Chip breaker pocket
By designing cutting inserts with recesses of rotary angle chip breakers, the problem of chips being difficult to break and easy to tangle in hole finishing tools is solved, and the effective curling and backward flow of chips is achieved, and processing efficiency and product quality are improved.
Patent Information
- Application Number
- CN202311485218.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-09
- Publication Date
- 2025-05-13
AI Technical Summary
When existing hole finishing tools process holes in workpieces, chips are difficult to break and tend to tangle, and may get stuck at the bottom of the hole and scratch the workpiece.
A hole finishing tool is designed, which includes a handle, a body and a plurality of cutting inserts. Each cutting insert has a cutting edge and a chip breaker pocket, the chip wall of the chip breaker pocket is arranged at a rotation angle relative to the cutting edge, with a rotation angle between 0° and 50°, for controlling the backward flow of the chips.
通过该设计，切屑能够有效地卷曲并向后流动到工件上，增加切屑的塑性变形，提高切屑断裂的可能性，减少对工件的刮擦，并提高加工效率。
Smart Images
Figure CN119973190A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to chip breaker pockets in hole finishing tools and cutting inserts. Background Art
[0002] Hole finishing tools can be used to machine holes in a workpiece. Depending on the material of the workpiece, such as aluminum or other materials, chips cut from the workpiece may be difficult to break, tend to tangle, may get stuck at the bottom of the hole, and may scratch the workpiece.
[0003] There is a need for hole finishing tools and methods of cutting workpieces that reduce or eliminate one or more problems associated with existing hole finishing tools and methods of using the same. Summary of the invention
[0004] In one embodiment, a hole finishing tool is provided. The hole finishing tool comprises a shank, a body and a plurality of cutting inserts. The body extends axially from the shank. The body comprises ribs. Each rib comprises a corresponding recess. Each cutting insert is attached to a corresponding recess of a corresponding rib. Each cutting insert comprises a cutting edge and a chip breaker recess. The chip breaker recess is disposed in the front face of the cutting insert. The chip breaker recess comprises a front boundary and a chip wall. The front boundary is parallel to the cutting edge. The chip wall is disposed at a rotation angle relative to the cutting edge. The rotation angle is in a range between 0° and 50°.
[0005] In another embodiment, a cutting insert is provided. The cutting insert includes a cutting edge and a chip breaker pocket. The chip breaker pocket is disposed in the rake face of the cutting insert. The chip breaker pocket includes a front boundary and a chip wall. The front boundary is parallel to the cutting edge. The chip wall is disposed at a rotation angle relative to the cutting edge. The rotation angle is in a range between 0° and 50°.
[0006] In yet another embodiment, a method for cutting a workpiece is provided. In one step, a hole finishing tool is rotated to cut the workpiece. In another step, chips cut from the workpiece flow into a chip breaker pocket of the hole finishing tool. In an additional step, the chips are curled from the surface of the chip breaker pocket so that the chips are turned over and flow back onto the workpiece. Then, in another step, the chips are broken against the workpiece.
[0007] The scope of the present disclosure is defined solely by the appended claims and is not affected by the statements of this summary. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure may be better understood with reference to the following drawings and descriptions. The components in the drawings are not necessarily drawn to scale, emphasis instead being placed on illustrating the principles of the present disclosure.
