Bending strength test fixture and test method for chip capacitors

Abstract

The application relates to a bending resistance strength test fixture and test method suitable for chip capacitors, which comprises a base, a limiting position baffle horizontally arranged on the base, and a supporting assembly arranged on the limiting position baffle; a PCB plate fixing structure is further arranged on the base, a PCB plate is arranged on the PCB plate fixing structure, and the PCB plate is located directly above the supporting assembly; a cover plate is arranged above the PCB plate, and a pressing bolt is arranged at the center position of the cover plate corresponding to the PCB plate. In the application, the bending of the chip capacitor welded on the PCB plate can be simulated, so that the failure limit capacity of the chip capacitor can be tested in an environment closer to the actual working state of the PCB plate, the higher screening demand of the user on the product is met, and the limiting position baffle is arranged on the base, so that the PCB plate will not be displaced relative to the test fixture in the bending resistance test, and the safety hidden danger is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of chip capacitor bending strength testing, and relates to a bending strength testing fixture and a testing method suitable for chip capacitors. Background Art

[0002] Chip multilayer ceramic capacitors are important electronic components in integrated circuits. They are widely used in various integrated circuits due to their advantages such as small size, wide capacitance range, low dielectric loss, and high stability. In the existing inspection of incoming materials, the number of chip multilayer ceramic capacitors entering the institute has shown a sharp increase, but once the chip capacitors fail during actual use, it will have a serious impact on the entire circuit. Therefore, it is necessary to conduct a bending strength test on the problem of chip capacitors of multiple package sizes being subjected to multi-dimensional bending stress in PCB boards, so as to simulate the actual working state of chip capacitors more closely and realize effective screening of chip capacitors. In the existing technology, the chip capacitor bending strength test fixture is large in size and low in precision, and can only realize bending resistance testing when the PCB board is in a horizontal plane, and cannot realize bending resistance testing of chip capacitors at multiple angles of the PCB board; moreover, the test fixture is not easy to operate, and there are no limiting measures for the PCB board, which easily causes safety hazards. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a bending strength test fixture and a test method suitable for chip capacitors.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A bending strength test fixture suitable for chip capacitors includes a base, a limit baffle is horizontally arranged on the base, and a support assembly is arranged on the limit baffle, and the support assembly is used to support the PCB board during the test; the base is also provided with a PCB board fixing structure, and the PCB board is arranged on the PCB board fixing structure, and the PCB board is located directly above the support assembly; a first soldering pad and a second soldering pad are provided on the PCB board, the first soldering pad is electrically connected to the first lead, and the second soldering pad is electrically connected to the second lead; a cover plate is provided above the PCB board, and the cover plate is fixedly connected to the base; a pressure bolt is passed through the cover plate at the center position corresponding to the PCB board, and a handle is provided at the upper end of the pressure bolt.

[0006] Furthermore, the pressure bolt includes a first thread segment and a first scale segment, and the lower end of the first thread segment 5 is rounded to form a smooth pressure contact portion; the first scale segment is exposed upward from the upper end surface of the cover plate and is connected to the handle, and the first scale segment is divided with scales.

[0007] Furthermore, the PCB board fixing structure includes fixing parts extending upward from the upper end surface of the limiting baffle on both sides of the base, and a strip notch is provided on the opposite side of the two fixing parts, and a stop block is provided at both ends of the strip notch.

[0008] 0 Further, the support assembly includes two limit bolts threadedly connected to the limit baffle.

[0009] The two limiting bolts are symmetrically arranged in the middle of the limiting baffle.

[0010] Furthermore, the limiting bolt includes a second threaded segment and a second scale segment, the upper end of the second threaded segment is rounded to form a smooth limiting contact portion; one end of the second scale segment is exposed downward from the lower end surface of the limiting baffle, and the second scale segment is divided with scales.

[0011] 5 Furthermore, the support assembly further includes four support bolts threadedly mounted on the limiting baffle.

[0012] The four support bolts are respectively arranged at the four corners of the limiting baffle.

