Drill and method of making same
By associating the rake angle and the back edge width of the drill bit in the PCB board with 2α-150n+3=0, a double circular arc cutting edge structure was designed, which solved the problems of drill bit chipping and hole wall roughness during the drilling process, achieving high-quality drilling effect and cost control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG DTECH TECH CO LTD
- Filing Date
- 2023-05-11
- Publication Date
- 2026-07-03
AI Technical Summary
Existing PCB board drill bits have problems such as chipping of the cutting edge and back of the cutting edge, and high roughness of the hole wall during the drilling process. Improper rake angle setting leads to poor drilling quality, high cost, and frequent tool replacement.
By relating the angle of the rake angle to the width of the cutting edge back as 2α-150n+3=0, a rigid structure for the cutting edge and the cutting edge back is designed. A double circular arc cutting edge with radial projection is adopted to ensure the rigidity of the cutting edge and its surroundings, reduce the width of the cutting edge back, and improve the machining quality of the hole wall.
It effectively improves the rigidity of the drill bit's cutting edge and surrounding area, reduces the drill bit's production cost, enhances the hole wall's processing quality and drilling effect, and reduces manufacturing difficulty.
Smart Images
Figure CN116476173B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a drilling tool, and more particularly to a drill bit and a method for manufacturing the same. Background Technology
[0002] Drilling PCBs often presents a combination of problems, including high hole wall roughness, chipping of the drill bit's cutting edge and back edge, and poor rigidity at the drill tip. Specifically, the cutting edge at the drill bit's tip has a rake angle (the rake angle is the angle between the rake face and the base plane measured in an orthogonal plane. The rake face directly acts on the material being cut and controls the chip discharge; the base plane is the plane passing through a specified point on the main cutting edge and perpendicular to the cutting velocity direction at that point). A back edge exists on the outer side of the cutting edge. During drilling, to improve drilling quality, an excessively large rake angle and a narrow back edge can easily cause chipping at the drill tip or back edge. Increased cutting edge wear leads to poor hole wall quality, frequent tool changes, and high costs. While a smaller rake angle combined with a wider back edge can improve the rigidity of the cutting edge and back edge and solve the chipping problem, an excessively wide back edge results in high hole wall roughness and reduced hole wall machining quality. Therefore, the setting of the rake angle and back edge of the drill bit used for drilling PCBs has become a key factor in improving the drilling quality of PCBs. Summary of the Invention
[0003] The purpose of this invention is to provide a drill bit that can ensure the rigidity of the cutting edge and its surroundings, making the cutting edge and back less prone to chipping, and improving the quality of hole wall machining.
[0004] Another objective of this invention is to provide a method for manufacturing a drill bit, wherein the drill bit has high rigidity of its cutting edge, back edge, and edge band, and high quality of hole wall machining.
[0005] To achieve the above objectives, the drill bit provided by the present invention includes a needle body, the front end of which is provided with a cutting edge, a back edge, and a cutting edge band. The cutting edge band is connected to the back edge. The cutting edge has a rake angle, and the angle of the rake angle and the width of the back edge satisfy the following relationship: 2α-150n+3=0, where α represents the angle of the rake angle, n represents the width of the back edge, and 0.02mm≤n≤0.06mm is used for calculation.
[0006] Compared with the prior art, the present invention links the angle α of the rake angle with the width n of the cutting edge back in a certain mathematical relationship, thereby enabling the drill bit to ensure the rigidity of the cutting edge and its surroundings, making the cutting edge and cutting edge back less prone to chipping, while effectively improving the processing quality of the hole wall. This not only controls the production cost of the drill bit and improves the processing effect of the drill bit, but also ensures the processing quality of the hole wall of the product.
[0007] Preferably, the width of the cutting edge back is 0.02 mm, and the rake angle is 0 degrees. This results in a very small rake angle, a straight cutting edge, ensuring the sharpness of the cutting edge, while the narrower cutting edge back reduces the squeezing friction with the hole wall, improving the quality of the hole wall.
[0008] Preferably, the projection line of the radial projection of the cutting edge includes a first arc segment and a second arc segment connected in sequence. By setting the first arc segment and the second arc segment, the circumferential width of the cutting edge back can be reduced while ensuring the rigidity of the cutting edge and its surroundings, making the cutting edge and cutting edge back less prone to chipping and improving the machining quality of the hole wall.
