Circuit board solder joint bending stress test device

Abstract

The present invention discloses a circuit board solder joint bending stress displacement measuring device, which includes a base and two clamping mechanisms matched to clamp the circuit board, wherein one clamping mechanism is fixed on the base, and the side of the other clamping mechanism is connected to a power mechanism that drives the clamping mechanism to translate; the lower end of the other side of the power mechanism is fixed on the base; displacement measuring mechanisms that measure the deformation of the circuit board under bending stress are installed above and below the circuit board clamped by the two clamping mechanisms through a mounting frame, and the mounting frame can slide left and right relative to the base. This solution clamps the circuit board through two clamping mechanisms, so that the circuit board can be kept horizontal and will not creep; one of the clamping mechanisms is driven to move by the power mechanism to achieve the application of deformation force to the circuit board to achieve bending deformation of the circuit board, and the deformation is measured by the displacement measuring mechanism, so as to achieve a simple and rapid circuit board bending performance test.

Description

Technical Field

[0001] The invention relates to a circuit board deformation monitoring device, in particular to a circuit board solder joint bending stress testing device. Background Art

[0002] With the continuous development of science and technology, electronic products have been developing towards miniaturization, low power loss, and high integration density. The demand for electronic products is also increasing, and the reliability of electronic products has always been a concern. In the process of electronic product packaging, a large part of the factors affecting reliability are mechanical loads, such as bending deformation, torsional deformation, random vibration and other factors, which lead to failure deformation of solder joints, which will further lead to the failure of the entire component. Therefore, it is necessary to study the reliability of BGA solder joints under bending loads.

[0003] Currently in the engineering field, whether it is the National 863 Program, the National Natural Science Foundation Project, or the military industry project, there are research topics involving the bending stress of solder joints. However, when conducting relevant scientific research, there is still a lack of devices that can accurately clamp the product being tested to cause it to bend and deform. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a circuit board solder joint bending stress test device capable of measuring the deformation of a circuit board under bending stress.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A circuit board solder joint bending stress test device is provided, which comprises a base and two clamping mechanisms matched to clamp the circuit board, wherein one clamping mechanism is fixed on the base, and the side surface of the other clamping mechanism is connected to a power mechanism for driving the clamping mechanism to translate; the lower end of the other side of the power mechanism is fixed on the base; displacement measuring mechanisms for measuring the deformation of the circuit board under bending stress are installed above and below the circuit board clamped by the two clamping mechanisms through mounting frames, and the mounting frames can slide left and right relative to the base.

[0007] The beneficial effects of the present invention are as follows: by clamping the circuit board with two clamping mechanisms, the circuit board can be kept horizontal and will not creep; when testing, since one of the clamping mechanisms is fixed and the other clamping mechanism is connected to the power mechanism, when force is applied to the clamping mechanism, since one side of the power mechanism is fixed on the base, it will move toward the side connected to the clamping mechanism when it is extended, so as to drive the clamping mechanism to slide toward the other clamping mechanism, thereby causing the circuit board to bend and deform.

[0008] Before the deformation test of the circuit board is carried out, the displacement measuring mechanism is brought into contact with the circuit board to obtain the initial displacement of the displacement measuring mechanism; after the circuit board is bent and deformed, the mounting frame is moved to make the displacement measuring mechanism contact with the circuit board to obtain the measured displacement, and the deformation of the circuit board is obtained through the initial displacement and the measured displacement, so as to achieve a simple and rapid test of the bending performance of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a three-dimensional diagram of the circuit board solder joint bending stress experimental device.

[0010] Figure 2 A three-dimensional diagram of the base.

[0011] Figure 3 A three-dimensional diagram of a clamping mechanism fixed to a base.

[0012] Figure 4 The present invention is a stereoscopic diagram showing a clamping mechanism connected to a power mechanism and connected to the power mechanism.

[0013] Figure 5 A perspective view of the mounting bracket.

