Method for preventing short slot hole deviation in PCB drilling

Abstract

The application discloses a method for preventing short slot hole deviation in PCB drilling, comprising the following steps: step 1, drilling design: designing first and second guide holes which need to be drilled in advance on the short slot hole which needs to be drilled; wherein the first guide hole is a long slot hole, and the center of the first guide hole coincides with the center of the short slot hole; the second guide hole is a round hole, and is symmetrically arranged between the outer peripheral edge of the first guide hole and the inner peripheral edge of the short slot hole; step 2, drilling sequence: first, drilling a plurality of pairs of second guide holes in the short slot hole which needs to be drilled, then drilling the first guide hole through the superposition of round holes, and finally drilling the short slot hole through the superposition of round holes. The application sets two types of guide holes, reduces or avoids the action force of the substrate on the drill bit in the opposite direction of the rotation direction of the drill bit, so that the deviation caused by the reaction of the substrate on the drill bit in the drilling process in the prior art is overcome, the accuracy of drilling is ensured, and the drilling quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PCB drilling processing, in particular to a method for preventing short slot hole deviation in PCB drilling. BACKGROUND

[0002] At present, in the production of PCB, the problem of short slot hole deviation in drilling processing has always existed, which is due to:

[0003] Referring to the attached Figure 1 , it is a short slot hole pattern, and the general form is an ellipse. When the ratio of the slot length to the slot width is <2, it is called a short slot hole. When this kind of short slot hole is processed by drilling, because the shape of the drill bit is circular, an ellipse-shaped short slot hole is processed by using the method of stacking circular holes. As shown in the attached Figure 2 , two circular holes are used for stacking, Figure 2 , the first circular hole a and the second circular hole b in the attached represent the positions of different circular holes in drilling.

[0004] Referring to the attached Figure 3 , when Figure 3 the first circular hole a is drilled, the position of the second circular hole b to be drilled will have a suspended part (non-shaded area). When the drill bit is processing the position of the second circular hole b, because part of the substrate is in a suspended state, the drill bit will be stressed, thereby causing deviation problems, as shown in the attached Figure 4 . Referring to the attached Figure 5 , it is the state of the substrate surface when the second circular hole b is drilled. The blank part is the suspended part of the substrate, and the shaded part is the substrate entity. When the second circular hole b is drilled, the drill bit will be subjected to the reaction force F of the substrate entity in the shaded part, i.e. F is the reaction force of the substrate on the drill bit. Because the rotation direction of the drill spindle is clockwise, the second circular hole b will finally deviate in the counterclockwise direction.

[0005] At the same time, the problem of short slot hole deviation becomes more and more serious with the decrease of the ratio of the slot length to the slot width and the increase of the number of stacked boards in the drilling process. And at present, the design of short slot holes in PCB processing is gradually increasing.

[0006] In view of this, the present application is proposed. SUMMARY

[0007] In order to overcome the above-mentioned defects, the present application provides a method for preventing short slot hole deviation in PCB drilling, which adds a guide hole in the short slot hole to reduce the uneven stress of the drill bit in the processing process and improve the problem of short slot hole deviation.

[0008] The technical scheme adopted by the present application to solve its technical problems is:

[0009] A method for preventing the deviation of a short slot hole in PCB drilling, comprising the following steps:

[0010] Step 1, drilling design: design a first guide hole and a second guide hole which need to be drilled in advance on the short slot hole which needs to be drilled:

[0011] Wherein, the first guide hole is a long slot hole, the center of the first guide hole coincides with the center of the short slot hole, and the distance between the outer peripheral edge of the first guide hole and the inner peripheral edge of the short slot hole is not less than 2 mil; the second guide hole is a circular hole, including at least two pairs, and symmetrically arranged between the outer peripheral edge of the first guide hole and the inner peripheral edge of the short slot hole, the distance between the outer peripheral edge of the second guide hole and the inner peripheral edge of the short slot hole is not less than 1 mil;

[0012] Step 2, drilling sequence: first drill several pairs of second guide holes designed according to step 1 in the short slot hole which needs to be drilled, then drill the first guide hole by superimposing the circular hole, and finally drill the short slot hole by superimposing the circular hole.

