Measurement method for monitoring offset of mechanical drill hole in inner layer of PCB (Printed Circuit Board)

Abstract

The invention discloses a measuring method for monitoring PCB inner layer mechanical drilling offset, comprising the following steps: step 1, arranging a conductive main circuit and target drilling positions in matrix arrangement on a test drilling panel, arranging conductive U-shaped patterns on the peripheries of the target drilling positions, connecting the conductive main circuit with the conductive U-shaped patterns, and connecting the conductive main circuit with the conductive U-shaped patterns; the target drilling position is located at the center of the semicircle bottom of the conductive U-shaped pattern; the semi-circle bottom radiuses of the conductive U-shaped patterns in the same row are the same, but the openings of the conductive U-shaped patterns face different directions; openings of the conductive U-shaped patterns in the same column face opposite directions, and the semi-circle bottom radius of the conductive U-shaped patterns is gradually reduced along with the number of rows. 2, drilling is conducted on the target drilling position through a mechanical drilling machine, and the drilling radius is R; and if the conductive drill bit is in contact with the m-th row of partially conductive U-shaped pattern, the detection system can monitor an electric signal, and drill hole offset information is calculated according to the monitored electric signal.

Description

Technical Field

[0001] The present invention relates to the field of PCB mechanical drilling, and particularly to a measuring method for monitoring the offset of inner-layer mechanical drilling of PCB. Background Art

[0002] In the process of printed circuit board manufacturing, multiple PCB units are divided on a panel, and operations such as drilling, electroplating, and outer-layer circuit processing are carried out with the panel as a whole. Finally, the panel is cut into PCB units. Among them, mechanical drilling is a crucial step, and the drilling accuracy directly affects the circuit connection quality and overall performance. However, in the existing mechanical drilling process, there is often a certain offset between the mechanical drilling machine and the target drilling position. If this offset exceeds the allowable range, it may lead to a series of problems such as poor circuit connection and signal transmission failure, seriously affecting the reliability and stability of the PCB. Therefore, the first-piece panel usually needs to be trial-drilled to detect the drilling offset and correct the mechanical drilling machine to ensure the accuracy of subsequent drilling.

[0003] In the prior art, an image detection device is usually used to detect the drilling offset. For example, a Chinese patent with the publication number CN104149125A discloses a method for detecting the drilling accuracy of a PCB mechanical drilling machine, which includes the following steps: a. Prepare a PCB board, a cover board, and a backing board, and drill pin holes respectively; b. Stack the cover board, the PCB board, and the backing board in sequence to form a stack, and place the corresponding pin holes coaxially. A pin is provided on the stack and the pin passes through the pin holes, and then the stack is clamped by a clamping device, and then the stack is placed on the workbench of the PCB mechanical drilling machine; c. Input processing parameters on the PCB mechanical drilling machine and drill holes; d. Remove the drilled stack, and separate the cover board, the PCB board, and the backing board of the stack; e. Remove the residues remaining on the PCB board during the drilling process; f. Analyze the deviation of the drilled holes on the PCB board through an image detection device; g. Judge the deviation value obtained by the image detection device. The above detection method requires removing the cover board and the PCB board after drilling, and then using an image detection device to detect the drilling deviation of the PCB board. If the drilling deviation of the PCB board exceeds the allowable range, it is necessary to repeatedly adjust the position of the mechanical drilling machine and re-fix the PCB and the cover board to the workbench, and repeat steps b to g, and the operation is complex.

[0004] In the prior art, an X-ray device is also used to directly detect the drilling deviation. However, the X-ray device and its operation and maintenance costs are relatively high, and for some relatively thick or special material cover boards, X-ray cannot penetrate, and its use has limitations.

