Drill bit and production process thereof

Abstract

A drill bit and its production process, wherein the drill bit includes a center drill tip and an outer drill tip located at the front end of the cutter head. The center drill tip is axially farther from the cutter head than the outer drill tips, and the cutter body diameter at the center drill tip is smaller than the cutter body diameter at the outer drill tips. The center drill tip includes at least two center drill tip cutting edges, and the outer drill tips include outer drill tip cutting edges corresponding to the center drill tip cutting edges. Spirally extending chip removal grooves are provided on the circumference of the cutter head. The drill bit, utilizing the center drill tip and outer drill tip configuration, can promptly remove burrs generated during drilling of carbon fiber composite materials while maintaining drilling positioning stability, thereby preventing defects such as tearing, burrs, and delamination of the carbon fiber composite materials.

Description

Technical Field

[0001] The present invention relates to the field of cutting tools, in particular to a drill bit for processing carbon fiber composite materials. Background Art

[0002] As a structural material with excellent performance, carbon fiber composite materials have attracted attention for their high strength, good heat resistance, good thermal shock resistance, light weight, corrosion resistance, and radiation resistance. They have been widely used in aerospace, automobile manufacturing, marine ships, sporting goods and other fields. However, due to the large anisotropy of the material and the low interlaminar strength, carbon fiber composite materials are prone to defects such as tearing, burrs, and delamination during processing. In addition, due to the special nature of the material, carbon fiber composite materials cannot be processed using coolant, and the heat dissipation rate of the cutting edge of traditional carbide tools during dry cutting is slow, resulting in the local high temperature generated by the tool when processing carbon fiber composite materials cannot be dissipated in time, accelerating tool wear and reducing the performance of the carbon fiber composite material.

[0003] Therefore, there is an urgent need for a drill bit with strong wear resistance, high hardness, fast heat dissipation and the ability to better handle defects such as tearing, burrs, and delamination of carbon fiber composite materials to address the shortcomings of existing technologies. Summary of the Invention

[0004] The purpose of the present invention is to provide a drill bit and a production process thereof. The drill bit adopts the arrangement of a central drill tip and an outer drill tip, which can promptly remove burrs generated when drilling carbon fiber composite materials while maintaining the drilling positioning stability, thereby avoiding defects such as tearing, burrs, and delamination of carbon fiber composite materials.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A drill bit comprising a center drill tip and an outer drill tip located at a front end of a cutter head, wherein the center drill tip is axially farther from a cutter shank than the outer drill tips, and a cutter body diameter at the center drill tip is smaller than a cutter body diameter at the outer drill tips, the center drill tip comprising at least two center drill tip cutting edges, the outer drill tip comprising an outer drill tip cutting edge corresponding to the center drill tip cutting edge, and a spirally extending chip removal groove being provided on a circumferential side of the cutter head;

[0007] Accordingly, the cutter head is a PCD-cemented carbide composite rod, which includes a PCD segment and a carbide segment, and the central drill tip and the outer drill tip are located in the PCD segment; thereby improving the hardness, wear resistance and thermal conductivity of the cutter head;

[0008] Correspondingly, the angle W of the center drill tip is 120° to 140°;

[0009] Correspondingly, the center drill tip includes two center drill tip cutting edges, each of which is provided with a first center drill tip clearance angle and a second center drill tip clearance angle, and respectively forms a first center drill tip clearance angle surface and a second center drill tip clearance angle surface, a chisel edge is formed at the connection of the two center drill tip cutting edges, and chip grooves are provided on both sides of the chisel edge;

[0010] Correspondingly, the first clearance angle of the center drill tip is 7° to 9°, and the second clearance angle B of the center drill tip is 20° to 30°;

[0011] Correspondingly, the angle Q of the outer drill tip is 175° to 180°;

[0012] Correspondingly, the outer drill tip cutting edge is provided with an outer drill tip first clearance angle and an outer drill tip second clearance angle, and forms an outer drill tip first clearance angle surface and an outer drill tip second clearance angle surface respectively;

[0013] Correspondingly, the first clearance angle of the outer drill tip is 7° to 9°, and the second clearance angle of the outer drill tip is 20° to 30°;

