JPH068836B2 - Printed circuit board inspector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a board electrification inspection machine for electrically conducting electric conduction inspection printing on a printed board on which components are mounted.

2. Description of the Related Art Inspection of a printed circuit board using a printed circuit board inspector is roughly classified into a function test and an in-circuit test.

The function test is a function test of a circuit incorporated in a printed circuit board. In the electric current inspection machine that performs this inspection, the contact pins may be brought into contact with the input side and the output side of the circuit, and the number of contact pins can be small.

On the other hand, the in-circuit inspection is an inspection for individually measuring individual components mounted on a printed circuit board. In an electric current inspection machine that performs this inspection, the contact pin is brought into contact with the land portion to which the lead of the component is soldered so that the influence of other components does not occur in the single item measurement. In this inspection machine, for example, a pin-pod jig in which a large number of contact pins of 500 to 600 are planted is used. The contact pin is brought into contact with the substrate at a needle pressure of about 200 g / piece. Therefore, if 500 contact pins are used, a load of 100 kg is applied to the printed circuit board. Therefore, only by holding the side edges of the printed circuit board, the printed circuit board is bent, and in particular, contact failure occurs in the contact pin at the central portion of the printed circuit board.

Therefore, in this type of inspection machine, when the contact pins are brought into contact with each other, the board surface is pressed from various directions of the printed board using a pressing jig. This pressing jig is formed by vertically arranging a plurality of pressing bars on a board. The presser bar is provided corresponding to the component mounting gap of the printed circuit board to be inspected, and the mounting gap portion presses the substrate surface from one side.

Problems to be Solved by the Invention However, the components mounted on the printed circuit board are not always mounted in a state in which all of them are correctly raised, and the clearance between the lead insertion hole of the printed circuit board and the lead diameter of the component. For example, the component body may be tilted or may be misaligned when mounted. Therefore, when pressing the board surface with the presser bar, the presser bar, which should correspond to the component mounting gap, collides with the misaligned or tilted part, and this part is unexpectedly damaged or damaged. Occurs.

Therefore, in the conventional electric current inspection machine, it is necessary to perform the pressing operation of the printed circuit board while confirming that the presser bar does not collide with the mounted component, and the handling is troublesome.
Moreover, it was not preferable in terms of the apparatus configuration.

SUMMARY OF THE INVENTION It is an object of the present invention to surely prevent breakage or damage of a mounted component due to a presser bar when a printed circuit board is energized.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a load detection means for detecting a load applied to the presser bar provided on a presser jig that supports the presser bar of a printed circuit board, When a load is applied to the presser bar within a range where the presser bar contacts the printed circuit board surface from the movement start position of the presser jig, an operation of receiving a signal from the load detection means and stopping the operation of the presser jig Stop means was the main component.

Function When the printed circuit board is pressed and held by the presser bar, if the load due to collision with multiple members is applied to the presser bar during the movement within the range where the presser bar contacts the board surface from the movement start position of the presser jig. The load detection means detects this and sends a signal. In response to this signal, the operation stopping means stops the operation of the holding jig, that is, the moving operation of the holding jig and the holding operation of the printed circuit board by this.

Therefore, when the presser bar collides with a component on the printed board, the movement of the presser jig stops at that position, and further movement is blocked. As a result, it is possible to prevent damage or damage to the components due to the excessive movement of the holding jig.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a printed circuit board electrification inspection machine according to the present invention. The main body 10 of the current-carrying inspection machine is provided with a pinboard jig inside and a lower body 11 on which the printed circuit board A to be inspected is placed, and a holding jig located above the lower body 11 so as to face it. It is composed of an upper body 12 and an operation system 13 arranged on one side of the lower body 11.

An opening 14 is formed on the upper surface of the lower body 11. A mounting table 15 on which the side edge of the printed circuit board A is placed is formed on the side edge of the opening 14. Printed circuit board A
Is positioned and installed inside the opening 14 of the lower main body 11 with the pattern surface facing downward and the side edge part placed on the mounting table 15. A pinball jig 16 is arranged inside and below the opening 14 of the lower body 11. The pin board jig 16 is composed of a pin board 17 in which a large number of contact pins 18 are erected upward, and is horizontally supported by a driving means (not shown) for moving the contact boards 18 in parallel. An example of the driving means for moving the pin board 18 up and down is an air cylinder.