[0009] Specifically, the radius of the first arc segment The radius of the second arc segment The relationship between the radius R of the drill bit and the following is: < <R。
[0010] Specifically, a rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit as the origin. The center P of the first arc segment is located at point (0, b) in the rectangular coordinate system, and the center O of the second arc segment is located at the origin (0, 0) in the rectangular coordinate system. The first arc segment is: (nL≤ ≤0.24R); the second arc segment is: (0.24R≤ ≤0.78R);
[0011] in, R is the radius of the drill bit, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit, nL < 0; b+ >R, and |b- |≤R; It is 85%-95% of R. By using numerical calculation methods to design the double circular arc cutting edge, the shape and size of the cutting edge can be quickly determined, and the optimal solution can be accurately designed, so that the drill bit achieves the optimal structure, effectively reducing the manufacturing difficulty of the drill bit, increasing the processing speed of the drill bit, and improving the drilling effect of the drill bit.
[0012] Specifically, b is 74% of the drill bit radius R. 30% of R It is 90% of R. By taking the above value, the first and second arc segments can achieve the best effect, ensuring that the drill bit has the optimal structure.
[0013] Preferably, the cutting edge, the back of the cutting edge, and the cutting edge band are arranged symmetrically around the center of the drill bit.
[0014] A method for manufacturing a drill bit includes the following steps:
[0015] Provide a drill bit, and determine the radius R, core thickness, rake angle α of the cutting edge, and helix angle of the drill bit;
[0016] Calculate the width n of the blade back. The angle α of the front angle and the width n of the blade back satisfy the following relationship: 2α-150n+3=0 (0.02mm≤n≤0.06mm).
[0017] The drill bit body is machined by slotting according to the core thickness and helix angle;
[0018] Based on the angle α of the front angle, the cutting edge is machined on the needle body using a grinding wheel;
[0019] The cutting edge is machined by adjusting the angle of the grinding wheel according to the helix angle and the width n of the cutting edge;
[0020] Adjust the angle of the grinding wheel according to the helix angle to machine the cutting edge.
[0021] Specifically, before processing the needle body, the following steps are also included: calculating the shape and size of the cutting edge based on the radius R, core thickness and width n of the cutting edge, wherein the cutting edge includes a first arc segment and a second arc segment connected in sequence.
[0022] Specifically, a rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit as the origin. The center of the first arc segment is located at point P(0, b) in the rectangular coordinate system, and the center of the second arc segment is located at the origin O(0, 0) of the rectangular coordinate system. The first arc segment is: (nL≤ ≤0.24R); the second arc segment is: (0.24R≤ ≤0.78R);
[0023] in, R is the radius of the drill bit, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit, nL < 0; b+ >R, and |b- |≤R; It is 85%-95% of R. Attached Figure Description
[0024] Figure 1 This is a perspective view of the drill bit of the present invention.
[0025] Figure 2 This is another perspective view of the drill bit of the present invention.
[0026] Figure 3 It is a bottom view of the cutting edge of the drill bit of the present invention.
[0027] Figure 4 It is a structural diagram of the cutting edge, the back of the edge and the land of the drill bit of the present invention.
[0028] Figure 5 It is a flow chart of the manufacturing method of the drill bit of the present invention. Detailed implementation manners
[0029] To describe in detail the technical content, structural features, and achieved effects of the present invention, the following will be described in detail in conjunction with the implementation manners and with reference to the drawings.
[0030] As Figures 1 to 4 shown, the drill bit 100 of the present invention includes a needle body 1, a spiral groove 2 is provided on the needle body 1, a cutting edge 3, a back of the edge 4, a land 5, a rake face and a flank face are provided at the front end of the needle body 1. The rake face is located on the side wall of the spiral groove 2 at the front end of the needle body 1, and the flank face is located at the end face of the front end of the needle body 1. The cutting edge 3, the back of the edge 4 and the land 5 are symmetrically arranged around the center of the drill bit 100. The land 5 is connected to the back of the edge 4. The cutting edge 3 has a rake angle, and the relationship between the angle α of the rake angle and the width n of the back of the edge 4 satisfies the following:
[0031] 2α - 150n + 3 = 0 (0.02 mm ≤ n ≤ 0.06 mm), and its numerical value is calculated.
[0032] Specifically, in this embodiment, preferably, the width n of the back of the edge 4 is 0.02 mm, and the rake angle is 0°. At this time, the cutting edge 3 is linear, ensuring the sharpness of the cutting edge 3, and the relatively narrow back of the edge 4 can reduce the extrusion friction with the hole wall and improve the quality of the hole wall.
[0033] Please refer to Figure 3 and Figure 4 , the projection line of the radial projection of the land 5 includes a first arc 51 and a second arc 52 connected in sequence. The first arc 51 is connected to the back of the edge 4. The radius of the first arc 51, the radius of the second arc 52, and the radius R of the drill bit 100 have the following size relationship: < < R. By setting the first arc 51 and the second arc 52, while reducing the circumferential width of the back of the edge 4, it can ensure the rigidity of the cutting edge 3 and its periphery, making the cutting edge 3, the back of the edge 4 and the land 5 not easy to break, thereby improving the machining quality of the hole wall.
