Micro drill bit and processing technology thereof

Abstract

The present application relates to the technical field of printed circuit board cutter, disclose a micro drill and its processing technology, micro drill includes drill handle and is arranged in the drill handle end portion drill body, the end of the drill body away from the drill handle is drill tip, and the other end is drill tail, the circumferential side of the drill body is provided with at least two spiral grooves which extend from the drill tip to the drill tail, by opening the spiral groove on the basis of the spiral groove edge along the trend of the spiral groove grinding back, and the length of the grinding back extends to the end of the spiral groove or the front end of the spiral groove end, to increase the width of the chip flute, the chip removal effect is better, the width of the grinding back gradually increases from the drill tip to the drill tail, so that the friction between the hole wall can be reduced when drilling, reduce the generation of drilling heat, ensure the hole position accuracy of drilling, therefore, by the above grinding back can realize the purpose of improving the chip removal effect and improving the hole wall roughness without reducing the rigidity of the micro drill core diameter, improve the comprehensive performance of the micro drill.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board cutters, and particularly relates to a micro drill bit and a processing technology thereof. BACKGROUND

[0002] With the comprehensive development and application of 5G technology, the structures and thicknesses of various printed circuit board (PCB) materials also change, and many materials with relatively thick thicknesses appear. In the processing of such materials, problems such as dust, copper scraps, impurities and rough hole walls in the hole caused by poor dust removal are prone to occur.

[0003] To solve the above problems, the existing technology often improves the poor dust removal by increasing the helix angle of the drill bit and reducing the core thickness of the drill bit, so as to improve the roughness of the hole wall. However, simply increasing the helix angle and reducing the core thickness will reduce the rigidity of the drill bit, and the decrease in rigidity will cause a series of problems such as drill breakage and poor hole position accuracy.

[0004] Therefore, it is urgent to design a new micro drill bit and a processing technology to improve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a micro drill bit and a processing technology, which can improve the dust removal performance of drilling the PCB material with relatively thick thickness and can not reduce the overall rigidity of the drill bit, so as to ensure the comprehensive performance of the drill bit.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The micro drill bit provided by the present application comprises a drill shank and a drill body arranged at the end of the drill shank. The end of the drill body away from the drill shank is a drill tip, and the other end is a drill tail. At least two spiral grooves are arranged on the side of the drill body and extend spirally from the drill tip to the drill tail. An edge of the spiral groove is provided with a grinding back along the spiral direction of the spiral groove. The grinding back starts at the drill tip and ends at the end of the spiral groove or the front end of the end of the spiral groove. The spiral groove and the grinding back constitute a chip removal groove. The groove width of the chip removal groove gradually increases from the drill tip to the drill tail.

[0008] As a preferred solution of the micro drill bit, the groove width of the chip removal groove at the drill tail is more than twice the groove width of the chip removal groove at the drill tip.

[0009] As a preferred solution of the micro drill bit, the drill body comprises:

[0010] a UC large head portion, which is the front end of the drill tip;

[0011] The neck, defined as the distance from the front end of the drill tip to the middle and rear end of the drill tee, wherein the diameter of the end of the neck near the drill tip is smaller than the diameter of the end of the neck near the drill tee; and

[0012] Tail end, which is the tail end of the drill bit.

[0013] As a preferred embodiment of the micro drill bit, two spiral grooves are provided, and two cutting edges are formed on the periphery of the drill body through the two spiral grooves. The width of the cutting edges is the same at the large head of the UC, and the width of the cutting edge at the neck is greater than the width of the cutting edge at the large head of the UC, and is maintained until the end of the grinding back position.

[0014] As a preferred embodiment of a micro drill bit, the length of the neck is less than the length of the chip removal groove along the axial direction of the drill body.

[0015] As a preferred embodiment of a micro drill bit, the helix angle of the helical groove at the drill tip is less than or equal to the helix angle of the helical groove at the drill tread.

