JPH0360607B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a reference hole machining device for a single-phase (single-sided or double-sided) printed circuit board.

(b) Conventional technology Holes for wiring on printed circuit boards are generally press-formed using a mold. To position the printed circuit board relative to the mold, fit the guide pins of the mold into the reference holes of the printed circuit board. Therefore, the reference hole needs to be accurately provided at a predetermined position on the printed circuit board. For this purpose, a hole processing device is used that detects a copper mark previously provided on a printed circuit board and drills at the detected position. Conventionally, optical sensor type position detectors have been used to detect copper marks on printed circuit boards. In other words, since the copper mark provided at the position where the reference hole is to be machined has a different light reflection state from the other parts where the resist is provided, this is detected by the optical sensor and the center position of the copper mark is determined. Detect.

(c) Problems to be Solved by the Invention However, in the case of using an optical sensor as described above, if there is a positional shift between the copper mark and the resist, it is difficult to accurately locate the center of the copper mark. The problem is that it is difficult to detect. In other words, when a part of the outer periphery of the copper mark where a resistor is not provided on the printed circuit board is exposed due to a misalignment between the copper mark and the resist, the optical sensor detects the position including this part. Therefore, the position detected by the optical sensor does not match the actual center position of the copper mark. Further, the detection accuracy of the optical sensor also decreases when rust occurs on the copper mark. Furthermore, in cases where paint is provided on the copper marks and resist, the position cannot be detected using the optical sensor method. Note that even in the case of a method of detecting a position using a television camera, problems exactly similar to those described above occur.

Therefore, for example, metal marks that serve as standards for determining the coordinates of hole marks are printed at multiple locations on the periphery of the inner layer circuit board of a multilayer printed wiring board at the same time as the circuit pattern. It is conceivable to measure the position of the metal mark by scanning a current-type position sensor based on changes in its output, and calculate the position of the hole mark based on this measurement result (Japanese Patent Laid-Open No. 125715/1983). reference),
In this method, it is necessary to provide a metal mark for coordinate reference in addition to the hole mark, and after detecting this metal mark, the position of the hole to be machined must be determined by coordinate transformation, so the equipment is The problem is that it is complicated and therefore expensive.

The present invention aims to solve the above problems.

(d) Means for Solving the Problems The present invention moves an eddy current position sensor over the copper mark on a single-layer printed circuit board, and determines the center position of the copper mark based on the signal from this and the signal from the position detector. The above problem is solved by detecting.

That is, the printed circuit board reference hole machining device of the present invention includes a first table 22 that can reciprocate in one direction on one plane, a first servo motor 20 that drives the first table 22, and a first table 22 that can move the first table 22. A first table position detector (pulse detector of the first servo motor) that detects the directional position, and a first table 2
2, a second servo motor 16 that drives the second table 18, and a second servo motor 16 that detects the position of the second table 18 in the moving direction. 2 table position detector (second servo motor pulse detector), drill head 14 fixed to second table 18, drill 12 attached to drill head 14, and eddy current position sensor attached to drill head 14. 10, and processes the signal from the eddy current position sensor 10, the signal from the first table position detector, and the signal from the second table position detector, and both servo motors 16, 2.
0, and the controller 24 outputs a signal for controlling 0. a signal to move the first table 22 so as to move the second table 18 so that the eddy current position sensor 10 reciprocates over the copper mark 32 of the single-layer printed circuit board 30 in the second table movement direction. is sequentially output to both servo motors 20 and 16, and the first table position at the point where the current obtained from this rises to a predetermined value when the eddy current position sensor 10 moves forward and backward in the first table movement direction, respectively. arithmetic mean value of position signals from the detector,
and the arithmetic average value of the position signal from the second table position detector at the point where the current obtained from this rises to a predetermined value when the eddy current position sensor 10 moves forward and backward in the second table movement direction. By determining the coordinates of the center position of the copper mark 32, a signal is sent to both servo motors 20 to move both tables 22 and 18 so that the drill 12 is located at the coordinates of the detected center position of the copper mark 32. and 16. Note that the symbols in parentheses refer to corresponding members in the embodiments.

(E) Effect The eddy current position sensor reciprocates in one direction (for example, the second table movement direction = X direction) above the copper mark, and the controller controls the forward and backward movements of the eddy current position sensor. At each time, the arithmetic mean value of the position signals from the first table position detector at the point where the current obtained from these rises to a predetermined value, that is, the center position of the copper mark in the X direction is determined. Then,
Similarly, the center position of the copper mark in the Y direction (first table movement direction) perpendicular to the X direction is determined. As a result, the coordinates of the center position of the copper mark are detected, and then the drill is moved to this center position to form a reference hole. The eddy current position sensor detects the position of the copper mark by the change in eddy current when it passes over the copper mark, so even if the resist is misaligned with the copper mark, it will accurately detect the copper mark. The center position of the mark can be detected. Furthermore, the center position of the copper mark can be detected even when the copper mark is rusted or covered with paint or the like.

(F) Embodiments Examples of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings.

FIGS. 1 and 2 show a printed circuit board reference hole machining apparatus according to the present invention. Eddy current position sensor 10
and a drill head 14 provided with a drill 12.
is attached to a second table 18 movable in the X direction by a second servo motor 16,
Furthermore, this second table 18 is connected to the first servo motor 2.
0 on a first table 22 that is movable in the Y direction orthogonal to the X direction. The operations of the second servo motor 16 and the first servo motor 20 are controlled by a controller 24, and the rotational positions of the second servo motor 16 and the first servo motor 20 are controlled by a controller 24.
That is, signals corresponding to the X-direction and Y-direction coordinates of the drill head 14 are detected by, for example, pulse detectors provided thereon, and are input to the controller 24. Eddy current position sensor 1
A detection signal of 0 is also input to the controller 24.