[0009] Figure 1 shows a perspective view of one embodiment of a hole finishing tool with an attached cutting insert;
[0010] Figure 2 Shows the pass that can be used Figure 1 A cross-sectional side view of one embodiment of a cutting insert in a hole finishing tool;
[0011] Figure 3 Shown through Figure 2 A top view of a cutting insert of an embodiment of the present invention;
[0012] Figure 4 Shows the available Figure 1 A partial perspective view of one embodiment of a cutting insert for cutting chips from a workpiece in a hole finishing tool;
[0013] Figure 5 Shows Shows Figure 1 A partial perspective view of the cross-sectional area identified in FIG. Figure 4 cutting inserts without showing chips;
[0014] Figure 6 Shown through Figure 7 A cross-sectional side view of the cutting insert taken along line 6-6;
[0015] Figure 7 Shown through Figure 4-5 A top view of a cutting insert of an embodiment of the present invention;
[0016] Figure 8 Shows the available Figure 1 A partial perspective view of another embodiment of a cutting insert for cutting chips from a workpiece in a hole finishing tool;
[0017] Fig. 9 Shows Shows Figure 1 A partial perspective view of the cross-sectional area identified in FIG. Figure 8 cutting inserts without showing chips;
[0018] Fig.10 Shown through Fig.11 A cross-sectional side view of the cutting insert taken along line 10-10;
[0019] Fig.11 Shown through Figure 8-9 A top view of a cutting insert of an embodiment of the present invention;
[0020] Fig.12 Shows the available Figure 1 A partial perspective view of yet another embodiment of a cutting insert for cutting chips from a workpiece in a hole finishing tool;
[0021] Fig.13 Shows Shows Figure 1A partial perspective view of the cross-sectional area identified in FIG. Fig.12 cutting inserts without showing chips;
[0022] Fig.14 Shown through Fig.15 A cross-sectional side view of the cutting insert taken along line 14-14;
[0023] Fig.15 Shown through Figure 12-13 A top view of a cutting insert of an embodiment of the present invention;
[0024] Fig.16 is a flow chart illustrating one embodiment of a method of cutting a workpiece. DETAILED DESCRIPTION
[0025] like Figure 1 As shown in, in one embodiment, the hole finishing tool 10 may include a shank 12, a body 14 and a plurality of cutting inserts 16. The hole finishing tool 10 may include an indexable hole finishing tool. In another embodiment, the hole finishing tool 10 may include a modular hole finishing tool. The hole finishing tool 10 may be made of steel. The hole finishing tool 10 may include a polycrystalline diamond cutting tool. In other embodiments, the hole finishing tool 10 may be different in type or material. At the rear end 13 of the hole finishing tool 10, the shank 12 may be attached to a machine 18, which is configured to rotate the hole finishing tool around an axis 20 to cut chips 21 from a workpiece 22. The body 14 may extend axially from the shank 12. The body 14 may include alternating spiral ribs 24 and spiral grooves 26. Each of the cutting inserts 16 may be attached to a corresponding pocket 28 of the spiral rib 24 at the front end 30 of the hole finishing tool 10. The cutting insert 16 may be placed adjacent to the corresponding spiral groove 26. Each cutting insert 16 may include a leading edge 32, an outer diameter edge 34, a rake face 36, a cutting edge 38, and a chip breaker pocket 40. In other embodiments, the hole finishing tool 10 including its components may include varying configurations, shapes, sizes, and orientations.
[0026] like Figure 2-3As shown in, in one illustrative embodiment, each cutting insert 16 may include a leading edge 32, an outer diameter edge 34, a rake face 36, a cutting edge 38, and a chip breaker pocket 40. The chip breaker pocket 40 may be disposed in the rake face 36. The chip breaker pocket 40 may include a bottom surface 42, side surfaces 44 and 46, and a chip wall 48. The chip breaker pocket 40 may further include side edges 50 and 52. The front boundary 54 of the chip breaker pocket 40 may be parallel to the cutting edge 38 of the cutting insert 16. The chip wall 48 may be disposed at a rotation angle 56 relative to the cutting edge 38 of the cutting insert 16. In a variant embodiment, the rotation angle 56 may be in a range between 0° and 50°. The backward flow of chips cut from the workpiece by the cutting edge 38 of the cutting insert 16 may be controlled by changing the rotation angle 56 of the chip wall 48 relative to the cutting edge 38 of the cutting insert 16. The bottom surface 42 may be disposed at a rake angle 58 relative to the rake face 36. In alternative embodiments, the rake angle 58 may be in a range between 15° and 20°. The chip wall 48 may be disposed at a chip wall angle 60 relative to the rake face 36. In alternative embodiments, the chip wall angle 60 may be in a range between 60° and 80°.
