Method for machining a cutting tool

Abstract

The invention relates to a method for machining a cutting tool, the cutting tool having a tool body with a hard coating (2), and the hard coating (2) being applied to the tool body (1) at least on a cutting edge (10, 14, 14a, 43), a clearance surface (5, 25, 45) and a cutting surface (6, 26, 46). First, a hard coating (2) is applied on the surface of the tool body of the cutting tool (1) on the surface of the workpiece in the region of a clearance surface (5, 25, 45) of the cutting edge (3, 23, 43) adjacent to the cutting edge (3, 23, 43) and a cutting surface (6, 26, 46) adjacent to the cutting edge (3, 23, 43). In order to sharpen the cutting edge, the hard coating (2) is then partially removed in the region of the cutting edge gap surface (5, 25, 45) by means of laser processing, thereby sharpening the cutting edge provided with the hard coating (2) and forming a blunt arc (4), such that the angle delta between the first geometric plane (16, 36) and the second geometric plane (18, 38) is suitable for 1 DEG < = delta < = 70, and the angle delta between the first geometric plane (16, 36) and the second geometric plane (18, 38) is suitable for 1 DEG < = delta < = 70. Wherein a surface (9) underlying the hard coating (2) of the clearance surface (5, 25, 45) of the tool body (1) extends in the first geometric plane, and wherein, in the region of the removed clearance surface (5, 25, 45), a surface (8, 28) delimited by the cutting edge (10, 14, 43) sharpened by the hard coating (2) extends on the second geometric plane.

Description

[0001] The invention is based on a method for machining a cutting tool having at least one cutting edge, wherein the cutting tool has a tool body which is provided with a hard coating at least in the region of the cutting edge.

[0002] Cutting tools include cutting tools for removing chips and tools for separation, which usually have a shaft and a cutting part, at least one end of the shaft is used to hold the cutting tool, such as in a machine interface in a machining tool. The cutting part is arranged on the shaft. The cutting part has at least one cutting edge, through which the cutting tool interacts with the workpiece to be processed, thereby removing material from the workpiece. Such cutting tools include, for example, files, drills, reamers, chisels, scrapers, planes and saws. The cutting tool can be solid, a tool composed entirely of a single material. Alternatively, the cutting part can also have a blade including a cutting edge, which is made of a different material from the shaft. The cutting tool is subjected to considerable mechanical and thermal loads during use, due to the forces and temperatures generated, including mechanical friction, oxidation and wear, as well as diffusion and scaling, especially during high-speed machining. This leads to tool wear in the cutting edge area of ​​the cutting tool.

[0003] In order to improve the wear resistance of cutting tools and extend their service life, cutting tools are equipped with a hard coating in the cutting edge area, which is applied to the tool body. For example, such hard coatings include diamond coatings, amorphous carbon coatings (called diamond-like carbon (DLC) in English) and titanium coatings. These are deposited on the tool body, for example, using chemical vapor deposition (CVD in English). After the hard coating is deposited, the coated cutting edge becomes blunt and rounded. At this time, it must be sharpened so that the cutting edge has the required edge radius. For this purpose, a portion of the hard coating in the cutting edge area is removed. For example, a laser processing machine can be used to sharpen the cutting edge by removing part of the hard material on the surface of the cutting tool. Material removal is also called laser ablation or laser vaporization, and the material can be removed in layers over a large area. The laser beam is essentially perpendicular to the surface of the portion to be removed to the hard coating. The surface can be a gap surface or a cutting surface. This method is known, for example, in documents such as DE102009004316A1 and DE102011076584A1. It is also possible to remove parts of the hard coating by continuous or pulsed laser radiation, wherein the laser beam is substantially parallel to the surface to be processed. This method is known, for example, from EP 2 682 219 A1. Figure 1 As shown, the laser beam can be irradiated onto the cutting tool to be processed so that material removal starts in the area of ​​the cutting edge to be processed. This is also called removing material from the front. Alternatively, material removal can also start from the side of the cutting tool away from the cutting edge to be processed, as described in EP2682219A1. Figure 3This is also known as material removal from the rear. The parameters of the laser beam must be adapted to the material to be processed and the desired process. Material removal can take place on the clearance surface, the cutting surface or both surfaces.