[0013] As a further improvement of the present application, the slot width of the first guide hole, i.e. the long slot hole, is equal to half of the slot width of the short slot hole, and the slot length of the first guide hole is less than the slot length of the short slot hole.

[0014] As a further improvement of the present application, the second guide hole is two pairs, and the two pairs partially overlap.

[0015] As a further improvement of the present application, the straight line passing through the centers of the first guide hole and the short slot hole passes through the centers of the second guide hole of the pair of second guide holes arranged oppositely.

[0016] As a further improvement of the present application, the ratio of the slot length to the slot width of the short slot hole is 1.2.

[0017] The beneficial effects of the present application are: by setting two types of guide holes, the present application reduces or avoids the action force of the substrate on the drill bit in the opposite direction of the rotation direction, thereby overcoming the deviation caused by the reaction of the substrate on the drill bit in the drilling process in the prior art, to ensure the accuracy of drilling and improve the quality of drilling. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic view of a short slot hole structure;

[0019] Figure 2 is a schematic view of the prior art of two circular holes superimposed to process a short slot hole;

[0020] Figure 3 is a schematic view of the prior art of the suspended state of the short slot hole processing;

[0021] Figure 4 Fig. 1 is a schematic diagram of the offset state of a short slot hole in the prior art processing;

[0022] Figure 5 Fig. 2 is a schematic diagram of the force analysis of a drill bit in the prior art short slot hole processing;

[0023] Figure 6 Fig. 3 is a schematic diagram of the drill hole design of the method of the present application;

[0024] Figure 7 Fig. 4 is a schematic diagram of one of the steps in the drill hole of the method of the present application;

[0025] Figure 8 、 9 Fig. 5 is a schematic diagram of the second step in the drill hole of the method of the present application;

[0026] Figure 10 Fig. 6 is a schematic diagram of the short slot hole structure drilled by the method of the present application;

[0027] Figure 11 Fig. 7 is a schematic diagram of the drill hole process of the method of the present application;

[0028] Figure 12 Fig. 8 is a force analysis of the drill bit when drilling the first circular hole a of the short slot hole 10 of the present application;

[0029] Figure 13 Fig. 9 is a force analysis of the drill bit when drilling the second circular hole b of the short slot hole 10 of the present application.

[0030] The following description is made in conjunction with the accompanying drawings:

[0031] a, first circular hole; b, second circular hole; F, reaction force; 10, short slot hole; 1, first guide hole; 2, second guide hole. DETAILED DESCRIPTION

[0032] The preferred embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0033] A method for preventing the offset of a short slot hole in PCB drilling, comprising the following steps:

[0034] Step 1, refer to Figure 6 Drill hole design: design the first guide hole 1 and the second guide hole 2 that need to be drilled in advance on the short slot hole 10 that needs to be drilled, and this embodiment takes the ratio of the slot length to the slot width of the short slot hole as 1.2 as an example:

[0035] The first guide hole 1 is a long slot hole, the center of the first guide hole 1 coincides with the center of the short slot hole 10, the distance between the outer peripheral edge of the first guide hole 1 and the inner peripheral edge of the short slot hole 10 is not less than 2 mil, and the embodiment is taken as an example for illustration; the slot width of the first guide hole 1, i.e. the long slot hole, is equal to half of the slot width of the short slot hole 10, and the slot length of the first guide hole 1 is less than the slot length of the short slot hole 10.

[0036] The second guide hole 2 is a circular hole, includes at least two pairs, and is symmetrically arranged between the outer peripheral edge of the first guide hole 1 and the inner peripheral edge of the short slot hole 10, the distance between the outer peripheral edge of the second guide hole and the inner peripheral edge of the short slot hole 10 is not less than 1 mil; the second guide hole 2 of the embodiment is provided as two pairs, and the two pairs partially overlap, and the straight line passing through the centers of the first guide hole 1 and the short slot hole 10 is arranged opposite to the pair of second guide holes 2.