[0013] Furthermore, the support bolt includes a third threaded segment and a third scale segment. The upper end of the third threaded segment is rounded to form a smooth supporting contact portion. One end of the third scale segment is exposed downward from the lower end surface of the limiting position baffle, and the third scale segment is divided with scales.

[0014] A method for testing the bending strength of chip capacitors, using a bending strength tester

[0015] The bending strength test fixture comprises the following steps:

[0016] S1. Connect the first lead and the second lead to a capacitance parameter tester, and calibrate the capacitance parameter tester;

[0017] S2, solder the two solder joints of the chip capacitor to be tested to the first solder pad and the second solder pad 5 of the PCB board respectively;

[0018] S3. Place the chip capacitor on the PCB board downward on the PCB board fixing structure;

[0019] S4, testing the chip capacitor to be tested; if the test result meets the requirements, executing step S5; otherwise, determining that the chip capacitor to be tested is unqualified;

[0020] S5. Adjust the support position of the support assembly;

[0021] S6. Rotate the pressure bolt so that the lower end of the pressure bolt contacts the PCB and bends the PCB downward by a predetermined distance.

[0022] S7. Test the chip capacitor again and compare it with the test result in step S4. If the variation range of the test result meets the requirements, the chip capacitor to be tested is determined to be qualified; otherwise, the chip capacitor to be tested is determined to be unqualified.

[0023] Furthermore, the support assembly includes two limit bolts threadedly installed on the limit baffle, and the two limit bolts are symmetrically arranged in the middle of the limit baffle; the limit bolt includes a second thread segment and a second scale segment, and the upper end of the second thread segment is rounded to form a smooth limit contact portion; the second scale segment is exposed downward from the lower end surface of the limit baffle, and the second scale segment is divided into scales; the S5 step includes the following sub-steps:

[0024] S501. Adjust the length of the second threaded sections of the two limiting bolts that protrude upward from the upper end surface of the limiting baffle according to the required downward bending distance of the PCB board, so that the PCB board abuts against the two limiting contact parts when the downward bending distance reaches a predetermined distance.

[0025] Furthermore, the support assembly further includes four support bolts threadedly provided on the limit baffle, and the four support bolts are respectively provided at the four corners of the limit baffle; the support bolt includes a third thread segment and a third scale segment, and the upper end of the third thread segment is rounded to form a smooth support contact portion; one end of the third scale segment is exposed downwardly from the lower end surface of the limit baffle, and the third scale segment is divided into scales; the S5 step further includes the following sub-steps:

[0026] S502. Adjust the length of the third threaded sections of the four support bolts that protrude upward from the upper end surface of the limiting baffle according to the required tilting direction and tilting angle of the PCB board before bending, so that the four supporting contact portions abut against the PCB board and the PCB board is tilted at a predetermined angle.

[0027] The present invention can realize the bending strength test of PCB board at multiple different angles, and can simulate the situation that chip capacitor is bent 1mm to 3mm when soldered on PCB board, so as to test the failure limit capacitance of chip capacitor in an environment closer to the actual working state of PCB board, and meet the user's higher screening needs for products.

[0028] By dividing the scale on the pressure bolt, limit bolt and support bolt, the bending accuracy of the PCB board can reach the μm level, thereby improving the test accuracy and being able to test the bending resistance of chip capacitors of various package sizes.

[0029] In addition, a limit stop plate is set on the fixture base to prevent the PCB board from moving relative to the test fixture during the bending test, which may cause safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The exemplary embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0031] In the accompanying drawings:

[0032] Figure 1 The figure is a schematic structural diagram of a preferred embodiment of the present invention, which is suitable for testing the bending strength of chip capacitors.

[0033] Figure 2 for Figure 1 Schematic diagram of the structure with the cover and PCB removed.

[0034] Figure 3 It is a structural diagram of the limit bolt.

[0035] Figure 4 Schematic diagram of the support bolt structure.

[0036] Figure 5 This is a structural diagram of the PCB board.

[0037] Figure 6 Schematic diagram of the structure of the pressure bolt.

[0038] Figure 7 FIG0 is a flow chart of a preferred embodiment of a method for testing the bending strength of a chip capacitor according to the present invention.