[0014] Among them, 1. base; 11. support panel; 12. support foot; 13. installation slot; 14. strip guide slot; 15. connecting rod; 16. slider; 2. scale; 3. clamping mechanism; 31. connecting lug; 311. straight slot; 32. support frame; 321. clamping block; 322. locking block; 323. square slot; 324. card slot; 325. strip slot; 33. pressing frame;

[0015] 4. Power mechanism; 41. Fixed plate; 42. Telescopic frame; 421. Connecting frame; 422. Connecting block; 423. Screw; 5. Mounting frame; 51. Top cover; 511. Slide rail; 52. Connecting plate; 521. Middle plate; 522. Strip hole; 523. Extension plate; 6. Displacement measuring mechanism; 61. Threaded connector; 62. Height gauge; 621. Strip slide; 63. Measuring ruler; 7. Circuit board. DETAILED DESCRIPTION

[0016] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0017] like Figure 1As shown, the circuit board solder joint bending stress test device of this scheme includes a base 1 and two clamping mechanisms 3 for clamping the circuit board 7; the base 1 of this scheme is mainly used to provide stable support for other components and tests, such as Figure 2 As shown, the base 1 includes a supporting panel 11 and at least one supporting foot 12 connected to the supporting panel 11 as a whole; a mounting groove 13 for placing the scale 2 is provided in the length direction of the base 1, and the mounting groove 13 is in contact with the edges of the two clamping mechanisms 3 as much as possible, so that through the mutual cooperation of the scale 2 and the power mechanism 4, the moving distance of the clamping mechanism 3 can be accurately controlled.

[0018] One of the clamping mechanisms 3 is fixed on the base 1, and the side of the other clamping mechanism 3 is connected to a power mechanism 4 that drives the clamping mechanism 3 to translate. The power mechanism 4 can be a matching structure of a motor and a screw nut, or it can be an electric push rod, or even a structure that expands and contracts to drive the clamping mechanism 3 to translate relative to the base 1 when a downward force is applied to it from the outside.

[0019] like Figure 3 As shown, the lower end of the clamping mechanism 3 fixed to the base 1 is provided with a connecting ear 31, and a straight slot 311 is opened on the connecting ear 31; Figure 4 As shown, a strip groove 325 is provided on the side of the clamping mechanism 3 connected to the power mechanism 4 and runs through the width direction thereof for installing the power mechanism 4 .

[0020] The lower end of the other side of the power mechanism 4 is fixed on the base 1; a displacement measuring mechanism 6 for measuring the deformation of the circuit board 7 under bending stress is installed above and below the circuit board 7 clamped by the two clamping mechanisms 3 through a mounting frame 5, and the mounting frame 5 can slide left and right relative to the base 1.

[0021] like Figure 3 and Figure 4 As shown, the clamping mechanism 3 includes a support frame 32 and a clamping frame 33, a connecting ear 31 is arranged at the lower end of one of the support frames 32, and a strip groove 325 is provided on the other support frame 32; the support frame 32 and the clamping frame 33 are both provided with a clamping block 321 for clamping one side of the circuit board 7 and a locking block 322 for matching with each other;

[0022] A square groove 323 is formed at the upper end of the support frame 32 , and sliding grooves are formed on the two side walls of the square groove 323 ; the clamping frame 33 is installed in the sliding groove, and the two clamping blocks 321 clamp the circuit board 7 through the locking pieces installed on the two locking blocks 322 .

[0023] If the thickness of the side wall of the clamping frame 33 at the square groove 323 is smaller than the width of the slide groove, the side wall of the clamping frame 33 can be directly placed in the slide groove. If the thickness of the side wall of the clamping frame 33 at the square groove 323 is greater than the width of the slide groove, a slider 16 can also be installed on each side wall of the clamping frame 33.

[0024] Among them, after the locking block 322 is set on the clamping frame 33, its appearance can be L-shaped or Z-shaped. When it is L-shaped, the top surface of the locking block 322 located on the support frame 32 is flush with the lower surface of the square groove 323; when it is Z-shaped, the distance between the top surface of the locking block 322 located on the support frame 32 and the lower surface of the square groove 323 is less than the length of the Z-shaped middle arm.

[0025] The clamping structure of the present solution is not limited to the above structure, and it can also adopt a relatively mature mechanical claw in the prior art to clamp one side of the circuit board 7 through the mechanical claw, and the mechanical claw is then fixed on the base 1 through a supporting structure.

[0026] In this solution, the power mechanism 4 preferably uses a structure that expands and contracts when subjected to a downward force to drive the clamping mechanism 3 to translate relative to the base 1. Figure 4 As shown, the power mechanism 4 includes a fixed plate 41 and a telescopic frame 42. The fixed plate 41 is provided with a strip groove 325 running through the width direction thereof. The lower ends / upper ends of the telescopic frame 42 are fixed in the strip grooves 325 on the fixed plate 41 and the clamping mechanism 3. When the telescopic frame 42 is subjected to a downward force, it moves downward along the strip grooves 325 to extend the telescopic frame 42.