[0004] The coated cutting edge is usually sharpened so that the wedge angle of the cutting wedge of the uncoated tool body formed by the clearance surface and the cutting surface matches the wedge angle of the coated and re-sharpened cutting wedge. However, a disadvantage of this method is that if the laser beam is parallel to the surface to be machined and material is removed from behind, the laser beam may be deflected in an undesirable manner at the secondary clearance surface or other surfaces of the cutting tool that correspond neither to the clearance surface nor to the cutting surface. This deflection of the laser beam may result in the laser machining not being able to obtain the desired sharp cutting edge.

[0005] The object of the present invention is to provide a method for machining hard-coated cutting tools, in which a predetermined cutting edge radius of the coated cutting edge can be achieved in a reliable manner even if part of the hard coating is removed by a laser beam to sharpen the coated cutting edge, wherein the laser beam is not perpendicular to the cutting tool surface to be machined and material removal can also be carried out from the back.

[0006] This task is solved by a method for machining a cutting tool having the features of claim 1. The method is characterized in that, after partial material removal, the hard coating surface in the gap surface area is not parallel to the lower surface of the tool body, but forms an angle δ between a first geometric plane (on which the tool body surface under the hard coating on the gap surface extends) and a second geometric plane (on which the hard coating surface extends in the gap surface area with a sharpened cutting edge as the boundary after material removal), and the angle applies to: 1°≤δ≤70. Considering that the tool body surface under the coating on the gap surface ends at an uncoated cutting edge, the geometric plane where the tool body surface is located extends infinitely. The surface of the tool body in the gap area after partial material removal extends to a sharp cutting edge, while the second geometric plane extends infinitely. The first geometric plane intersects the second geometric plane along a geometric straight line. This geometric straight line can be

[0007] - coincides with the uncoated cutting edge of the tool body

[0008] - coincides with the sharp cutting edge of the cutting tool

[0009] - extends outside the tool body and inside the hard coating on the cutting surface, or

[0010] -Extends outside the cutting tool.

[0011] After material removal is completed, the hard coating surface in the clearance surface area is preferably tilted so that the hard coating thickness on the clearance surface increases with the distance from the cutting edge. If a hard coating of uniform thickness is deposited on the cutting edge, clearance surface and cutting surface, then during the subsequent sharpening of the cutting edge, only a certain amount of material needs to be removed directly on the cutting edge. The amount of hard coating material that needs to be removed decreases with the distance from the cutting edge. This results in a cutting edge with a predetermined edge radius while leaving more hard coating material on the cutting tool. Since less material needs to be removed, the time to remove the material is also shorter.

[0012] The cutting tool may be elongated and extend along a geometric longitudinal axis. These tools include, for example, milling cutters or drill bits. At least one cutting edge may be a primary cutting edge or a secondary cutting edge. It may be located on the end face of the elongated cutting tool or may extend along the axis in the cutting edge region.

[0013] The hard coating material is removed by laser processing. For this purpose, a laser beam emitted by a laser processing machine is aligned at a specific angle relative to the hard coating surface on the gap surface to partially remove the hard coating. The angle of the laser beam with its geometrical beam axis relative to the surface of the coated cutting tool depends on the angle δ enclosed by the first geometrical plane and the second geometrical plane after the material removal is completed. The laser beam is preferably aligned so that the geometrical beam axis is parallel or tangential to the surface to be processed on the gap surface. Since the laser beam is usually focused on the surface of the cutting tool, the opening angle of the laser beam is preferably taken into account when aligning the laser beam. If the hard coating has a uniform coating thickness in the gap surface area after coating, the laser beam can be aligned at an angle δ with its geometrical beam axis to the surface to be processed at the beginning of material removal. If the opening angle of the focused laser beam is taken into account, this angle corresponds to the sum of the opening angle and half of the angle δ. The hard coating can be removed in particular from the back side. This means that the removal work starts from one of the gap surfaces, which faces away from the sharp cutting edge to be processed. This avoids unnecessary deflection of the laser beam. This also ensures that all points where the laser beam hits the cutting tool during the material removal process are removed. As a result, the surface formed on the gap surface is smooth. It has good surface quality. The edge quality of the cutting edge sharpened according to the predetermined edge radius meets the requirements.

