JPS6246249A - Apparatus for centering electrode in apparatus for measuring resistance of through-hole - Google Patents

Abstract

PURPOSE:To easily measure the plated film of a through-hole, by providing a narrow engageable insert part to the electrode received in the guide cylinder of an upper probe. CONSTITUTION:When an actuator is driven, a mount plate 20 upwardly inclines and a lower probe 30b rises while the detection end 40 of an electrode 35b is contacted with the lower peripheral edge (z) of a through-hole (y) through an operation hole. Electrodes 35a, 35b float against springs 43, 43 in such a state that the electrodes 35a, 35b are contacted with the lower peripheral edge (z) of the through-hole (y) and the engageable insert part 37 of the electrode 35a is escaped from an insert hole 33. Therefore, a taper part 38 is positioned in the insert hole 33 and the electrodes 35a, 35b can be properly inclined by the inclined surface of said taper part 38 without being largely inclined and detection ends 40, 40 accurately follow the upper and lower peripheral edges (z), (z) of the through-hole (y). By this method, the plated film of the through- hole (y) can be easily measured.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to the centering of electrodes in a resistance measuring device for measuring the resistance sound of through-holes in a plating-coated wiring board and detecting the state of the through-hole plating area. Regarding equipment.

<Prior art> An easy and simple way to know the plating thickness and plating quality of through-hole plating areas is to measure the voltage drop at the plated areas.
There is a resistance measurement method that detects this resistance.

In this resistance measurement method, the voltage drop is minute, so the best way to accurately measure it is to place electrodes with detection ends formed by insulating the current supply contact and the voltage detection contact above and below. However, a four-terminal method is used in which each contact point is brought into contact with the upper and lower peripheral edges of the through hole.

As an apparatus for carrying out such a method, Japanese Patent Application Laid-Open No. 1986-
There is one disclosed in No. 222771 or Japanese Patent Application No. 10711/1983.

In this probe, an electrode having a detection end having a current supply contact and a voltage detection contact is mounted in a guide cylinder, and the detection end protrudes from an insertion hole in the cylinder end. The upper and lower probes are disposed so as to face each other at the upper and lower positions of the operation hole of the mounting table, and the upper and lower probes can be moved in a relatively close direction, and by moving in the approaching direction, the respective detection ends are It is made by contacting the upper and lower edges of the through hole.

By the way, in such a device, it is necessary to make the detection end follow the periphery of the through hole in an even manner.

Therefore, as disclosed in Japanese Patent Application No. 59-10711, as an electrode centering device, an electrode having a current supply contact and a voltage detection contact is placed relative to the through-hole of the printed wiring board. The electrode is mounted so as to be movable up and down in the guide cylinder that is moving away from the electrode, and its detection end protrudes from the insertion hole of the cylinder, and the biasing force of the spring provided in the guide cylinder is applied to the collar of the electrode. The force presses the flange against the inner wall surface of the periphery of the insertion hole of the cylindrical body, and as the guide cylindrical body moves, the flange is pressed against the spring with the contact end of the electrode in contact with the through hole. An electrode was proposed in which the electrode floats against the surface and can be slightly tilted, and the contact end of the electrode is brought into contact with the through hole.

By the way, in this device, before bringing the detection end of the lower probe into contact, it is first necessary to bring only the detection end of the upper probe into contact with the through hole and adjust its position. It has been found that during adjustment, if the horizontal movement of the electrode is not restrained by the cylindrical body, the electrode will tilt, wobble, and become unstable, making it impossible to perform good position adjustment.

An object of the present invention is to provide a centering device having the above-mentioned configuration with an m-stroke for holding the electrode during position adjustment.

Means for Solving the Problems> The present invention provides an electrode housed in a guide cylinder of an upper probe, which has a flange that abuts the inner surface of the peripheral wall of the insertion hole of the guide cylinder, and a flange that is continuous to the abutting side. A fitting part having a narrow width and approximately equal to the inner diameter of the insertion hole of the guide cylinder is provided, and a spring is attached inside the guide cylinder to apply the elastic force to the collar part. It is.

