JPH0485900A - Printed board testing stand - Google Patents

Abstract

PURPOSE:To enhance universality and the reliability of connection of many probe pins to soldered lands by arranging the pins on an insulating plate in which the lower part of a printed board to be tested is reduced and the upper part is increased under pressure. CONSTITUTION:An insulating plate 15 in which many probe pins 10 are arranged to be passed at a predetermined lattice interval, is provided at the intermediate stage of a frame-shaped box 30. A supporting frame plate 32 for airtightly supporting the lower surfaces of four sides of a printed board 1 to be tested, superposed thereon through an elastic member 33 is mounted vertically movably in the opening of the box 30 horizontally in parallel with the plate 15 to form a lower air chamber 35. On the other hand, in order to compose an upper air chamber 45 above the plate 1, a cover 40 airtightly and detachably covering the sidewall 31 of the box 30 is provided. The air of the chamber 35 is sucked from a suction port 36, high pressure air of less than two atms is diffused from an air port 46 provided at the cover 40 into the chamber 45, the plate 1 is moved down to bring soldered lands of the rear surface into pressure contact with the heads of the corresponding pins 10.

Description

[Detailed Description of the Invention] [Summary] Regarding a printed board test stand for an in-circuit tester, it is applicable to large-sized printed boards, is versatile, low cost, and has probe pins and a printed board under test. The purpose of this test stand is to provide a printed circuit board test stand that has a high degree of reliability in connection with soldering lands. A supporting frame plate is installed horizontally in the opening of the box body so as to be movable up and down; An insulating board that constitutes a lower air chamber together with a printed board;
A large number of probe pins are arranged and penetrated through the insulating plate at predetermined grid intervals, and a cap is airtightly and removably mounted on the side wall of the box body to form an upper air chamber above the printed board under test. By suctioning the air in the lower air chamber and blowing high pressure air of less than 2 atmospheres into the upper air chamber, the printed board to be tested is lowered and the printed board to be tested is Each of the soldering lands on the back surface of the probe pin is pressed against the head of the corresponding probe pin.

[Industrial application field]

The present invention relates to a printed board test stand for an in-circuit tester.

It is common for printed circuit boards with mounted components to undergo circuit testing using an in-circuit tester before being mounted on electronics/communications products, etc.

In this case, a printed board test stand is required to set the printed board to be tested.

Figure 3 shows the main points of such a printed board test stand.

In the third time, the probe pin 10 includes a mantle 12 that accommodates the needle 11 in a vertically movable manner, a compression coil spring 13 inserted into the mantle 12 and seated at the bottom, and a part that penetrates the insulating plate 15 to hold the mantle 12. It is composed of a holding outer cylinder 14 provided therein.

The needle 11 is made of a highly conductive metal (for example gold-plated phosphor bronze) and has a loose detail inserted into the mantle 12 .

A crown-shaped projection is provided on the periphery of the head of the needle 11,
When the printed board 1 under test is lowered, the elasticity of the compression coil spring 3 causes its protrusion to bite into the solder on the soldering land (the part where the lead terminal is inserted into the through hole and soldered) of the printed board 1 under test. There is.

The holding outer cylinder 14 is arranged on an insulating plate 15 made of synthetic resin at a predetermined lattice interval (the pitch is, for example, 2.54 mm), and is insert-molded so that the opening faces upward and extends straight through the insulating plate 15. has been done.

By press-fitting and resetting the mantle 12 into the holding outer cylinder 14, the probe pins IO are arranged and penetrated through the insulating plate 15 at predetermined lattice intervals.

Further, the lower end of each probe pin IO protruding below the insulating plate 15 (lower end of the holding outer cylinder I4) is wrapped with the end of a cable wire connected to an in-circuit tester (not shown).

On the other hand, a mounted component 2 is mounted on the printed board 1 under test,
The lead terminal 3 is inserted into the through hole 4, and the land of the through hole 4 and the lead terminal 3 are soldered.

Note that the strength of the components mounted on the printed board against external pressure is 2 kg/c+j.