[0014] According to a preferred embodiment of the present invention, a hard coating having a thickness between 2 μm and 40 μm is deposited on the tool body.

[0015] According to another preferred embodiment of the present invention, the angle δ for removing the hard coating is: 2°≤δ≤10°, preferably 3°≤δ≤6°. The angle δ generally depends on the thickness of the hard coating on the gap surface, the material of the hard coating and the wedge angle of the cutting wedge.

[0016] According to another preferred embodiment of the present invention, the angle δ for removing the hard coating is 30°≤δ≤70°. For example, if the first geometric plane and the second geometric plane intersect along a geometric straight line coinciding with the uncoated cutting edge of the tool body, such an angle range is advantageous. This exposes the uncoated cutting edge. This can avoid mechanical or thermal stress between the tool body and the hard coating.

[0017] According to another preferred embodiment of the present invention, during the partial removal of the hard coating, the hard coating thickness on the gap surface decreases, so that the hard coating thickness on the gap surface starts from the sharpened cutting edge and increases with the increase of the distance from the sharpened cutting edge.

[0018] According to another preferred embodiment of the present invention, the first geometric plane and the second geometric plane intersect at the uncoated cutting edge. In this case, the tool body has no hard coating in the uncoated cutting edge area, thereby avoiding mechanical stress or thermal stress between the tool body and the hard coating.

[0019] According to another preferred embodiment of the present invention, during the laser processing, the laser beam is aligned with its geometrical beam axis at an angle δ to the first geometrical plane. In this case, the beam axis of the laser beam is parallel to or tangential to the second geometrical plane. The geometrical beam axis is a straight line in the mathematical sense, which extends infinitely and passes through the hard coating.

[0020] According to another preferred embodiment of the present invention, during the laser processing, the laser beam is aligned with its beam axis at an angle α with the second geometric plane, i.e., 1°≤α≤10°. Considering that the laser beam can be focused on the workpiece surface, there is an opening angle. The angle α is preferably equivalent to half of the laser beam opening angle.

[0021] According to another preferred embodiment of the present invention, the material removal of the hard coating starts from the portion away from the cutting edge on the hard coating gap surface and ends at the cutting surface. In this case, the material is removed from the rear portion.

[0022] According to another preferred embodiment of the present invention, the cutting edge with a hard coating is sharpened by additionally partially removing the hard coating in the cutting surface area, so that after the partial removal of the hard coating, the angle between the third geometric plane and the fourth geometric plane from which the surface of the tool body under the hard coating on the cutting surface extends is ε, which is applicable to 0°≤ε≤70°; wherein the surface of the tool body under the hard coating on the cutting surface extends in the third geometric plane; the hard coating surface defined by the sharpened cutting edge extends in the fourth geometric plane after partial removal of material in the cutting surface area. The size of the angle δ can be the same as the angle ε or different. In this case, in order to re-sharpen the cutting edge after removing the hard coating, it is necessary to reduce the hard coating thickness not only on the clearance surface but also on the cutting surface. The material removal method can make the new surface formed after the material removal parallel to the surface under the tool body, that is, ε=0° or form an angle other than 0° with the surface. If the latter case is met, it is preferred to reduce the coating thickness on the cutting surface in the same way as the clearance surface, so that the thickness of the hard coating increases with the increase of the distance from the cutting edge.

[0023] According to another preferred embodiment of the present invention, the hard coating is removed from the cutting surface such that the angle ε is 2°≤ε≤10°, particularly preferably 3°≤ε≤6°.

[0024] According to another preferred embodiment of the present invention, the thickness of the hard coating on the cutting surface is reduced during the partial removal of the hard coating, so that the thickness of the hard coating on the cutting surface increases with increasing distance from the cutting edge.

[0025] According to another preferred embodiment of the invention, a diamond hard coating is deposited on the tool body. This can be a crystalline or polycrystalline diamond layer, the latter having a non-uniform distribution of crystalline domain sizes. Instead of diamond, a DLC hard coating, a nitride-based material such as titanium nitride, other titanium-containing materials or other materials suitable for hard coatings can also be applied to the tool body. The abbreviation DLC stands for Diamond Like Carbon. Such hard coatings are also known as amorphous diamond.