Operation> A wiring board is mounted on the mounting table, the through hole is positioned directly below the electrode of the upper probe, the upper probe is lowered relative to the wiring board, and the detection end of the electrode is It is brought into contact with the upper periphery of the through hole. At this time, the wiring board is slightly slid or rotated along the mounting table to make the contact state almost stable. At this time, the insertion portion of the electrode is positioned in the insertion hole of the guide cylinder in a substantially tight fit manner, and the electrode is only allowed to move vertically, and is not allowed to move horizontally. Therefore, even if the detection end is brought into contact with the through hole and moved during the position adjustment, the detection end will not be tilted and will be stably held.

After such adjustment, when the detection end of the electrode of the lower probe is brought into contact with the lower periphery of the through-hole and the upper and lower probes are brought closer to the through-hole, the respective electrodes float against the spring inside the cylinder, and the above-mentioned fitting occurs. The insertion portion escapes from the insertion hole into the cylindrical body. This escape allows for tilting of the electrode. Therefore, the detection end can precisely follow the periphery of the through hole.

Then, the centering is completed, a current is passed through the current supply contact of the electrode, a voltage drop is detected by the voltage detection contact, and the resistance value is measured. The state of the plating film can be detected from such measured values.

<Example> An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a resistance measuring device, in which an upper frame 2 is held at the rear of a case-like lower frame 1, which is disposed substantially parallel to the lower frame 1 and creates a mounting gap 3 with the lower frame 1. ing.

Further, on the lower frame 1, a mounting table 4 having an operation hole 5 formed in the front part is fixedly arranged.

A leaf spring 6a is mounted on the lower surface of the upper frame 2 within the mounting gap 3.
A mounting plate 6 with a mounting plate 6 attached thereto is arranged, and its rear end is supported by a port 7. A tension spring 9 is hung between the mounting plate 6 and the spring hook in the frame 2, and the mounting plate 6 is suspended in an upwardly oblique direction with the port 7 as the center. .

An upper probe 30 is attached to the front end of the mounting plate 6 above the operation hole 5.
a is held, with its electrode 35a protruding downward.

Furthermore, an elevating nodle 11 is held on the upper surface of the upper frame 2. The lowering handle 11 has its R lowering rod 12 inserted through a guide holding member 13 fixed on the upper frame 2. Further, a detection switch 14 is mounted on the mounting plate 6 at a position directly below the lifting rod 12, and the detection switch 14 detects the M, l! The lower end of the i-rod 12 is supported to support the load of the lift handle 11. The contact 16 that is opened and closed by the detection roll 15 is biased to protrude by an internal spring member, and the biasing force can support the load of the lifting handle 11, and is also capable of supporting the load of the lifting handle 11, which will be described later. It should also be able to withstand the restoring elasticity of the mounting plate 6.

A stopper is provided on the lower surface of the mounting plate 6, which contacts the upper surface of the wiring board 17 are provided.

A mounting plate 20 to which a leaf spring 20a is attached is disposed at the lower part of the loading table 4 along the loading table 4 so as to be swingable with its rear end supported by a port 21. A lower probe 30b is fixed to the tip of the mounting plate 20 through the operation hole 5 at a position directly below the upper probe 30a, with its electrode 35b projecting upward.

Furthermore, an actuator 22 made of a solenoid is disposed at the lower part of the mounting plate 20, and its rod end is brought into contact with the lower surface of the mounting plate 20. The actuator 22 is driven by opening the detection switch 14,
Raise the rod and attach the mounting plate 20 to the port 21.
tilt upwards around the center.

Additionally, a display device 25 is provided at the front end of the upper frame 2.

The probes 30a and 30b according to the main part of the present invention are
The diagram will be explained.

The probes 30a, 30b include a guide cylinder 31a,
Electrodes 35a and 35b are fitted inside the 3lb.