[0014] Correspondingly, a center drill tip cleaning edge is provided on the peripheral side of the cutter body where the center drill tip is located, and a center drill tip edge is provided on the center drill tip cleaning edge on the same side as the center drill tip cutting edge; the center drill tip cleaning edge provides the required clearance to reduce the drilling resistance of the center drill tip, and the center drill tip edge provides extrusion and support for the hole wall during center drill tip machining;

[0015] Correspondingly, the length of the edge of the center drill tip is 0.5 to 2.5 mm;

[0016] Accordingly, an inner concave structure is provided on the peripheral side of the cutter body where the center drill tip is located, and the inner concave structure is located at the connection between the center drill tip and the outer drill tips; the inner concave structure improves the problem of poor processing effect caused by poor transition between the center drill tip and the outer drill tips, and can effectively distinguish the cutting edges on the center drill tip and the outer drill tips;

[0017] Correspondingly, the width of the concave structure is 0.02 to 0.05 mm;

[0018] Correspondingly, the concave structure is an R angle; the R angle transition between the center drill tip and the outer drill tip can reduce the stress concentration problem of the center drill tip during processing;

[0019] Correspondingly, the radius of the R angle is 0.1 to 0.8 mm;

[0020] Correspondingly, a spirally extending circumferential edge cleaning device is provided on the circumferential side of the cutter head, and a circumferential edge is provided on the circumferential edge cleaning device, which is on the same side as the outer drill tip cutting edge and has the same spiral extension direction as the circumferential edge cleaning device;

[0021] Correspondingly, the circumferential blade includes a circumferential blade edge, a cylindrical blade band, and a supporting blade, which are arranged in sequence from near to far from the outer drill tip. The cutting edges of the circumferential blade edge and the cylindrical blade band are round blades and are arranged in an inverted cone. The cylindrical blade band is also provided with a back angle. The blade profile of the three composite structures of the circumferential blade edge, the cylindrical blade band, and the supporting blade is adopted to complete the reaming process during the drilling process of the carbon fiber composite plate, which can greatly save the time of frequent tool changes or increasing the load of the cutter head during the processing process, improve the processing efficiency, and reduce the cost of equipment use.

[0022] Correspondingly, the peripheral edge and the cylindrical edge band are PCD edges, and the supporting edge is a cemented carbide edge;

[0023] Correspondingly, the reverse taper range of the peripheral edge and the cylindrical land is BT0.08 to 0.15 / 100;

[0024] Accordingly, the back angle of the cylindrical land is 2° to 5°, so that the cylindrical land has a certain cutting ability;

[0025] Correspondingly, the cylindrical lands are set to have equal widths, with a width of 0.02 to 0.05 mm;

[0026] Correspondingly, the edge diameter of the cylindrical land is greater than the edge diameter of the peripheral edge, and the difference ranges from 0.1 to 0.3 mm;

[0027] Correspondingly, the blade diameter of the cylindrical blade is larger than the blade diameter of the supporting blade, and the difference range is 0.005-0.008 mm.

[0028] A drill bit production process comprises slotting a bar stock and processing the aforementioned drill bit;

[0029] Accordingly, the cutter head and the cutter handle are V-welded.

[0030] The beneficial effects of the present invention are:

[0031] 1) A center drill tip and an outer drill tip are provided at the front end of the cutter head. During the drilling process of the drill bit, the outer drill tip can cut off all the fibers in time, avoiding the stress between the sheets caused by the axial force of drilling and causing the carbon fiber composite sheet to be delaminated; during the drilling process of the drill bit, the outer drill tip can cut off all the fibers in time when the center drill tip peels off the fibers, avoiding the center drill tip cutting edge exceeding the strength of the matrix resin, thereby causing the carbon fiber composite material to crack and spread along the direction of the surface fibers; during the drilling process of the drill bit, the outer drill tip can cut off all the fibers in time, avoiding the sheet hole outlet splitting caused by the chisel edge not being able to cut the carbon fiber in time when the tool drills out;

[0032] 2) The center drill tip is more protruding than the outer drill tips (i.e., the center drill tip is farther axially from the tool holder than the outer drill tips), which can ensure the centering stability of the drill bit and avoid lateral displacement during the drilling process;

[0033] 3) An R-angle concave structure is set at the connection between the center drill tip and the outer drill tip to avoid air transition, improve the problem of poor processing effect caused by poor transition between the center drill tip and the outer drill tip, effectively distinguish the cutting edges on the center drill tip and the outer drill tip, and reduce the stress concentration of the center drill tip during tool head processing, reduce the possibility of cracks in the center drill tip, and extend the service life of the center drill tip;

