阅读说明：本技术 一种提升不对称结构印制电路板钻孔精度的方法及其装置 (Method and device for improving drilling precision of printed circuit board with asymmetric structure ) 是由 梁鸿飞 巫萃婷 陈世金 许伟廉 冯冲 韩志伟 徐缓 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种提升不对称结构印制电路板钻孔精度的方法及其装置,涉及PCB生产技术。针对现有技术中偏孔的问题提出本方案,通过翘曲高度h的平均值获取翘曲度,利用每组对边的翘曲度获取该组对边延伸方向上的拉伸系数,利用所述拉伸系数修正钻带在该组对边延伸方向上的钻孔资料,利用修正后的钻带对印制电路板进行钻孔。其优点在于,可以将实际孔与预设孔尽可能重合,有效降低了成品板的报废率。(The invention discloses a method and a device for improving the drilling precision of a printed circuit board with an asymmetric structure, and relates to the PCB production technology. The method includes the steps that the warping degree is obtained through the average value of the warping height h, the warping degree of each group of opposite sides is used for obtaining the tensile coefficient of the pair of opposite sides in the extending direction, the drilling data of the drilling belt in the pair of opposite sides in the extending direction are corrected through the tensile coefficient, and the drilling of the printed circuit board is conducted through the corrected drilling belt. The method has the advantages that the actual holes and the preset holes can be overlapped as much as possible, and the rejection rate of the finished plate is effectively reduced.)

1. A method for improving the drilling precision of a printed circuit board with an asymmetric structure is characterized by comprising the following steps:

s0, placing the printed circuit board (20) to be drilled on the horizontal table top (10);

s1, measuring the warping height h of a group of opposite sides of the printed circuit board (20);

s2, calculating the average value of the warping height h;

s3, acquiring the warping degree of the paired edges;

s4, obtaining the stretching coefficient of the pair of opposite sides in the extending direction by using the warping degree of the pair of opposite sides;

s5, correcting the drilling data of the drill belt in the extending direction of the paired edges by using the tensile coefficient;

s6, measuring the warping height h of the other pair of opposite sides of the printed circuit board (20) and repeating the steps S2 to S5;

and S7, drilling the printed circuit board (20) by using the corrected drill tape.

2. The method for improving the drilling precision of the printed circuit board with the asymmetric structure according to claim 1, wherein the tensile coefficient is 1-warp degree by 8%;

the warp is 100% of the average value/(diagonal length 2) of the warp height h;

the diagonal length is a theoretical value of the printed circuit board (20) in a flat state.

3. The method for improving the drilling accuracy of the asymmetric-structure printed circuit board as claimed in claim 1, wherein the drawing coefficient in step S5 is corrected by drawing using the coordinates corresponding to the center point of the printed circuit board (20) in the drilling data as a reference point.

4. The method for improving the drilling accuracy of the printed circuit board with the asymmetric structure as claimed in claim 1, wherein the value of the warpage height h is obtained at certain step intervals in step S1.

5. The method for improving the drilling precision of the printed circuit board with the asymmetric structure as claimed in claim 1, wherein the lower limit value of the tensile coefficient is 0.9997.

6. A device for improving the drilling precision of a printed circuit board with an asymmetric structure is characterized by comprising an acquisition unit, a control unit and a drilling unit which are in signal connection in sequence;

the acquisition unit is used for measuring the warping height h of each side of the printed circuit board (20) to be drilled relative to the horizontal table top (10) and sending the warping height h to the control unit; the printed circuit board (20) is placed on the horizontal table top (10);

the control unit calculates an average value of the warping heights h belonging to the same group of opposite sides, obtains the warping degree of each group of opposite sides, obtains the tensile coefficient of the pair of opposite sides in the extending direction by using the warping degree of each group of opposite sides, corrects the drilling data of the drill belt in the extending direction of the pair of opposite sides by using the tensile coefficient, and sends the corrected drill belt to the drilling unit;

the drilling unit uses the corrected drill tape to drill the printed circuit board (20).

7. The apparatus for improving the drilling accuracy of the asymmetric-structure printed circuit board according to claim 6, wherein the tensile coefficient is 1-warp degree by 8%;

the warp is 100% of the average value/(diagonal length 2) of the warp height h;

the diagonal length is a theoretical value of the printed circuit board (20) in a flat state.

8. The apparatus for improving the drilling accuracy of the PCB with the asymmetric structure as claimed in claim 6, wherein the control unit performs the stretching correction on the stretching coefficient by using the coordinates corresponding to the center point of the PCB (20) in the drilling data as a reference point.

9. The device for improving the drilling precision of the printed circuit board with the asymmetric structure as claimed in claim 6, wherein the collecting unit obtains the value of the warping height h at certain intervals.