[0026] According to another preferred embodiment of the invention, the hard coating on the gap surface is at least partially completely removed, so that the tool body is exposed in the relevant part. This applies in particular to the uncoated cutting edge of the tool body, and possibly also to the adjacent area. The tool body is freed from the hard coating at or near the cutting edge. In this way, mechanical or thermal stresses between the tool body and the hard coating can be prevented or at least reduced.

[0027] According to another preferred embodiment of the present invention, the hard coating on the cutting surface is completely removed at least partially to expose the tool body in the relevant part, preferably in the area of ​​the uncoated cutting edge of the tool body. This can reduce or avoid mechanical and / or thermal stresses between the tool bodies.

[0028] According to another preferred embodiment of the invention, the laser processing is performed with a pulsed laser beam, wherein the pulse duration is between 50 ns and 150 fs. The advantage of processing with such ultrashort laser pulses is that a very high energy density can be generated locally on the workpiece surface, so that material can be removed without spreading heat in the workpiece in an undesirable manner.

[0029] According to another preferred embodiment of the present invention, the pulse duration is between 190 fs and 10 ps.

[0030] According to another preferred embodiment of the present invention, the pulse frequency is between 100 kHz and 1000 kHz.

[0031] With a pulse duration of 190 fs to 10 ps, ​​a pulse frequency of 100 kHz to 1000 kHz, and an average laser power of 4 to 40 W, the CNC machine tool axis of the laser processing device can achieve a processing speed of 10 mm / min to 40 mm / min.

[0032] According to another preferred embodiment of the present invention, the pulse duration is between 6 ns and 45 ns, and the pulse frequency is between 15 kHz and 200 kHz. In this case, the average laser power is preferably between 9 W and 18 W. For example, relative to the CNC machine tool axis of the laser processing device, a processing speed of 45 mm / min to 100 mm / min can be achieved.

[0033] According to another preferred embodiment of the present invention, the beam diameter of the focused laser beam is between 7 microns and 25 microns. The focal point is preferably located at or close to the surface of the workpiece to be processed.

[0034] According to another preferred embodiment of the present invention, the tool body consists of cemented carbide.

[0035] According to another preferred embodiment of the invention, the layer thickness of the hard coating in the cutting edge clearance surface and cutting surface area where no material is removed is between 2 and 40 μm.

[0036] Further advantages and preferred embodiments of the invention can be seen from the following description, the drawings and the claims.

[0037] Attached photos

[0038] The figure shows a practical application embodiment of the present invention, wherein:

[0039] Figure 1 is a perspective view of a cutting tool without a hard coating.

[0040] Figure 2 is based on Figure 1 A cross-sectional view of the cutting tool shown,

[0041] Figure 3 is based on Figure 1 A perspective view of the cutting tool shown immediately after application of the hard coating and before sharpening of the cutting edge.

[0042] Figure 4 is based on Figure 3 A cross-sectional view of the cutting tool shown,

[0043] Figure 5 is based on Figure 3 The cross-section of the cutting tool shown in the end cutting edge area,

[0044] Figure 6 is based on Figure 5 In the cross section shown, the hard coating on the cutting edge clearance surface has been partially removed.

[0045] Figure 7 is based on Figure 6 Diagram for angle δ,

[0046] Figure 8 is based on Figure 7 Diagram for angle α,

[0047] Fig. 9 is based on Figure 3 and Figure 5 A cross-sectional view of a cutting tool is shown in which the hard coating on the cutting edge clearance surface and the cutting surface has been partially removed.

[0048] Fig.10 is based on Figure 3 and Figure 5 A cross-sectional view of a cutting tool with a portion of the hard coating on the clearance surface of the cutting edge removed and Fig. 9 Different parts of the hard coating on the cutting surface are removed.

[0049] Fig.11 is based on Figure 3 The cutting tool shown in Fig. 9 As shown, the clearance surface of the cutting edge and the hard coating on the cutting surface have been removed.