[0034] Please refer to again Figure 3 and Figure 4 A rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit 100 as the origin, with the origin O (0, 0). The cutting edge 3 extends from the origin O to point A, and the cutting back 4 extends from point A to point B. The center of the first arc 51 is located at point P (0, b) in the rectangular coordinate system, and the first arc 51 extends from point B to point C. The second arc 52 extends from point C in a direction away from point B, and the center of the second arc 52 is located at the origin O (0, 0) of the rectangular coordinate system. The first arc 51 and the second arc 52 must satisfy the following relationship:
[0035] The first arc segment is:
[0036] (nL≤ ≤0.24R);
[0037] The second arc segment is:
[0038] (0.24R≤ ≤0.78R);
[0039] in, R is the radius of the drill bit, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit, nL < 0; b+ >R, and |b- |≤R; The radius R is 85%-95% of the core thickness. The radius R and core thickness of the drill bit 100 can be directly obtained by querying or measuring the selected drill bit 100. By using numerical calculation methods to design the double arc cutting edge 5, the shape and size of the cutting edge 5 can be quickly determined, and the best solution can be accurately designed, so that the drill bit 100 achieves the optimal structure, effectively reducing the manufacturing difficulty of the drill bit 100, increasing the processing speed of the drill bit 100, and improving the drilling effect of the drill bit 100.
[0040] For example, to make a drill bit with a radius R of 4mm, a core thickness of 0.350mm, a thread angle of 40°, a primary face angle of 15°, a secondary face angle of 30°, and a rake angle of 0°, the value of the rake angle α and the width n of the cutting edge can be obtained as 0.02mm; based on the drill bit radius R of 4mm, It is 30% of R, which is 1.2mm. 90% of R, which is 3.6mm, and b, which is 74% of the drill bit radius R, which is 2.96mm. Using these values, the cutting edge width n and the first arc ( ), second arc ( The position and radius of the drill bit 100. In this example, b is 74% of the radius R of the drill bit 100. 30% of R Setting R to 90% is a better option. By taking the above values, the first arc segment 51 and the second arc segment 52 can achieve the best effect, ensuring that the drill bit 100 has the optimal structure.
[0041] Compared with the prior art, the present invention links the angle α of the front angle with the width n of the back edge 4 in a certain mathematical relationship, thereby enabling the drill bit 100 to ensure the rigidity of the cutting edge 3 and its surroundings, making the cutting band 5 and the back edge 4 less prone to chipping, while effectively improving the processing quality of the hole wall. This not only controls the production cost of the drill bit 100 and improves the processing effect of the drill bit 100, but also ensures the processing quality of the hole wall of the product.
[0042] Combination Figure 5 The method for manufacturing the drill bit 100 provided by the present invention includes the following steps:
[0043] Step S1: Provide a needle post and determine the radius R, core thickness, rake angle α of the cutting edge 3, and helix angle of the drill bit 100;
[0044] Step S2: Calculate the width n of the blade back 4. The angle α of the front angle and the width n of the blade back 4 satisfy the following relationship: 2α-150n+3=0 (0.02mm≤n≤0.06mm), and take its value for calculation.
[0045] Step S3: Design the cutting edge 5 so that the radial projection of the cutting edge 5 includes a first arc 51 and a second arc 52 connected in sequence. The first arc 51 and the second arc 52 are determined according to the radius R of the drill bit 100, the core thickness, the width n of the cutting edge back 4 and the point P (0, b) to determine the shape and size of the cutting edge 5.
[0046] Step S4: Grooving is performed according to the core thickness and helix angle to process the needle body 1 of the drill bit 100;
[0047] Step S5: Based on the angle α of the front angle, use a grinding wheel to machine the cutting edge 3 on the needle body 1;
[0048] Step S6: Adjust the angle of the grinding wheel to process the cutting edge 4 according to the helix angle and the width n of the cutting edge 4;
[0049] Step S7: Adjust the angle of the grinding wheel according to the helix angle to process the first arc 51 and the second arc 52.
[0050] Specifically, in step 3, a rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit 100 as the origin. The center of the first arc 51 is located at point P(0, b) in the rectangular coordinate system, and the center of the second arc 52 is located at the origin O(0, 0) of the rectangular coordinate system.