10. The apparatus for improving the drilling accuracy of the PCB with the asymmetric structure as claimed in claim 6, wherein the lower limit value of the stretch coefficient is 0.9997.

Technical Field

The invention relates to a PCB manufacturing technology, in particular to a method for improving the drilling precision of a printed circuit board with an asymmetric structure.

The invention also relates to a device for improving the drilling precision of the printed circuit board with the asymmetric structure.

Background

In the manufacturing process of the PCB of the printed circuit board, after line patterns are etched on the top and the bottom of the multilayer PCB, the warping deformation of a produced board can be caused due to inconsistent residual copper rates on the two surfaces. It may occur that the middle of the plate top is arched upwards, as shown in fig. 1. It is also possible that two-sided lifting occurs as shown in fig. 2. When the drilling process is carried out, the warping position deforms, so that deviation exists between the actual hole A and the preset hole B of the drill belt, the condition of hole deviation is caused, and the product plate is seriously scrapped.

Disclosure of Invention

The invention aims to provide a method and a device for improving the drilling precision of a printed circuit board with an asymmetric structure, so as to solve the problems in the prior art.

The invention relates to a method for improving the drilling precision of a printed circuit board with an asymmetric structure, which comprises the following steps:

s0, placing the printed circuit board to be drilled on the horizontal table-board;

s1, measuring the warping height h of a group of opposite sides of the printed circuit board;

s2, calculating the average value of the warping height h;

s3, acquiring the warping degree of the paired edges;

s4, obtaining the stretching coefficient of the pair of opposite sides in the extending direction by using the warping degree of the pair of opposite sides;

s5, correcting the drilling data of the drill belt in the extending direction of the paired edges by using the tensile coefficient;

s6, measuring the warping height h of the other pair of opposite sides of the printed circuit board, and repeating the steps S2 to S5;

and S7, drilling the printed circuit board by using the corrected drill tape.

The tensile coefficient is 1-warpage of 8%;

the warp is 100% of the average value/(diagonal length 2) of the warp height h;

the diagonal length is a theoretical value of the printed circuit board in a flat state.

In step S5, the stretching coefficient is corrected by using the coordinates corresponding to the center point of the pcb in the drilling data as the reference point.

In step S1, the value of the warp height h is acquired at a constant step interval.

The lower limit of the stretch coefficient is 0.9997.

The invention relates to a device for improving the drilling precision of a printed circuit board with an asymmetric structure, which comprises an acquisition unit, a control unit and a drilling unit which are in signal connection in sequence;

the acquisition unit is used for measuring the warping height h of each edge of the printed circuit board to be drilled relative to the horizontal table top and sending the warping height h to the control unit; the printed circuit board is placed on the horizontal table-board;

the control unit calculates an average value of the warping heights h belonging to the same group of opposite sides, obtains the warping degree of each group of opposite sides, obtains the tensile coefficient of the pair of opposite sides in the extending direction by using the warping degree of each group of opposite sides, corrects the drilling data of the drill belt in the extending direction of the pair of opposite sides by using the tensile coefficient, and sends the corrected drill belt to the drilling unit;

and the drilling unit is used for drilling the printed circuit board by using the corrected drill belt.

The tensile coefficient is 1-warpage of 8%;

the warp is 100% of the average value/(diagonal length 2) of the warp height h;

the diagonal length is a theoretical value of the printed circuit board in a flat state.

And the control unit performs stretching correction on the stretching coefficient by taking the coordinates corresponding to the central point of the printed circuit board in the drilling data as reference points.

And the acquisition unit acquires the value of the warping height h at certain step length intervals.

The lower limit of the stretch coefficient is 0.9997.

The method and the device for improving the drilling precision of the printed circuit board with the asymmetric structure have the advantages that the actual hole can be overlapped with the preset hole as much as possible, and the rejection rate of finished boards is effectively reduced.

Drawings

FIG. 1 is a schematic diagram illustrating deviation of drilling holes in a state of arching of a printed circuit board in the prior art;

fig. 2 is a schematic diagram illustrating deviation of drilling in a state where two sides of a printed circuit board are tilted in the prior art.

FIG. 3 is a schematic diagram of a first deformation measurement of the method for improving the drilling accuracy of the printed circuit board with the asymmetric structure according to the present invention;

FIG. 4 is a schematic diagram of the measurement of the method for improving the drilling accuracy of the asymmetric-structure printed circuit board in the second deformation condition according to the present invention;

FIG. 5 is a schematic diagram of the measurement of the method for improving the drilling accuracy of the asymmetric-structure printed circuit board under the deformation condition III.