[0034] 4) The cutter head is made of PCD-carbide composite rod, and the center drill tip and the outer drill tip are located in the PCD section. Compared with the use of carbide, the hardness, wear resistance and thermal conductivity of the cutter head can be improved. The local high temperature heat generated by the tool when machining carbon fiber composite materials can be dissipated in time, which reduces the tool wear rate while also avoiding the high temperature affecting the performance of carbon fiber composite materials and prolonging the tool life. Compared with the use of PCD material for the entire cutter head, the cost can be reduced.

[0035] 5) The circumferential blade includes three composite structure blade forms: circumferential blade edge, cylindrical blade band and supporting blade. Specifically, the circumferential blade edge and cylindrical blade band are circular blades and are set with an inverted cone. The circular blade of the cylindrical blade band is set with a back angle. The circumferential blade edge and cylindrical blade band are PCD blades, and the supporting blade is a carbide blade. In the process of drilling carbon fiber composite plates, the drilling and reaming processes can be completed in one process, which can greatly save the time of frequent tool changes or increasing the load of the cutter head during high-speed processing, improve processing efficiency, and reduce the cost of equipment use. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a schematic diagram of the overall structure of a drill bit according to an embodiment of the present invention;

[0037] Figure 2-4 Schematic diagram of the structure of the cutter head according to one embodiment of the present invention at different viewing angles;

[0038] Figure 5 is a schematic diagram of a center drill tip angle W according to an embodiment of the present invention;

[0039] Figure 6 Schematic diagram of the outer drill tip angle Q according to one embodiment of the present invention;

[0040] In the picture:

[0041] 1. Blade head; 2. Handle;

[0042] 3. Center drill tip; 31. Center drill tip cutting edge; 32. Center drill tip first clearance surface; 33. Center drill tip second clearance surface; 34. Chisel edge; 35. Chip flute; 36. Center drill tip cleaning edge; 37. Center drill tip edge; 38. Round angle;

[0043] 4. Outer drill tip; 41. Outer drill tip cutting edge; 42. Outer drill tip first clearance surface; 43. Outer drill tip second clearance surface;

[0044] 5. Clear the edge of the blade;

[0045] 6. Circumferential blade; 61. Circumferential blade edge; 62. Cylindrical blade; 63. Support blade;

[0046] 7. Chip groove. DETAILED DESCRIPTION

[0047] In the description of the present invention, it should be understood that the terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0048] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples provided are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. It should be noted that the drawings are all simplified and not to exact scale, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0049] like Figure 1 As shown, in one embodiment of the present invention, a drill bit includes a cutter head 1 and a shank 2. In this embodiment, the cutter head 1 is a PCD-cemented carbide composite rod, which includes a PCD segment and a carbide segment. The shank 2 is a carbide rod of the same diameter. In this embodiment, the PCD is monolithic synthetic polycrystalline diamond, and the carbide is GU20 alloy. The carbide end of the PCD-cemented carbide composite rod and the carbide rod are V-shaped and welded using a silver brazing process.

[0050] like Figure 2-4As shown, the cutter head 1 includes a center drill tip 3 and an outer drill tip 4 located at the front end of the cutter head 1. The center drill tip 3 is axially farther from the shank 2 than the outer drill tips 4 (i.e., the center drill tip 3 is arranged to protrude as a whole), and the cutter body diameter at the center drill tip 3 is smaller than the cutter body diameter at the outer drill tips 4. For example, the cutter body diameter at the center drill tip is 0.4 to 0.5 times the cutter body diameter at the outer drill tips. The center drill tip 3 includes at least two center drill tip cutting edges 31, which can be set to two or more, and is compared with setting two center drill tip cutting edges 31 and three center drill tip cutting edges 31. According to common sense in the art, the difference between three center drill tip cutting edges 31 and two center drill tip cutting edges 31 is that during processing, the three center drill tip cutting edges 31 require a hole to be reserved on the workpiece to be processed for drilling, while the two center drill tip cutting edges 31 do not require a hole to be reserved on the workpiece to be processed due to the presence of the chisel edge 34, and can be drilled, making processing more convenient. Therefore, in this embodiment, only two center drill tip cutting edges 31 are provided for explanation. The center drill tip 3 includes two center drill tip cutting edges 31, each center drill tip cutting edge 31 is provided with a first center drill tip clearance angle and a second center drill tip clearance angle, and forms a first center drill tip clearance angle surface 32 and a second center drill tip clearance angle surface 33, respectively. A chisel edge 34 is formed at the connection of the two center drill tip cutting edges 31, and a chip groove 35 is provided on both sides of the chisel edge 34. Among them, the angle of the first center drill tip clearance angle is 7° to 9°, the angle of the second center drill tip clearance angle is 20° to 30°, and the angle W of the center drill tip 3 is 120° to 140° (W is the angle between the two center drill tip cutting edges 31, as shown in FIG. Figure 5 shown);

