A selective wave solder flux spraying performance test fixture and test method
By designing a multi-dimensional integrated selective wave soldering flux spraying performance testing fixture and quantitative evaluation method, the problem of low efficiency of existing testing fixtures is solved, and the full-dimensional evaluation of flux spraying performance and process optimization support are realized.
Patent Information
- Application Number
- CN202610618251.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-07
- Publication Date
- 2026-08-25
AI Technical Summary
Existing testing fixtures have limited functionality and low testing efficiency. They cannot objectively and quantitatively evaluate the stability, uniformity, linearity, and accuracy of flux spraying, making it difficult to achieve long-term monitoring and quality traceability of flux spraying performance during the production process.
A selective wave soldering flux spraying performance testing fixture was designed, comprising a substrate and a cover plate structure. Multi-dimensional testing integration is achieved through multiple test chambers and their configuration. The fixture employs quantitative evaluation methods based on gravimetric method and CPK value, combined with fax paper and software analysis, to achieve accurate detection of flux spraying amount and process stability assessment.
It enables comprehensive evaluation of flux spraying performance, improves testing efficiency and data reliability, provides objective quantitative basis, provides accurate data support for process parameter optimization, meets process control standards, and facilitates long-term monitoring and quality traceability.
Smart Images
Figure CN122631830A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of testing fixture technology, and in particular to a testing fixture for selective wave soldering flux spraying performance. Background Technology
[0002] In the selective wave soldering process of the electronics assembly industry, flux needs to be sprayed onto the pads and component leads and preheated before the soldering operation to remove oxides and enhance the wettability of the solder. The flux spraying effect, including the stability of the spraying amount, the uniformity of the area, the penetration ability of PCB boards of different thicknesses and vias of different diameters, the spraying linearity, and the pinpoint accuracy, is a core key factor that determines the subsequent soldering quality, directly affecting the solder joint strength and related to the control of soldering defects such as cold solder joints, missing solder joints, and bridging.
[0003] However, traditional test fixtures can only perform flux spraying uniformity or penetration tests individually. For selective wave soldering tests, which require specific point spraying accuracy and linearity tests, as well as penetration tests for PCBs of different thicknesses and vias of different diameters, multiple fixture changes and separate tests using different fixtures are necessary. This is cumbersome and inefficient. Furthermore, existing tests rely heavily on visual observation of the color change of paper when exposed to flux, which can only qualitatively determine the spraying coverage area. They cannot objectively quantify the stability, uniformity, linearity, and accuracy of the spraying amount. They also do not incorporate industry-standard process control indicators such as the process capability index (CPK), making it difficult to achieve long-term monitoring and quality traceability of flux spraying performance during production and failing to provide accurate data support for process parameter optimization. Summary of the Invention
[0004] The purpose of this invention is to provide a selective wave soldering flux spraying performance testing fixture to solve the technical problems of existing testing fixtures having single function, low testing efficiency, and large testing errors.
[0005] Based on this, the present invention provides a selective wave soldering flux spraying performance testing fixture, comprising: A substrate has a first test groove, a second test groove, and a third test groove spaced apart along its width. The bottom wall of the first test slot is a first test plate. Along the length of the substrate, the thickness of the first test plate gradually increases and then gradually decreases. The first test plate is provided with a first test through hole penetrating the substrate. The bottom wall of the second test slot, along the length of the substrate, consists of a left test plate, a middle test plate, and a right test plate, with the thickness of the left test plate gradually decreasing and the thickness of the right test plate gradually increasing along the length of the substrate. Both the left and right test plates are provided with multiple first test vias. Along the length of the substrate, the apertures of the plurality of first test vias on the left test plate and the right test plate are the same. Along the width direction of the substrate, the plurality of first test vias of the left test plate and the right test plate are spaced apart to form a plurality of first test via groups. From the first test slot to the third test slot, with the first test via group as a node, the diameter of the plurality of first test vias gradually increases, and the diameter of the first test vias in each first test via group is the same. The test plate is provided with a second test via. The bottom wall of the third test slot is a third test plate, and the third test plate is provided with a third test through hole that penetrates the substrate; A cover plate structure that snaps into the first test slot, the second test slot, and the third test slot.