[0016] As a preferred embodiment of micro drill bits, the large head of the UC maintains the same helix angle.

[0017] As a preferred embodiment of a micro drill bit, the drill body is configured in a UC type.

[0018] As a preferred embodiment of a micro drill bit, the end periphery of the drill shank is provided with a transition tapered surface, and the end face formed by the transition tapered surface of the drill shank is fixedly connected to the drill tail of the drill body.

[0019] The processing technology for the micro drill bit provided by this invention includes the aforementioned micro drill bit, and its processing steps are as follows:

[0020] S1: Welding, which involves welding one end of the drill shank to the drill tail of the drill body for fixation;

[0021] S2: Shank and drill diameter grinding process, the diameter of the drill shank is finely ground to the required diameter, and the drill body is ground to the required diameter;

[0022] S3: Chip removal groove machining, the chip removal groove is ground out on the circumference of the drill body;

[0023] S4: Drill tip machining of the drill body, grinding a sharp point at the drill tip of the drill body;

[0024] S5: Grind the back and cut out the neck diameter. Grind the back on the circumference of the drill body using a grinding wheel, and then grind out the neck diameter of the drill body.

[0025] The beneficial effects of this invention are:

[0026] The present invention provides a miniature drill bit that, based on the existing spiral groove, grinds a back along the direction of the spiral groove at its edge, with the length of the back extending to the end of the spiral groove or the front end of the end of the spiral groove. This increases the width of the chip removal groove, resulting in better chip removal. At the same time, the width of the back gradually increases from the drill tip to the drill tail, thereby reducing friction with the hole wall during drilling, reducing drilling heat generation, and ensuring the accuracy of the hole position. Therefore, by grinding the back, the miniature drill bit can improve chip removal and hole wall roughness without reducing the core diameter rigidity, thus improving the overall performance of the miniature drill bit.

[0027] The present invention provides a processing technology for a micro drill bit, which improves chip removal effect and hole wall roughness by grinding chip grooves on the circumference of the drill body. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the semi-finished structure of the micro drill bit provided in the embodiment of the present invention before the chip removal groove is set;

[0029] Figure 2 This is a schematic diagram of the overall structure of the micro drill bit provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic cross-sectional view of the chip removal groove of the micro drill bit provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the cross-sectional structure of the micro drill bit and its three parts provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a micro drill bit for machining a grinding back provided in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the micro drill bit cutting out the neck diameter provided in an embodiment of the present invention;

[0034] Figure 7 This is a flowchart of the processing technology of the micro drill bit provided in the embodiments of the present invention.

[0035] In the picture:

[0036] 1. Drill shank; 11. Transition taper surface;

[0037] 2. Drill body; 21. UC head; 22. Neck; 23. Tail;

[0038] 3. Chip removal groove; 31. Spiral groove; 32. Grinding back;

[0039] 4. Blade band. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0041] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0044] When processing thick printed circuit board materials, problems such as dust, copper shavings, impurities, and rough hole walls can easily occur due to poor dust removal. Existing solutions often improve dust removal by increasing the helix angle of the drill bit and reducing the core thickness, thereby improving the roughness of the hole wall. However, simply increasing the helix angle and reducing the core thickness will reduce the rigidity of the drill bit. The decrease in rigidity will lead to a series of problems such as drill breakage and poor hole position accuracy.

[0045] To solve the above problems, combined with Figures 1-4As shown, this embodiment provides a miniature drill bit, including a drill shank 1 and a drill body 2 disposed at the end of the drill shank 1. The end of the drill body 2 away from the drill shank 1 is the drill tip, and the other end is the drill tail. At least two spiral grooves 31 are provided on the periphery of the drill body 2, extending spirally from the drill tip to the drill tail. A grinding back 32 is provided on the edge of the spiral groove 31 along its spiral direction. The grinding back 32 starts at the drill tip and ends at the end of the spiral groove 31 or at the front end of the end of the spiral groove 31. The spiral groove 31 and the grinding back 32 constitute a chip removal groove 3. The width of the chip removal groove 3 gradually increases from the drill tip to the drill tail.