Next, the operation of this embodiment will be explained. First, as shown in FIG. 3, the eddy current position sensor 10 is positioned approximately above the copper mark 32 on the printed circuit board 30 (point A in FIG. 3), and then the second servo motor 16 is activated to type position sensor 1
0 is reciprocated in the X direction as shown by the broken line in FIG. When moving to the right through point B as shown in Figure 3, the output current detected by the eddy current position sensor 10 changes as shown in Figure 4. The controller 2 determines the coordinate b indicated by the pulse signal from the second servo motor 16 at the point where the current rises to a predetermined value (that is, this corresponds to point B).
4 is stored. Also, the eddy current position sensor 1 when moving to the left in FIG. 3 through point C.
The output current at point C also changes as shown in Figure 5.
The coordinate value c at is stored. The controller 24 performs the calculation x=(b+c)/2, and this x
indicates the coordinate of the center position of the copper mark 32 in the X direction. Next, the first servo motor 20 is operated to reciprocate the eddy current position sensor 10 in the Y direction, and the center position of the copper mark 32 in the Y direction is calculated by the same operation as above. This means that the center position of the copper mark 32 has been detected. Next, the second servo motor 16 and the first servo motor 20 are operated to move the drill 12 to this center position. That is, the eddy current position sensor 1 is placed at the center position of the detected copper mark 32.
Eddy current type position sensor 10 from the state where 0 coincides
The second servo motor 16 is operated to move the drill head 14 by the distance l between the drill head 12 and the drill head 12. As a result, the drill 12 matches the intermediate test position of the copper mark 32. Next, drill 12
is lowered and the reference hole is machined. As a result, a reference hole is accurately formed in the center of the copper mark 32. The eddy current position sensor 10 has a copper mark 32
Since this type detects eddy current that changes depending on the presence of the copper mark 32, the center position of the copper mark 32 can be detected without being affected by the state of the resist on the printed circuit board 30. Moreover, even if rust occurs on the copper mark 32, it will hardly be affected. Furthermore, even if the copper mark 32 is covered with paint or the like, it is possible to detect the center position of the copper mark 32.

(G) Effects of the Invention As explained above, according to the present invention, the center position of the copper mark on the surface of the printed circuit board is detected using the eddy current position sensor.
It becomes possible to always accurately detect the center position of the copper mark. Compared to the method of providing another metal mark on the periphery of the printed circuit board to serve as reference coordinates, detecting the position of this mark, and calculating the drilling position, there is no need to provide another metal mark, and therefore, there is no need to provide another metal mark. This eliminates the need for coordinate conversion and other calculations to determine the drilling position from this reference position, simplifying the apparatus. Since the drill head is provided with a drill and a current position sensor, only one drive mechanism for the table and the like is required, making the device inexpensive. Further, accurate drilling can be performed without errors caused by signal transmission and reception between the copper mark detection device and the drilling machine. In addition, the coordinates of the center position of the copper mark are calculated from the arithmetic mean value of the position signal from the position detector at the point where the current obtained from the forward and backward movements of the eddy current position sensor rises to a predetermined value. Compared to finding the coordinates of the center position from the peak value of the eddy current,
There is no need for waveform processing operations, and the coordinates of the center position can be determined easily and accurately.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a reference hole machining device for a printed circuit board according to the present invention, Fig. 2 is a view seen in the direction of the arrow in Fig. 1, and Fig. 3 shows the locus of a copper mark and an eddy current position sensor. 4 and 5 are diagrams showing changes in the output current of the eddy current type position sensor. 10... Eddy current position sensor, 12... Drill, 14... Drill head, 16... Second servo motor, 18... Second table, 20... First servo motor, 22... First table, 24 ...Controller, 30...Printed circuit board, 32...Copper mark.

Claims (1)

[Claims] 1. A first table 22 that can reciprocate in one direction on one plane, a first servo motor 20 that drives the first table 22, and a first servo motor 20 that detects the position of the first table 22 in the moving direction. a second table 18 disposed on the first table 22 and capable of reciprocating in a direction perpendicular to the movement direction of the first table 18;
Second servo motor 16 that drives table 18
, a second table position detector that detects the position of the second table 18 in the moving direction, a drill head 14 fixed to the second table 18 , and a drill head 1 fixed to the second table 18 .
4 and an eddy current position sensor 10 attached to the drill head 14.
and the signal from the eddy current position sensor 10, the first
It has a controller 24 that processes the signal from the table position detector and the signal from the second table position detector and outputs a signal to control both servo motors 16 and 20, and the controller 24 , the first table 2 is moved so that the eddy current position sensor 10 reciprocates over the copper mark 32 of the single-layer printed circuit board 30 in the first table movement direction.
2 and a signal to move the second table 18 so that the eddy current position sensor 10 reciprocates over the copper mark 32 of the single-layer printed circuit board 30 in the second table movement direction. and 16, and a position signal from the first table position detector at the point where the current obtained from this rises to a predetermined value when the eddy current position sensor 10 moves forward and backward in the first table movement direction, respectively. and the position signal from the second table position detector at the point where the current obtained from this rises to a predetermined value when the eddy current position sensor 10 moves forward and backward in the second table movement direction, respectively. The coordinates of the center position of the copper mark 32 are detected by calculating the arithmetic mean value of
Both servo motors 2 send signals to move 2 and 18.
1. A reference hole machining device for a printed circuit board, characterized in that the device is configured to output signals at 0 and 16.