On the other hand, inside the upper body 12, an air cylinder 19 is arranged vertically downward. An air pipe 21 is connected to the air cylinder 19 via an air valve 20. At the lower end of the rod 22 of the air cylinder 19, a holding jig 23
Is installed. The holding jig 23 is composed of a board 24 horizontally attached to the lower end of the rod 22 and a plurality of holding rods 25 ... Standing downward on the board 24. The holding rods 25 are set on the board 24 so as to correspond to the vacant spaces (component mounting gaps) between the components formed on the inspected printed circuit board A installed on the lower body 11.

2 and 3 show the sectional structure of the holding jig 23 according to the present invention. The holding jig 23 includes a board 24 and a holding rod 25.

The board 24 is made of a flexible pressure-sensitive conductive seed 26.
Is sandwiched between two boards 24a, 24a. The pressure-sensitive conductive sheet 26 is formed into a sheet shape with the carbon film 26a sandwiched between the pair of electrode films 26b and 26b, and is made conductive by being pressed, and the conductive state has a resistance value ∞.
Changes to a state where the resistance value is close to 0Ω. As a result, the pair of electrode films 26b and 26b are electrically connected.

One of the two boards 24b, 24b 24
Attachment holes 241 of the presser bar 25 are formed at a plurality of positions in b. One end of the presser bar 25 is inserted and supported in the mounting hole 241.

One end of the presser bar 25 is retained inside the mounting hole 241 so as to project and stand upright on one side of the board 24. As shown in FIG. 2, the retaining structure is such that one end has a large-diameter taper in the distal end direction and is received by the inner peripheral surface of a mounting hole 241 formed in the same shape, and one end shown in FIG. Any of those may be provided with a collar portion 251 for preventing slipping out.

One end of the presser bar 25 is pressed and held by the board 24b and the pressure-sensitive conductive sheet 26, and is elastically pressed to the pressure-sensitive conductive sheet 26 through the mounting hole 241. When a load is applied to the presser bar 25 and is axially pressed against the board 24, the pressure-sensitive conductive sheet 26 is pressed at one end thereof,
Conduction is established between the pair of electrode films 26b, 26b.

At one end of the board 24 of the holding jig 23, the terminals 2 connected to the electrode films 26b, 26b of the pressure-sensitive conductive sheet 26 are connected.
7, 27 are provided. A lead wire 28 is drawn out from the terminals 27, 27.

Power is previously supplied to one electrode film 26b of the pressure-sensitive conductive sheet 26 through the terminal 27. The other electrode film 26b is connected to a co-comparator 29 via a terminal 27 and a lead wire 28. The output of the pressure-sensitive conductive sheet 26 is input to the comparator 29. Comparator 29
Detects a signal from the conductive sheet 26 to detect the signal processing system 3
Send signal to 0. The signal from the comparator 29 is a sensor signal and is given to the AND gate 31 of the signal processing system 30.

Next, the operation of the holding jig 23 will be described with reference to FIGS.

In the energization test of the printed circuit board, the holding jig 23 is driven downward by the drive of the air cylinder 19 from the lowering start position t1 to the position t3 where the tip of the holding rod 25 contacts the board surface t3 of the printed board A to be inspected. At the same time, the pinball jig 16 starts moving upward.

When the holding jig 23 descends, the detection gate T opens and turns on at the descending start position t1. This detection gate T is used to set and detect the vertical movement position of the holding jig 23, and its output is, as shown in FIG.
When the descent is started at the descent start position t1, H (= high) is stopped at the position where the presser bar 25 is in contact with the substrate surface t3, and L = (low), and H during the period (t1 to t3). Is set. This H signal is applied to the AND gate 31 in FIG. A signal from the conductive sheet 26 is input to the AND gate 31.