[0027] The chip breaker pocket 40 may include a groove width 62. In a variant embodiment, the groove width 62 may be in a range between 0.5 mm and 1.0 mm. Each cutting insert 16 may have a land width 64 between the cutting edge 38 and the chip breaker pocket 40. In a variant embodiment, the land width 64 may be in a range between 0.05 mm and 0.12 mm. There may be a transition radius 66 between the chip wall 48 and the bottom surface 42 of the chip breaker pocket 40. In a variant embodiment, the transition radius 66 may be in a range between 0.05 mm and 0.1 mm. The side edge 50 of the chip breaker pocket 40 may be disposed at a retraction angle 68 relative to the outer diameter edge 34 of the cutting insert 16. In a variant embodiment, the retraction angle 68 may be in a range between 5° and 15°. The side edge 52 of the chip breaker pocket 40 may be disposed at a retraction angle 70 relative to the front edge 32 of the cutting insert 16. In a variant embodiment, the retraction angle 70 may be in a range between 0° and 45°. The chip breaker pocket 40 may further include a radius 72 that transitions between the bottom surface 42, the side surfaces 44 and 46, and the chip wall 48. The radius 72 and the slope / angle of the bottom surface 42, the side surfaces 44 and 46, and the chip wall 48 may provide edge strength. In other embodiments, the shape, configuration, and size of each cutting insert 16 and its chip breaker pocket 40 may vary.
[0028] like Figure 4-7As shown in , in another embodiment, each cutting insert 116 may include a leading edge 132, an outer diameter edge 134, a rake face 136, a cutting edge 138, and a chip breaker pocket 140. The chip breaker pocket 140 may be disposed in the rake face 136. The chip breaker pocket 140 may include a bottom surface 142, side surfaces 144 and 146, and a chip wall 148. The chip breaker pocket 140 may further include side edges 150 and 152. The side edge 152 may be perpendicular to the cutting edge 138 of the cutting insert 116, and the side surface 144 may have a slope 153 of 30°. The side edge 152 may flip the chips 121 of the workpiece 122 cut by the cutting edge 138 of the cutting insert 116, thereby causing the chips 121 to flow backward. The front boundary 154 of the chip breaker pocket 140 may be parallel to the cutting edge 138 of the cutting insert 116. The chip wall 148 may be disposed at a rotation angle 156 relative to the cutting edge 138 of the cutting insert 116. The rotation angle 156 may be 0° such that the chip wall 148 is parallel to the cutting edge 138 of the cutting insert 116.
[0029] The chips 121 of the workpiece 122 cut by the cutting edge 138 of the cutting insert 116 can vertically hit the chip wall 148, so that there is a negligible speed difference on both sides of the chip 121. The chip wall 148 can cause the chip 121 to curl and flow to the workpiece 122. This can cause the chip 121 to break when it first hits the workpiece 122, resulting in shorter chips 121. The bottom surface 142 can be arranged at a rake angle 158 relative to the front cutting edge 136. The rake angle 158 can be 15°. The chip wall 148 can be arranged at a chip wall angle 160 relative to the front cutting edge 136. The chip wall angle 160 can be 60°. The chip breaker pocket 140 can include a groove width 162. The groove width 162 can be 0.7 mm. Each cutting insert 116 can have a land width 164 between the cutting edge 138 and the chip breaker pocket 140. The land width 164 may be 0.05 mm. The groove width 162 of 0.7 mm and the land width 164 of 0.05 mm may make the curling radius of the chip 121 smaller.
[0030] There may be a transition radius 166 between the chip wall 148 and the bottom surface 142 of the chip breaker pocket 140. The transition radius 166 may be 0.06 mm. The side edge 150 of the chip breaker pocket 140 may be disposed at a retraction angle 168 relative to the outer diameter edge 134 of the cutting insert 116. The retraction angle 168 may be 15°. The side edge 152 of the chip breaker pocket 140 may be disposed at a retraction angle 170 relative to the front edge 132 of the cutting insert 116. The retraction angle 170 may be 45°. The chip breaker pocket 140 may further include a fillet 172 transitioning between the bottom surface 142, the side surfaces 144 and 146, and the chip wall 148. The fillet 172 and the slope / angle of the bottom surface 142, the side surfaces 144 and 146, and the chip wall 148 may provide edge strength. In other embodiments, the shape, configuration, and size of each cutting insert 116 and its chip breaker pocket 140 may vary.
[0031] like Figure 8-11 As shown in , in another embodiment, each cutting insert 216 may include a front edge 232, an outer diameter edge 234, a front cutting face 236, a cutting edge 238 and a chip breaker pocket 240. The chip breaker pocket 240 may be arranged radially in the front cutting face 236. The chip breaker pocket 240 may include a bottom surface 242, side surfaces 244, 245 and 246, and a chip wall 248. The chip breaker pocket 240 further includes side edges 250 and 252. The front boundary 254 of the chip breaker pocket 240 may be parallel to the cutting edge 238 of the cutting insert 216. The chip wall 248 may be arranged at a rotation angle 256 relative to the cutting edge 238 of the cutting insert 216. The rotation angle 256 may be 50°. The chip wall 248 may be arranged at an angle 257 relative to the outer diameter edge 234. The angle 257 may be 5°, which, in combination with the radial configuration of the chip breaker pocket 240 , may cause the chips 221 of the workpiece 222 cut by the cutting edge 238 of the cutting insert 216 to flip and flow backward.
