PEELING PLATE

Abstract

A peeling plate has upper and lower sides, lateral faces extending between the upper and lower sides, and primary and secondary cutting edges at the transition from the lateral faces to the upper side. The peeling plate in a plan view of the upper side has the shape of a substantially regular n-gon, n being five or six, and n lateral edges lying between the n lateral faces. A primary cutting edge and a secondary cutting edge are formed at the transition from at least one lateral face to the upper surface, wherein active primary cutting edges and active secondary cutting edges are spaced apart from a lateral edge. The lateral edge at the transition to the upper side forming an active cutting corner to the respective active primary cutting edge and active secondary cutting edge.

Claims

1-19. (canceled)

20. A peeling plate, comprising: an upper side and a lower side; n lateral faces extending between said upper side and said lower side, n being five or six, and n lateral edges formed between said n lateral faces; said upper side, in a plan view thereof, having a shape of a substantially regular n-gon; a primary cutting edge and a secondary cutting edge formed at a transition from at least one said lateral face to said upper side; wherein active primary cutting edges and active secondary cutting edges are spaced apart by a lateral edge, said lateral edge, at the transition to said upper side, forming an active cutting corner to the respective said active primary cutting edge and said active secondary cutting edge.

21. The peeling plate according to claim 20, wherein n equals six.

22. The peeling plate according to claim 20, wherein in each case one primary cutting edge and one secondary cutting edge are configured at the transition from each lateral face to said upper side.

23. The peeling plate according to claim 20, wherein said secondary cutting edges have a length of to of a length of said primary cutting edges.

24. The peeling plate according to claim 20, wherein said primary cutting edges and/or said secondary cutting edges are linear edges.

25. The peeling plate according to claim 20, which comprises: at least one first part-face, which conjointly with said upper side forms a secondary cutting edge, configured on at least one said lateral face; at least one further part-face, which conjointly with said upper side forms at least a portion of a primary cutting edge, configured on said at least one lateral face; and wherein said first part-face encloses with said further part-face an external angle of greater than 180 and smaller than 220.

26. The peeling plate according to claim 20, wherein the external angle is 190.

27. The peeling plate according to claim 25, wherein said first part-face and said further part-face are a multiplicity of part-faces respectively formed on each said lateral face.

28. The peeling plate according to claim 25, wherein those part-faces that conjointly with said upper side form at least part of a primary cutting edge and that are mutually spaced apart from a lateral edge are in each case disposed to enclose an angle of 60, the angle being measured as an internal angle between plane normals.

29. The peeling plate according to claim 25, which comprises a third part-face formed on each said lateral face.

30. The peeling plate according to claim 20, configured as a double-side peeling plate.

31. The peeling plate according to claim 30, comprising a primary cutting edge that is associated with said lower side and a secondary cutting edge that is associated with said lower side formed at a transition from at least one said lateral face to said lower side.

32. The peeling plate according to claim 25, configured as a double-side peeling plate and wherein a primary cutting edge that is associated with said lower side is configured at a transition from said part-faces to said lower side, and a secondary cutting edge that is associated with said lower side is configured at a transition from a third part-face of said lateral face to said lower side.

33. The peeling plate according to claim 30, formed with n primary cutting edges associated with said lower side and n secondary cutting edges associated with said lower side, where n equals five or six.

34. The peeling plate according to claim 30, formed with n primary cutting edges associated with said upper side, and exactly n secondary cutting edges associated with said upper side, and n primary cutting edges associated with said lower side, and n secondary cutting edges associated with said lower side, where n equals five or six.

35. The peeling plate according to claim 20, comprising a chip removal geometry formed on at least one of said upper side or said lower side.

36. The peeling plate according to claim 25, wherein a transition of said part-faces on a lateral face is rounded, having a curvature radius between 1 and 20 mm.

37. The peeling plate according to claim 20, wherein said primary cutting edge is a round cutting edge having a curvature radius of greater than 50 mm.