That is, the guide cylinders 31a and 31b are connected to the mounting plate 6.
Or, the cover tube 3 is attached to the base tube 32 fixed to the mounting plate 20.
4 is attached to form mounting holes for electrodes 35a and 35b inside. Further, an insertion hole 33 from which a detection end 40 (described later) of the electrodes 35a, 35b protrudes is formed in the mounting surface of the base tube 32.

The electrodes 35a, 35b include a flange portion 36 that abuts the inner surface of the peripheral wall of the insertion hole 33, a fitting portion 37 that is continuous to the contact side and has approximately the same diameter as the insertion hole 33, and further the fitting portion 37.
A tapered portion 38 whose diameter is reduced toward the tip end is coupled with a narrow rod portion 39 that protrudes from the reduced diameter end and has a detection end 40 at its tip.

An electrode piece 42 is inserted into the slit 41 formed in the vertical direction.
is inserted. The front and back width of the insertion part 37 is 1.5cm
Due to the inward escape from the insertion hole 33, which will be described later,
Slight tilting of the electrodes 35a and 35b is allowed.

Further, a spring 43 is attached inside the guide cylinders 31a and 31b, and one end of the spring 43 is hung on the flange 36, and the electrode 35
a and 35b are urged toward the protruding side.

In the embodiment described above, the electrodes 35a and 35b are made of the same material except for the electrode piece 42, and are integrally constructed. A molded body made of the like is provided, and the molded body forms the flange portion 36. A fitting portion 37 and a tapered portion 38 may be formed.

The configuration of the detection end 40 will be explained with reference to FIG. 5.6. The detection end 40 has a conical shape with a pointed tip, and is formed by the front edge of the electrode piece 42 along the conical surface from the tip. The face of the small mountain is used as a voltage detection contact 51, and the detection contact 5
A fan-shaped surface extending rearward from the tip at a position facing 180 degrees from the current supply contact 52 is the current supply contact 52, and the voltage detection contact 51
．． The current supply contact 52 is insulated by an insulating film 53. The voltage detection contact 51. When the current supply contact 52 is in contact with the upper and lower peripheral edges 2 of the through hole y, it is discontinuous due to the presence of smooth-cut surfaces 54° 54 with an inclination angle of about 45°. The detection end 40 is disclosed in Japanese Patent Application Laid-Open No. 32-10
0572, a conical electrode formed by insulating each other, with the hilly surface part along the conical direction from the tip of the conical electrode serving as a voltage detection contact, and the other face part serving as a current supply contact, etc.
There are various others, and any one may be used.

As shown in FIG. 6, a resistance measuring device 55 is connected to the voltage detection contact 51.51 of the electrode 35a, 35bc7) detection end 40.40, and a DC constant current source 56 is connected to the current supply contact 52.52. , are connected via a measurement switch 57.

When measuring the resistance of the through hole y, the detection end 40.
40 is brought into contact with the seventh F circumference 2 of the through hole y, the measurement switch 57 is closed, a current is passed between the current supply contacts 52 and 52, and the resistance is detected by the resistance detector 55 from the voltage detection contact 51 and 51. do.

The operation of the above embodiment will be explained.

The wiring board X is inserted onto the table 5 from the front, and the through hole y is visually positioned directly below the detection end 40 of the upper surface electrode 35a. At this time, since the detection end 40 of the lower surface electrode 35b is positioned below the -L surface of the mounting table 4, the mounting of the wiring board X on the mounting table 4 is controlled by the lower surface electrode 35b. This can be done without damaging the detection end 40 of.

After determining the approximate position 21 of the through hole y as described above, the lifting handle 11 is pushed down to tilt the mounting plate 6 downward against the tension spring 9 as shown by the chain line in FIG. 1 and in FIG. The probe 30a is lowered until the stopper 17 lightly touches the upper surface of the wiring board X.

In this state, the electrode 35a is inserted into the through hole y of the wiring board
Since the detection end 40 of the wiring board
Move it slightly to find the best position. At this time, electrode 3
Since the insertion part 37 of the electrode 35a is fitted into the insertion hole 33 of the cylindrical body 31a in a substantially tight fit, the fine movement operation is performed on the electrode 35a.
It can be applied stably without any wobbling.