[0051] The center drill tip 3 also includes a center drill tip clean edge 36, a center drill tip edge 37, and an indented structure. The center drill tip clean edge 36 is provided on the peripheral side of the cutter body where the center drill tip 3 is located, and the center drill tip edge 37 is provided on the center drill tip clean edge 36 on the same side as the center drill tip cutting edge 31. It should be noted that the "center drill tip clean edge 36" and the "center drill tip edge 37" are structurally a clean edge and an edge, and the prefix "center drill tip" is only used to distinguish the position from the "circumferential edge clean edge 51" and "circumferential edge edge 52" described below. The same applies to the "circumferential edge clean edge 51" and "circumferential edge edge 52" described below. A concave structure is provided around the cutter body where the center drill tip 3 is located, and the concave structure is located at the junction of the center drill tip 3 and the outer drill tip 4. In this embodiment, the concave structure is an R-angle 38, with a width of 0.02-0.05 mm and a radius of 0.1-0.8 mm. This not only improves the problem of poor machining results caused by the poor transition between the center drill tip 3 and the outer drill tip 4, but also reduces stress concentration on the center drill tip 3 during machining.

[0052] The outer drill tip 4 includes outer drill tip cutting edges 41 corresponding to the number and position of the center drill tip cutting edges 31. In this embodiment, two outer drill tip cutting edges 41 are provided, thereby forming a three-point structure with two outer drill tips 4 and one center drill tip 3. Each outer drill tip cutting edge 41 is provided with an outer drill tip first back angle and an outer drill tip second back angle, and forms an outer drill tip first back angle surface 42 and an outer drill tip second back angle surface 43 respectively. The positions of the outer drill tip first back angle surface 42 and the outer drill tip second back angle surface 43 correspond to the center drill tip first back angle surface 32 and the center drill tip second back angle surface 33 respectively. Among them, the angle of the outer drill tip first back angle is 7°~9°, the angle of the outer drill tip second back angle is 20°~30°, and the angle Q of the outer drill tip 4 is 175°~180° (Q is the angle between the two outer drill tip cutting edges 41, as shown in FIG. Figure 6 shown);

[0053] A spirally extending circumferential blade cleaning edge 5 is provided on the circumferential side of the cutter head, and a circumferential blade 6 is provided on the circumferential blade cleaning edge 5 which is on the same side as the outer drill tip cutting edge 41 and has the same spiral extension direction as the circumferential blade cleaning edge 5. The circumferential blade 6 includes a circumferential blade edge 61, a cylindrical blade band 62 and a supporting blade 63 which are arranged in sequence from near to far from the outer drill tip 4. The cutting edges of the circumferential blade edge 61 and the cylindrical blade band 62 are circular blades and are set in an inverted cone. The cylindrical blade band 62 is also provided with a back angle, and the blade diameter size of the cylindrical blade band 62 is respectively larger than the blade diameter size of the circumferential blade edge 61 and the blade diameter size of the supporting blade 63. The inverted taper range of the peripheral edge 61 and the cylindrical land 62 is BT0.08-0.15 / 100, the back angle of the cylindrical land 62 is 2°-5°, the cylindrical land 62 is uniformly width-set, and its width is 0.02-0.05 mm. The difference between the edge diameter of the cylindrical land 62 and the edge diameter of the peripheral edge 61 is 0.2 mm, and the difference between the edge diameter of the cylindrical land 62 and the edge diameter of the supporting edge 63 is 0.005 mm.