[0050] Fig.12 is based on Fig.11 A cross-sectional view of the cutting tool shown,

[0051] Fig.13 The laser beam is in use Figures 6 to 12Schematic diagram of the direction of material removal by the cutting tool shown, wherein the material removal is carried out in the cutting edge area on the end side of the cutting tool,

[0052] Fig.14 is based on Figure 3 The other cutting edges of the cutting tools shown,

[0053] Fig.15 is based on Figures 6 to 12 Schematic diagram of laser beam alignment when the cutting tool is removing material on the edge area of ​​the clearance surface of the cutting edge,

[0054] Fig.16 The laser beam is used according to Figures 6 to 12 Schematic diagram of the alignment of the cutting edge area on the cutting surface of the cutting edge during the material removal process of the cutting tool shown. When the material removal starts,

[0055] Fig.17 is based on Fig.16 Material removal continues on the cutting surface area of ​​the cutting edge. DETAILED DESCRIPTION

[0056] Figures 1 to 10 The head of the cutting tool is shown at different stages of machining. The cutting tool is a square shank milling cutter. Figure 1 and Figure 2 The head of a cutting tool body 1 is shown without a hard coating. The end face of the tool body has a cutting edge 3 with an associated clearance surface 5 and an associated cutting surface 6.

[0057] Figure 3 , Figure 4 and Figure 5 The cutting tool is shown after a hard coating 2 is applied to the tool body 1. The hard coating covers Figure 1 The entire surface of the tool body 1 is shown. Due to the hard coating, a blunt arc 4 is formed on the uncoated cutting edge 3 of the tool body 1. Adjacent to the blunt arc 4 are the surface 7 of the hard coating 2 on the clearance surface 5 and the hard coating surface 11 on the cutting surface 6. Figure 5 The cross section shown has a uniform coating thickness.

[0058] Figure 5 It is shown that the edge radius of the blunt arc 4 is larger than the edge radius of the edge 3 of the uncoated tool body 1. In order to reduce the edge radius of the coated edge, the edge is sharpened by partially removing the hard coating 2 after coating.

[0059] Removal of hard coating Figures 6 to 10 First, as Figure 6 and Figure 7As shown, part of the hard coating is removed from the gap surface, while the cutting surface remains unchanged. To this end, the laser beam is aligned with its geometric beam axis 15 so that the beam axis makes an angle δ with the first geometric plane 16. On the first geometric plane 16, the surface 9 of the tool body 1 is located below the hard coating on the gap surface 5. The surface 9 of the tool body 1 is bounded by the cutting edge 3 of the uncoated tool body 1. It is adjacent to the coating 2. The first geometric plane is not restricted. It extends beyond the surface 9 of the tool body 1. The original direction 7 of the surface of the hard coating 2 on the gap surface is indicated by a dotted line. The partial removal of material forms a new hard coating surface 8 on the gap surface. This surface 8 extends on a second geometric plane 18. The first geometric plane 16 and the second geometric plane 18 are not parallel to each other. They intersect at a geometric straight line 20, due to Figure 7 In the viewing direction, only one point can be seen. The geometric straight line 20 extends outside the cutting tool. The first geometric plane 16 and the second geometric plane 18 form an angle δ. In this embodiment, the angle δ is 10°. Figure 7 Removing some material from the gap surface can form a new sharpened cutting edge 10. Figure 7 It is shown that the beam axis 15 of the laser beam is substantially parallel or tangential to the second geometrical plane 18, wherein the hard coating extends in the surface 8 formed by the material removal from the gap surface. Figure 7 It is also shown that the material removal starts from the portion of the clearance surface remote from the cutting edge and extends along the second geometrical plane 18 up to the cutting surface.

[0060] Figure 8 Shows Figure 7 Another way of collimating the beam axis 15 of the laser beam is shown, in which the beam axis 15a of the laser beam is tilted by an angle α relative to the collimator 15, wherein the angle α corresponds to half the opening angle of the laser beam.