[0046] It is understandable that by grinding a back 32 along the direction of the spiral groove 31 on the edge of the spiral groove 31, and extending the length of the back 32 to the end of the spiral groove 31 or the front end of the end of the spiral groove 31, the width of the chip removal groove 3 is increased, resulting in better chip removal. At the same time, the width of the back 32 gradually increases from the drill tip to the drill tail, thereby reducing friction with the hole wall during drilling, reducing drilling heat generation, and ensuring the hole position accuracy. Therefore, by using the aforementioned back 32, the chip removal effect and hole wall roughness can be improved without reducing the core diameter rigidity of the micro drill bit, thus improving the overall performance of the micro drill bit.

[0047] Specifically, the drill body 2 is a UC-type design. The UC-type design can reduce the contact area and friction between the drill body 2 and the PCB board, resulting in a lower drilling temperature and improved hole wall quality. Since the UC-type drill body 2 is existing technology, it will not be described in further detail here.

[0048] Specifically, the width of the spiral groove 31 formed by opening the spiral groove 31 is Gw1, and the width of the grinding back 32 provided along the edge of the spiral groove 31 is Gw2. Thus, the width of the chip removal groove 3 is further widened by the grinding back 32, making the width of the chip removal groove 3 Gw, where Gw = Gw1 + Gw2. Preferably, the width of the chip removal groove 3 at the drill tee is more than twice the width of the chip removal groove 3 at the drill tip, thereby ensuring the overall width of the chip removal groove 3.

[0049] like Figure 1 As shown, in this embodiment, the drill shank 1 is made of steel, and the drill body 2 is made of cemented carbide. A transition tapered surface 11 is provided on the periphery of the end of the drill shank 1, and the end face formed by the transition tapered surface 11 is welded and fixed integrally with the drill tail of the drill body 2. Exemplarily, high-frequency brazing is used for the connection. The diameter of the drill body 2 ranges from 0.075mm to 0.45mm, thus forming a small-diameter or extremely small-diameter micro-drill bit. Preferably, in this embodiment, the diameter of the drill body 2 is 0.095mm, and the shank diameter of the drill shank 1 is 3.175mm.

[0050] Specifically, such as Figures 1-3As shown, the drill body 2 includes a UC head 21, a neck 22, and a tail 23. The UC head 21 is the front end of the drill tip, and its length is Lh. The neck 22 extends from the front end of the drill tip to the middle and rear end of the drill tail, and its length is Luc. The tail 23 is the tail end of the drill tail. The diameter of the neck 22 near the drill tip is smaller than the diameter of the neck 22 near the drill tail. It should be noted that the diameter of the neck 22 forms a certain taper, i.e., the diameter of the neck 22 near the drill tip is Duc1, the diameter of the neck 22 near the drill tail is Duc2, and the diameter of the drill hole is D (not shown in the figure), satisfying the following formula: Duc1 < Duc2 ≤ D. In this embodiment, the necking taper is 0.002 / 1mm. This design ensures the overall strength of the tail 23 of the drill body 2 and reduces friction to decrease the occurrence of tool breakage.

[0051] Furthermore, such as Figure 2 As shown, the length of the neck 22 is less than the grooving length of the chip removal groove 3 along the axial direction of the drill body 2. Specifically, the grooving length of the spiral groove 31 is L2, the length of Lh ranges from 0.35mm to 0.65mm, and the length of Luc ranges from L2 / 2 ≤ Luc ≤ L2. The length of the grinding back 32 is L4, which is equal to or greater than the length of the neck 22, and less than or equal to the grooving length of the spiral groove 31, i.e., Luc ≤ L4 ≤ L2. It should be noted that in the prior art, the length of the grinding back 32 usually ends just past the large head 21 of the UC. In this embodiment, the length of the grinding back 32 is usually lengthened to further improve the chip removal and heat dissipation effects.