When the holding jig 23 is moved downward, the holding rod 25 is moved to the printed circuit board A.
If it comes into contact with the board surface t3 without contacting the upper part,
The output of the detection gate T becomes L as shown in FIG. Then, even if the signal from the conductive sheet 26 is ON and the sensor signal input to the AND gate 31 through the comparator 29 is H, the output of the AND gate 31 becomes L and the air valve operating system 32 is kept in the ON state. To be done.
Therefore, the printed circuit board A is pressed downward by the pressurizing rod 25 by the pressure of the air cylinder 19. At the same time, the contact pins 18 of the pin board jig 16 are pressed against the lower surface pattern surface of the printed board A. This presser bar 2
The pressing force of 5 ... and the pressing force of the contact pins 18 ... are set so as to oppose each other on the front and back of the printed circuit board A.

As described above, the contact pins 18 ... Are pressed against the pattern surface of the printed circuit board A, and the printed circuit board is subjected to an energization test through the contact pins 18.

On the other hand, as shown by the solid line in FIG. 4 while the holding jig 23 is descending, if one of the holding rods 25 ...
Is pressed by part B and receives a reaction force. Then, the pressure-sensitive conductive sheet 26 is pressed by the presser bar 25 and the electrode film 2 is pressed.
6b and 26b are electrically connected to each other and turned on. The ON signal from the conductive sheet 26 is detected by the comparator 29, and the sensor signal H is output from the comparator to the signal processing system 30.

In response to the sensor signal H at the lowered position t2 of the holding jig 23 and the signal H from the detection gate T, the AND gate 31 outputs the signal H. The signal H from the AND gate 31 becomes a closing signal for the air valve. By this closing signal, the air valve 20 is closed via the air valve operating system 32, the air cylinder 19 is stopped, and at the same time, the lowering operation of the holding jig 23 is stopped. Pinboard jig 1 at the same time
The ascending operation of 6 stops.

As described above, when the pressing rod 25 collides with the component B on the substrate A while the pressing jig 23 is descending, the pressing jig 23 is stopped at that position, and the downward movement is prevented. It Therefore, it is possible to prevent an excessive force from being applied to the component B by the presser bar.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, when the presser bar makes contact with the component on the printed circuit board during the pressing operation of the printed circuit board to be inspected by the pressing jig, the operation of the pressing jig is prevented. It will be reliably stopped at that position and further movement will be blocked. Therefore, it is possible to prevent an unreasonable force from being applied to the parts that are abutted by the holding jig, and to prevent the breakage and damage.

[Brief description of drawings]

FIG. 1 is an external perspective view of a printed circuit board inspecting machine according to the present invention, FIG. 2 is a sectional view showing a holding jig for the printed board, and FIG. 3 is a sectional view showing the holding jig. A sectional view and a block diagram for explaining the operation of the holding jig.
FIG. 6 is a timing chart showing the operation timing of the holding jig, and FIG. 6 is a circuit diagram for explaining the operation of the holding jig. 16 ... Pin board jig, 23 ... Press jig, 24 ... Board, 25 ... Press rod, 26 ... Pressure-sensitive conductive sheet, 19 ... Air cylinder, 20 ... Air valve, 29 ... Comparator, 30 ... Signal processing system, 31 ... AND gate, A ... Printed circuit board, B ... Parts.

Claims (2)

[Claims] 1. A current-carrying test of a printed circuit board for conducting a current test by pressing a printed circuit board mounted on a printed circuit board mounting base from one surface with a plurality of presser bars while pressing a contact pin against the other surface to make a contact test. In the machine, load detection means for detecting a load applied to the presser bar, which is provided in a presser jig that supports the presser bar, and an operation of contacting the presser bar with the substrate surface from a movement start position of the presser jig. A printed circuit board inspecting machine comprising: an operation stopping means for stopping the operation of the pressing jig upon receiving a signal from the load detecting means when a load is generated on the pressing rod within the range. 2. A flexible pressure-sensitive conductive sheet sandwiched by a pair of electrodes is provided inside a board forming the pressing jig, and when a load is applied to the pressing bar, one end of the board is formed. The printing machine electrification inspection machine according to claim 1, wherein the conductive sheet is pressed and the pair of electrodes are electrically connected to each other to output a load detection signal to the operation stopping means.