[0006] In some embodiments of this application, the cover plate structure includes a first cover plate, a second cover plate, and a third cover plate. The first cover plate is hinged to the substrate and snaps into the first test slot to abut against the first test plate. The second cover plate is hinged to the substrate and snaps into the second test slot to abut against the left test plate, the middle test plate, and the right test plate. The third cover plate is hinged to the substrate and snaps into the third test slot to abut against the third test plate.
[0007] In some embodiments of this application, the second cover plate includes a left cover plate, a middle cover plate, and a right cover plate arranged sequentially along the length direction of the substrate. Along the length direction of the substrate, the thickness of the left cover plate gradually increases, and the thickness of the right cover plate gradually decreases.
[0008] In some embodiments of this application, along the length direction of the substrate, each of the first test via groups includes a plurality of spaced-apart first test via groups, and each of the first test via groups includes at least two first test vias spaced-apart along the width direction of the substrate.
[0009] In some embodiments of this application, the first test slot, the second test slot, and the third test slot are all arranged in a long strip shape along the length direction of the substrate.
[0010] In some embodiments of this application, the top of the first test plate is provided with a first positioning pin, and a plurality of the first positioning pins are sequentially arranged along the edge of the first test plate. The first cover plate is provided with a plurality of first positioning holes that match and correspond one-to-one with the first positioning pins. The top of the left test plate, the middle test plate, and the right test plate are provided with second positioning pins. Multiple second positioning pins are sequentially arranged along the edges of the left test plate, the middle test plate, and the right test plate, respectively. The second cover plate is provided with multiple second positioning holes that match and correspond one-to-one with the second positioning pins. The top of the third test plate is provided with a third positioning pin, and multiple third positioning pins are arranged sequentially along the edge of the third test plate. The third cover plate is provided with multiple third positioning holes that match and correspond one-to-one with the third positioning pins.
[0011] In some embodiments of this application, a first transparent glass is fixedly disposed on the side of the first cover plate away from the substrate, a second transparent glass is fixedly disposed on the side of the second cover plate away from the substrate, and a third transparent glass is fixedly disposed on the side of the third cover plate away from the substrate.
[0012] In some embodiments of this application, the substrate is provided with locking members for locking the first cover plate, the second cover plate and the third cover plate. The first cover plate, the second cover plate and the third cover plate are respectively matched with a set of locking members. The locking member includes a limiting shell, a limiting block and a return spring. The limiting block is slidably disposed in the limiting shell along the length direction of the substrate. A return groove is opened on the rear side of the limiting block. The return spring is disposed in the return groove and abuts against the limiting block and the limiting shell respectively.
[0013] In some embodiments of this application, the two ends of the rear side of the limiting shell extend along the width direction of the substrate to form limiting hooks, the cavity inside the limiting shell is convex, the limiting hooks abut against the limiting shell, and the top of the limiting block is also provided with an operating protrusion.
[0014] Another objective of this application is to provide a method for testing flux spraying performance using the above-mentioned test fixture, which includes the following steps: S1. Take multiple sheets of fax paper and weigh them using an electronic balance. Define the initial weight of the fax paper as W0. S2. Place the weighed fax paper into the first test slot, the second test slot, and the third test slot respectively. Rotate the first cover plate to make it abut against the first test plate, rotate the second cover plate to make it abut against the left test plate, the middle test plate, and the right test plate, and rotate the third cover plate to make it abut against the third test plate. S3. Install the test fixture on the carrier of the selective wave soldering equipment to ensure that the test area of the fixture corresponds precisely to the spraying range of the equipment nozzle; S4. Start the control system of the selective wave soldering equipment, call the preset spraying program, and spray flux onto the first test tank, the second test tank and the third test tank from the bottom of the substrate. The spraying parameters such as spraying flow rate, spraying time, nozzle height and moving speed are consistent with the actual production conditions. S5. After the spraying is completed, remove the fax paper from the first test tank, the second test tank and the third test tank, and weigh it again using the same electronic balance. Record the weight as W1. Calculate the weight difference of each fax paper before and after spraying ΔW=W1-W0. This weight difference is the actual amount of flux sprayed in the corresponding area. S6. Record the wetting area of the fax paper caused by flux spraying, evaluate the penetration ability of flux on PCBs with different thicknesses and apertures, record the straightness of the flux spraying trajectory on the fax paper and the actual spraying length, evaluate the linearity of flux spraying, record the deviation of the flux spraying landing point on the fax paper, and evaluate the accuracy of spraying positioning. S7. Repeat steps S1 to S6 above to complete multiple tests, and organize the CPK results based on the multiple test data. Generate a comprehensive evaluation report based on the quantitative analysis results and the generated CPK values to clarify the qualification status of flux spraying performance.