[0039] Figure 8 This is a schematic diagram showing that the two limiting contact parts and the four supporting contact parts are located in the same plane before the static parameter test is performed.

[0040] Figure 9 This is a schematic diagram after adjusting the two limit bolts during the bending strength test.

[0041] Figure 10 This is a schematic diagram of the PCB being bent downward from a horizontal position.

[0042] The meanings of the reference numerals in the accompanying drawings are:

[0043] Base 100; PCB board 110; first solder pad 111; second solder pad 112; first lead 113; second lead 114; fixing portion 120; strip-shaped notch 121; block 122; cover 130; fixing bolt 131; pressure bolt 141; first threaded segment 142; first scale segment 143; pressure contact portion 144; handle 145; limit baffle 150; limit bolt 160; second threaded segment 161; second scale segment 162; limit contact portion 163; support bolt 170; third threaded segment 171; third scale segment 172; support contact portion 173; chip capacitor 200. DETAILED DESCRIPTION

[0044] The following describes the implementation of the present invention through specific examples. The illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention. The following embodiments and features in the embodiments may be combined with each other unless there is any conflict.

[0045] like Figure 1 As shown, a preferred embodiment of the bending strength test fixture for chip capacitors of the present invention includes a base 100, a limiting baffle 150 is horizontally arranged on the base 100, and a supporting assembly is arranged on the limiting baffle 150, and the supporting assembly is used to support the PCB board 110 during the test.

[0046] like Figure 2 As shown, the support assembly may include two limit bolts 160 that are screwed through the limit baffle 150, and the two limit bolts 160 are symmetrically arranged in the middle of the limit baffle 150, so as to support the middle of the PCB board 110 after the middle of the PCB board 110 is bent and moved downward a predetermined distance, thereby preventing the PCB board 110 from bending too much.

[0047] like Figure 3 As shown, the limiting bolt 160 may include a second threaded section 161 and a second scale section 162. The upper end of the second threaded section 161 is rounded to form a smooth limiting contact portion 163 to increase the contact area between the limiting bolt 160 and the PCB board 110. One end of the second scale section 162 is exposed downward from the lower end surface of the limiting baffle 150, and the second scale section 162 is divided into scales to facilitate accurate adjustment of the height of the limiting contact portion 163 from the upper end surface of the limiting baffle 150.

[0048] In order to facilitate the adjustment of the tilt angle of the PCB board 110, so as to facilitate the bending of the PCB board 110 at different tilt angles, the support assembly may further include four support bolts 170 threadedly connected to and passing through the limiting baffle 150. The four support bolts 170 are respectively arranged at the four corners of the limiting baffle 150 to facilitate the adjustment of the tilt angle of the PCB board 110. Figure 4 As shown, the support bolt 170 includes a third threaded section 171 and a third scale section 172. The upper end of the third threaded section 171 is rounded to form a smooth support contact portion 173 to increase the contact area between the support bolt 170 and the PCB board 110. One end of the third scale section 172 is exposed downward from the lower end surface of the limit stop plate 150. The third scale section 172 is divided into a scale to facilitate accurate adjustment of the height of the support contact portion 173 from the upper end surface of the limit stop plate 150.

[0049] The base 100 is also provided with a PCB board 110 fixing structure. The PCB board 110 fixing structure includes fixing parts 120 that extend upward from the upper end surface of the limiting baffle 150 on both sides of the base 100. A strip-shaped notch 121 is provided on the opposite side of the two fixing parts 120 to facilitate the placement of the PCB board 110. A stopper 122 is provided at each end of the strip-shaped notch 121 to limit the PCB board 110 and prevent the PCB board 110 from jumping during the bending process.

[0050] The PCB board 110 is provided on the fixing structure. The PCB board 110 is used for soldering the chip capacitor 200 to be tested. The PCB board 110 is located directly above the supporting assembly. Figure 5 As shown, the PCB board 110 is provided with a first solder pad 111 and a second solder pad 112. The first solder pad 111 and the second solder pad 112 can be arranged at the center of the PCB board 110, or can be arranged at other positions of the PCB board 110. The first solder pad 111 and the second solder pad 112 can be arranged sequentially along the length direction of the PCB board 110, or can be arranged sequentially along the width direction of the PCB board 110. The first solder pad 111 is electrically connected to a first lead 113, and the second solder pad 112 is electrically connected to a second lead 114. The first lead 113 and the second lead 114 are used to connect to a capacitance parameter tester.