When the printed board 1 to be tested is set above the insulating board 15 on the printed board test stand and the printed board 1 to be tested is pushed down,
The head of the needle 11 bites into the solder B solder land filled in the soldered through hole 4, the lead terminal of the mounted component is connected to the in-circuit tester, and a test circuit is constructed.

In the above-mentioned printed circuit board test stand, the contact pressure between the probe pin 10 and the soldering land on the back side of the printed circuit board under test is approximately IQOg per probe pin in order to ensure continuity reliability in circuit tests. has been done.

Note that in order to obtain a contact pressure of 100 g, the needle must be pushed down 4M, although this varies depending on the spring constant of the compression coil spring in the probe pin.

On the other hand, when the needle of the probe pin that is in contact with the soldering land is pushed down by 4 mm, the head of the other probe pin that is not in contact with the soldering land, that is, the head of the needle, is ) will also be pushed down by 2.5 mm (if the height of the solder on the soldering land is 1.5 mm).

In this way, the reaction force of the compression coil spring of the probe pin that is not in contact with the soldering land is approximately 75 g per probe pin.

Now, if the size of the printed board to be tested is 300 meters x 200 meters, the number of grid intersections is approximately 800.
There will be 0 pieces.

It is thought that through holes are provided at 20% of these intersection points (about 20% when a large number of multi-bin semiconductor components are mounted).

Furthermore, if probe bins are planted in the insulation Ifi 15 corresponding to all the intersection points of the grid, the number of probe bins will be 800.
Of these, 8000 x 0.2 = 1600 become probe pins that contact the soldering land.

Therefore, as mentioned above, on a printed board test stand equipped with a large number of probe pins, the printed board under test is 100g x 1600 pieces + 75g x 6400 pieces =
It is necessary to push it down with a force of 640 (kg).

[Prior Art] FIG. 4 is a sectional view of a conventional printed board test stand, and FIG. 5 is a sectional view of another conventional example.

In FIG. 4, reference numeral 20 is a rectangular box that is larger than the printed board 1 to be tested and is open at the top.

An insulating plate I5 is airtightly installed in the middle of the box body 20 parallel to the opening surface, and the probe bins 10 are placed on the insulating plate 15 at predetermined grid intervals.
are installed and penetrated.

Reference numeral 22 denotes a support frame plate having a rectangular outer shape and inserted horizontally into the opening of the box body 20.

By attaching an elastic frame-shaped rubber plate 24 to the upper surface of the support frame plate 22 and attaching the lower surface of the outer peripheral part of the frame-shaped rubber plate 24 to the upper end surface of the side wall 21 of the box body 20, the support frame The plate 22 is held horizontally on the opening surface of the box body 20 and is movable up and down.

Further, an elastic member such as a frame-shaped rubber plate is attached to the inside of the frame-shaped rubber plate 24.

Note that an inlet 23 is provided on the insulating plate 15, and the inlet 23
is connected to a vacuum pump (not shown).

When the printed board 1 under test is aligned and placed on the support frame plate 22 of such a printed board test stand, the printed board 1. The side wall 21 and the insulation mechanism 5 constitute a lower air chamber.

Therefore, when the vacuum pump is driven to discharge the air in the lower air chamber, the printed board 1 under test is attracted to the elastic member on the support frame plate 22, the lower air chamber becomes airtight, and the frame-shaped rubber plate 24 is The printed board 1 to be tested is elastically deformed and lowered in a horizontal state.

Then, the soldered land is connected to the probe bin 1.
0, and further push down the needle of the probe bottle against the elasticity of the compression coil spring inside the probe pin 10.

Therefore, the head of the needle bites into the soldering land, and the lead terminals of the mounted components are connected to the in-circuit tester, forming a test circuit.

In FIG. 5, an insulating plate 15 is attached on the frame-shaped base,
Guide bars 26 are installed at each of the four corners of the insulating plate 15. Compression coil springs are fitted into the guide bars 26, respectively.