[0015] This invention provides a selective wave soldering flux spraying performance testing fixture, which has the following advantages compared with the prior art: This application provides a selective wave soldering flux spraying performance testing fixture. Based on the arrangement of a first test slot, a second test slot, and a third test slot, multiple test areas with clear boundaries and no interference are formed, achieving integrated multi-dimensional testing. Furthermore, based on the integrated design of the multi-functional areas, it achieves collaborative innovation in the design and quantitative evaluation process for adapting to different PCB thicknesses and via diameters. It can complete the full-dimensional evaluation of flux spraying stability, uniformity, spraying penetration on PCBs of different thicknesses and via diameters, spraying point accuracy, and spraying linearity in a single clamping operation, significantly improving testing efficiency and data reliability. Simultaneously, it provides objective and accurate quantitative basis for optimizing selective wave soldering process parameters, solving the core pain points of existing technologies such as fragmented functions, subjective evaluation, and poor scenario adaptability. It significantly improves testing efficiency and avoids positioning errors caused by multiple clamping operations, thus improving the accuracy of test data.
[0016] This invention also provides a selective wave soldering flux spraying performance testing method, which innovatively adopts a quantitative evaluation method of "weight method + CPK value". Combining the characteristics of fax paper, it achieves accurate detection. Through the multi-point array design of the intermediate test area, it generates CPK results by combining photo upload software analysis or manual entry into the CPK table. It is suitable for scenarios where the fixture has no communication function. It not only transforms the traditional subjective visual observation into objective quantitative data, but also simplifies the fixture structure and reduces costs. It can not only accurately calculate the flux spraying amount, but also evaluate the stability, intermediate point accuracy and linearity of the spraying process through CPK value. It meets the process control standards of the electronics manufacturing industry, facilitates long-term monitoring and quality traceability of flux spraying performance, and provides accurate data support for process optimization. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of a selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 2 This is a schematic diagram of the selective wave soldering flux spraying performance test fixture according to some embodiments of the present invention, in which the first test tank, the second test tank and the third test tank are opened; Figure 3 This is a schematic diagram of the top structure of the substrate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 4 This is a schematic diagram of the bottom structure of the substrate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 5 This is a top view of the substrate of a selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 6 This is a schematic diagram of the top structure of the first cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 7 This is a schematic diagram of the bottom structure of the first cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 8 This is a schematic diagram of the top structure of the second cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 9 This is a schematic diagram of the bottom structure of the second cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 10 This is a schematic diagram of the top structure of the third cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention. Figure 11This is a schematic diagram of the bottom structure of the third cover plate of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention. Figure 12 This is a schematic diagram of the locking component of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 13 This is a schematic diagram of the bottom structure of the locking component of a selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention; Figure 14 A schematic diagram of the limiting block of the selective wave soldering flux spraying performance testing fixture according to some embodiments of the present invention.