38. The peeling plate according to claim 20, wherein said secondary cutting edge has a curvature radius of greater than 50 mm or said secondary cutting edge is a linear cutting edge.

39. An assembly, comprising a tool holder and one or a plurality of peeling plates each according to claim 20 to be mounted to said tool holder.

Description

[0041] The invention will be explained in more detail hereunder by means of the figures in which:

[0042] FIG. 1 shows a peeling plate according to the prior art;

[0043] FIG. 2 shows a peeling plate according to the invention in a perspective view;

[0044] FIG. 3 shows a peeling plate according to the invention in the horizontal plan;

[0045] FIGS. 4-5 show a peeling plate according to the invention in the cross section;

[0046] FIG. 6 shows a peeling plate according to the invention engaging in a workpiece; and

[0047] FIG. 7 shows a peeling plate in a further exemplary embodiment.

[0048] FIG. 1 shows a peeling plate 1 according to the prior art in a plan view of an upper side 2.

[0049] The peeling plate 1 in the plan view of the upper side 2 has a basic shape of an equilateral triangle having three lateral edges 10 (here projecting). Primary cutting edges 5 and secondary cutting edges 6 are configured at the transition from the lateral faces 4 to the upper side 2. In use, the primary cutting edges 5 and secondary cutting edges 6 that are in each case assigned to one lateral face 4 are active. Primary cutting edges 5 and secondary cutting edges 6 of one lateral face 4 enclose a cutting corner 12. Chip geometries 11 are configured on the upper side 2.

[0050] The lateral faces 4 are arranged in such a manner that the primary cutting edge 5 conjointly with the secondary cutting edge 6 encloses a flat angle. In the present example the primary cutting edge 5 and the secondary cutting edge 6 are at a mutual external angle of approximately 193.

[0051] The maximum chip removal depth a.sub.p max of the primary cutting edge 5 is indicated by the auxiliary lines. Due to the flat angle between the primary cutting edge 5 and the secondary cutting edge 6 only minor maximum chip removal depths a.sub.p max can be achieved.

[0052] FIG. 2 shows a peeling plate 1 in an exemplary embodiment according to the invention in a perspective view. The peeling plate 1 in a plan view of the upper side 2 has the design of a substantially regular hexagon. There exists a six-fold symmetry in relation to a symmetry axis S. While a peeling plate 1 having a hexagonal basic shape is discussed hereunder, similar conditions apply to a peeling plate 1 having a pentagonal basic shape.

[0053] The peeling plate 1 has an upper side 2, a lower side 3, and lateral faces 4 that extend between the upper side 2 and the lower side 3. The lateral faces 4 on the circumference of the peeling plate 1 are spaced apart from lateral edges 10. The lateral edges 10 are preferably not configured as sharp edges but have a curvature radius of 5 mm, for example.

[0054] The lateral faces 4 preferably run parallel with the symmetry axis S. This causes a simple production capability by way of a powder-metallurgical production method, since a simple die can be used for pressing a powder mixture. The material of the peeling plate 1 is preferably a hard metal or another material that is producible by way of powder metallurgy.

[0055] A bore 7 by way of which the peeling plate 1 is capable of being fastened to a tool holder (not shown) by means of a tension screw and which penetrates the peeling plate 1 is provided so as to be concentrically parallel with the symmetry axis S. On account of a form-fitting plate seat, the peeling plate 1 in use can no longer be rotated and there is no risk of the tension screw being loosened in use. A loss of the peeling plate 1 is thus excluded.

[0056] A first cutting edge 8 is configured at the transition from the upper side 2 to the lateral faces 4.

[0057] The peeling plate 1 in the present exemplary embodiment is configured so as to be double-sided. A second cutting edge 9 is therefore configured at the transition from the lower side 3 to the lateral faces 4. Double-sided means that both the cutting edges 8, 9 between the upper side 2 and the lateral faces 4, as well as between the lower side 3 and the lateral faces 4, can be used for subtraction. Accordingly, in the use of portions of the cutting edge 8, the upper side 2 acts as the cutting face; in the case of a reversed peeling plate 1, that is to say in the use of portions of the cutting edge 9 for the removal of material, the lower side 3 acts as the cutting face. A cutting face is that face of a cutting edge on which a chip that is formed by a cutting edge runs off.