[0005] In view of this, the present invention proposes a measuring method for monitoring the offset of inner-layer mechanical drilling of PCB to solve the above problems. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the above technologies and provides a measurement method for monitoring the offset of inner-layer mechanical drilling of a PCB, which has a relatively low cost and is simple to operate.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A measurement method for monitoring the offset of inner-layer mechanical drilling of a PCB, comprising the following steps:

[0009] Step 1: Provide a trial drilling panel, on which a registration monitoring module is provided. The registration monitoring module includes a conductive main line and a plurality of target drilling positions arranged in a matrix. A conductive U-shaped pattern is provided on the outer periphery of each target drilling position. The conductive main line is connected to the conductive U-shaped patterns respectively through conductive branches. The conductive U-shaped pattern includes a semi-circular bottom and straight portions tangent to both ends of the semi-circular bottom. The target drilling position is located at the center of the semi-circular bottom; the radius A of the semi-circular bottoms of the conductive U-shaped patterns in the same row m is the same, but the openings of the conductive U-shaped patterns face different directions; the openings of the conductive U-shaped patterns in the same column face the same direction, and the radius A of the semi-circular bottoms of the conductive U-shaped patterns m (m is the row number where the conductive U-shaped pattern is located) gradually decreases with the increase of the row number;

[0010] Step 2: Drill holes in the target drilling positions in sequence through a mechanical drilling machine. The drilling radius is R, A m >R and R>A m -A m+1 , and the drill bit of the mechanical drilling machine can conduct electricity; the distance d between any two target drilling positions is known. After the mechanical drilling machine finishes drilling one target drilling position, it moves a distance of d and drills the next target drilling position; during the drilling process, the conductive main line is detected by a monitoring system. When the drill bit touches the conductive U-shaped pattern, the monitoring system will detect an electrical signal on the conductive main line;

[0011] If the monitoring system detects that only some of the conductive U-shaped patterns in the m-th row have electrical signals and the rest of the conductive U-shaped patterns have no electrical signals, at this time, A m -R≤drilling offset x≤A m +R. Further, if there is only one conductive U-shaped pattern without an electrical signal in the m-th row, then the drilling offset direction is the same as the opening direction of the conductive U-shaped pattern without an electrical signal in the m-th row; if there are at least two conductive U-shaped patterns without an electrical signal in the m-th row, then the drilling offset direction is between the opening directions of the conductive U-shaped patterns without an electrical signal;

[0012] If the monitoring system detects that some of the conductive U-shaped patterns (23) in the m-th to (m + k)-th rows have electrical signals and the rest of the conductive U-shaped patterns have no electrical signals, at this time, A m+1 -R≤drilling offset x≤Am -R, the direction of the drilling offset is between the openings of the conductive U-shaped patterns without electrical signals in the m-th to the (m + k)-th rows.

[0013] Preferably, the opening directions of the conductive U-shaped patterns in the same row change successively in the clockwise / counterclockwise direction, and the opening directions of the conductive U-shaped patterns in two adjacent columns differ by 360° / N, where N is the number of columns of the conductive U-shaped patterns of the alignment monitoring module, and N≥3.

[0014] Preferably, in step two, the target drilling positions are drilled successively from the first row to the last row.

[0015] Preferably, the conductive main line is provided with a conductive joint, and the monitoring system monitors the electrical signal at the conductive joint.

[0016] Preferably, the length of the straight part ≥A m 。

[0017] Preferably, the distance between the target drilling position at the m-th row and the n-th column and the target drilling position at the (m + 1)-th row and the n-th column is D 1 +A m +A m+1 , D 1 is a fixed value, and A m is the radius of the bottom of the semi-circle in the m-th row, and A m+1 is the radius of the bottom of the semi-circle in the m-th row.

[0018] Preferably, the distance between the target drilling position at the m-th row and the n-th column and the target drilling position at the m-th row and the (n + 1)-th column is D 2 , D 2 is a fixed value.

[0019] Preferably, the alignment monitoring module is arranged at the edge of the trial drilling panel, and the other parts of the trial drilling panel are divided into multiple PCB units.

