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 pin comprises a pin body, a chip breaker groove is formed in the middle of a cutting edge of the pin body, the chip breaker groove is sequentially provided with a negative inverted section, a linear section and an arc section from the outer diameter to the inner diameter, and the intersecting line of the negative inverted section and the linear section is lower than the intersecting line of the arc section and the cutting edge. The chip breaker groove is formed in the middle of the cutting edge, a traditional linear arc-shaped groove body structure is optimized into the chip breaker groove with the negative chamfer, the chip breaker groove is formed in the middle of the cutting edge and can divide the chip cutting action into two parts, chips close to the outer edge of the needle body are cut off through the chip breaker groove, and chips close to the axis of the needle body directly enter the chip discharging groove. Due to the design of the negative inverted section, the chip breaking capacity of the chip breaker groove is improved, finally, chips in the chip groove are divided into short chips and long chips, and the utilization rate of the chip groove is improved.

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] At present, the chip size and shape obtained by the chip breaker are relatively consistent. If the chip size is too small, the chips will accumulate in the chip removal groove and the chip removal effect will be poor. If the chip size is too large, the chip removal groove will be quickly filled up, resulting in low chip removal groove utilization. The high aspect ratio drill bit is a slender structure, and the above chip size problem is more prominent during chip removal, and it is urgent to make adjustments to the chip shape. 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 breaker groove is opened in the middle of the cutting edge of the needle body, and the chip breaker groove is composed of a negative inverted segment, a straight line segment and an arc segment from the outer diameter to the inner diameter, and the intersection line of the negative inverted segment and the straight line segment is lower than the intersection line of the arc segment and the cutting edge.

[0005] Furthermore, a core-thickness thinning groove is provided on the needle body, and the core-thickness thinning groove is provided at the end of the transverse blade.

[0006] Furthermore, the width of the negative inverted section is A, A=λΦ, wherein Φ is the drill bit diameter, 0.05≤λ≤0.07.

[0007] Furthermore, the length of the chip breaker groove along the radial direction of the needle body is the chip breaker groove width, and the chip breaker groove width is F, F=4A±Δ1, wherein Δ1 is the negative radial difference.

[0008] Furthermore, the distance between the large diameter end of the negative inverted segment and the large diameter end of the cutting edge is the cutting edge height, and the cutting edge height is D, 0.1 mm≤D.

[0009] Furthermore, the distance between the large diameter end of the cutting edge and the minimum outer diameter of the arc segment is the chip breaking depth, and the chip breaking depth is E, E=3D±Δ2, wherein Δ2 is the negative axial difference.

[0010] Furthermore, a negative chamfer angle is formed between the negative chamfer segment and the axis of the needle body, and the magnitude of the negative chamfer angle is B, 5°≤B≤11°.

[0011] Furthermore, a chip-breaking front angle is formed between the straight line segment and the axis of the needle body, and the size of the chip-breaking front angle is C, 15°≤C≤28°.

[0012] Beneficial effect: The utility model sets the chip breaker groove in the middle of the cutting edge, and optimizes the traditional straight arc groove structure into a chip breaker groove with negative chamfer. The chip breaker groove is set in the middle of the cutting edge to divide the chip cutting action into two parts. The chip breaker groove cuts off the chips close to the outer edge of the needle body, and the chips close to the axis of the needle body directly enter the chip groove. The design of the negative chamfer improves the chip breaking ability of the chip breaker groove. Finally, the cutting in the chip groove is divided into short chips and long chips, and the utilization rate of the chip groove is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the drill needle in the utility model;

[0014] Figure 2 This is a front view of the drill needle in the utility model;

[0015] Figure 3 The utility model is Figure 2 Enlarged view of point G in the middle.

[0016] The reference numerals are: 1, cutting edge; 2, chip breaker groove; 21, negative section; 22, straight line section; 23, arc section; 3, center-thick thinning groove; 4, chip removal groove; 5, transverse edge. DETAILED DESCRIPTION

[0017] 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.

[0018] like Figure 1-Figure 3 As shown, a drill needle for a PCB board includes a needle body, and the needle body is a high aspect ratio structure. Specifically, the needle body structure with a high aspect ratio is a structure in which the ratio of the blade length to the needle body diameter is greater than 17. The chip removal difficulty of the high aspect ratio needle body is large, which is closely related to the chip size and shape. In order to improve the chip removal effect, a chip breaker groove 2 is opened in the middle of the cutting edge 1 of the needle body. The chip breaker groove 2 is a negative inverted segment 21, a straight line segment 22 and an arc segment 23 from the outer diameter to the inner diameter. The intersection line of the negative inverted segment 21 and the straight line segment 22 is lower than the intersection line of the arc segment 23 and the cutting edge 1.

[0019] The utility model arranges the chip breaker groove 2 in the middle of the cutting edge 1, and optimizes the traditional straight arc groove structure into a chip breaker groove 2 with a negative chamfer. The chip breaker groove 2 is arranged in the middle of the cutting edge 1, which can divide the chip cutting action into two parts. The chip breaker groove 2 cuts off the chips close to the outer edge of the needle body, and the chips close to the axis of the needle body directly enter the chip removal groove 4. The design of the negative chamfer 21 improves the chip breaking ability of the chip breaker groove 2. Finally, the cutting in the chip removal groove 4 is divided into short chips and long chips, and the utilization rate of the chip removal groove 4 is improved.