[0052] Furthermore, the diameter of the grinding back 32 at the tread of the drill bit is DR2, and the diameter of the grinding back 32 at the drill tip of the drill bit is DR1. DR2 > DR1, and the range of DR2 is (80% to 90%) × φD (outer diameter of the drill bit), while the range of DR1 is (85% to 95%) × φD (outer diameter of the drill bit).

[0053] Preferably, such as Figure 2 As shown, the helix angle of the helical groove 31 at the drill tip is less than or equal to the helix angle of the helical groove 31 at the drill tread, and the large head 21 of the UC maintains the same helix angle. The helix angle of the helical groove 31 at the drill tip is y1 and ranges from 35° to 45°, and the helix angle of the helical groove 31 at the drill tread is y2 and ranges from 45° to 55°. For example, y1 = 45° ± 2°; y2 = (45° to 52°) ± 2°.

[0054] Preferably, two spiral grooves 31 are provided, forming two cutting edges 4 on the periphery of the drill body 2 through the two spiral grooves 31. The width of the cutting edges 4 remains the same at the large head 21 of the UC, and the width of the cutting edges 4 at the neck 22 is greater than that at the large head 21 of the UC, and is maintained until the end of the back grinding 32. The width of the cutting edges 4 at the large head 21 of the UC is b and remains unchanged. The width of the cutting edges 4 near the drill tip is b1, and the width of the cutting edges 4 near the drill tee is b2, where b1 ≤ b2. The range of the width of the cutting edges 4 near the drill tip is (10% to 20%) × φD (drill bit outer diameter), and the range of the width of the cutting edges 4 near the drill tee is (20% to 30%) × φD (drill bit outer diameter).

[0055] Of course, in other embodiments, four spiral grooves 31 may be provided, and the number of cutting edges 4 corresponds to the number of spiral grooves 31. Increasing the number of spiral grooves 31 can also improve the chip removal effect of the micro drill bit. Therefore, this embodiment does not limit the specific number of spiral grooves 31.

[0056] like Figures 5-7 As shown, this embodiment also provides a processing technology for a micro drill bit, including the aforementioned micro drill bit, the processing steps of which are as follows (see...). Figure 7 ):

[0057] S1: Welding, welding one end of the drill shank 1 to the drill tail of the drill body 2 to fix them together;

[0058] S2: Shank and drill diameter grinding process, the diameter of drill shank 1 is finely ground to 3.175mm, and drill body 2 is ground to the required diameter: φ0.075~φ0.45mm;

[0059] S3: Chip removal groove 3 machining: Two spiral grooves 31 are ground on the periphery of the drill body 2, and a grinding back 32 is ground on the edge of the spiral grooves 31. Ensure that the grinding back 32 starts at the drill tip of the drill body 2 and ends at the end of the spiral grooves 31 or the front end of the end of the spiral grooves 31. The angle change of the chip removal groove 3 formed by the spiral grooves 31 and the grinding back 32 is specifically set on the machining equipment.

[0060] S4: Drill tip machining of drill body 2, grinding a sharp point at the drill tip of drill body 2, wherein the grinding angle can be adjusted adaptively according to design requirements, and this embodiment does not specifically limit it;

[0061] S5: Grind the back 32mm and cut out the neck diameter 22mm (see...) Figure 5 and Figure 6The grinding back 32 is machined on the periphery of the drill body 2 using a grinding back 32 grinding wheel, and the neck 22 diameter of the drill body 2 is machined using a UC grinding wheel. It should be noted that the grinding back 32 and the neck 22 diameter are machined in the same station. The grinding back 32 grinding wheel and the UC grinding wheel are mounted on the same grinding wheel shaft. The specific structure is existing technology and will not be described in detail.