Reference numeral 25 denotes a frame-shaped support plate on which the printed board 1 to be tested is superimposed, and the frame-shaped support plate 25 is mounted so as to be movable up and down by inserting guide bars 26 into guide holes at four corners. ing.

27 is a rod holder plate which is driven in the vertical direction by an air cylinder 29, and has a rod holder plate on its lower surface so as to press a desired position on the mounting surface of the printed circuit board 1 to be tested, avoiding the mounted components 2; A large number of Ron 12th plants were placed and planted.

Therefore, by lowering the rod holder plate 27 after placing the printed board 1 under test on the frame-shaped support plate 25, the printed board 1 under test is pushed down by the rod 28, and the soldered lands are removed. The head of the probe pin 10 is press-contacted, and the lead terminal of the mounted component 2 is connected to an in-circuit tester, thereby forming a test circuit.

[Problem to be solved by the invention]

However, in the former case, as the number of probe bins increases, the sum of the elasticity of the compression coil springs installed in each probe bin increases, and even if the lower air chamber is depressurized, the printed board under test does not descend.

Therefore, there is a problem in that the contact pressure between each probe pin and the soldering land is reduced, and the reliability of the connection is reduced.

In addition, in order to avoid the above-mentioned problem, it is conceivable to arrange the probe pins only at the locations corresponding to the soldering lands to be inspected on the printed circuit board under test. A problem arises in that the position of the probe pin must be changed every time the type of the probe changes.

In addition, if this is done, the probe pins will be unevenly distributed, causing the printed board under test to warp.As a result, among the components mounted on the mounting surface, circuit components made of thin ceramic substrates, etc. Cracks may occur and cause damage.

On the other hand, in the latter case, the mounting positions of the mounted components naturally differ depending on the type of printed board under test.

Therefore, each time the type of printed board under test differs,
There was a problem in that the rond holder plate had to be replaced.

The present invention was created in view of these points, and is applicable to large-sized printed circuit boards, is versatile, low cost, and can be used to connect probe pins and soldering lands of the printed circuit board under test. The purpose is to provide a printed circuit board test stand with highly reliable connections.

[Means for Solving the Problems] In order to achieve the above object, the present invention, as shown in FIG. , is provided in the middle of the frame-shaped box body 30.

Further, a support frame plate 32 airtightly supports the lower surface of the four circumferences of the printed board under test l superimposed on the upper part via an elastic member 33.
is mounted horizontally in the opening of the box body 30 parallel to the insulating plate 15 so as to be movable up and down.

Thus, a lower air chamber 35 is formed, which is surrounded by the printed board 1 to be tested, the side wall 31 of the box body 30, and the insulating plate 15.

On the other hand, in order to form an upper air chamber 45 above the printed board 1 to be tested, a cover body 40 is installed on the side wall 31 of the box body 30 in an airtight and detachable manner.

Then, the air in the lower air chamber 35 is sucked through the intake port 36, and high-pressure air of less than 2 atmospheres is blown into the upper air chamber 45 from the air supply port 46 provided in the cover body 40, and the printed board 1 under test is lowered. Each of the soldering lands on the back surface of the printed circuit board 1 to be tested is brought into pressure contact with the head of the corresponding probe pin 0.

[Function] As mentioned above, the pressure is reduced below the printed board 1 to be tested, and a pressure of less than 2 atmospheres is applied to the upper surface of the printed board 1 to be tested. will be granted.

Therefore, a large number of probe pins 10 are arranged in a matrix.
are arranged, and even if the sum of the elasticity of the compression coil springs installed in each probe pin becomes large, the printed circuit board under test descends and the contact pressure between each probe pin and the soldering land is guaranteed.

That is, regardless of the type of printed board to be tested, probe pins can be arranged at all the intersection points of the grid of insulating plates, so the printed board test stand of the present invention is highly versatile.

Furthermore, since the probe pins are arranged equally on the insulating plate, the reaction force of the probe pins is applied to the printed board under test as a uniformly distributed load.