[0018] In the figure, 1. Substrate; 101. First test slot; 102. First test plate; 103. First test through hole; 104. Second test slot; 105. Left test plate; 106. Middle test plate; 107. Right test plate; 108. First test via; 109. Second test via; 110. Third test slot; 111. Third test plate; 112. Third test through hole; 113. First positioning pin; 114. Second positioning pin; 115. Third positioning pin; 2. First cover plate; 201, first positioning hole; 202, first transparent glass; 3, second cover plate; 31, left cover plate; 32, middle cover plate; 33, right cover plate; 301, second positioning hole; 302, second transparent glass; 4, third cover plate; 401, third positioning hole; 402, third transparent glass; 5, locking element; 501, limiting shell; 502, limiting block; 503, chamber; 504, limiting hook; 505, operating protrusion; 506, reset groove; 6, hinge. Detailed Implementation
[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0020] like Figures 1 to 14As shown, this embodiment of the invention provides a selective wave soldering flux spraying performance testing fixture, including a substrate 1 and a cover plate structure. The top of the substrate 1 is provided with a first test groove 101, a second test groove 104, and a third test groove 110 spaced apart along the width direction of the substrate 1. Specifically, in this embodiment, the first test groove 101, the second test groove 104, and the third test groove 110 are all elongated strips along the length direction of the substrate 1. The bottom wall of the first test groove 101 is a first test plate 102. Along the length direction of the substrate 1, the first test plate 102... The thickness of the second test plate 104 gradually increases and then gradually decreases. The first test plate 102 has a first test through-hole 103 penetrating the substrate 1. The bottom wall of the second test groove 104, along the length of the substrate 1, consists of a left test plate 105, a middle test plate 106, and a right test plate 107. Along the length of the substrate 1, the thickness of the left test plate 105 gradually decreases, while the thickness of the right test plate 107 gradually increases. Both the left and right test plates 105 and 107 have multiple first test vias 108. Along the length of the substrate 1, the thickness of the left test plate 105 and 107... The multiple first test vias 108 have the same aperture; furthermore, along the width direction of the substrate 1, the multiple first test vias 108 of the left test plate 105 and the right test plate 107 are divided into multiple groups of first test vias 108 at intervals. From the first test slot 101 to the third test slot 110, with the first test vias 108 as nodes, the aperture of the multiple first test vias 108 gradually increases, and the aperture of the first test vias 108 in each group of first test vias 108 is the same. The middle test plate 106 is provided with a second test via 109, and the third test via 109... The bottom wall of the groove 110 is a third test plate 111, and the third test plate 111 is provided with a third test through hole 112 penetrating the substrate 1; the cover plate structure includes a first cover plate 2, a second cover plate 3 and a third cover plate 4. The first cover plate 2 is hinged to the substrate 1 and inserted into the first test groove 101 to abut against the first test plate 102; the second cover plate 3 is hinged to the substrate 1 and inserted into the second test groove 104 to abut against the left test plate 105, the middle test plate 106 and the right test plate 107; the third cover plate 4 is hinged to the substrate 1 and inserted into the third test groove 110 to abut against the third test plate 111.
[0021] Based on the above structure, in use, fax paper is placed in the first test slot 101, and the first cover plate 2 is rotated to abut against the first test plate 102. At this time, the fax paper in the first test slot 101 is fixed in the first test slot 101 by the clamping of the first cover plate 2 and the first test plate 102. The operator can spray flux into the first test slot 101 along the first test through hole 103 at the bottom of the substrate 1 to complete the flux spraying linearity test. Furthermore, in use, fax paper is placed in the second test slot 104, and the second cover plate 3 is rotated to abut against the left test plate 105 and the middle test plate 102. 06 and the right test plate 107. At this time, the fax paper in the second test slot 104 is fixed in the second test slot 104 by the clamping of the second cover plate 3, the left test plate 105, the middle test plate 106 and the right test plate 107. The operator can continue to spray flux into the second test slot 104 along the first test via 108 and the second test via 109 at the bottom of the substrate 1 to continue to complete the test. It should be noted that, since the depth of the multiple first test vias 108 on the left test plate 105 gradually decreases along the length direction of the substrate 1, and the depth of the first test vias 109 on the right test plate 107 is... The hole depth of the 108 holes gradually increases along the length of the substrate 1. The left test board 105 and the right test board 107 can simulate multiple PCBs with different hole depths under the same hole diameter to complete the flux spray penetration test. Furthermore, since the diameter of the multiple first test vias 108 on the left test board 105 and the right test board 107 gradually increases along the width of the substrate 1 from the first test groove 101 to the third test groove 110, the left test board 105 and the right test board 107 can simulate multiple PCBs with different hole diameters under the same hole depth to complete the flux spray penetration test. The diameter of the second test via 109 on the test plate is much larger than that of the first test via 108, which can complete the flux spraying point accuracy test. Furthermore, when in use, a fax paper is placed in the third test slot 110, and the third cover plate 4 is rotated to abut against the third test plate 111. At this time, the fax paper in the third test slot 110 is fixed in the second test slot 104 by the clamping of the third cover plate 4 and the third test plate 111. The operator can continue to spray flux into the third test slot 110 along the third test through hole 112 at the bottom of the substrate 1 to continue to complete the flux spraying linearity test.