[0020] Preferably, the mechanical drilling in step two is carried out on the workbench. A backing plate, a trial drilling panel, and a cover plate are stacked successively on the workbench, and the stack of the backing plate, the trial drilling panel, and the cover plate is fixed on the workbench through pins. The side of the trial drilling panel with the alignment monitoring module faces the cover plate.

[0021] Preferably, the method for measuring the offset of the mechanical drilling of the inner layer of the monitoring PCB further includes step three: adjusting the position of the mechanical drilling machine according to the drilling offset and the offset direction; then repeating steps two and three until the drilling offset is within the allowable range.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. Compared with directly detecting drilling deviation using X-ray equipment in the prior art, the equipment used in the present invention is simpler and does not require high-cost X-ray equipment, thus reducing the overall detection cost.

[0024] 2. When the drill bit in the present invention contacts the conductive U-shaped pattern, the monitoring system will monitor the presence of an electrical signal in the conductive main line, thereby measuring the drilling offset amount and offset direction. The detection process is achieved through conductivity and is not limited by the cover plate material and thickness, with a wide range of applications.

[0025] 3. By setting a registration monitoring module on the trial drilling panel, this method can monitor the drilling offset amount in real time during the drilling process, eliminating the need to remove the cover plate and PCB board for detection after drilling. This simplifies the operation process, shortens the detection cycle, and improves the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the trial drilling panel of the present invention;

[0027] Figure 2 is a schematic diagram of monitoring the mechanical drilling offset of the inner layer of the PCB of the present invention Figure 1 ;

[0028] Figure 3 is a schematic diagram of monitoring the mechanical drilling offset of the inner layer of the PCB of the present invention Figure 2 ;

[0029] Figure 4 is a schematic diagram of monitoring the mechanical drilling offset of the inner layer of the PCB of the present invention Figure 3 ;

[0030] Figure 5 is a schematic diagram of monitoring the mechanical drilling offset of the inner layer of the PCB of the present invention Figure 4 ;

[0031] The implementation, functional features, and advantages of the present invention will be further described in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following further details the features of the present invention and other related features through embodiments for the understanding of those skilled in the same industry:

[0033] Referring to Figures 1 to 5 , an embodiment of a method for measuring the mechanical drilling offset of the inner layer of a PCB according to the present invention is proposed:

[0034] A method for measuring the mechanical drilling offset of the inner layer of a PCB includes the following steps:

[0035] Step 1: Provide a trial drilling panel 1, on which a positioning monitoring module 2 is provided. The positioning monitoring module 2 includes a main conductive line 21 and a plurality of target drilling positions 22 arranged in a matrix. A conductive U-shaped pattern 23 is provided outside each target drilling position 22, and the conductive U-shaped patterns 23 are also arranged in a matrix. The main conductive line 21 is connected to the conductive U-shaped patterns 23 respectively through conductive branches 24. The conductive U-shaped pattern 23 includes a semicircular bottom 231 and straight portions 232 tangent to both ends of the semicircular bottom 231. The target drilling position 22 is located at the center of the semicircular bottom 231; the radius A of the semicircular bottom 231 of the conductive U-shaped patterns 23 in the same row m is the same, but the opening directions of the conductive U-shaped patterns 23 are different; the opening directions of the conductive U-shaped patterns 23 in the same column are the same, and the radius A of the semicircular bottom 231 of the conductive U-shaped patterns 23 m (The subscript of A is the row number where the U-shaped pattern is located, A m i.e., the radius of the semicircular bottom of the m-th row) gradually decreases with the row number.