Therefore, there is no risk of warping of the printed board under test, so there is no risk of damage to the mounted components, and there is no possibility that the contact pressure between the land provided at a specific position and the probe pin becomes particularly weak.

Furthermore, since the air pressure applied to the mounted components mounted on the printed circuit board under test is less than 2 atmospheres, there is no fear that the mounted components will be damaged.

〔Example〕

The present invention will be specifically described below with reference to the drawings. Note that the same reference numerals refer to the same objects throughout the plan.

FIG. 2 is a cross-sectional view of an embodiment of the invention.

In FIG. 2, 30 is a box with a frame shape larger than the printed board under test l and open at the top, and is installed on a lower frame 30A.

An insulating plate 15 is airtightly provided in parallel to the opening surface in the middle part of the box body 30, and a large number of insulating plates (for example, about 8,000
The book) is placed through it. In addition, the probe pin IO is
They are arranged at all the intersection points of the grid with a pitch of 2.54 mm on the insulating plate 15.

A lead wire is ramped to the lower end of each of the probe pins 10 that protrude below the insulating plate 15 to attach the lower frame 30.
Connect the probe pin 10 to the connector 16 installed on the side wall of A, and connect the probe pin 10 to the in-circuit tester (
(not shown).

32 is a guide bar (
The compression coil spring 18 (attached to the outer periphery of the guide bar) is inserted horizontally into the opening of the box 30 and is seated around the insulation @ 15 (not shown).
This is a support frame plate supported horizontally by

The inner frame dimensions of the support frame plate 32 are in phase with and smaller than the printed board 1 to be tested.

An elastic frame-shaped rubber plate 34 is attached to the periphery of the upper surface of the support frame plate 22. The outer periphery of this frame-shaped rubber plate 34 expands in the direction of the side wall 31, and as the support frame plate 32 descends, the lower surface of the outer periphery of the frame-shaped rubber plate 34 comes into airtight contact with the upper end surface of the side wall 31. .

On the other hand, guide pins are provided at the corners of the support frame plate 32. By inserting the reference hole of the printed board 1 under test into this guide pin and placing the printed board 1 under test on the support frame board 32, the grid of the insulating board 15 and the grid of the printed board 1 under test are aligned. will be held.

Further, a frame-shaped elastic member (elastic rubber) 33 having a U-shaped cross section is adhered to the inner frame edge of the support frame plate 32.

Therefore, when the printing machine under test is placed on the support frame plate 32 and the printed board 1 under test is pushed down, the lower surface of the peripheral edge of the printed board 1 under test is airtightly attached to the support frame plate 32 via the elastic member 33. Close.

Note that an intake port 36 is provided in the side wall 31, and the intake port 36 is connected to a vacuum pump (not shown).

Since the box body 30 is configured as described above, the lower air chamber 35 surrounded by the printed board 1 to be tested, the side wall 3I, and the insulating plate I5 is configured below the printed board 1 to be tested.

40 is a cover body that is airtightly and removably mounted on the side wall 31 of the box body 30.

The cover body 40 consists of four cover side walls 42 facing the side walls 31 of the box body 30 and a ceiling plate 41 that covers the upper part of the cover side walls 42. A frame-shaped rubber ring 47 is attached to the upper end surface of the side wall 31 in close contact.

Therefore, when the cover body 40 is lowered and attached to the box body 30, an upper air chamber 45 is formed above the printed board 1 to be tested.

Further, an air supply port 46 is provided on the cover side wall 42, and the air supply port 46 is
6 is connected to a blower pump (not shown).

On the other hand, a rod holding plate 43 is installed inside the cover body 40, and a presser rod 44 is attached to this rod holding plate 43, which comes into contact with the upper surface portion of the peripheral edge of the printed board 1 to be tested.

Therefore, when the cover body 40 is attached to the box body 30 after the printed board l to be tested is set on the support frame plate 32 of the box body 30, the frame-shaped rubber ring 47 is pressed against the upper end surface of the side wall 31, and the side wall The upper air chamber 45 is sealed off from the outside air, making the upper air chamber 45 airtight.