[0058] On account thereof, as opposed to a one-sided embodiment in which a cutting edge 8 is configured only between the upper side 2 and the lateral face 4, a substantially better utilization of the material of the cutting insert results. At least one support chamfer 15 is preferably configured at least in portions on the cutting edges 8, 9 toward the lateral faces 4. A support chamfer 15 causes a stable cutting performance and reduces the vibrations and the risk of breakouts on cutting edges.

[0059] The cutting edge 8 is subdivided into cutting edge portions in the form of primary cutting edges 5 and secondary cutting edges 6. Six primary cutting edges 5 that are assigned to the upper side 2, and six secondary cutting edges 6 are configured. Of course, fewer than six primary cutting edges 5 and secondary cutting edges 6 can also be implemented.

[0060] The cutting edges 10 at the intersection point with the upper side 2 form cutting corners 12.

[0061] Each primary cutting edge 5 conjointly with the secondary cutting edge 6 that is connected by way of a cutting corner 12 forms a pair of cutting edges which in the use of the peeling plate 1 simultaneously engage in a material to be subtracted (not shown).

[0062] In the use of the peeling plate 1 said peeling plate 1 in relation to a workpiece to be machined is positioned such that an active primary cutting edge 5 and the active secondary cutting edge 6 that neighbors the latter counter to the clockwise direction and is connected to the latter by way of an active cutting corner 12, engage in a workpiece. For applications having a rotation of the peeling plate 1 in the clockwise direction in relation to the workpiece the arrangement is correspondingly mirror-imaged.

[0063] The active secondary cutting edge 6 herein is substantially parallel with a longitudinal axis of the workpiece. The term active cutting corner refers to the transition between a primary cutting edge 5 and a secondary cutting edge 6, both being specified for simultaneous use, that is to say both being simultaneously used for machining the material in the use of the cutting insert. Accordingly, portions of the cutting edges are differentiated by active and passive cutting edges, depending on whether or not said cutting edges in the operation of the cutting insert are utilized for machining the material. The reference to the orientation in the clockwise direction refers to a viewing direction in the plan view of the upper side 2.

[0064] In the case of the present peeling plate 1, not the primary cutting edges 5 and secondary cutting edges 6 that are configured on one and the same lateral face 4 thus engage in the workpiece when in use, but an active primary cutting edge 5 conjointly with an active secondary cutting edge 6 that is configured on the neighboring lateral face 4 form the pair of simultaneously engaging cutting edges. The active cutting edges are thus spaced apart from a lateral edge 10.

[0065] As compared to peeling plates known from the prior art, in which primary cutting edges and secondary cutting edges provided for simultaneous use are configured on one and the same lateral face, this has the substantial advantage that a steeper angle can be implemented between the active secondary cutting edge 6 and the active primary cutting edge 5. This in turn, in the case of given dimensions of the cutting edges, permits a larger maximum cutting depth a.sub.p max, since the maximum cutting depth a.sub.p max is the result of the product of the available cutting-edge length multiplied by sin (setting angle).

[0066] The primary cutting edge 5 herein carries out the rough subtraction operation, i.e. the roughing while the secondary cutting edge 6 that follows in the advancing direction assumes the finishing, thus the polishing.

[0067] The respective extents of a primary cutting edge 5 and of a secondary cutting edge 6 are identified by way of chain dotted auxiliary lines. The secondary cutting edges 6 herein are significantly shorter than the primary cutting edges 5. The secondary cutting edges 6 are to of the length of the primary cutting edges 5, for example.

[0068] Chip geometries 11 by way of which chips that are formed by the primary cutting edges 5 or the secondary cutting edges 6, respectively, are dischargeable are configured on the upper side 2. In the embodiment as a double-sided peeling plate 1, chip geometries 11 are configured in the same manner also on the lower side 3.