[0032] The chip wall 248 can cause the chip 221 of the workpiece 222 cut by the cutting edge 238 to curl upward after hitting the chip wall 248. Due to the angle at which the chip 221 hits the chip wall 248, the chip 221 can twist, deform, evacuate backward, hit the workpiece surface 222, and continue to curl and hit the workpiece surface 222 multiple times until the chip 221 breaks into multiple short spiral chips 221. The bottom surface 242 can be arranged at a rake angle 258 relative to the front cutting edge 236. The rake angle 258 can be 15°. The chip wall 248 can be arranged at a chip wall angle 260 relative to the front cutting edge 236. The chip wall angle 260 can be 75° to enhance the curling effect of the chip 221. The chip breaker pocket 240 can include a groove width 262. The groove width 262 can be 0.6 mm. Each cutting insert 216 may have a land width 264 between the cutting edge 238 and the chip breaker pocket 240. The land width 264 may be 0.05 mm. A groove width 262 of 0.6 mm and a land width 264 of 0.05 mm may make the curling radius of the chip 221 smaller.
[0033] There may be a transition radius 266 between the chip wall 248 and the bottom surface 242 of the chip breaker pocket 240. The transition radius 266 may be 0.05 mm. The side edge 250 of the chip breaker pocket 240 may be disposed at a retraction angle 268 relative to the outer diameter edge 234 of the cutting insert 216. The retraction angle 268 may be 5°. The side edge 252 of the chip breaker pocket 240 may be disposed at a retraction angle 270 relative to the front edge 232 of the cutting insert 216. The retraction angle 270 may be 0°. The chip breaker pocket 240 may further include a fillet 272 transitioning between the bottom surface 242, the side surfaces 244, 245 and 246, and the chip wall 248. The fillet 272 and the slope / angle of the bottom surface 242, the side surfaces 244, 245 and 246, and the chip wall 248 may provide edge strength. In other embodiments, the shape, configuration, and size of each cutting insert 216 and its chip breaker pocket 240 may vary.
[0034] like Figure 12-15As shown in, in another embodiment, each cutting insert 316 may include a front edge 332, an outer diameter edge 334, a front cutting face 336, a cutting edge 338 and a chip breaker pocket 340. The chip breaker pocket 340 may be disposed in the front cutting face 336. The chip breaker pocket 340 may be trapezoidal, which may provide edge strength. The chip breaker pocket 340 may include a bottom surface 342, side surfaces 344 and 346, and a chip wall 348. The chip breaker pocket 340 may further include side edges 350 and 352. The front boundary 354 of the chip breaker pocket 340 may be parallel to the cutting edge 338 of the cutting insert 316. The chip wall 348 may be disposed backward at a rotation angle 356 relative to the cutting edge 338 of the cutting insert 316. The rotation angle 356 may be 30°.
[0035] The chip wall 348 can cause the chips 321 of the workpiece 322 cut by the cutting edge 338 of the cutting insert 316 to continuously curl and flow backward to the workpiece 322. The chips 321 may break when they hit the workpiece 322. The curling radius of the chip 321 can be affected by the configuration and can be changed from a large curling radius to a small curling radius. The bottom surface 342 can be arranged at a rake angle 358 relative to the front cutting edge 336. The rake angle 358 can be 15°. The chip wall 348 can be arranged at a chip wall angle 360 relative to the front cutting edge 336. The chip wall angle 360 can be 75°. The chip breaker pocket 340 may include a groove width 362. The groove width 362 can be 0.5mm. Each cutting insert 316 can have a land width 364 between the cutting edge 338 and the chip breaker pocket 340. The land width 364 can be 0.05mm. The groove width 362 of 0.5 mm and the land width 364 of 0.05 mm can make the curling radius of the chip 321 smaller.