At the same time, since the presser rod 44 presses down the printed board 1 to be tested, the lower surface of the printed board 1 to be tested comes into close contact with the elastic member 33.

Then, the vacuum pump is driven to suck the air in the lower air chamber 35 through the intake port 36, and at the same time, high pressure air of less than 2 atmospheres is blown into the upper air chamber 45 from the air supply port 46 provided in the cover body 40. Lower the printed board l.

By creating a high pressure inside the upper air chamber 45, the frame-shaped rubber plate 34 is pressed against the upper end surface of the side wall 31 of the box body 30 and comes into airtight contact with the lower air chamber 35 and the upper air chamber 45. Completely isolated.

When the printing machine under test descends, the printed board under test 1
Each of the soldering lands on the back surface of the probe contacts the head of the corresponding probe pin 10, and pushes down the needle of the probe pin by a predetermined stroke against the elasticity of a compression coil spring installed in the probe pin.

Therefore, the head of the probe pin 10 bites into the solder of the soldering land of the printed circuit board 1 under test, and each of the lead terminals of the mounted component 2 is connected to the in-circuit tester, thereby forming a test circuit.

When the area of the printed board 1 under test is 600 d, the pressure in the lower air chamber is reduced to 0.1 kg/cd, and the pressure in the upper air chamber is reduced to 1.5 kg/cd.
When the pressure is increased to cffl, the printed board under test has a pressure of 84
A force of 0 kg is applied.

Therefore, even if the number of probe bins is 8000, the contact pressure between the soldering land and the probe pin is sufficiently guaranteed.

In addition, since a means for maintaining the cover body 40 in a crowned state is provided on the upper part of the ceiling plate 41, the cover body 40 will not be lifted up even if high pressure air is blown into the upper air chamber 45.

Further, in the present invention, although the presser rod 44 is not essential, it is preferable to provide the presser rod.

C Effects of the Invention As explained above, the present invention provides a printed board test stand in which a large number of probe pins are arranged on an insulating board, which reduces the pressure below the printed board under test and increases the pressure above it. It is a practical method that can be applied to large-sized printed circuit boards, is versatile, low cost, and has a high degree of reliability in connecting the probe pin and the soldering land of the printed circuit board under test. It has excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a cross-sectional view of an embodiment of the present invention, Fig. 3 is a cross-sectional view of important points of a printed board test stand, Fig. 4 is a cross-sectional view of a conventional example, FIG. 5 is a sectional view of another conventional example. In the figure, 1 is the printed board under test, 2 is the mounted component, 3 is the lead terminal, 4 is the through hole, 10 is the probe pin,
11 is a needle, 15 is an insulating plate, 2
0.30 is the box body, 2L31 is the side wall, 22.3
2 is a support frame plate, 33 is an elastic member, 34 is a frame-shaped rubber plate, 35 is a lower air chamber, 36 is an intake port, 4
0 is a cover body, 41 is a ceiling plate, 42 is a cover side wall, 45 is an upper air chamber, and 46 is an air inlet. Key points of the book project - 1 night f-view Figure 3 Figure 4

Claims (1)

[Claims] In order to airtightly support the lower surface of the four circumferences of the printed board to be tested (1) placed on top, it is mounted horizontally to the opening of a frame-shaped box (30) so as to be movable up and down. A supporting frame plate (32) is placed below and parallel to the printed board under test (1).
an insulating plate (15) provided at the middle stage of the box (30) and forming a lower air chamber (35) together with the side wall of the box body (30) and the printed board to be tested (1); Arranged and penetrated with a grid spacing of
A large number of probe pins (10) and the printed board under test (
1) to form an upper air chamber (45) above the box (
The cover body (40) is airtightly and removably attached to the side wall (31) of the air chamber (30), and the air chamber (35) is suctioned from the lower air chamber (35). By blowing high-pressure air below atmospheric pressure, the printed board under test (
1) is configured such that each soldering land on the back surface of the printed circuit board under test is pressed against the head of the corresponding probe pin (10). Printed board test stand.