[0062] It is understandable that by grinding a spiral groove 31 on the periphery of the drill body 2, and grinding a back 32 along the direction of the spiral groove 31 at the edge of the spiral groove 31, with the length of the back 32 extending to the end of the spiral groove 31 or the front end of the end of the spiral groove 31, the width of the chip removal groove 3 is increased, resulting in better chip removal. At the same time, the width of the back 32 gradually increases from the drill tip to the drill tail, thereby reducing friction with the hole wall during drilling and reducing the generation of drilling heat. In this way, the chip removal effect and hole wall roughness are improved without reducing the rigidity of the micro drill core diameter.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A miniature drill bit, characterized in that, The drill body includes a drill shank (1) and a drill body (2) disposed at the end of the drill shank (1). One end of the drill body (2) away from the drill shank (1) is the drill tip, and the other end is the drill tail. At least two spiral grooves (31) extending spirally from the drill tip to the drill tail are provided on the periphery of the drill body (2). A grinding back (32) is provided along the spiral direction of the edge of the spiral groove (31). The grinding back (32) starts at the drill tip and ends at the end of the spiral groove (31) or at the front end of the end of the spiral groove (31). The spiral groove (31) and the grinding back (32) constitute a chip removal groove (3). The width of the chip removal groove (3) gradually increases from the drill tip to the drill tail. The diameter of the grinding back (32) at the drill tail is DR2, and the diameter of the grinding back (32) at the drill tip is DR1, where DR2 > DR1.

2. The miniature drill bit according to claim 1, characterized in that, The width of the chip removal groove (3) located at the drill twig is more than twice the width of the chip removal groove (3) located at the drill tip.

3. The miniature drill bit according to claim 2, characterized in that, The drill body (2) includes: UC large head (21), wherein the UC large head (21) is the front end of the drill tip; Neck (22), the neck (22) being the distance from the front end of the drill tip to the middle and rear end of the drill tee, wherein the diameter of the end of the neck (22) near the drill tip is smaller than the diameter of the end of the neck (22) near the drill tee; and Tail (23), the tail (23) is the tail end of the drill tail.

4. The miniature drill bit according to claim 3, characterized in that, Two spiral grooves (31) are provided, and two cutting edges (4) are formed on the periphery of the drill body (2) through the two spiral grooves (31). The width of the cutting edges (4) is the same as that of the large head (21) of the UC. The width of the cutting edge (4) of the neck (22) is greater than that of the cutting edge (4) of the large head (21) of the UC, and is maintained until the end of the grinding back (32).

5. The miniature drill bit according to claim 3, characterized in that, The length of the neck (22) is less than the length of the chip removal groove (3) along the axial direction of the drill body (2).

6. The miniature drill bit according to claim 3, characterized in that, The helix angle of the helical groove (31) at the drill tip is less than or equal to the helix angle of the helical groove (31) at the drill tail.

7. The miniature drill bit according to claim 6, characterized in that, The large head (21) of the UC maintains the same helix angle.

8. The miniature drill bit according to any one of claims 1 to 7, characterized in that, The drill body (2) is of the UC type.

9. The miniature drill bit according to any one of claims 1 to 7, characterized in that, The end of the drill shank (1) is provided with a transition cone surface (11), and the end face formed by the transition cone surface (11) of the drill shank (1) is fixedly connected to the drill tail of the drill body (2).

10. The processing technology of micro drill bits, characterized in that, For machining the micro drill bit as described in any one of claims 1-9, the machining steps are as follows: S1: Welding, welding one end of the drill shank (1) to the drill tail of the drill body (2) for fixation; S2: Shank diameter and drill diameter grinding process, the diameter of the drill shank (1) is finely ground to the required diameter, and the drill body (2) is ground to the required diameter; S3: Chip removal groove (3) machining, the chip removal groove (3) is ground out on the circumferential side of the drill body (2); S4: Drill tip machining of the drill body, grinding a sharp point at the drill tip of the drill body (2); S5: Machining the back (32) and cutting out the neck (22) diameter. The back (32) is machined on the periphery of the drill body (2) using a grinding wheel, and then the neck (22) diameter of the drill body (2) is machined.

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