[0036] Step 2: Drill the target drilling positions 22 in sequence through a mechanical drilling machine. The radius of the drill hole 3 is R, and R < A m , and R > A m - A m+1 , that is, the difference in the radius of the semicircular bottom 231 of the conductive U-shaped patterns 23 in adjacent rows is less than the radius of the drill hole 3. The drill bit of the mechanical drilling machine can conduct electricity; since the trial drilling panel 1 is set in advance, the distance between any two positions on the trial drilling panel 1 is a known condition. The distance between two target drilling positions 22 is d. After the mechanical drilling machine finishes drilling the previous target drilling position 22, it moves a distance of d and drills the next target drilling position 22; during the drilling process, the main conductive line 21 is detected by the monitoring system. When the drill bit touches the conductive U-shaped pattern 23, the monitoring system will detect an electrical signal on the main conductive line 21.

[0037] (1) If the monitoring system detects that only some of the conductive U-shaped patterns 23 in the m-th row have electrical signals and the rest of the conductive U-shaped patterns 23 have no electrical signals, at this time, A m - R ≤ drilling offset x ≤ A m + R. Further, if only one conductive U-shaped pattern 23 in the m-th row has no electrical signal, then at this time the drilling offset direction is the same as the opening direction of the conductive U-shaped pattern 23 without electrical signal in the m-th row.

[0038] For example Figure 3 as shown, some of the conductive U-shaped patterns in the second row intersect with the drill hole 3, that is, some of the conductive U-shaped patterns in the second row will generate electrical signals on the main conductive line 21, and the conductive U-shaped pattern in the second column of the second row will not generate electrical signals on the main conductive line 21. At this time, A 2 - R ≤ drilling offset x ≤ A 2+R, the drilling offset direction is the same as the opening orientation of the conductive U-shaped pattern in the second row and the second column.

[0039] (2) If the monitoring system detects that only some of the conductive U-shaped patterns 23 in the m-th row have electrical signals and at least two conductive U-shaped patterns 23 in the m-th row have no electrical signals, then at this time, the drilling offset direction is between the opening orientations of the conductive U-shaped patterns without electrical signals.

[0040] For example Figure 4 As shown, when drilling, some of the conductive U-shaped patterns in the second row have electrical signals, and the conductive U-shaped patterns in the second and third columns of the second row do not generate electrical signals on the main conductive line 21. Then, A 2 -R ≤ drilling offset x ≤ A 2 +R, the drilling offset direction is between the opening orientations of the conductive U-shaped patterns in the second and third columns.

[0041] (3) If the monitoring system detects that some of the conductive U-shaped patterns 23 in the m-th to (m + k)-th rows have electrical signals (k is a positive integer) and the remaining conductive U-shaped patterns (23) have no electrical signals, at this time, A m+1 -R ≤ drilling offset x ≤ A m -R, the drilling offset direction is between the opening orientations of the conductive U-shaped patterns without electrical signals in the m-th to (m + k)-th rows.

[0042] For example Figure 5 As shown, when drilling, some of the conductive U-shaped patterns in the first and second rows have electrical signals, and the conductive U-shaped patterns in the first and second columns of the first row and the second column of the second row do not generate electrical signals on the main conductive line 21. Then, A 2 -R ≤ drilling offset x ≤ A 1 -R, the drilling offset direction is between the opening orientations of the conductive U-shaped patterns in the first and second columns.

[0043] If the opening orientations of all the conductive U-shaped patterns 23 are the same, even if the monitoring system detects electrical signals, it is impossible to determine the drilling deviation.

[0044] If drilling at the target drilling position 22 and the monitoring system does not detect electrical signals on the main conductive line 21, it means that the drilling offset x is greater / less than A m , or A m -R ≤ drilling offset x ≤ A m +R, but the drilling offset direction differs too much from the opening orientation of the conductive U-shaped pattern.

[0045] Specifically, the mechanical drilling in step two is carried out on the workbench. A backing plate, a trial drilling panel 1, and a cover plate are stacked in sequence on the workbench, and the stack of the backing plate, the trial drilling panel 1, and the cover plate is fixed on the workbench through pins. One side of the trial drilling panel 1 with the alignment monitoring module 2 faces the cover plate. The backing plate is used to prevent the drill bit from damaging the workbench, and the cover plate is used to make the drill bit more stable during drilling.