[0027] During implementation, the present solution preferably comprises at least one connecting frame 421 composed of at least two scissor-type frames. When there is only one connecting frame 421, a connecting block 422 is installed at the connection between the two scissor-type frames; when there are at least two connecting frames 421, the connecting frames 421 are connected by installing a connecting block 422 at the connection between the scissor-type frames located in the same row.

[0028] Specifically, all the connecting frames 421 are arranged side by side, with the width direction of the multiple connecting frames 421 being a row and the length direction of one connecting frame 421 being a column, and the connecting frames 421 are installed at the connection of the scissor frames in the same row.

[0029] The two connecting blocks 422 located on the same vertical plane are both provided with mounting holes for the screw rod 423 to pass through; a strip-shaped guide groove 14 for the screw rod to pass through is provided in the length direction of the base 1 directly below the screw rod 423 .

[0030] The mounting hole here can be a through hole without threads or a threaded hole. If it is a through hole without threads, when performing a bending test on the circuit board 7, after applying force downward to the screw rod 423, the corresponding force cannot be removed if the test is not completed. Therefore, in this scheme, the mounting hole on the connecting block 422 is preferably a threaded hole.

[0031] After the power mechanism 4 of this solution adopts the above structure, the realization process of driving the clamping mechanism 3 connected thereto to move is as follows:

[0032] By rotating the screw rod 423 downward, the distance between the two connecting blocks 422 installed with the same screw rod 423 is gradually reduced. Since only the upper end or the lower end of the connecting frame 421 is fixed, and the other end is installed in the strip groove 325, this will force one end of the connecting frame 421 to slide relative to the strip groove 325, so that the length of the entire connecting frame 421 becomes longer. In addition, the side of the fixed plate 41 is fixed on the base 1, so the connecting frame 421 will naturally drive the clamping mechanism 3 connected to it to move toward the other clamping mechanism 3.

[0033] In one embodiment of the present invention, there are two displacement measuring mechanisms 6, which are installed on the upper and lower sides of the circuit board 7 through the mounting frame 5; the displacement measuring mechanism 6 includes a threaded connector 61 fixed to the mounting frame 5 by threads for controlling the bending direction of the circuit board 7 and a height gauge 62 fixed to the mounting frame 5, and a strip slide groove 621 is provided on the height gauge 62, and a measuring ruler 63 is installed in the strip slide groove 621 to cooperate with the threaded connector 61 to measure the deformation of the circuit board 7.

[0034] The following first describes the process by which the threaded connector 61 can control the bending direction of the circuit board 7:

[0035] When conducting the bending stress test of the circuit board 7, first fix both ends of the circuit board 7 on the clamping blocks 321 of the clamping mechanism 3. If the circuit board 7 is to bend downward, the threaded connector 61 of the displacement measuring mechanism 6 above the circuit board 7 can be adjusted to make it contact with the circuit board 7. Since the threaded connector 61 is fixedly connected to the mounting frame 5 by threads, the threaded connector 61 of the displacement measuring mechanism 6 above the circuit board 7 is equivalent to being fixed; as for the threaded connector 61 of the other displacement measuring mechanism 6, adjust it to be away from the circuit board 7.

[0036] Afterwards, under the action of the power mechanism 4, when the clamping mechanism 3 connected to the power mechanism 4 moves toward the other clamping mechanism 3, the deformation force of the circuit board 7 is formed by the extrusion force of the clamping mechanism 3; since the circuit board 7 is blocked by the threaded connector 61 above and there is no obstruction from the bottom, it is difficult for the circuit board 7 to bend upward, and it will naturally bend downward, so as to finally achieve the bending direction of the circuit board 7 controlled by the threaded connector 61 of the displacement measuring mechanism 6.

[0037] like Figure 5 As shown, the mounting frame 5 includes a top cover 51 and a connecting plate 52, the upper end of the connecting plate 52 is fixedly connected to the top cover 51, the top cover 51 contacts the top end of the clamping mechanism 3 and is supported by the clamping mechanism 3; the lower end of the connecting plate 52 is mounted on the base 1 and can slide relative to the base 1; a middle plate 521 is provided in the middle of the connecting plate 52, the middle plate 521 and the top cover 51 are respectively located below and above the circuit board 7; two displacement measuring mechanisms 6 are respectively mounted on the middle plate 521 and the top cover 51.