[0069] Furthermore to be seen are bearing faces 13, the upper side 2 in the region of said bearing faces 13 between the chip geometries 11 extending at the same level as about the bore 7 up to the periphery of the peeling plate 1. This has the advantage that in the case of the peeling plate 1 being clamped in a tool, supporting said peeling plate 1 is feasible up to the circumference of the peeling plate 1.

[0070] In order for a clearance angle to be achieved between a secondary cutting edge 6 and a primary cutting edge 5 that is assigned to the same lateral face 4, lateral faces 4 are subdivided into mutually tilted part-faces 41, 42. The part-faces 41, 42 are mutually set at an external angle 1 of, for example, 190. This angle has the effect that a passive primary cutting edge 5 that in the counter clockwise direction neighbors an active secondary cutting edge 6 does not engage in the material.

[0071] For peeling plates 1 that are usable in a double-sided manner, a third part-face 43 which in relation to the further part-face 42 is likewise inclined by an external angle 2 is provided on the lateral faces 4. The external angle 2 preferably has the same value as the external angle 1. This can be explained in that portions of those part-faces 42, 43 which in the non-reversed position of the peeling plate form tool flanks to the primary cutting edge 5 that is assigned to the upper side 2, by reversing the peeling plate 1 in the reversed state act as tool flanks to the secondary cutting edge 6 that is assigned to the lower side 3. For use in the reversed position, the third part-face 43 conjointly with the lower side 3 forms a secondary cutting edge 6 that is assigned to the lower side 3.

[0072] The secondary cutting edges 6 that are assigned to the upper side 2 are configured between the part-faces 41 and the upper side 2. The primary cutting edges 5 that are assigned to the upper side 2 are configured at the transition from the part-faces 42, 43 to the upper side 2. The primary cutting edges 5 extend in each case, in a manner adjacent to the secondary cutting edges 6, up to the cutting corners 12.

[0073] The exemplary embodiment of FIG. 2 shows a peeling plate 1 that is usable in a double-sided manner. Primary cutting edges 5 and secondary cutting edges 6 that are assigned to the lower side 3 are configured at the transition from the lateral faces 4 to the lower side 3. Therefore, 12 pairs of primary cutting edges 5, 5, and of secondary cutting edges 6, 6 can be utilized. Reference is made of a cutting insert that is capable of being indexed 12 times.

[0074] It is preferably provided that the secondary cutting edges 6, 6 have a length of to of the length of the primary cutting edges 5, 5. Accordingly, the lateral extents of the part-faces 41, 42, 43 are at a ratio of, for example, :: (for a length of the secondary cutting edge of of the primary cutting edge). The part-face 41 which conjointly with the upper side 2 forms a secondary cutting edge 6 is thus preferably of the same width as a part-face 43 which conjointly with the lower side 3 forms a secondary cutting edge 6 that is assigned to the lower side 3.

[0075] This becomes evident in a horizontal plan of the peeling plate 1 as is illustrated in FIG. 3.

[0076] The part-faces 41, 42, 43 are projecting in the horizontal plan. The part-face 41 is tilted by al in relation to the further part-face 42, the third part-face 43 is tilted by 2 in relation to the further part-face 42, wherein preferably 1=2. In other words, the part-faces 41, 43 in relation to the part-face 42 have the same angle. The facet feature results in a convex design of the lateral faces 4.

[0077] The primary cutting edge 5 that is formed between the part-face 42, the part-face 43, and the upper side 2 in this case of a peeling plate 1 that is usable in a double-sided manner in a plan view of the peeling plate 1 shows a kinked profile.

[0078] The further part-faces 42 of the peeling plate are in each case at a mutual angle of 60 (measured between the plane normals of the part-faces 42). The peeling plate 1 has a six-fold symmetry.