[0051] The first arc 51 is: (nL≤ ≤0.24R);
[0052] The second arc 52 is: (0.24R≤ ≤0.78R);
[0053] in, R is the radius of the drill bit 100, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit 100, nL < 0; b+ >R, and |b- |≤R; It is 85%-95% of R.
[0054] The drill bit in this design has a diameter of 4mm, a thread angle of 40°, a core thickness of 0.350mm, a main cutting face angle of 15°, and a secondary cutting face angle of 30°. Furthermore, comparative experiments were conducted on existing drill bits and the drill bit 100 of this design, and the results are as follows:
[0055] Test conditions: The diameter of the existing drill bit (white knife) and the drill bit 100 of this application is 4mm, the processed material is FR4 board, 2 layers, and the board thickness is 2mm.
[0056] Roughness test results of the hole wall (unit: mm):
[0057]
[0058] The test results show that the average hole wall roughness of existing drill bits is 56.35. The average hole wall roughness of drill bit 100 in this application is 16.01. The hole wall roughness of existing drill bits is relatively large, dispersed, and unstable. The hole wall roughness of drill bit 100 in this application is very small, concentrated, and more stable.
[0059] The structure and processing method of the needle body 1 involved in the drill bit 100 and its manufacturing method of the present invention are well known to those skilled in the art, and will not be described in detail here.
[0060] The above-disclosed examples are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention shall still fall within the scope of the present invention.
Claims
1. A drill bit, characterized by: The needle includes a needle body, the front end of which is provided with a cutting edge, a back edge, and a cutting band. The cutting band is connected to the back edge. The cutting edge has a rake angle, and the angle of the rake angle and the width of the back edge satisfy the following relationship: 2α-150n+3=0 Where α represents the angle of the front angle, n represents the width of the back edge of the blade, 0.02mm≤n≤0.06mm, and the values are used for calculation.
2. The drill bit as described in claim 1, characterized in that: The width of the blade back is 0.02 mm, and the rake angle is 0 degrees.
3. The drill bit as described in claim 1, characterized in that: The projection line of the radial projection of the blade includes a first arc segment and a second arc segment connected in sequence.
4. The drill bit as described in claim 3, characterized in that: The radius of the first arc segment The radius of the second arc segment The relationship between the radius R of the drill bit and the following is: < <R。 5. The drill bit as described in claim 3, characterized in that: A rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit as the origin. The center P of the first arc is located at point (0, b) in the rectangular coordinate system, and the center O of the second arc is located at the origin (0, 0) in the rectangular coordinate system. The first arc segment is: (nL≤ ≤0.24R); The second arc segment is: (0.24R≤ ≤0.78R); in, R is the radius of the drill bit, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit, nL < 0; b+ >R, and |b- |≤R; It is 85%-95% of R.
6. The drill bit as described in claim 5, characterized in that: b is 74% of the drill bit radius R. 30% of R It is 90% of R.
7. The drill bit according to any one of claims 1-6, characterized in that: The cutting edge, the back of the cutting edge, and the cutting band are arranged symmetrically around the center of the drill bit.
8. A method for manufacturing a drill bit, characterized in that, Includes the following steps: Provide a drill bit, and determine the radius R, core thickness, rake angle α of the cutting edge, and helix angle of the drill bit; Calculate the width n of the cutting edge back. The angle α of the rake angle and the width n of the cutting edge back satisfy the following relationship: 2α-150n+3=0 (0.02mm≤n≤0.06mm), and its value is used for calculation; The drill bit body is machined by slotting according to the core thickness and helix angle; Based on the angle α of the front angle, the cutting edge is machined on the needle body using a grinding wheel; The cutting edge is machined by adjusting the angle of the grinding wheel according to the helix angle and the width n of the cutting edge; Adjust the angle of the grinding wheel according to the helix angle to machine the cutting edge.
9. The method for manufacturing a drill bit as described in claim 8, characterized in that, Before processing the needle body, the following steps are also included: calculating the shape and size of the cutting edge based on the radius R, core thickness and width n of the cutting edge, wherein the cutting edge includes a first arc surface and a second arc surface connected in sequence.
10. The method for manufacturing a drill bit as described in claim 9, characterized in that, A rectangular coordinate system is established with the radial projection plane as the base plane and the center of the drill bit as the origin. The center P of the first arc is located at point (0, b) in the rectangular coordinate system, and the center O of the second arc is located at the origin (0, 0) in the rectangular coordinate system. The first arc segment is: (nL≤ ≤0.24R); The second arc segment is: (0.24R≤ ≤0.78R); in, R is the radius of the drill bit, ranging from 3mm to 6.5mm; L is half the core thickness of the drill bit, nL < 0; b+ >R, and |b- |≤R; It is 85%-95% of R.