[0038] The threaded connector 61 and the height gauge 62 located above the circuit board 7 are installed on the top cover 51 , and the threaded connector 61 and the height gauge 62 located above the circuit board 7 are installed on the middle plate 521 .

[0039] During implementation, the preferred structure of the connecting plate 52 sliding relative to the base 1 in this solution includes at least one strip hole 522 opened at the lower end of the connecting plate 52 , and a rod body fixed on the side of the base 1 , the rod body passing through the strip hole 522 .

[0040] After the strip hole 522 is set, when the clamping mechanism 3 clamps circuit boards 7 of different lengths, the two displacement measuring mechanisms 6 can be positioned as close to the middle of the length direction of the circuit board 7 as possible by moving the mounting frame 5; at the same time, the displacement measuring mechanisms 6 can be easily moved to measure the deformation at different positions of the circuit board 7.

[0041] Next, the measurement of the deformation of the circuit board 7 by the displacement measuring mechanism 6 is described:

[0042] The first measurement method: after the circuit board 7 is clamped, first adjust the threaded connector 61 of the displacement measuring mechanism 6 that controls the bending direction of the circuit board 7, then adjust another threaded connector 61 of the displacement measuring mechanism 6 to contact the circuit board 7, and move the measuring ruler 63 located in the strip slide groove 621 to make the threaded connector rod 15 contact, and record the initial height through the height gauge 62;

[0043] The threaded rod is then adjusted to move away from the circuit board 7. When the circuit board 7 is bent, the threaded connector 61 and the movable mounting frame 5 are adjusted to make the threaded connector 61 contact the convex surface of the circuit board 7. The heights of the circuit board 7 at different positions after deformation are recorded. The deformation amounts at multiple positions of the circuit board 7 are obtained through the initial height and the final heights after deformation.

[0044] The second measurement method: after the circuit board 7 is clamped, first adjust the threaded connector 61 of the displacement measuring mechanism 6 that controls the bending direction of the circuit board 7, then adjust the threaded connector 61 of another displacement measuring mechanism 6 to make it away from the circuit board 7; move the measuring ruler 63 that matches the fixed threaded connector 61, and record the initial height through the height gauge 62;

[0045] After the circuit board 7 is bent, the mounting frame 5 is moved and the threaded connector 61 for controlling the bending direction of the circuit board 7 is adjusted to make it contact with the concave surface of the circuit board 7, and the height of the circuit board 7 at different positions after deformation is recorded. The deformation amount at multiple positions of the circuit board 7 is obtained through the initial height and the final height after deformation.

[0046] Reference again Figure 2 A connecting rod 15 is installed between the two supporting feet 12 directly below the mounting frame 5, and the connecting plate 52 extends to the connecting rod 15 of the base 1. Extension plates 523 extending toward the connecting rod 15 are arranged on both sides, and a mounting hole for the connecting rod 15 to pass through is opened on the extension plate 523.

[0047] The lower end of the mounting frame 5 is further connected to the connecting rod 15 on the base 1 through an extension plate 523. In this way, when the mounting frame 5 is moved, the mutual cooperation between the connecting rod 15, the strip hole 522 and the clamping mechanism can ensure the stability of the movement of the mounting frame 5 with the two displacement measuring mechanisms 6.

[0048] like Figure 1 and Figure 2 As shown, at least one slide rail 511 is connected to the top cover 51 and / or a slider 16 is installed on the base 1 to cooperate with the slot 324 at the lower end of the clamping mechanism connected to the power mechanism 4, and the upper ends of the two clamping mechanisms are installed in the slide rail 511; specifically, after the square groove 323 is opened on the support frame 32 of the clamping mechanism, the width of the support frame 32 on both sides of the direction groove is relatively small, and the clamping mechanism can be installed in the slide rail 511 through the structure on both sides of the support frame 32.

[0049] After the present solution sets the slide rail 511 and / or the slot 324 cooperating with the slider 16 on the base 1, when the power mechanism 4 drives the clamping mechanism to move, the smoothness of the movement of the clamping mechanism can be ensured and the friction during the movement can be reduced; at the same time, the slide rail 511 can also guide the movement of the mounting frame 5 and ensure the smoothness of the movement of the mounting frame 5.

