclined downward toward the cutting edge. This variant is advantageous in applications requiring greater cutting edge strength, for example when machining hardened materials. Angle a5 is approximately 90° to 120°
The angle is preferably in the range of about 90° to 100°.

FIG. 9 shows yet another variant of the embodiment of FIGS. 5 to 7, in which the pedestal or control surface 4' of each corner extends downwardly at an angle a6 to the plane of the chip breaker surface. ing. The angle a6 is selected to be smaller than the angle a1 of the first slope 2 (the seventh
figure). Because of the downward slope, the corner control surface 4' provides less resistance to free flowing chips in the insert cutting corner area.

A triangular insert designed in accordance with the principles of the present invention is shown in FIGS. 10 and 11. For standard triangular inserts tested at relatively severe feed rates of 0.508 mm (0.020 inch) per revolution or more, the insert 20 with conventional mounting holes 29 has a land 23 that is preferably is about
0.457 mm (0.018 inch) wide with flank 22
intersects at an angle of about 90°, thereby cutting edge 21
Configure. The first slopes 24A, 24B are approximately below the plane of the land 23 from the inner boundary of the land 23.
It extends downwardly at an approximately 15° angle to an inner boundary located at 0.1524 mm (0.006 inch). The second slope 27 extends from the inner boundary of the slope 24A to the land 23.
and extends downwardly at an angle of approximately 7° to a floor surface 28 located at a depth of approximately 0.016 inches below the plane of the plane. At each corner, the base 25
intercepts slope 24B at a depth of approximately 0.0762 mm (0.003 inch) below the plane of land 23. The third slope 26 extends downwardly at an angle of about 20 degrees and connects the inner boundary of the platform 25 and the slope 27.

The invention has been described with respect to preferred embodiments solely for purposes of illustration and without excluding variations that may be obvious to those skilled in the art. For example, the various control surfaces and slopes described above may be connected tangentially in such a way that the intersections of the various surfaces eliminate chip collision barriers.
It may be arcuate instead of flat. The invention is to be limited only by the scope of the claims that follow.

[Brief explanation of the drawing]

1-4 illustrate cross-sectional views of various prior art chip control geometries used in the chip breaker or rake face of known cutting inserts. Fifth
The figure is a perspective view of an insert designed in accordance with the principles of the present invention. FIG. 6 is a sectional view taken along line 6--6 in FIG. 5. FIG. 7 is a sectional view taken along line 7-7 in FIG. 5. FIG. 8 shows a sectional view of the first variant embodiment. FIG. 9 shows a sectional view of the second variant embodiment. FIG. 10 is a plan view of a modified cutting insert designed in accordance with the principles of the present invention. FIG. 11 is a sectional view taken along line 11-11 in FIG. 10. 100,200,400...cutting blade, 102,2
04,404...shoulder, 308...flank surface, 302
... Land, 10 ... Cutting insert, 7 ... Side wall or flank, 1 ... Land area, 3, 27 ...
...Second slope, 11...Central mounting hole, 4...Corner control surface, 5, 26...Third slope, 2, 2a
...First slope, 1'...Land surface, 4'...Corner control surface, 20...Insert, 23...Land, 24A, 24B...First slope, 27...Second slope, 25... table surface, 28... floor surface.

Claims (1)

[Scope of Claims] 1. A polygonal surface having opposing top and bottom surfaces lying on substantially parallel planes and a polygonal circumferential surface formed by side surfaces substantially perpendicular to the planes and joined at polygonal cutting corners. In the cutting insert having a rectangular body, at least one of the top surface and the bottom surface extends continuously around the entire circumference of the polygon,
and a substantially flat land that intersects on each side to form a peripheral cutting edge extending between the cutting corners; a generally flat first slope extending downwardly at a first angle relative to the plane; and a second substantially flat slope extending downwardly from the inner boundary of the first slope at a second angle relative to the plane. a beveled surface; and a generally planar corner control surface each located only at each cut corner so as to block a portion of the first bevel and reduce the width of the first bevel at each cut corner area; Set the inner boundary of the corner control surface to the second
a substantially flat third slope connecting to the slope of the slope and terminating the intersection of the first slope and the second slope at each cutting corner region. 2. The cutting tool of claim 1, wherein the corner control surface extends substantially parallel to the plane. 3. The cutting tool according to claim 2, wherein the land extends substantially parallel to the plane. 4. The cutting tool according to claim 2, wherein the land intersects the flank surface at an obtuse angle. 5. The corner control surface extends downwardly from its intersection with the first slope at an angle less than the first angle relative to the plane of the chip breaker surface. Cutting tools. 6. The cutting insert according to claim 1, wherein the land is substantially perpendicular to the side surface. 7. The cutting insert according to claim 2, wherein the land extends inward from the cutting edge by a distance of about 0.381 mm (0.015 inch) to 0.889 mm (0.035 inch). 8 The first slope is 0.101 below the plane containing the land.
Claim 2, characterized in that it extends downwardly at a first angle of about 10° to 20° to intersect with a second slope of about 0.004 inch to 0.254 mm (0.010 inch). Cutting inserts as described in Section. 9 The second slope shall be extended to a distance of at least 0.3048 mm (0.012 inch) below the plane containing the land.
3. A cutting insert according to claim 2, wherein the cutting insert extends downwardly at a second angle of the order of 15° to 15°. 10 Each corner control surface is 0.0508 mm (0.002 inch) to 0.1270 mm below the plane containing the land.
The cutting insert according to claim 2, wherein the cutting insert intersects the first slope at a distance of about (0.005 inch). 11. The cutting insert according to claim 2, wherein each of the third slopes extends downwardly at an angle of about 10° to 25° with respect to the parallel planes of the top and bottom surfaces. 12 Land is 0.457mm (0.018 inch) from the cutting edge
the first slope extends inwardly at a distance of approximately 15° to intersect with the second slope approximately 0.152 mm (0.006 inch) below the plane containing the land; The slope of 2 is below the plane containing the land.
extending downwardly at a second angle of about 7° to a distance on the order of 0.406 mm (0.016 inch), each control surface intersects the first slope about 0.0762 mm (0.003 inch) below the plane containing the land; 3. The cutting insert according to claim 2, wherein each of the slopes of 3 extends downwardly at an angle of about 20 degrees with respect to parallel planes of the top and bottom surfaces.