[0036] There may be a transition radius 366 between the chip wall 348 and the bottom surface 342 of the chip breaker pocket 340. The transition radius 366 may be 0.06 mm. The side edge 350 of the chip breaker pocket 340 may be disposed at a retraction angle 368 relative to the outer diameter edge 334 of the cutting insert 316. The retraction angle 368 may be 15°. The side edge 352 of the chip breaker pocket 340 may be disposed at a retraction angle 370 relative to the front edge 332 of the cutting insert 316. The retraction angle 370 may be 15°. The chip breaker pocket 340 may further include a fillet 372 transitioning between the bottom surface 342, the side surfaces 344 and 346, and the chip wall 348. The fillet 372 and the slope / angle of the bottom surface 342, the side surfaces 344 and 346, and the chip wall 348 may provide edge strength. In other embodiments, the shape, configuration, and size of each cutting insert 316 and its chip breaker pocket 340 may vary.
[0037] like Fig.16As shown, in one embodiment, a method 480 of cutting a workpiece is provided. The method 480 can utilize any of the hole finishing tools 10, cutting inserts 16, 116, 216, and 316 and chip breaker pockets 40, 140, 240, and 340 disclosed herein. In other embodiments, the method 480 can utilize different hole finishing tools, cutting inserts, and chip breaker pockets.
[0038] In step 482, the hole finishing tool may be rotated to cut the workpiece. In step 484, the chips cut from the workpiece may flow into the chip breaker pocket of the hole finishing tool. In step 486, the chips may curl off the surface of the chip breaker pocket so that the chips flip and flow back onto the workpiece. Then, in step 488, the chips may break against the workpiece.
[0039] In one embodiment, the method 480 may further include the step of vertically impacting a chip wall of a chip breaker pocket.The chip may impact the chip wall of the chip breaker pocket with a negligible velocity difference on opposite sides of the chip.
[0040] In another embodiment, the method 480 may further include breaking the chip when it first contacts the workpiece.
[0041] In further embodiments, the method 480 may further include the chips impacting a chip wall of a chip breaker and then curling upward.
[0042] In yet another embodiment, the method 480 may further include twisting, deforming, and flowing the chips backward onto the workpiece after curling upward.
[0043] In yet another embodiment, the method 480 may further include the chips curling a plurality of times and then breaking into spiral chips after flowing backward onto the workpiece.
[0044] In other embodiments, one or more steps of method 480 may not be followed, one or more steps of method 480 may be modified substantially and / or sequentially, and / or one or more additional steps may be added to method 480 .
[0045] One or more embodiments of the present disclosure may be used to cut difficult materials, such as aluminum, to increase plastic deformation of chips, break chips more easily in a shorter time, increase chip curling, increase control over chip flow and direction, increase edge strength of chip breaker pockets, maintain strength of cutting edge of cutting insert, and reduce chip scratching of workpiece. The chip breaker pocket may be a simple structure and may be easily manufactured by laser forming process or other manufacturing methods. In other embodiments, one or more additional problems associated with current hole finishing tools and methods of using the same may be reduced or eliminated.
[0046] The abstract is provided to allow the reader to quickly determine the nature of the technical disclosure. The abstract is submitted with the understanding that it is not used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing detailed description, it can be seen that various features are grouped together in various embodiments for the purpose of simplifying the disclosure. The method of the present disclosure should not be interpreted as reflecting the intention that the claimed embodiments require more features than those expressly stated in each claim. On the contrary, as reflected in the appended claims, the inventive subject matter lies in less than all the features of a single disclosed embodiment. Therefore, the appended claims are hereby incorporated into the detailed description, and each claim is separately regarded as a separately claimed subject matter.
[0047] Although particular aspects of the inventive subject matter described herein have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the subject matter described herein and its broader aspects based on the teachings herein, and therefore the appended claims are intended to cover within their scope all such changes and modifications that come within the true scope of the subject matter as described herein. Furthermore, it should be understood that the present disclosure is defined by the appended claims. Therefore, the present disclosure is not to be limited except in accordance with the appended claims and their equivalents.
Claims
1. A hole finishing tool, comprising: handle; a body extending axially from the shank, the body including ribs, each of the ribs including a respective recess; as well as a plurality of cutting inserts, each cutting insert being attached to the respective pocket of the respective rib; Each cutting insert includes: cutting edge; and A chip breaker pocket is disposed in the rake face, the chip breaker pocket comprising: a front boundary parallel to the cutting edge; and A chip wall is arranged at a rotation angle relative to the cutting edge, and the rotation angle ranges from 0° to 50°. 2 . The hole finishing tool according to claim 1 , wherein the chip breaker pocket further comprises a bottom surface, the bottom surface being disposed at a rake angle relative to the rake face, the rake angle ranging between 15° and 20°.