[0037] Step 2, drilling sequence:

[0038] First, drill several pairs of second guide holes 2 according to the design of step 1 in the short slot hole 10 to be drilled, refer to the attached Figure 7 ;

[0039] Then, drill the first guide hole 1 by the way of superimposed circular holes, refer to Figure 8 , Figure 9 ;

[0040] Finally, drill the short slot hole 10 by the way of superimposed circular holes, refer to Figure 10 , that is, the short slot hole of the application is obtained.

[0041] In the drilling method of the application, the second guide hole 2 (circular hole) is drilled first, which can reduce the area of the substrate entity in the Figure 11 shadow area.

[0042] In the second step of the drilling sequence, the long slot hole as the first guide hole 1 forms the final guide hole of the short slot hole 10, and plays a positioning role.

[0043] Referring to the attached Figure 12 , the force analysis of the drill bit when drilling the first circular hole a of the short slot hole 10 of the application can be seen, at this time, the drill bit is mainly subjected to the action force of the substrate in two directions, and the two kinds of action forces are opposite, so that the drill bit can be ensured not to deviate.

[0044] Referring to the attached Figure 13 , the force analysis of the drill bit when drilling the second circular hole b of the short slot hole 10 of the application can be seen, at this time, the reaction force given by the substrate is consistent with the rotation direction of the drill bit, so that subsequent deviation will not occur.

[0045] Therefore, the application reduces or avoids the force of the base material in the opposite direction of the rotation direction of the drill bit during the processing of the drill bit, so as to overcome the deviation caused by the reaction of the base material to the drill bit during the drilling processing, ensure the accuracy of the drilling, and improve the drilling quality.

[0046] In the above description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the above description is merely a preferred embodiment of the present application, and the present application can be implemented in many different ways other than those described herein, and therefore the present application is not limited to the specific implementation disclosed above. Meanwhile, any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments, by using the methods and technical contents disclosed above, without departing from the scope of the technical solutions of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical solutions of the present application, still belongs to the protection scope of the technical solutions of the present application.

Claims

1. A method for preventing short slots from shifting during PCB drilling, characterized in that, Includes the following steps: Step 1, Drilling Design: Design a first guide hole (1) and a second guide hole (2) to be pre-drilled on the short slot (10) to be drilled: wherein, the first guide hole (1) is a long slot hole, the center of the first guide hole (1) coincides with the center of the short slot (10), and the distance between the outer peripheral edge of the first guide hole (1) and the inner peripheral edge of the short slot (10) is not less than 2mil; the second guide hole (2) is a round hole, including at least two pairs, and symmetrically arranged between the outer peripheral edge of the first guide hole (1) and the inner peripheral edge of the short slot (10), and the distance between the outer peripheral edge of the second guide hole and the inner peripheral edge of the short slot (10) is not less than 1mil; Step 2, drilling sequence: First, drill several pairs of second guide holes (2) designed according to Step 1 in the short slot hole (10) to be drilled, then drill the first guide hole (1) by superimposing round holes, and finally drill the short slot hole (10) by superimposing round holes. The width of the first guide hole (1), i.e. the long slot, is equal to half the width of the short slot (10), and the length of the first guide hole (1) is less than the length of the short slot (10).

2. The method for preventing short slots from shifting during PCB drilling according to claim 1, characterized in that: The second guide hole (2) consists of two pairs, and the two pairs partially overlap.

3. The method for preventing short slots from shifting during PCB drilling according to claim 2, characterized in that: The straight line between the centers of the pair of second guide holes (2) arranged opposite to each other passes through the center of the first guide hole (1) and the short slot (10).

4. The method for preventing short slots from shifting during PCB drilling according to claim 1, characterized in that: The ratio of the length to the width of the short slot is 1.2.

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