Next, as shown in FIGS. 2 and 4, the lifting handle 1
Press 1. By this suppressing operation, the mounting plate 6 is
Since the stopper 17 comes into contact with the upper surface of the wiring board X and cannot be lowered, the lifting rod 12 of the lifting handle 11
6 is lowered, causing the detection switch 14 to close. Therefore, the actuator 22 is driven, and the mounting plate 20 tilts upward due to its rod extension, and the lower probe 30b at its front end rises, and the detection end 40 of the electrode 35b is inserted into the through hole y from the operation hole 5. Lower periphery 2
come into contact with.

These electrodes 35a and 35b are the upper and lower peripheral edges 2 of the through hole y.
As shown in FIG.
5a, 35b float against the springs 43, 43 and escape through the insertion holes 33 through their fitting portions 37. Therefore, the tapered portion 38 is located in the insertion hole 33, and due to its inclined surface, the electrodes 35a and 35b are not tilted significantly.
Appropriate inclination is possible, and the detection @40, 40 uniformly follows the upper and lower peripheral edges 2.2 of the through hole y.

Therefore, as described above, a constant DC current is applied to the current supply contacts 52, 52, and a voltage drop from the source 56 is applied to the voltage detection contact 5.
1.51, a voltage drop is detected, the resistance detector 55 reads and calculates the value, and calculates the resistance value.
It is displayed by the display device and 25.

<Effects of the Invention> As described above, the present invention provides the electrode housed in the guide cylinder of the upper probe with a fitting portion that is approximately equal to the inner diameter of the insertion hole of the guide cylinder and has a small width. Place the wiring board on the mounting table, bring the detection end of the electrode of the upper probe into contact with the periphery of the through hole, and position the wiring board by slightly sliding or rotating 5 along the mounting table. When approximately centering is performed, the insertion portion is positioned in the insertion hole of the guide cylinder in a substantially tight fit shape to restrain horizontal movement and hold the electrode, so such operations can be stabilized. It can be applied by

Therefore, it is possible to easily measure the plating film of the through hole y, and due to this, there are excellent effects such as being able to derive an accurate resistance value with as much reproducibility as possible.

[Brief explanation of drawings]

The accompanying drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal side view of the measuring device, FIG. 2 being an enlarged longitudinal side view of the main parts showing the operating state, and FIGS. 3 and 4 showing the centering operation. probe 30a
, 30b, and FIG. 5 is an end view of the detection end 40.
FIG. 6 is a circuit diagram showing current control of the electrodes 35a and 35b. 1. Lower frame 2: Upper frame 4: Mounting table 5: Operation hole
30a, 30b; probe 33; through hole 35a, 35
b; Electrode 36; Flange part 37, insertion part 38; Taper part 40; Detection end 51, city pressure detection contact! 52: "Commercially supplied connection

Claims (1)

[Scope of Claims] A probe is provided in which an electrode having a detection end having a current supply contact and a voltage detection contact is mounted in a guide cylinder, and the detection end protrudes from an insertion hole in the cylinder end. The upper and lower probes are arranged so that their detection ends face each other at the upper and lower positions of the operating hole of the mounting table, and the upper and lower probes can be moved relatively toward and away from each other, and by moving in the approach direction, the respective detection ends In a through-hole resistance measuring device in which the electrodes are placed in contact with the upper and lower peripheries of the through-hole, the electrode housed in the guide cylinder of the upper probe has a flange that contacts the inner surface of the peripheral wall of the insertion hole of the guide cylinder, and a flange that contacts the inner surface of the peripheral wall of the insertion hole of the guide cylinder. A fitting portion having a narrow width and approximately equal to the inner diameter of the insertion hole of the guide cylinder that continues to the side is provided, and a spring is provided inside the guide cylinder to apply the elastic force to the collar portion. Features: Electrode centering device in through-hole resistance measuring device.