[0046] Step three: Adjust the position of the mechanical drilling machine according to the drilling offset x and the offset direction;

[0047] Then repeat steps two and three until the drilling offset is within the allowable range, that is, the position correction of the mechanical drilling machine is completed, and formal mechanical drilling can be carried out on the panel with the same size as the trial drilling panel 1.

[0048] Compared with directly detecting the drilling deviation using X-ray equipment in the prior art, the equipment used in the present invention is simpler and does not require high-cost X-ray equipment, thereby reducing the overall detection cost.

[0049] As Figure 1 shown, the openings of the conductive U-shaped patterns 23 in the same row face in the clockwise / counterclockwise direction in sequence, and the openings of the conductive U-shaped patterns 23 in adjacent two columns differ by 360° / N, which can comprehensively monitor the drilling offset direction.

[0050] In the present invention, 4 columns of conductive U-shaped patterns are provided, that is, 4 conductive U-shaped patterns with different opening directions are provided. In other embodiments, the number of columns N of the conductive U-shaped patterns 23 of the alignment monitoring module 2 is ≥ 3, and the more the number of columns of the conductive U-shaped patterns 23, the more accurately the drilling offset direction can be monitored.

[0051] Since the judgment formula for the drilling offset x in the present invention is A m+1 -R ≤ drilling offset x ≤ A m -R, and preferably drill the conductive U-shaped pattern with a larger A m value first, which can speed up the judgment of the drilling offset x. Therefore, in step two, drill the target drilling positions in sequence from the first row to the last row.

[0052] The radius A m of the semicircular bottom 231 of the conductive U-shaped patterns 23 in the same column m can be matched and set according to the actual situation according to the gradient. The smaller the difference between the As

[0053] set by the alignment monitoring module 2, and the more rows of the target drilling positions 22, the more accurately the drilling offset can be monitored. m The length of the straight part 232 ≥ A

[0054] The distance between the target drilling position at the m-th row and n-th column and the target drilling position at the (m + 1)-th row and n-th column is D 1 +A m +A m+1 , D 1 is a fixed value, and A m is the radius of the bottom of the semi-circle in the m-th row, and A m+1 is the radius of the bottom of the semi-circle in the m-th row. The distance between the target drilling position 22 at the m-th row and n-th column and the target drilling position 22 at the m-th row and (n + 1)-th column is D 2 , D 2 is a fixed value. This design enables the drilling positions to be more evenly distributed on the PCB board, avoiding overcrowding or sparseness between the drilling positions, and the distance between the drilling positions is known. Therefore, no complex calculations or positioning are required during the measurement process.

[0055] The main conductive line 21 is provided with a conductive joint 25, and the monitoring system monitors the electrical signal at the conductive joint 25.

[0056] Other parts of the trial drilling panel 1 are divided into multiple PCB units, and the alignment monitoring module 2 is arranged at the edge of the trial drilling panel 1, optimizing the layout of the trial drilling panel 1 and facilitating the connection between the monitoring system and the conductive joint 25.