[0054] As previously known, the cutter head 1 is made of a PCD-cemented carbide composite rod. Therefore, in this embodiment, the center drill tip 3, the outer drill tip 4, the peripheral cutting edge 61, and the cylindrical cutting land 62 are all provided on the PCD segment, i.e., PCD cutting edges, while the supporting cutting edge 63 is provided on the cemented carbide segment, i.e., cemented carbide cutting edges, thereby forming cutting edge forms with different structures and materials.

[0055] A chip removal groove 7 is formed on the circumference of the cutter head 1 and spirally extends from the outer drill tip 3 toward the tool shank 2 .

[0056] The processing technology of the drill bit according to one embodiment of the present invention is as follows:

[0057] 1) Select PCD-carbide composite rod (PCD and carbide are composited together through a composite sheet, with a PCD segment at one end and a carbide segment at the other end) as the cutter head 1, and select a carbide rod of the same diameter for the cutter handle 2;

[0058] 2) Using slow wire cutting equipment to perform V-shaped cutting on the carbide end of the PCD-carbide composite rod and the carbide rod to form matching V-shaped ends;

[0059] 3) Using a silver brazing process to weld the V-shaped end of the PCD-carbide composite rod and the carbide rod to form a drill bit;

[0060] 4) Bonding a small carbide block to the end face of the PCD segment of the PCD-carbide composite rod, using an electric spark fine hole discharge machine to discharge-drill the ends of the carbide block and the carbide rod, and using a hole grinding device to grind the small holes drilled by discharge at a 60° cone angle to form a top hole on the carbide block and the carbide rod. Using the top hole, the drill bit is placed on the external cylindrical grinder for processing;

[0061] 7) Use external cylindrical grinding to process the outer diameter, step difference and back taper of the drill bit. The outer diameter runout of PCD-carbide composite rods is required to be ≤0.003mm and the roughness is ≤Ra0.3. The outer diameter runout of carbide rods is required to be ≤0.005μm and the roughness is ≤Ra0.4.

[0062] 8) Remove the carbide block and chamfer the tool handle using a tool grinder;

[0063] 9) Using a CNC grinder, a PCD-carbide composite rod is slotted and a center drill tip 3, an outer drill tip 4, and a peripheral cutting edge 6 are machined. The PCD segment is electro-discharge machined using a copper wheel, and the carbide segment is ground using a diamond grinding wheel. The slotting angle A ranges from 10°≤A≤40°, the slotting rake angle B ranges from 8°≤B≤15°, and the cutter head core thickness dimension is d=k*d2 (d is the core thickness dimension; k is a constant, generally 0.25-0.35; d2 is the actual cutting edge diameter dimension of the drill bit);

[0064] 10) In order to ensure smooth chip removal, use a grinding wheel to polish the slotting rake face, the first clearance angle surface 32 of the center drill tip and the chip groove 35. The polishing depth of the slotting rake face is 0.002~0.005mm, and the polishing depth of the first clearance angle surface 32 of the center drill tip and the chip groove 35 is 0.002~0.005mm.

[0065] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A drill bit, characterized in that: The cutter head comprises a center drill tip and an outer drill tip located at the front end thereof, wherein the center drill tip is axially farther from the tool shank than the outer drill tip, and the cutter body diameter at the center drill tip is smaller than the cutter body diameter at the outer drill tip, the center drill tip comprises at least two center drill tip cutting edges, the outer drill tip comprises an outer drill tip cutting edge corresponding to the center drill tip cutting edge, and a spirally extending chip removal groove is provided on the circumference of the cutter head; A center drill tip cleaning edge is provided on the peripheral side of the cutter body where the center drill tip is located, and a center drill tip edge is provided on the center drill tip cleaning edge on the same side as the center drill tip cutting edge; An inner concave structure is provided on the peripheral side of the cutter body where the central drill tip is located, and the inner concave structure is located at the connection between the central drill tip and the outer drill tip; The angle Q of the outer drill tip is 175° to 180°.

2. The drill bit according to claim 1, characterized in that The cutter head is a PCD-hard alloy composite rod, which includes a PCD segment and a hard alloy segment. The central drill tip and the outer drill tip are located in the PCD segment.

3. The drill bit according to claim 1, characterized in that The angle W of the center drill tip is 120°~140°.

4. The drill bit according to claim 1, wherein The center drill tip includes two center drill tip cutting edges, each of the center drill tip cutting edges is provided with a first center drill tip clearance angle and a second center drill tip clearance angle, and respectively forms a first center drill tip clearance angle surface and a second center drill tip clearance angle surface. A chisel edge is formed at the connection of the two center drill tip cutting edges, and chip grooves are provided on both sides of the chisel edge.