[0051] A cover plate 130 is provided above the PCB board 110, and the cover plate 130 is fixedly connected to the base 100. In this embodiment, the cover plate 130 is screwed to the base 100 by four fixing bolts 131, so that the cover plate 130 can be easily removed. A pressure bolt 141 is provided at the center of the cover plate 130 corresponding to the PCB board 110. A handle 145 is provided at the upper end of the pressure bolt 141 so that the pressure bolt 141 can be rotated to apply pressure to the PCB board 110. Figure 6 As shown, the pressure bolt 141 includes a first threaded section 142 and a first graduated section 143. The lower end of the first threaded section 142 is rounded to form a smooth pressure contact portion 144. This increases the contact area between the pressure bolt 141 and the PCB 110, facilitating accurate measurement of the distance the central portion of the PCB 110 moves after bending downward. The first graduated section 143 extends upward from the upper end surface of the cover 130 and is connected to a handle 145. Graduations are provided on the first graduated section 143 to facilitate adjustment of the downward movement of the bent portion of the PCB 110 when pressure is applied to the PCB 110.

[0052] The bending strength test fixture of this embodiment can perform bending strength tests on the PCB board 110 at multiple different angles, simulating a chip capacitor 200 being bent by 1mm to 3mm when soldered to the PCB board 110. This allows the failure limit capacitance of the chip capacitor 200 to be tested in an environment closer to the actual working state of the PCB board 110, meeting users' higher product screening requirements. By dividing the scale on the pressure bolt 141, the limit bolt 160, and the support bolt 170, the principle of a micrometer screw can be used to achieve high-precision displacement adjustment, bringing the bending accuracy of the PCB board 110 to the μm level, thereby improving test accuracy. This embodiment has a simple structure and is easy to disassemble. It can perform bending strength tests on chip capacitors 200 of various package sizes (e.g., 0603, 0805, 1210, and 1812). In addition, a limit stop 150 is provided on the base 100 of the fixture to prevent the PCB board 110 from displacing relative to the test fixture during the bending test, thereby improving the safety of the test.

[0053] like Figure 7 As shown, a preferred embodiment of the present invention is applicable to a method for testing the bending strength of a chip capacitor, comprising the following steps:

[0054] S1. Connect the first lead 113 and the second lead 114 to a capacitance parameter tester (not shown) and calibrate the capacitance parameter tester. The capacitance parameter tester can be an E4980A tester. When calibrating the capacitance parameter tester, calibration can be performed under open circuit, short circuit, and load conditions to correct for additional errors caused by the test fixture and test leads.

[0055] S2. Solder the two solder joints of the chip capacitor 200 to be tested to the first solder pad 111 and the second solder pad 112 of the PCB board 110 respectively, so that the first lead 113 and the second lead 114 are electrically connected to the two solder joints of the chip capacitor 200 respectively, so as to test the chip capacitor 200.

[0056] S3, loosen the four fixing bolts 131, remove the cover 130 from the base 100; then place the chip capacitor 200 on the PCB board 110 downward on the PCB board 110 fixing structure, and then tighten the four fixing bolts 131 to fix the cover 130 on the base 100. Figure 8 As shown, the two limiting bolts 160 and the four supporting bolts 170 can also be rotated so that the two limiting contact portions 163 and the four supporting contact portions 173 are all located in the same plane, so as to facilitate the static parameter test in step S4.

[0057] S4. Select corresponding test parameters on the capacitor parameter tester for chip capacitors 200 with different packages, and perform a static parameter test on the chip capacitor 200 to be tested when the PCB board 110 is in a horizontal state and no pressure is applied to bend; if the test result meets the requirements, execute step S5 to perform a bending strength test; otherwise, the chip capacitor 200 to be tested is determined to be unqualified and the bending strength test is no longer performed.