FIG. 6 is a schematic structural diagram of a device for improving the drilling accuracy of a printed circuit board with an asymmetric structure according to the present invention.

FIG. 7 is a schematic view of the pin attachment location of the printed circuit board during drilling.

Detailed Description

As shown in fig. 6, the device for improving the drilling precision of the printed circuit board with the asymmetric structure comprises a collecting unit, a control unit and a drilling unit which are in signal connection in sequence. The printed circuit board 20 to be drilled is laid flat on the horizontal table top 10, and it is generally default that the top of the printed circuit board 20 is placed on top and the bottom of the printed circuit board is placed on the bottom. The working principle of the device and the corresponding method are as follows:

the warp height h of one set of opposite sides is first measured by the acquisition unit, for example, the first long side 21 and the second long side 23 are first measured. The measurement can be performed continuously along the y-axis direction, or can be performed at certain step intervals. For example, the setting of the step length can be selected from 0.01 mm-1.00 mm, and can also be adjusted according to the actual precision requirement. The measurement at the step intervals can reduce the calculation amount and improve the measurement speed, but naturally abandons the measurement precision.

Where the warp height h is the distance between the measured position on the edge and the horizontal table top 10.

The acquisition unit acquires all the warping heights h of the opposite side and then sends the warping heights h to the control unit, and the control unit calculates the average value of the warping heights h. The warp of the pair of edges is calculated using the average value.

The warpage is mostly considered to be "defined numerically as the distance between two points at which the warpage plane is most distant in the height direction", and the units of mm, μm, mil, etc. are generally used. But in the PCB production industry, it is more commonly used as the ratio of the highest warpage to the diagonal of the PCB, as the calculation method described in CN 102901434 a.

However, unlike the maximum height in CN 102901434 a, in the present invention, the warpage is the average value/(diagonal length 2) × 100% of the warpage height h, wherein the diagonal length is the theoretical value of the printed circuit board 20 in the flat state. Warp is therefore a percentage value without units in the present invention.

After the warping degree of the paired edges is obtained, a formula is used: the stretch coefficient is 1-warp 8%, and the stretch coefficient of the paired edges is calculated, wherein 8% is an empirical coefficient. For example, if the average value of the warp height h is 3mm and the diagonal length of the printed circuit board 20 is 730mm when it is kept flat without the influence of the residual copper ratio, the tensile modulus of the pair of edges in the y-axis direction should be: 1- [3/(730 × 2) × 100% ] × 8% ═ 0.999835616.

The printed circuit board 20 is fixed by the pin 11 during the drilling process, as shown in fig. 7, and the installation height of the pin 11 is fixed. The printed circuit board 20 is pressed by the pin 11 even if the board is warped greatly, by the height of the pin 11. That is, if the warping height h of the pcb 20 exceeds the fixed height of the peg 11, it is stretched once before drilling and is limited to the same stretching state. From production experience, the lower limit of the stretch coefficient is preferably 0.9997, if by the formula: the stretch coefficient is 1-warp 8%, and the calculated stretch coefficient is lower than the lower limit value, which is the final value of the stretch coefficient.

The acquisition unit then replaces the pair of edges to acquire the warp height h, in this embodiment, the first short edge 22 and the second short edge 24 along the x-axis direction. After collection, the data is sent to a control unit, and the control unit calculates the stretching coefficients of the first short side 22 and the second short side 24 in the x-axis direction by using the process.

After the two sets of opposite sides have been obtained, the drill string is corrected using the coordinates corresponding to the center point of the printed circuit board 20 in the drilling data as the reference point. The corrected drill tape is sent to a drilling unit, which uses the corrected drill tape to drill the printed circuit board 20.

Since the residual copper rates on both sides of the printed circuit board 20 are different in different layout designs, the following three deformation conditions may be caused:

situation one

As shown in fig. 3, the middle portion is arched toward the top of the board, and one set of opposite edges is warped but less warped than the other set of opposite edges.

Situation two

As shown in fig. 4, the middle portion is arched toward the top of the board, and one set of opposite sides is not warped and flatly attached to the horizontal table top 10. At this time, the warp height h at the bonding position is 0.

Situation three

As shown in fig. 5, a pair of opposite sides of the printed circuit board 20 are warped upward such that the printed circuit board 20 protrudes toward the bottom of the board and four corners thereof have a certain height.

The method and the device for improving the drilling precision of the printed circuit board with the asymmetric structure can effectively solve the deformation correction of the three conditions and are not limited by deformation types.

It will be apparent to those skilled in the art that various other changes and modifications may be made in the above-described embodiments and concepts and all such changes and modifications are intended to be within the scope of the appended claims.