[0061] Fig. 9 , Fig.10 , Fig.11 and Fig.12 The condition of the cutting tool after a portion of the hard coating 2 has been removed from the cutting surface is shown. Fig. 9 The dotted line in FIG. 1 shows the original direction 11 of the hard coating surface on the cutting surface. The removal of part of the material forms a new hard coating surface 12 on the cutting surface. The surface 12 is parallel to the lower surface 13 of the tool body 1. The surface 13 extends on the third geometric plane 17. The surface 12 extends on the fourth geometric plane 19. The angle ε between the two surfaces 12 and 13 is 0°. Therefore, the angle ε between the third geometric plane 17 and the fourth geometric plane 19 is also 0°. The third geometric plane 17 and the fourth geometric plane 19 do not intersect. The material partially removed from the cutting surface forms a new sharpened cutting edge 14.

[0062] Fig.10 Shows Fig. 9 Another case is that material is removed from the cutting surface so that the angle ε is different from 0°. The new surface 12a of the hard coating formed on the cutting surface after the material removal is not parallel to the surface 13 under the tool body 1. The fourth geometric plane 19a extending from the new surface 12a intersects the third geometric plane 17 along a straight line and forms an angle E=3° with the third geometric plane 17. A new sharpened cutting edge 14a is formed by removing part of the material on the cutting surface.

[0063] Fig.13 The figure shows how the laser beam is aligned with its beam axis during material removal on the clearance surface and on the cutting surface when the relevant cutting edge is located in the area of ​​the end face of the cutting tool. The first alignment of the beam axis 30 is performed during material removal on the clearance surface. It is basically the same as Figure 7 Alignment of the beam axis 15 of the laser beam or Figure 8 The laser beam irradiates the surface of the hard coating 2 of the tool body 1 at point 32. Material removal starts from the portion of the gap surface away from the cutting edge and ends at the cutting surface along the sharpened cutting edge. The advantage of this laser beam alignment is that the area impacted by the laser beam is completely removed. There are no impact points on the hard coating remaining on the cutting tool. Therefore, the surface formed on the gap surface by material removal is very smooth. The same principle applies to the removal of material on the cutting surface: here, the beam axis 31 of the laser beam is also parallel or tangential to the surface to be machined, or forms an angle of 1° to 10° with the surface. In this way, a very smooth hard coating surface can be machined on the cutting surface. Material removal starts from the portion of the cutting surface away from the cutting edge and ends at the gap surface along the sharpened cutting edge.

[0064] Fig.14 Shows Figure 3 The material removal on another cutting edge 23 of the cutting tool is shown in . The hard coating 2 on the tool body 1 is removed from the clearance surface 25 to the cutting surface 26, so that a new surface 28 is formed on the cutting surface of the hard coating. The new surface 28 extends on a second geometric plane 38. The surface of the tool body 1 is located below the hard coating 2 on the clearance surface 25 and extends on the first geometric plane 36. The first geometric plane 36 and the second geometric plane 38 intersect at an angle δ on the cutting edge 23 of the tool body 1. In this case, the angle δ is 50°. The hard coating on the cutting edge 23 of the tool body 1 is removed by material removal and the new surface 28 formed in the process, so that there is no hard coating on the cutting edge 23.

[0065] Fig.15 , Fig.16 and Fig.17 Shows along Figures 1 to 12The clearance surface and partial material removal on the cutting surface of the cutting edge 40 of the cutting tool are shown. Another cutting edge 43 with a clearance surface 45 and a cutting surface 46 extends along the cutting edge 40. This cutting edge 43 is also sharpened by partial material removal after the hard coating is applied. The cutting edge 40 is an elongated depression between two cutting edges that extend helically outside the axis of the cutting tool. Of the two cutting edges, only the cutting edge 43 is Figures 15 to 17 The other cutting edge is located on the side of the cutting tool facing away from the viewer. The cutting edge 40 is used to receive chips when the cutting tool is engaged with a workpiece not shown in the figure.

[0066] Fig.15 It shows how the laser beam is aligned with a geometric beam axis 47 to remove material from the gap surface 45. The geometric beam axis 47 forms an angle β with a tangent 48 to the surface of the gap surface 45. This is typically equivalent to half the opening angle of the laser beam. The angle β can be Figure 8 This corresponds to the angle α in . However, this is not absolutely necessary. Since the clearance surface 45 of the cutting edge 43 is located at the outward part of the cutting tool, the laser beam can be aligned with its geometric beam axis 47 in a plane that is substantially perpendicular to the geometric longitudinal axis of the cutting tool.