[0058] S5. Adjust the support position of the support assembly according to test requirements. This may include the following sub-steps:

[0059] S501. Adjust the length of the second threaded sections 161 of the two limiting bolts 160 that protrude upward from the upper end surface of the limiting baffle 150, based on the desired downward bending distance of the PCB 110. Because the limiting bolts 160 are graduated, the height of the limiting contact portions 163 from the upper end surface of the limiting baffle 150 can be precisely adjusted based on the graduations. This ensures that the PCB 110 abuts against the two limiting contact portions 163 when the downward bending distance reaches a predetermined value, preventing the PCB 110 from bending excessively.

[0060] like Figure 9 As shown, for example, when the PCB board 110 needs to be bent downward by 2 mm from a horizontal position, Figure 8 On the basis of the middle, the positions of the four supporting bolts 170 are maintained unchanged, and the two limiting bolts 160 are rotated according to the scale value on the second scale segment 162 and moved downward by 2 mm.

[0061] When it is necessary to perform a bending strength test when the PCB board 110 is tilted, before executing step S501, step S502 may be executed first:

[0062] S502, according to the required tilt direction and tilt angle of the PCB 110 before bending, the third threaded section 171 of the four supporting bolts 170 is adjusted to expose the length of the upper end surface of the limit stop plate 150, so that the four supporting contact portions 173 abut against the PCB 110. Since the supporting bolt 170 is divided by a scale, the height of the four supporting contact portions 173 from the upper end surface of the limit stop plate 150 can be accurately adjusted according to the scale value, so that the PCB 110 is tilted at a predetermined angle in a predetermined direction.

[0063] S6, rotate the handle 145 to move the pressing bolt 141 downward, and make the pressing contact portion 144 abut against the PCB 110. Then, according to the scale of the first scale section 143, the pressing contact portion 144 presses the PCB 110 to bend downward by a predetermined distance. The distance of the PCB 110 bending downward after being pressed can be accurately adjusted by the scale value divided on the pressing bolt 141, thereby improving the test accuracy. As shown in FIG. 6, for example, on the basis of the distance of the pressing contact portion 144 abutting against the PCB 110, when the pressing bolt 141 is further moved downward by 2 mm, the two limit contact portions 163 abut against the PCB 110, thereby preventing the PCB 110 from continuing to bend, so that the limiting effect can be achieved, and the PCB 110 is prevented from being excessively bent. Figure 10 Figure 9

[0064] S7, in the state that the PCB 110 is pressed and bent, the parameters of the chip capacitor 200 are tested again, and the test results are compared with those in the S4 step. If the change range of the test results meets the requirements, it is determined that the chip capacitor 200 to be tested is qualified; otherwise, it is determined that the chip capacitor 200 to be tested is unqualified.

[0065] After the test is completed, the pressing bolt 141 is loosened upward by rotating the handle 145, the cover plate 130 is removed from the base 100, and then the PCB 110 is taken out.

[0066] The embodiment can test the case that the chip capacitor 200 welded on the PCB 110 is bent by 1-3 mm, and the static (i.e., the state that the PCB 110 is not bent) parameter test of the chip capacitor 200 is completed by using the bending resistance test fixture. Then, the limit bending value of the chip capacitor 200 is compared with the relevant specification to establish a corresponding database, and the failure mode, failure mechanism and material characteristics of the chip capacitor 200 can be further studied and analyzed through comparison of various cases. The designer can be provided with an optimized design reference of the chip capacitor 200, and the test process meets the GB 2693-90 standard.