5. The drill bit according to claim 4, characterized in that The first clearance angle of the center drill tip is 7° to 9°, and the second clearance angle of the center drill tip is 20° to 30°.

6. The drill bit according to claim 4, characterized in that The outer drill tip cutting edge is provided with an outer drill tip first clearance angle and an outer drill tip second clearance angle, and forms an outer drill tip first clearance angle surface and an outer drill tip second clearance angle surface respectively.

7. The drill bit according to claim 6, wherein The first clearance angle of the outer drill tip is 7° to 9°, and the second clearance angle of the outer drill tip is 20° to 30°.

8. The drill bit according to claim 1, wherein The length of the center drill tip edge is 0.5 to 2.5 mm.

9. The drill bit according to claim 1, wherein The width of the concave structure is 0.02 ~ 0.05 mm.

10. The drill bit according to claim 1, wherein The concave structure is an R angle.

11. The drill bit according to claim 10, wherein The radius of the R angle is 0.1 ~ 0.8 mm.

12. The drill bit according to claim 1, wherein A spirally extending circumferential edge cleaning is provided on the circumference of the cutter head, and a circumferential edge is provided on the circumferential edge cleaning which is on the same side as the outer drill tip cutting edge and has the same spiral extending direction as the circumferential edge cleaning.

13. The drill bit according to claim 12, wherein: The circumferential blade includes a circumferential blade edge, a cylindrical land, and a supporting edge, which are arranged in sequence from near to far from the outer drill tip. The cutting edges of the circumferential blade edge and the cylindrical land are circular and inverted tapered. The cylindrical land is also provided with a relief angle. The cutting edge diameter of the cylindrical cutting edge is larger than the cutting edge diameter of the peripheral cutting edge and the cutting edge diameter of the supporting cutting edge.

14. The drill bit according to claim 13, wherein The peripheral blade edge and the cylindrical blade band are PCD blades, and the supporting blade is a cemented carbide blade.

15. A production process for a drill bit, characterized in that: Slotting a bar and processing a drill bit according to any one of claims 1 to 14, comprising the following steps: 1) Select PCD-carbide composite rod as the cutter head: PCD and carbide are composited together through a composite sheet, with one end being a PCD segment and the other end being a carbide segment; the tool holder is made of carbide rod of the same diameter; 2) Welding the cutter head and handle; 3) Bond a small carbide block to the end face of the PCD segment of the PCD-carbide composite rod, use an electric spark fine hole discharge machine to discharge drill holes in the carbide block and the end of the carbide rod, and use a hole grinding device to grind the small holes drilled by discharge at a 60° cone angle to form a top hole on the carbide block and the carbide rod. Use the top hole to place the drill bit on the external cylindrical grinder for processing; 4) When using external cylindrical grinding to process the outer diameter, step difference, and back taper of the drill bit, the outer diameter runout of the PCD-carbide composite rod must be ≤0.003mm and the roughness must be ≤Ra0.

3. The outer diameter runout of the carbide rod must be ≤0.005μm and the roughness must be ≤Ra0.

4. 5) Remove the carbide block and chamfer the tool holder using a tool grinder; 6) Use a CNC grinder to slot the PCD-carbide composite rod and machine the center drill tip, outer drill tip, and peripheral cutting edge. The PCD segment is electro-discharge machined using a copper wheel, and the carbide segment is ground using a diamond grinding wheel. The slot angle A ranges from 10°≤A≤40°, and the slot rake angle B ranges from 8°≤B≤15°. The core thickness of the cutter head is d = k * d², where d is the core thickness; k is a constant, generally 0.25 to 0.35; and d² is the actual cutting edge diameter of the drill bit. 7) In order to ensure smooth chip removal, use a grinding wheel to polish the slotting rake face, the first clearance angle surface of the center drill tip and the chip groove. The polishing depth of the slotting rake face is 0.002~0.005mm, and the polishing depth of the first clearance angle surface of the center drill tip and the chip groove is 0.002~0.005mm.

16. The production process of a drill bit according to claim 15, characterized in that: The cutter head and the cutter handle are V-welded.

Images