[0067] Fig.16 and Fig.17 It is shown how the laser beam is aligned with its geometrical beam axis 49 in order to remove material from the cutting surface 46 . Fig.16 Shows the alignment of the geometric beam axis when the cutting tool end side starts to remove material from the cutting tool surface. Fig.17 The geometrical beam axis 49 is shown as it advances along the cutting edge 40 in the axial direction during material removal. In both cases, the geometrical beam axis 49 is tilted at an angle γ relative to the tangent lines 50, 51 of the surface to be machined. Since the cutting surface 46 is located on the inwardly curved surface of the cutting edge, the laser beam must be deflected Fig.15 The geometric beam axis 49 shown is aligned with the target location so as to hit the surface of the cutting tool in a tangential direction at a predetermined location.

[0068] All features of the present invention may be essential features of the present invention and may be used individually or in combination with each other.

[0069] Reference numerals

[0070] 1 Tool body

[0071] 2 Hard coating

[0072] 3 Cutting edge of tool body

[0073] 4 Obtuse arc

[0074] 5 Clearance surface

[0075] 6 Cutting surface

[0076] 7 Gap surface hard coating surface original track

[0077] 8 Direction of the hard coating surface on the gap surface after removing part of the material

[0078] 9 The surface of the tool body at the gap surface

[0079] 10. Re-sharpen the coated cutting edge

[0080] 11 Original direction of the hard coating surface on the cutting surface

[0081] 12 Direction of the hard coating surface on the cutting surface after part of the material is removed

[0082] 12a Alternative orientation of the hard coating surface on the cutting surface after partial material removal

[0083] 13 Surface of the tool body at the cutting surface

[0084] 14Re-sharpened coated cutting edge

[0085] 14a Re-sharpened alternative coated cutting edge

[0086] 15 Geometric beam axis of the laser beam

[0087] 15a Geometric beam axis of the laser beam

[0088] 16 The first geometric plane

[0089] 17 The third geometric plane

[0090] 18 Second geometric plane

[0091] 19 The fourth geometric plane

[0092] 19a Alternatives to the Fourth Geometric Plane

[0093] 20 Geometric straight line where the first and second geometric planes intersect

[0094] 23 Cutting edge of cutting tool

[0095] 25 Clearance surface

[0096] 26 Cutting surface

[0097] 28 Direction of the hard coating surface on the gap surface after removing part of the material

[0098] 30 First alignment of the laser beam axis

[0099] 31 Second alignment of the laser beam axis

[0100] 32 Impact point of laser beam on hard coating surface

[0101] 36 First Geometric Plane

[0102] 38 Second geometric plane

[0103] 40 blade edge

[0104] 43 cutting edges

[0105] 45 Clearance Surface

[0106] 46 Cutting surface

[0107] 47Geometric beam axis of the laser beam

[0108] 48 Tangent line of the gap surface to be processed

[0109] 49Geometric beam axis of the laser beam

[0110] 50 Tangent line of the gap surface to be processed

[0111] 51 Tangent of the gap surface to be processed

Claims

1. A method for machining a cutting tool, the cutting tool comprising a tool body with a hard coating, wherein the hard coating (2) is applied to the tool body (1) at least in the area of ​​the cutting edge (10, 14, 14a, 43), the clearance surface (5, 25, 45) and the cutting surface (6, 26, 46), characterized in that The following method steps: The hard coating (2) is deposited on a clearance surface (5, 25, 45) adjacent to the cutting edge (3, 23, 43) and a cutting surface (6, 26, 46) adjacent to the cutting edge (3, 23, 43) of a tool body (1) surface of the cutting tool, The hard coating (2) is partially removed in the cutting edge gap surface (5, 25, 45) region by laser processing, thereby sharpening the cutting edge provided with the hard coating (2) and forming a blunt arc (4), so that the angle δ between the first geometric plane (16, 36) and the second geometric plane (18, 38) is suitable for 1°≤δ≤70, wherein the surface (9) below the hard coating (2) of the gap surface (5, 25, 45) of the tool body (1) extends on the first geometric plane, wherein in the gap surface (5, 25, 45) region after removal, the surface (8, 28) defined by the cutting edge (10, 14, 43) sharpened by the hard coating (2) extends on the second geometric plane.