[0022] Thus, the selective wave soldering flux spraying performance testing fixture of this application forms multiple test areas with clear boundaries and no interference based on the setting of the first test slot 101, the second test slot 104 and the third test slot 110, realizing the integration of multi-dimensional testing. Based on the integrated design of the multi-functional area, it realizes the collaborative innovation of the design and quantitative evaluation process for adapting to different PCB thicknesses and apertures. It can complete the full-dimensional evaluation of flux spraying amount stability, uniformity, spraying penetration of PCBs of different thicknesses and through holes of different apertures, spraying point accuracy and spraying linearity in a single clamping, which greatly improves the testing efficiency and data reliability. At the same time, it provides objective and accurate quantitative basis for the optimization of selective wave soldering process parameters, solving the core pain points of existing technologies such as fragmented functions, subjective evaluation and poor scenario adaptability.
[0023] Since the thickness of the first test plate 102 first increases and then decreases along the length direction of the substrate 1, in order to ensure effective adhesion between the first cover plate 2 and the first test plate 102, in some embodiments of this application, the thickness of the first cover plate 2 gradually decreases and then gradually increases along the length direction of the substrate 1. In this way, the fax paper inside the first test plate 102 can be stably held by the first cover plate 2 and the first test plate 102, and the test can be completed in conjunction with the flux spraying equipment based on the first test through-hole 103 of the first test plate 102.
[0024] It should be noted that both the first test tank 101 and the third test tank 110 of this application are used to complete the flux spraying linearity test. However, unlike the first test tank 101, the thickness of the third test plate 111 in the third test tank 110 remains unchanged. That is, along the length direction of the substrate 1, the thickness of the third cover plate 4 and the third test plate 111 remains unchanged. The fax paper in the first test tank 101 is squeezed and bent, while the fax paper in the third test tank 110 remains horizontal at all times. In this way, the first test tank 101 and the third test tank 110 can simulate different working conditions for the flux linearity test, thereby realizing the effective performance of the flux linearity test.
[0025] Similar to the first cover plate 2 and the third cover plate 4, in order to achieve effective adaptation between the second cover plate 3 and the second test slot 104, in some embodiments of this application, the second cover plate 3 includes a left cover plate 31, a middle cover plate 32 and a right cover plate 33 arranged sequentially along the length direction of the substrate 1. Along the length direction of the substrate 1, the thickness of the left cover plate 31 gradually increases, and the left cover plate 31 abuts against the left test plate 105 when in use. The thickness of the right cover plate 33 gradually decreases, and the right cover plate 33 abuts against the right test plate 107 when in use. The middle cover plate 32 abuts against the middle test plate 106, and the thickness of the middle cover plate 32 remains unchanged. It should be further noted that, for the first test via 108 of this application, along the length direction of the substrate 1, each group of first test vias 108 includes multiple spaced groups of first test vias 108, and each group of first test vias 108 includes at least two spaced first test vias 108 along the width direction of the substrate 1. Specifically, in the embodiments of the present invention, each group of first test vias 108 includes three spaced first test vias 108 along the width direction of the substrate 1. That is, the first test vias 108 of this application are arranged in multiple groups of three rows along the width direction of the substrate 1, and the test vias of this application are arranged in multiple columns along the length direction of the substrate 1, such as... Figure 5 As shown, the first test vias 108 of the left test plate 105 and the right test plate 107 are provided in six groups of thirteen columns, and the first test vias 108 in each group are provided in three rows.
[0026] Thus, the first test vias 108 of this application are arranged in an array, which can accurately simulate the via structure and distribution pattern of the actual PCB board. Moreover, the depth and diameter of the first test vias 108 in the same group of first test vias 108 are the same, which is beneficial to control variables and reduce test errors. Along the width direction of the substrate 1, from the first test slot 101 to the third test slot 110, the diameter of the first test vias 108 of the left test board 105 and the right test board 107 is 0.6-1.6mm.
[0027] Optionally, in some embodiments of this application, the top of the first test plate 102 is provided with a first positioning pin 113, and a plurality of first positioning pins 113 are arranged sequentially along the edge of the first test plate 102. The first cover plate 2 is provided with a plurality of first positioning holes 201 that match and correspond one-to-one with the first positioning pins 113. The top of the left test plate 105, the middle test plate 106 and the right test plate 107 are provided with second positioning pins 114, and a plurality of second positioning pins 114 are arranged sequentially along the edges of the left test plate 105, the middle test plate 106 and the right test plate 107 respectively. The second cover plate 3 is provided with a plurality of second positioning holes 301 that match and correspond one-to-one with the second positioning pins 114. The top of the third test plate 111 is provided with a third positioning pin 115, and a plurality of third positioning pins 115 are arranged sequentially along the edge of the third test plate 111. The third cover plate 4 is provided with a plurality of third positioning holes 401 that match and correspond one-to-one with the third positioning pins 115.
