Drill point for PCB (printed circuit board)

Abstract

The utility model discloses a drill point for a PCB, and belongs to the technical field of drill points. The drill point comprises a point body, a chip groove is formed in the point body, a chisel edge is formed at the intersecting line of two main tool faces of the point body, a center thickness thinning groove is formed in the main tool face of the point body in the spiral direction of the point body and formed in the end of the chisel edge, and a transverse grinding tool face is ground at the intersecting line of the center thickness thinning groove and the main tool face. And the transverse grinding cutter surface and the main cutter surface form a drill tip at the midpoint of the transverse cutting edge. The center thickness thinning groove and the transverse grinding knife face are arranged on the needle body, a needle point appears on the main knife face, the needle point can improve drilling positioning accuracy, on the basis that the two main knife faces are based on a large vertex angle, the intersecting line of the transverse grinding knife face and the main knife faces is larger than the length of a chisel edge when the transverse grinding knife face does not exist, and cutting force under unit area is reduced. In conclusion, the needle body is improved, so that the needle body has high positioning accuracy and good operation stability.

Description

Technical Field

[0001] The utility model belongs to the technical field of drill pins, in particular to a drill pin for a PCB board. Background Art

[0002] When drilling with existing PCB drills, the smaller the apex angle of the drill, the more concentrated the contact between the drill and the plate, which means that the initial positioning accuracy of the drilling is high and the drilled hole has good straightness. However, a small apex angle means a small cutting area, which increases the cutting force per unit area, increases the vibration amplitude of the drill when it rotates at high speed, and leads to poor operating stability, and increases the risk of the drill breaking. In order to improve the cutting performance of the drill, a new chip-splitting drill for PCB boards is proposed. Utility Model Content

[0003] Purpose of the utility model: to provide a drill needle for a PCB board to solve the above problems existing in the prior art.

[0004] Technical solution: A drill needle for PCB board, including a needle body, a chip removal groove is provided on the needle body, two main cutting surfaces of the needle body form a transverse edge at the intersection line, a core thickness thinning groove is provided on the main cutting surface of the needle body along the spiral direction of the needle body, the core thickness thinning groove is provided at the end of the transverse edge, a transverse grinding surface is ground at the intersection line of the core thickness thinning groove and the main cutting surface, and the transverse grinding surface and the main cutting surface form a drill tip at the midpoint of the transverse edge.

[0005] Furthermore, a chip breaker groove is provided on the chip removal groove, and the chip breaker groove extends to the main tool surface.

[0006] Furthermore, the ratio of the thickness of the blade of the needle body to the minimum spacing of the core thinning groove is not greater than 2.

[0007] Furthermore, a cutting zone is provided on the side wall of the margin, the cutting zone is aligned with the main cutting surface, and an escape gap is formed between the cutting zone and the margin.

[0008] Furthermore, the needle body is provided with an auxiliary cutting surface, and a back angle is formed between the auxiliary cutting surface and the main cutting surface.

[0009] Beneficial effect: The utility model opens a core-thickening groove and a transverse grinding blade on the needle body, so that a needle tip appears on the main blade surface, and the needle tip can improve the drilling positioning accuracy; based on the large vertex angle, the intersection line of the transverse grinding blade surface and the main blade surface is greater than the length of the transverse edge when there is no transverse grinding blade surface, so that the cutting force per unit area becomes smaller. In summary, the improvement of the needle body by the utility model enables the needle body to have high positioning accuracy and good operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the utility model;

[0011] Figure 2 It is the front view of the utility model;

[0012] Figure 3 It is a cross-sectional schematic diagram of the utility model.

[0013] The accompanying drawings are marked as follows: 1. chip removal groove; 2. core thinning groove; 3. chip breaker groove; 4. auxiliary tool surface; 5. main tool surface; 6. transverse grinding tool surface; 7. cutting belt; 8. needle body. DETAILED DESCRIPTION

[0014] In the following description, a large number of specific details are given to provide a more thorough understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without one or more of these details. In other examples, in order to avoid confusion with the utility model, some technical features known in the art are not described.

[0015] like Figures 1 to 3 As shown, a drill needle for a PCB board includes a needle body 8, a chip removal groove 1 is provided on the needle body 8, two main cutting surfaces 5 of the needle body 8 form a transverse edge at the intersection, a core thickness thinning groove 2 is provided on the main cutting surface 5 of the needle body 8 along the spiral direction of the needle body 8, the core thickness thinning groove 2 is provided at the end of the transverse edge, a transverse grinding surface 6 is ground at the intersection of the core thickness thinning groove 2 and the main cutting surface 5, and the transverse grinding surface 6 and the main cutting surface 5 form a drill tip at the midpoint of the transverse edge.