3. The hole finishing tool of claim 1, wherein the chip wall is disposed at a chip wall angle relative to the rake face, the chip wall angle ranging between 60° and 80°.
4. The hole finishing tool of claim 1, wherein the chip breaker pocket comprises a groove width ranging between 0.5 mm and 1.0 mm.
5. The hole finishing tool of claim 1, further comprising a land width between the cutting edge and the chip breaker pocket ranging between 0.05 mm and 0.12 mm.
6. The hole finishing tool of claim 1, wherein the chip breaker pocket further comprises a bottom surface, a transition radius between the chip wall and the bottom surface ranging from 0.05 mm to 0.1 mm.
7. The hole finishing tool according to claim 1, wherein the chip breaker pocket further includes a side edge, and the cutting insert further includes an outer diameter edge, wherein the side edge is disposed at a retracted angle relative to the outer diameter edge, and the retracted angle ranges between 5° and 15°.
8. The hole finishing tool according to claim 1, wherein the chip breaker pocket further includes a side edge and the cutting insert further includes a front edge, the side edge is disposed at a retracted angle relative to the front edge, and the retracted angle ranges between 0° and 45°.
9. The hole finishing tool of claim 1, wherein the chip breaker pocket further comprises fillets between surfaces of the chip breaker pocket.
10. A cutting insert comprising: Cutting edge; as well as A chip breaker pocket is disposed in the rake face, the chip breaker pocket comprising: a front boundary parallel to the cutting edge; as well as A chip wall is arranged at a rotation angle relative to the cutting edge, and the rotation angle ranges from 0° to 50°.
11. The cutting insert of claim 10, wherein the chip breaker pocket further comprises a bottom surface disposed at a rake angle relative to the rake face, the rake angle ranging between 15° and 20°.
12. The cutting insert of claim 10, wherein the chip wall is disposed at a chip wall angle relative to the rake face, the chip wall angle ranging between 60° and 80°.
13. The cutting insert of claim 10, wherein the chip breaker pocket comprises a groove width ranging between 0.5 mm and 1.0 mm.
14. The cutting insert of claim 10, further comprising a land width between the cutting edge and the chip breaker pocket ranging between 0.05 mm and 0.12 mm.
15. The cutting insert of claim 10, wherein the chip breaker pocket further comprises a bottom surface, a transition radius between the chip wall and the bottom surface ranging from 0.05 mm to 0.1 mm.
16. The cutting insert of claim 10, wherein the chip breaker pocket further comprises a side edge, and the cutting insert further comprises an outer diameter edge, the side edge being disposed at a retracted angle relative to the outer diameter edge, the retracted angle ranging between 5° and 15°.
17. The cutting insert of claim 10, wherein the chip breaker pocket further comprises a side edge, and the cutting insert further comprises a front edge, the side edge being disposed at a retracted angle relative to the front edge, the retracted angle ranging between 0° and 45°.
18. The cutting insert of claim 10, wherein the chip breaker pocket further comprises fillets between surfaces of the chip breaker pocket.
19. A method for cutting a workpiece, comprising: rotating a hole finishing tool to cut the workpiece; causing chips cut from the workpiece to flow into a chip breaker pocket of the hole finishing tool; curling the chips from the surface of the chip breaker pocket so that the chips flip over and flow backward onto the workpiece; and subsequently The chips are broken against the workpiece.
20. The method of claim 19, further comprising vertically impacting the chips against a chip wall of the chip breaker pocket.
21. The method of claim 20, further comprising the chip striking the chip wall of the chip breaker pocket with a negligible velocity difference on opposite sides of the chip.
22. The method of claim 19, further comprising breaking the chip when it first contacts the workpiece.
23. The method of claim 19, further comprising the chips striking a chip wall of the chip breaker and then curling upward.
24. The method of claim 23, further comprising the chips twisting, deforming and flowing backward onto the workpiece after curling upward.
25. The method of claim 24, further comprising the chips curling a plurality of times and then breaking into spiral chips after they flow backward onto the workpiece.