[0020] Among them, the needle body is provided with a core-thick thinning groove 3, which is provided at the end of the transverse edge 5. The core-thick thinning groove 3 further expands the effective space of the chip removal groove 4, so that the heat dissipation and chip removal capacity of the chip removal groove are improved.

[0021] The width of the negative inverted section 21 is A, A=λΦ, where Φ is the drill needle diameter, the drill needle diameter is between 1.0mm and 6.5mm, and 0.05≤λ≤0.07. The negative inverted section 21 can protrude the tip of the tool. The larger the width of the negative inverted section 21, the blunter the tip of the tool, and the greater the cutting force. The smaller the width of the negative inverted section 21, the worse the tip strength will be, which will affect the tool life. The selection range of the negative inverted section 21 is based on ensuring the tip strength and increasing the needle cutting force as much as possible.

[0022] The distance between the large diameter end of the negative inverted segment 21 and the large diameter end of the cutting edge 1 is the edge height, and the edge height is D, 0.1mm≤D. A drop is set between the negative inverted segment 21 and the cutting edge 1 so that the chips can transition more smoothly from the negative inverted segment 21 to the straight segment 22. The edge height is the drop size, and the drop is for the chips to make room. The space for making room should be larger than the chip thickness, but it should not be too large. If it is too large, it will limit the ligament thickness and affect the tool performance.

[0023] The radial length of the chip breaker groove 2 along the needle body is the chip breaker groove width, and the size of the chip breaker groove width is F, F=4A±Δ1. The chip breaker groove width should ensure a smooth transition before the chip breaks, so that the chip has enough inward bending space after passing the end of the negative inverted section 21.

[0024] The distance between the large diameter end of the cutting edge 1 and the minimum outer diameter of the arc segment 23 is the chip breaking depth. The chip breaking depth is E, E = 3D ± Δ2. The chip breaking depth provides space for chip reflexion. The size should be such that the chip entering the arc segment 23 and the negative segment 21 are significantly deformed. Therefore, it should be greater than three times the cutting edge height.

[0025] Among them, Δ1 is the negative radial difference, Δ2 is the negative axial difference. Δ1 and Δ2 are the processing error and wear compensation, and their sizes are both 0.002mm.

[0026] The chip breaker groove width and chip breaking depth are the main factors affecting chip breaking. When designing the chip breaker groove type, the influence of groove width and groove depth on chip breaking is interrelated. When selecting the groove geometry parameters, the ratio of groove width to groove depth is usually considered as a parameter.

[0027] A negative chamfer angle is formed between the negative chamfer section 21 and the axis of the needle body, and the size of the negative chamfer angle is B, 5°≤B≤11°. The larger the negative chamfer angle, the greater the chip deformation, the smaller the curling radius, and the easier the chip breaks. Combined with the width of the negative chamfer section 21, if the negative chamfer angle is too large, the cutting edge 1 on both sides of the chip breaker groove 2 will have a large drop, which is not conducive to tool feeding. If it is too small, the chip size will increase, which is not conducive to chip removal.

[0028] A chip-breaking front angle is formed between the straight segment 22 and the needle body axis, and the size of the chip-breaking front angle is C, 15°≤C≤28°. The larger the chip-breaking front angle is, the easier it is for the chips to break. The chip-breaking front angle should be greater than the negative chamfer angle so that the chips are tilted to increase the chip-breaking rate. If the chip-breaking front angle is too large, the chips will accumulate in the straight segment 22 and the arc segment 23, which is not conducive to the chips entering the chip discharge groove 4.

[0029] 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, characterized in that: A chip breaker groove (2) is provided in the middle of the cutting edge (1) of the needle body. The chip breaker groove (2) is composed of a negative inverted section (21), a straight section (22) and an arc section (23) in sequence from the outer diameter to the inner diameter. The intersection line of the negative inverted section (21) and the straight section (22) is lower than the intersection line of the arc section (23) and the cutting edge (1).

2. A drill needle for a PCB board according to claim 1, characterized in that: The needle body is provided with a core-thickening groove (3), and the core-thickening groove (3) is provided at the end of the transverse blade (5).

3. A drill needle for a PCB board according to claim 1, characterized in that: The width of the negative inverted section (21) is A, A=λΦ, wherein Φ is the diameter of the drill needle, and 0.05≤λ≤0.

07.

4. A drill needle for a PCB board according to claim 3, characterized in that: The length of the chip breaker groove (2) along the radial direction of the needle body is the chip breaker groove width, and the size of the chip breaker groove width is F, F=4A±Δ1, wherein Δ1 is the negative reverse radial difference.

5. A drill needle for a PCB board according to claim 4, characterized in that: The distance between the large diameter end of the negative inverted section (21) and the large diameter end of the cutting edge (1) is the cutting edge height, and the cutting edge height is D, 0.1 mm≤D.

6. A drill needle for a PCB board according to claim 5, characterized in that: The distance between the large diameter end of the cutting edge (1) and the minimum outer diameter of the arc segment (23) is the chip breaking depth, and the chip breaking depth is E, E=3D±Δ2, wherein Δ2 is the negative reverse axial difference.

7. A drill needle for a PCB board according to claim 6, characterized in that: A negative chamfer angle is formed between the negative chamfer section (21) and the axis of the needle body, and the magnitude of the negative chamfer angle is B, 5°≤B≤11°.

8. A drill needle for a PCB board according to claim 7, characterized in that: A chip-breaking front angle is formed between the straight line segment (22) and the axis of the needle body, and the size of the chip-breaking front angle is C, 15°≤C≤28°.

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