[0016] The angle between the two main cutting surfaces 5 of the needle body 8 is the vertex angle. The vertex angle of the needle body 8 is usually between 118° and 135°. When a small vertex angle drill starts drilling, the contact points are more concentrated and the positioning accuracy is better. However, the cutting force per unit area of ​​a small vertex angle drill is large. A large cutting force will cause the vibration of the needle tip to intensify. The vibration effect is obvious when drilling harder or more brittle materials. The present application selects the largest vertex angle possible in the range of 118° to 135°. This is because the appearance of the transverse grinding blade 6 causes the original transverse blade position to be ground into a sharp point without affecting the vertex angle. Because the transverse grinding blade 6 sinks relative to the main cutting surface 5, the length of the intersection line between the transverse grinding blade 6 and the main cutting surface 5 is greater than the length of the original transverse blade, and the cutting force per unit area becomes smaller when it participates in cutting. Thus, a needle tip that participates in drilling positioning is obtained, which makes the drilling positioning accuracy higher, and the hole position accuracy and straightness of the hole are improved. The improvement of forming a sharp point by transversely grinding the blade surface 6 not only improves the stability of the large vertex angle drill, but also makes the positioning accuracy between the drill and the workpiece higher.

[0017] The chip groove 1 is provided with a chip breaker groove 3, which extends to the main cutting face 5. The chip breaker groove 3 can divide the cutting of the main cutting edge on the main cutting face 5 into two parts, thereby effectively controlling the size and shape of the chips, and dividing the chips to prevent the long chips from being entangled on the tool or the workpiece; with the chip groove 1 with the core thinning groove 2, the fine chips can be discharged more smoothly.

[0018] The core-thick thinning groove 2 increases the space of the chip removal groove 1, which is beneficial to improving the chip removal and heat dissipation capabilities of the needle body 8. The ratio of the edge thickness of the needle body 8 to the minimum spacing of the core-thick thinning groove 2 is not greater than 2. Figure 3 As shown, the thickness of the blade is H, and the minimum spacing of the core-thick thinning groove 2 is h; under the premise that the material of the drill bit 8 is certain, the thickness of the blade is positively correlated with the structural strength of the drill bit 8, and a wider blade thickness can provide better support and stability; the core-thick thinning groove 2 can avoid stress concentration of the drill bit during the drilling process, thereby reducing the risk of drill bit breakage caused by stress concentration; the weakest part of the overall strength of the drill bit 8 is also at the core-thick thinning groove 2, that is, if the core-thick thinning groove 2 is opened too deep, it will affect the strength of the needle body 8, and if it is opened too shallow, it will weaken its performance in chip removal, heat dissipation and stress dispersion. Therefore, the minimum spacing of the core-thick thinning groove 2 should be reduced as much as possible to h while meeting the strength condition. When H / h>2, the fracture rate of the needle body 8 is higher than that of the needle body 8 without the core-thick thinning groove 2.

[0019] A cutting zone 7 is provided on the side wall of the edge band, and the cutting zone 7 is aligned with the main cutting surface 5, and an escape gap is formed between the cutting zone 7 and the edge band. Figure 2 As shown, when the needle body 8 rotates, the cutting diameter formed by the cutting belt 7 is D, and when the cutting belt 7 is not added, the escape diameter formed by the edge belt is D T , the escape gap should be larger than the chip thickness to facilitate chip discharge, the cutting belt 7 is in direct contact with the hole wall, and the length of the cutting belt 7 along the axial direction of the needle body 8 determines the friction area between the needle body 8 and the hole wall. The friction between the cutting belt 7 and the hole wall can reduce the generation of friction heat. Specifically, 0.82≤D T When / D≤0.92, the hole wall quality is good.

[0020] The needle body 8 is provided with an auxiliary cutting surface 4, and a back angle is formed between the auxiliary cutting surface 4 and the main cutting surface 5. The blade inclination angle of the auxiliary cutting surface 4 is greater than the blade inclination angle of the main cutting surface 5. The formation of the back angle can reduce the cutting force, which is helpful for the discharge of the chips, and is beneficial to improve the surface quality of the drilled hole when the needle body 8 is cut at a high speed.

[0021] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A drill needle for a PCB board, comprising a needle body (8), wherein the needle body (8) is provided with a chip removal groove (1), and two main cutting surfaces (5) of the needle body (8) form a chisel edge at the intersection, characterized in that: A core-thickness thinning groove (2) is provided on the main cutting surface (5) of the needle body (8) along the spiral direction of the needle body (8), the core-thickness thinning groove (2) is provided at the end of the transverse blade, a transverse grinding surface (6) is ground at the intersection of the core-thickness thinning groove (2) and the main cutting surface (5), and the transverse grinding surface (6) and the main cutting surface (5) form a drill tip at the midpoint of the transverse blade.

2. A drill needle for a PCB board according to claim 1, characterized in that: The chip removal groove (1) is provided with a chip breaker groove (3), and the chip breaker groove (3) extends to the main tool surface (5).

3. A drill needle for a PCB board according to claim 1, characterized in that: The ratio of the thickness of the edge band of the needle body (8) to the minimum spacing of the core thinning groove (2) is not greater than 2.

4. A drill needle for a PCB board according to claim 3, characterized in that: A cutting band (7) is provided on the side wall of the edge band, the cutting band (7) is aligned with the main cutting surface (5), and an escape gap is formed between the cutting band (7) and the edge band.

5. A drill needle for a PCB board according to claim 1, characterized in that: The needle body (8) is provided with an auxiliary cutting surface (4), and a back angle is formed between the auxiliary cutting surface (4) and the main cutting surface (5).

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