2. The method according to claim 1, characterized in that A hard coating (2) with a thickness between 2 micrometers and 40 micrometers is deposited on the tool body (1).

3. The method according to claim 1 or 2, characterized in that: The hard coating (2) is removed in such a way that the angle δ is 2≤δ≤10°, particularly preferably 3°≤δ≤6°.

4. The method according to any one of the preceding claims, characterized in that During the process of partially removing the hard coating (2), the thickness of the hard coating (2) on the gap surface (5, 25, 45) decreases, so that the thickness of the hard coating (2) starting from the sharpened cutting edge (10, 14, 14a, 43) increases as the distance from the sharpened cutting edge (10, 14, 14a, 43) increases.

5. The method according to any one of the preceding claims, characterized in that During laser processing, the laser beam is aligned with its geometric beam axis (15, 15a, 30, 31, 47, 49) so that the geometric beam axis forms an angle δ with the first geometric plane (16, 36).

6. The method according to any one of claims 1 to 5, characterized in that During laser processing, the laser beam is aligned with its geometric beam axis (15, 15a, 30, 31, 47, 49) so as to form an angle α with the second geometric plane (16, 36), and the angle α is suitable for 1°≤α≤10°.

7. The method according to any one of the preceding claims, characterized in that Material removal of the hard coating (2) on the clearance surface (5, 25, 45) starts from the clearance surface (5, 25, 45) of the hard coating (2) away from the cutting edge (3, 23) of the tool body (1) and ends at the cutting surface (6, 26, 46).

8. The method according to any one of the preceding claims, characterized in that The cutting edge (10, 14, 14a, 43) provided with the hard coating (2) is sharpened by partially removing the hard coating (2) in the area of ​​the cutting surface (6, 46), wherein, after the partial removal of the hard coating (2), the angle ε between the third geometric plane (17) and the fourth plane (19) is suitable for 0°≤ε≤70°, wherein the surface (9) of the tool body (1) under the hard coating (2) located on the cutting surface (6, 46) extends in the third geometric plane; and in the area of ​​the cutting surface (6) after the removal of the hard coating (2), the surface (12) of the hard coating (2) defined by the sharpened cutting edge (14, 43) extends in the fourth plane.

9. The method according to claim 8, characterized in that The hard coating (2) is removed in the following manner: 2°≤ε≤10°, and particularly preferably 3°≤ε≤6°.

10. The method according to claim 8 or 9, characterized in that: During the process of partially removing the hard coating (2), the thickness of the hard coating (2) on the cutting surface (6, 46) decreases, so that the thickness of the hard coating (2) on the cutting surface (6, 46) starts from the sharpened cutting edge (14, 43) and increases as the distance from the sharpened cutting edge (14, 43) increases.

11. The method according to any one of the preceding claims, characterized in that A diamond layer is deposited as a hard coating (2) on the tool body (1).

12. The method according to any one of the preceding claims, characterized in that The hard coating (2) on the gap surface (5, 25, 45) is at least partially completely removed, exposing the tool body (1) at the relevant portion.

13. The method according to any of the preceding claims, characterized in that The hard coating (2) on the cutting surface (6, 26, 46) is at least partially completely removed, exposing the tool body (1) at the relevant portion.

14. The method according to any of the preceding claims, characterized in that Laser processing is performed with a pulsed laser beam, where the pulse duration is between 50 ns and 150 fs.

15. The method according to claim 14, characterized in that The pulse duration is between 190 fs and 10 ps.

16. The method according to claim 14 or 15, characterized in that The pulse frequency is between 100 kHz and 1000 kHz.

17. The method according to any one of the preceding claims, characterized in that The average power of the laser is between 4 and 40W.

18. The method according to claim 15, characterized in that The pulse duration is between 6 ns and 45 ns, and the pulse frequency is between 15 kHz and 200 kHz.

19. The method according to claim 18, characterized in that The average power of the laser is between 9W and 18W.

20. The method according to any one of the preceding claims, characterized in that The beam diameter of the focused laser beam is between 7 microns and 25 microns.

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