[0028] Based on the above structure, this application can achieve precise positioning of the first cover plate 2 and the first test plate 102 through the cooperation of the first positioning pin 113 and the first positioning hole 201; achieve precise positioning of the second cover plate 3 and the left test plate 105, the middle test plate 106 and the right test plate 107 through the cooperation of the second positioning pin 114 and the second positioning hole 301; and achieve precise positioning of the third cover plate 4 and the third test plate 111 through the cooperation of the third positioning pin 115 and the third positioning hole 401. This effectively avoids errors in the position of the fax paper caused by the positional offset of the first cover plate 2, the second cover plate 3 or the third cover plate 4, and can significantly improve the testing effect.
[0029] Accordingly, in the embodiments of the present invention, the first cover plate 2, the second cover plate 3 and the third cover plate 4 are all hinged to the substrate 1 via hinges 6.
[0030] In fact, since the existing test fixtures do not design corresponding test structures for PCB boards with different thicknesses and via holes with different apertures, nor do they design a special positioning structure for the precise spraying of selective wave soldering equipment, this leads to easy positioning deviation of the fax paper after clamping, making the test working conditions inconsistent with the actual production working conditions, and there is a large deviation between the test results and the actual spraying effect. It is difficult to effectively guide the optimization and adjustment of the production process and cannot meet the quality control requirements of the refinement and high efficiency of the selective wave soldering process. In order to further improve the locking effect on the fax paper, in some embodiments of the present application, a locking member 5 for locking the first cover plate 2, the second cover plate 3 and the third cover plate 4 is provided on the substrate 1. The first cover plate 2, the second cover plate 3 and the third cover plate 4 are respectively matched with a set of locking members 5. The locking member 5 includes a limiting shell 501, a limiting block 502 and a return spring. The limiting block 502 is slidably arranged in the limiting shell 501 along the length direction of the substrate 1. A return groove 506 is formed on the rear side surface of the limiting block 502. The return spring is arranged in the return groove 506 and abuts against the limiting block 502 and the limiting shell 501 respectively. Limiting hooks 504 extend along the width direction of the substrate 1 at both ends of the rear side surface of the limiting shell 501. The chamber 503 in the limiting shell 501 is "convex" shaped. The limiting hook 504 abuts against the limiting shell 501. An operation protrusion 505 is further provided on the top of the limiting block 502.
[0031] Based on the above structure, when in use, one end of the limiting block 502 is disposed inside the limiting shell 501 and abuts against the return spring. The other end of the limiting block 502 extends to the top of the first test groove 101, the second test groove 104, or the third test groove 110. That is, at this time, the limiting block 502 can partially cover the first test groove 101, the second test groove 104, or the third test groove 110, thereby abutting against the first cover plate 2, the second cover plate 3, or the third cover plate 4. Since the return spring tends to move away from the return spring, the limiting block 502 can continuously lock the first cover plate 2 in the first test groove 101, the second cover plate 3 in the second test groove 104, and the third cover plate 4 in the third test groove 110. At this time, the limiting hook 504 at the end of the limiting block 502 abuts against the limiting shell 501, preventing the limiting block 502 from popping out of the limiting shell 501 due to the abutment of the return spring. Taking the setting of the first cover plate 2 as an example, it needs to be rotated. When the first cover plate 2 is removed from the first operating groove or rotated to the first test groove 101, the operator moves the operating protrusion 505 along the length of the substrate 1. Under the manual operation of the operator, the limiting block 502 moves along the length of the substrate 1 and penetrates into the limiting shell 501. As the limiting block 502 continues to penetrate deeper into the limiting shell 501, the end of the limiting block 502 away from the limiting shell 501 no longer covers the first test groove 101 at a certain moment. At this time, the first cover plate 2 can be rotated to enter the first test groove 101. After the first cover plate 2 enters the first test groove 101, the operator releases the operating protrusion 505. At this time, the limiting block 502 moves out of the limiting shell 501 again under the action of the return spring and reaches the top of the first cover plate 2. The first cover plate 2 is fixed in the first test groove 101 in conjunction with the substrate 1. The setting of the second test groove 104 and the third test groove 110 is the same as that of the first test groove 101.