[0079] The part-face transitions 14 between the part-faces 41, 42, 43 on a lateral face 4 are preferably not embodied as sharp edges but have a curvature radius R.sub.x of 5 mm, for example. The lateral edges 10 are likewise embodied in a rounded manner, having a curvature radius R.sub.y, for example having a curvature radius R.sub.y of 5 mm.

[0080] In the case of a reversed peeling plate 1, that is to say the lower side 3 functioning as a cutting face, that portion of the cutting edge 9 that extends between the lower side 3 and the part-face 43 acts as the secondary cutting edge 6. The primary cutting edge 5 and the secondary cutting edge 6 in this case form a pair of active cutting edges which are connected by way of the cutting corner 12. In the case of this advantageous embodiment of a double-sided peeling plate 1, in each case six pairs of primary cutting edges 5, 5 and secondary cutting edges 6, 6 can thus be utilized on the upper side 2 or the lower side 3, respectively.

[0081] If the peeling plate 1, in a manner deviating from the exemplary embodiment shown here, is embodied so as to be one-sided, a division of the lateral faces 4 into three part-faces is not required. In this case, a division into two part-faces 41 and 42 suffices in such a manner that an active secondary cutting edge 6 has an angle in relation to an adjoining passive primary cutting edge 5. Observing a lateral face 4, the part-face 42 in the case of an one-sided embodiment of the peeling plate 1 can extend up to the lateral edge 10. The primary cutting edge 5 that is formed between the part-face 42 and the upper side 2 in this case, in a plan view of the peeling plate 1, displays a linear profile.

[0082] FIG. 4 shows a peeling plate 1 according to the invention in the cross section along the section plane A-A indicated in FIG. 3. The chip geometries 11 on the upper side 2 and on the lower side 3 of the peeling plate 1 can be seen.

[0083] FIG. 5 shows a section of the peeling plate 1 along the section plane B-B indicated in FIG. 3.

[0084] On account of the position of the section, details of a support chamfer 15, or of a protective chamfer 16, respectively, in the region of the primary cutting edge 5 can be seen. A support chamfer 15 having a chamfer angle 1 of, for example, 3 to 7 exists on the external face 4. A protective chamfer 16 having a chamfer angle 2 of, for example, 5 to 20 is configured on the side of the cutting face on the upper side 2. Following a planar portion, the chip geometry 11 having a chip angle .sub.1 of, for example, 5 to 30 in relation to the horizontal, enters so as to be configured as a depression in the upper side 2.

[0085] The angular ranges are mentioned in an exemplary manner and are not to be understood as limiting.

[0086] The variable placement of support chamfers 15 or protective chamfers 16, respectively, in different portions of the cutting edge is a particular advantage of the peeling plates 1 according to the invention as compared to round peeling plates. For example, a chamfer angle of the support chamfer 15 or of the protective chamfer 16, respectively, can thus be implemented in a region of a primary cutting edge 5 that is different from said chamfer angle in a region of a secondary cutting edge 6.

[0087] FIG. 6 shows a peeling plate 1 according to the invention engaging in a cylindrically symmetrical workpiece 17.

[0088] A tool (not shown) that supports the peeling plate 1 rotates about a rotation axis R. The rotation direction points perpendicularly out of the image plane toward the observer. An advancing direction of the workpiece 17 is indicated by a block arrow. It goes without saying that the machining depends on the relative movement between the tool and the workpiece 17. A rotation of the workpiece 17 and an advancement of the tool could thus also be implemented. The workpiece 17 has an initial radius r.sub.0 and a radius r.sub.1 after machining.

[0089] The secondary cutting edge 6 is set so as to be substantially parallel with the rotation axis R. In other words, the orbit of the secondary cutting edge 6 is substantially a cylindrical shell, while the primary cutting edge 5 has an orbit in the shape of two-stepped truncated cones.

[0090] The active primary cutting edge 5 can be set up to the part-face transition 14 that delimits the part-face 41 in relation to the part-face 42. This results in a maximum chip removal depth a.sub.p max. In the event of the peeling plate 1 plunging beyond the part-face transition 14 that delimits the part-face 41 in relation to the part-face 42, the (here passive) secondary cutting edge 6 that adjoins thereto would be worn.

