JPH0144040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for assembling a circuit board, such as a printed circuit board or a hybrid integrated circuit board, which can be used in the mass production of electronic device parts.

Conventional configurations and their problems In general, when assembling relatively small electronic circuit boards, it is necessary to reduce board material costs, automatically attach parts,
For the purpose of increasing the operating rate of automatic machines, etc., as shown in Figure 1, a method in which multiple small circuit boards are simultaneously formed on a single large board, and after assembly, it is divided into parts by folding, splitting, etc., to complete the process. is taken.

However, if one or more circuit boards become defective before parts are installed, mounting the components on all circuit boards will increase component material costs and reduce the operating rate of the automatic mounting machine. It was hot.

For this reason, the conventional method was to mark the defective circuit board with colored ink, detect this optically using an automatic placement machine, and then not place any components on the defective circuit board. It was on. However, in this method, the equipment is expensive, and the reliability is low because defective boards cannot be accurately detected due to the influence of dust, external light, etc.

OBJECTS OF THE INVENTION The present invention eliminates these conventional drawbacks, and provides a method for assembling a circuit board that allows equipment to be constructed at a lower cost than that of an optical type, and that is highly reliable.

Structure of the Invention In the circuit board assembly method of the present invention, a marking conductor is provided on one surface, and the other surface is separated, and a first conductor is connected to one end of the marking conductor, and a second conductor is connected to one end of the marking conductor. Detecting the resistance value of a resistor formed on the surface of the circuit board configured to be electrically connected to the other end, and cutting the marking conductor when the resistance value is either outside the range or within the range, It is equipped with pins that can contact both ends of the marking conductor, detects the resistance value at both ends of the marking conductor, and skips mounting of components when the resistance value is either outside the range or within the range. This is a method of assembling a circuit board in which the quality of the circuit board is determined before mounting so that parts are not mounted on a defective circuit board, and it is possible to detect either the front or back of the circuit board.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, a marking conductor 3 for defect detection is provided on each circuit board 2 of a large board 1 as shown in FIG. Details are shown in Figures 2, 3, and 4. The marking conductor 3 is connected to a first conductor 6 provided on the back side via electrical connection means 4 and 5 such as through holes.
and is electrically connected to the second conductor 7.

If one of the circuit boards is determined to be defective, such as when the printed resistance deviates from the standard in a hybrid integrated circuit, the marking conductor 3 of that circuit board should be removed as shown in Figure 5. cut. Hybrid integrated circuits are cut by laser processing using a laser resistance trimming machine or the like.

Using this, as shown in FIGS. 6 and 7, the contact pin attached to the component mounting machine in the later process is pressed down and brought into contact with the cutting part 8 of the marking conductor 3.
The presence or absence of is detected by the resistance meter 11. At this time, control is performed so that components are not mounted on a circuit board whose marking conductor 3 has been cut due to a defect, but are skipped to the next circuit board for mounting.

Furthermore, even if the circuit board has components mounted on both sides, it is possible to detect it using similar contact pins as shown in FIG.

Effects of the Invention As described above, according to the present invention, a defective circuit board on a large board, etc., on which a large number of circuit boards are assembled, is electrically detected by checking whether or not the marking conductor is cut by a laser processing machine for trimming the resistor. Therefore, compared to the conventional optical type, the processing can be performed using an existing laser processing machine with inexpensive equipment and with high reliability based on electrical discrimination. In particular, even on boards with double-sided component mounting,
This can be achieved using the same method and is extremely effective.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a circuit board assembled by the circuit board assembly method according to an embodiment of the present invention, FIG. 2 is an enlarged plan view showing the same marking conductor, FIG. 3 is a cross-sectional view thereof, and FIG. FIG. 5 is a plan view showing the cutting state of the marking conductor at the time of failure, and FIGS. 6 and 7 are partially sectional side views showing an example of the detection section. 1...Large board, 2...Circuit board, 3...Marking conductor, 4, 5...Electrical connection means, 6...
First conductor, 7... Second conductor, 8... Cutting part,
9, 10... Contact pin, 11... Resistance meter.

Claims (1)

[Claims] 1 A marking conductor is provided on one surface, and the first conductor is separated on the other surface and electrically connected to one end of the marking conductor, and the second conductor is electrically connected to the other end of the marking conductor. detecting the resistance value of the printed resistor formed on the surface of the hybrid integrated circuit board configured as above, and cutting the marking conductor by laser processing using a laser resistance trimming machine when the resistance value is either outside the range or within the range; A method for assembling a circuit board in which pins for detecting resistance of the marking conductor are brought into contact with both ends of the marking conductor, the resistance value at both ends of the marking conductor is detected, and component installation is skipped when the resistance value is either outside the range or within the range. .