[0067] ​​Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A flexural strength test fixture for chip capacitors, characterized by: The tester comprises a base, a limit baffle being horizontally arranged on the base, a support assembly being arranged on the limit baffle, and the support assembly being used to support the PCB board during the test process; a PCB board fixing structure being further arranged on the base, a PCB board being arranged on the PCB board fixing structure, and the PCB board being located directly above the support assembly; a first soldering pad and a second soldering pad being arranged on the PCB board, the first soldering pad being electrically connected to a first lead, and the second soldering pad being electrically connected to a second lead; a cover plate being arranged above the PCB board, and the cover plate being fixedly connected to the base; a pressure bolt being passed through the cover plate at a center position corresponding to the PCB board, and a handle being arranged at an upper end of the pressure bolt; The pressure bolt includes a first threaded section and a first scale section. The lower end of the first threaded section is rounded to form a smooth pressure contact portion. The first scale section is exposed upward from the upper end surface of the cover plate and is connected to the handle. The first scale section is divided into scales. The support assembly includes two limit bolts threadedly connected to the limit baffle, and the two limit bolts are symmetrically arranged in the middle of the limit baffle; The limiting bolt includes a second threaded segment and a second scale segment. The upper end of the second threaded segment is rounded to form a smooth limiting contact portion. One end of the second scale segment is exposed downward from the lower end surface of the limiting baffle, and the second scale segment is divided into scales.

2. The bending strength test fixture for chip capacitors according to claim 1, characterized in that: The PCB board fixing structure includes fixing parts extending upward from the upper end surface of the limiting baffle from both sides of the base, and a strip notch is provided on the opposite side of the two fixing parts, and a stop block is provided at both ends of the strip notch.

3. The bending strength test fixture for chip capacitors according to any one of claims 1 to 2, characterized in that: The support assembly further comprises four support bolts threadedly connected to and passing through the limiting baffle, and the four support bolts are respectively arranged at the four corners of the limiting baffle.

4. The bending strength test fixture for chip capacitors according to claim 3, characterized in that: The support bolt includes a third threaded segment and a third scale segment. The upper end of the third threaded segment is rounded to form a smooth supporting contact portion. One end of the third scale segment is exposed downward from the lower end surface of the limiting baffle, and the third scale segment is divided into scales.

5. A method for testing the bending strength of chip capacitors, characterized by: Using the bending strength test fixture for chip capacitors according to any one of claims 1 to 4, the test method comprises the following steps: S1. Connect the first lead and the second lead to a capacitance parameter tester, and calibrate the capacitance parameter tester; S2. Solder the two solder joints of the chip capacitor to be tested to the first solder pad and the second solder pad of the PCB board respectively; S3. Place the chip capacitor on the PCB board downward on the PCB board fixing structure; S4, testing the chip capacitor to be tested; if the test result meets the requirements, executing step S5; otherwise, determining that the chip capacitor to be tested is unqualified; S5. Adjust the support position of the support assembly; S6. Rotate the pressure bolt so that the lower end of the pressure bolt contacts the PCB and bends the PCB downward by a predetermined distance. S7, test the chip capacitor again and compare it with the test result in step S4. If the variation range of the test result meets the requirements, the chip capacitor to be tested is determined to be qualified; otherwise, the chip capacitor to be tested is determined to be unqualified; The support assembly includes two limit bolts threadedly installed on the limit baffle, and the two limit bolts are symmetrically arranged in the middle of the limit baffle; the limit bolts include a second thread segment and a second scale segment, and the upper end of the second thread segment is rounded to form a smooth limit contact portion; the second scale segment is exposed downward from the lower end surface of the limit baffle, and the second scale segment is divided into scales; the step S5 includes the following sub-steps: S501. Adjust the length of the second threaded sections of the two limiting bolts that protrude upward from the upper end surface of the limiting baffle according to the required downward bending distance of the PCB board, so that the PCB board abuts against the two limiting contact parts when the downward bending distance reaches a predetermined distance.

6. The bending strength testing method for chip capacitors according to claim 5, wherein: The support assembly further includes four support bolts threadedly provided on the limit baffle, wherein the four support bolts are respectively provided at the four corners of the limit baffle; the support bolts include a third threaded segment and a third scale segment, the upper end of the third threaded segment is rounded to form a smooth support contact portion; one end of the third scale segment is downwardly exposed from the lower end surface of the limit baffle, and the third scale segment is divided into scales; the step S5 further includes the following sub-steps: S502. Adjust the length of the third threaded sections of the four supporting bolts that protrude upward from the upper end surface of the limiting baffle according to the required tilting direction and tilting angle of the PCB board before bending, so that the four supporting contact portions abut against the PCB board and the PCB board is tilted at a predetermined angle.

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