[0091] As compared to round peeling plates known from the prior art it is particularly advantageous that the contact lengths of the cutting edges, that is to say the length of the cutting edge that actually engages in the workpiece in the case of cutting edges that are formed by linear portions is shorter than in the case of arcuate cutting edges, assuming the same maximum chip removal depth a.sub.p max A shorter contact length results in lower cutting forces.

[0092] As compared to round peeling plates it is furthermore advantageous that the setting angle of the primary cutting edge 5 of the present peeling plate 1 is substantially consistent across the length of the primary cutting edge 5. In the case of round peeling plates, however, the setting angle of the cutting edge in the region of the minimum spacing of the cutting edge from the rotation axis R is almost nil and increases as the radial spacing from the rotation axis R increases. Depending on the chosen cutting depth, a setting angle of approximately 90 can arise in the case of round peeling plates in the region of the exit of the cutting edge from the workpiece. A setting angle that is variable across the length of the cutting edge means non-uniform cutting forces along the length of the cutting edge.

[0093] A further disadvantage of arcuate primary cutting edges, as is the case in round peeling plates, are undulated workpiece surfaces. Therefore, an additional finishing plate is necessary for polishing the surfaces in the case of round peeling plates. By contrast, an additional finishing plate is not necessarily required in the case of a peeling plate according to the invention.

[0094] FIG. 7 shows a peeling plate 1 in a further exemplary embodiment having the design of a substantially regular pentagon in a plan view of the upper side 2. The pentagonal peeling plate 1 has five lateral faces 4, cutting edges being configured at the transition from said five lateral faces 4 to the upper side 2.

[0095] The pentagonal peeling plate 1 in the present exemplary embodiment has five pairs of primary cutting edges 5 and secondary cutting edges 6, wherein for the sake of clarity only the conditions pertaining to one pair of a primary cutting edge 5 and a secondary cutting edge 6 are illustrated.

[0096] An active primary cutting edge 5 is spaced apart from the active secondary cutting edge 6 by way of a cutting corner 12. The maximum external angle of the part-faces (facets) 41, 42, 43 is 216, the external angle preferably being 190.

[0097] In a variant that is usable in a double-sided manner, cutting edges are also configured at the transition from the lateral faces 4 to the lower side 3. If in each case five pairs of primary cutting edges 5 and secondary cutting edges 6 are configured on the upper side 2 and the lower side 3, the pentagonal peeling plate 1 is capable of being indexed 10 times.

[0098] In terms of possibilities of the design embodiment (radii, support chamfers, protective chamfers, et cetera) reference is made to the explanations pertaining to the hexagonal exemplary embodiment.

[0099] As compared to a hexagonal peeling plate 1, a pentagonal peeling plate 1 has a lower number of independent cutting edges; however a larger maximum cutting depth a.sub.p max can be achieved at the same external dimensions.

[0100] In practice, a larger number of utilizable cutting edges is more interesting than the maximum cutting depth, which is why hexagonal plates are typically preferred.

LIST OF REFERENCE SIGNS USED

[0101] 1 Peeling plate [0102] 2 Upper side [0103] 3 Lower side [0104] 4 Lateral face [0105] 41, 42, 43 Part-faces [0106] 5 Primary cutting edge [0107] 6 Secondary cutting edge [0108] 7 Bore [0109] 8, 9 Cutting edge [0110] 10 Lateral edge [0111] 11 Chip geometry [0112] 12 Cutting corner [0113] 13 Bearing face [0114] 14 Part-face transition [0115] 15 Support chamfer [0116] 16 Protective chamfer [0117] 17 Workpiece [0118] S Symmetry axis [0119] R Rotation axis [0120] a.sub.p max Maximum cutting depth [0121] r.sub.0 Initial radius [0122] r.sub.1 Radius after machining