[0050] During implementation, the preferred circuit board 7 solder joint bending stress test device of this scheme also includes a strain rosette pasted on the circuit board 7, and the bending stress measured by the strain rosette is input into the computer through the circuit and serial port mode; the test personnel can carry out relevant test research on the circuit board 7 according to the bending strain force input into the computer and the deformation of the circuit board 7 recorded.

Claims

1. Circuit board solder joint bending stress test device, characterized in that: It comprises a base and two clamping mechanisms matched to clamp the circuit board, wherein one clamping mechanism is fixed on the base, and the side of the other clamping mechanism is connected to a power mechanism for driving the clamping mechanism to translate; the lower end of the other side of the power mechanism is fixed on the base; displacement measuring mechanisms for measuring the deformation of the circuit board under bending stress are installed above and below the circuit board clamped by the two clamping mechanisms through mounting frames, and the mounting frames can slide left and right relative to the base; A strip groove running through the width direction of the clamping mechanism connected to the power mechanism is provided on the side surface thereof for installing the power mechanism; the power mechanism comprises a fixed plate and a telescopic frame, the fixed plate is provided with a strip groove running through the width direction thereof, and the lower ends or upper ends of both sides of the telescopic frame are fixed in the strip grooves on the fixed plate and the clamping mechanism; when the telescopic frame is subjected to a downward force, it moves downward along the strip groove to extend the telescopic frame; There are two displacement measuring mechanisms, which are installed on the upper and lower sides of the circuit board through a mounting frame; the displacement measuring mechanism includes a threaded connector fixed to the mounting frame by threads for controlling the bending direction of the circuit board and a height gauge fixed to the mounting frame, the height gauge is provided with a strip-shaped slide groove, and a measuring ruler is installed in the strip-shaped slide groove to cooperate with the threaded connector to measure the deformation of the circuit board; The clamping mechanism comprises a support frame and a pressing frame, and the support frame and the pressing frame are both provided with clamping blocks that cooperate with each other to clamp one side of the circuit board and locking blocks that match each other; A square groove is provided at the upper end of the support frame, and sliding grooves are provided on the two side walls of the square groove; the pressing frame is installed in the sliding groove, and the two clamping blocks clamp the circuit board through the locking pieces installed on the two locking blocks; The mounting frame includes a top cover and a connecting plate, a middle plate is arranged in the middle of the connecting plate, and the middle plate and the top cover are respectively located below and above the circuit board; two displacement measuring mechanisms are respectively installed on the middle plate and the top cover; at least one slide rail is connected to the top cover and / or a slider is installed on the base that cooperates with the slot at the lower end of the clamping mechanism connected to the power mechanism, and the upper ends of the two clamping mechanisms are installed in the slide rail.

2. The circuit board solder joint bending stress test device according to claim 1, characterized in that: A connecting lug is arranged at the lower end of the clamping mechanism fixed to the base, and a straight slot is opened on the connecting lug.

3. The circuit board solder joint bending stress test device according to claim 1, characterized in that: The telescopic frame includes at least one connecting frame composed of at least two scissor frames. When there is one connecting frame, a connecting block is installed at the connection between the two scissor frames; when there are at least two connecting frames, the connecting frames are connected by installing a connecting block at the connection of the scissor frames located in the same row; Two connecting blocks located on the same vertical plane are both provided with mounting holes for the screw rods to pass through; a strip-shaped guide groove for the screw rods to pass through is provided in the length direction of the base just below the screw rods.

4. The circuit board solder joint bending stress test device according to claim 1, characterized in that: The upper end of the connecting plate is fixedly connected to the top cover, the top cover contacts the top of the clamping mechanism and is supported by the clamping mechanism; the lower end of the connecting plate is installed on the base and can slide relative to the base.

5. The circuit board solder joint bending stress test device according to claim 4, characterized in that: The structure for the connecting plate to slide relative to the base comprises at least one strip hole provided at the lower end of the connecting plate, and a rod body fixed on the side surface of the base, wherein the rod body passes through the strip hole.

6. The circuit board solder joint bending stress test device according to any one of claims 1 to 5, characterized in that: It also includes a strain rosette pasted on the circuit board, and the bending stress measured by the strain rosette is input into a computer through a circuit and a serial port.

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