[0057] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A method for monitoring the offset of mechanical drilling in the inner layer of a PCB, characterized in that: The following steps are involved: Step 1: providing a test drilling panel (1), wherein the test drilling panel (1) is provided with a positioning monitoring module (2), wherein the positioning monitoring module (2) comprises a conductive main circuit (21), and a plurality of target drilling positions (22) arranged in a matrix, wherein a conductive U-shaped pattern (23) is provided on the periphery of each target drilling position (22), wherein the conductive main circuit (21) is connected to the conductive U-shaped pattern (23) through a conductive branch circuit (24), wherein the conductive U-shaped pattern (23) comprises a semicircular bottom (231), and a straight line portion (232) tangent to both ends of the semicircular bottom (231), wherein the target drilling position (22) is located at the center of the semicircular bottom (231); and the radius A of the semicircular bottom (231) of the conductive U-shaped pattern (23) located in the same row is m The conductive U-shaped patterns (23) have the same size, but the openings of the conductive U-shaped patterns (23) are oriented in different directions; the openings of the conductive U-shaped patterns (23) in the same row are oriented in the same direction, and the radius A of the semicircular bottom (231) of the conductive U-shaped patterns (23) is m (m is the row number of the conductive U-shaped pattern) and gradually decreases with the number of rows; Step 2: Use a mechanical drilling machine to drill holes at the target drilling positions (22) in sequence, with a drilling radius of R, A m >R and R>A m -A m+1 , the drill bit of the mechanical drilling machine can conduct electricity; the distance d between any two target drilling positions (22) is known, the mechanical drilling machine completes drilling of the previous target drilling position (22), then moves a distance d to drill the next target drilling position (22); during the drilling process, the conductive main line (21) is detected by the monitoring system, and when the drill bit contacts the conductive U-shaped pattern (23), the monitoring system will detect that the conductive main line (21) has an electrical signal; If the monitoring system detects that only some of the conductive U-shaped patterns (23) in the mth row have electrical signals, and the remaining conductive U-shaped patterns (23) have no electrical signals, then A m -R≤drilling offset x≤A m +R, further, if only one conductive U-shaped pattern (23) in the m-th row has no electrical signal, then the drilling offset direction is the same as the opening direction of the conductive U-shaped pattern (23) in the m-th row without electrical signal; if at least two conductive U-shaped patterns (23) in the m-th row have no electrical signal, then the drilling offset direction is between the opening directions of the conductive U-shaped patterns without electrical signal; If the monitoring system detects that some of the conductive U-shaped patterns (23) in the mth to m+kth rows have electrical signals, and the remaining conductive U-shaped patterns (23) have no electrical signals, then A m+1 -R≤drilling offset x≤A m -R, the drilling offset direction is between the opening directions of the conductive U-shaped patterns without electrical signals in the mth to m+kth rows.

2. A method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1, characterized in that: The opening directions of the conductive U-shaped patterns (23) in the same row change in sequence in a clockwise / counterclockwise direction, and the opening directions of the conductive U-shaped patterns (23) in two adjacent columns differ by 360° / N, where N is the number of columns of the conductive U-shaped patterns (23) of the alignment monitoring module (2), and N≥3.

3. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1 is characterized in that: In step 2, holes are drilled sequentially from the target drilling positions of the first row to the last row.

4. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1 is characterized in that: The conductive main line (21) is provided with a conductive joint (25), and the monitoring system monitors the electrical signal at the conductive joint (25).

5. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1 is characterized in that: The length of the straight portion (232) is ≥ A m .

6. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1, characterized in that: The distance between the target drilling position (22) in the mth row and nth column and the target drilling position (22) in the m+1th row and nth column is D1+A m +A m+1 , D1 is a constant value.

7. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1, characterized in that: The distance between the target drilling position (22) in the mth row and nth column and the target drilling position (22) in the mth row and n+1th column is D2, and D2 is a constant value.

8. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1 is characterized in that: The alignment monitoring module (2) is arranged at the edge of the test drilling panel (1), and the other parts of the test drilling panel (1) are divided into a plurality of PCB units.

9. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1, characterized in that: The mechanical drilling in step 2 is performed on a workbench, on which a pad, a test drilling panel (1), and a cover plate are stacked in sequence, and the stack of the pad, the test drilling panel (1), and the cover plate is fixed on the workbench by pins, wherein the test drilling panel (1) is provided with an alignment monitoring module (2) with one side facing the cover plate.

10. The method for measuring the offset of mechanical drilling in the inner layer of a PCB according to claim 1, characterized in that: The method also includes step three: adjusting the position of the mechanical drilling machine according to the drilling offset x and the offset direction; and then repeating steps two and three until the drilling offset x is within the allowable range.

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