[0032] Furthermore, in some embodiments of this application, a first transparent glass 202 is fixedly disposed on the side of the first cover plate 2 away from the substrate 1, a second transparent glass 302 is fixedly disposed on the side of the second cover plate 3 away from the substrate 1, and a third transparent glass 402 is fixedly disposed on the side of the third cover plate 4 away from the substrate 1. Based on the above structure, the operator can directly observe the flux spraying on the fax paper through multiple transparent glasses, thereby obtaining the changes in the flux spraying process, which is beneficial to further improve the test results.
[0033] In addition, this application also provides a method for testing flux spraying performance using the above-mentioned test fixture, comprising the following steps: S1. Take multiple sheets of fax paper, weigh the initial weight of the fax paper using an electronic balance, and define the initial weight of each sheet of fax paper as W0. S2. Place the weighed fax paper into the first test slot 101, the second test slot 104 and the third test slot 110 respectively. Rotate the first cover plate 2 to make it abut against the first test plate 102, rotate the second cover plate 3 to make it abut against the left test plate 105, the middle test plate 106 and the right test plate 107, and rotate the third cover plate 4 to make it abut against the third test plate 111. S3. Install the test fixture on the carrier of the selective wave soldering equipment to ensure that the test area of the fixture corresponds precisely to the spraying range of the equipment nozzle; S4. Start the control system of the selective wave soldering equipment, call the preset spraying program, and spray flux onto the first test tank 101, the second test tank 104 and the third test tank 110 from the bottom of the substrate 1 respectively. The spraying parameters such as spraying flow rate, spraying time, nozzle height and moving speed are consistent with the actual production conditions. S5. After the spraying is completed, remove the fax paper from the first test tank 101, the second test tank 104 and the third test tank 110, and weigh it again using the same electronic balance, which is recorded as W1. Calculate the weight difference ΔW=W1-W0 of each fax paper before and after spraying. This weight difference is the actual amount of flux sprayed in the corresponding area. S6. Record the wetting area of the fax paper caused by flux spraying, evaluate the penetration ability of flux on PCBs with different thicknesses and apertures, record the straightness of the flux spraying trajectory on the fax paper and the actual spraying length, evaluate the linearity of flux spraying, record the deviation of the flux spraying landing point on the fax paper, and evaluate the accuracy of spraying positioning. S7. Repeat steps S1 to S6 above to complete multiple tests, and organize the CPK results based on the multiple test data. Generate a comprehensive evaluation report based on the quantitative analysis results and the generated CPK values to clarify the qualification status of flux spraying performance.
[0034] For the generation of CPK results in step S7 of this application, the fax paper after spraying, the scale of the test area, and related recorded data can be photographed and uploaded to dedicated analysis software. The software will automatically recognize the data and calculate and generate CPK results. Alternatively, all test data can be manually entered into a preset CPK calculation table, and CPK results can be generated through the table's built-in calculation function. Based on the generated CPK value, the stability of the spraying amount, the accuracy of the intermediate fixed point, and the linearity of the intermediate spraying are evaluated. The wetting area of the fax paper under different apertures and different perforated boards (corresponding to different PCB thicknesses) is compared to analyze the penetration ability of flux on PCB boards of different thicknesses and apertures. The straightness deviation and length difference of the spraying trajectory in the left and right test areas are statistically analyzed to evaluate the linearity of flux spraying on the left and right sides.
[0035] Furthermore, in order to better understand the test fixtures and test methods of this application, supplementary explanations are provided for various test parameters of the flux.
[0036] The penetration capability of the first test via 108 refers to the ability of flux to penetrate into the micro-vias of a PCB board. This directly affects soldering quality. If the flux cannot effectively penetrate into the via, the pads inside the via cannot receive sufficient flux, leading to serious problems such as cold solder joints and false solder joints, affecting the strength and reliability of the solder joints. Therefore, in actual operation, it is necessary to set up simulated PCB boards with different hole diameters, such as 0.6mm, 0.8mm, and 1.0mm, on the test fixture (i.e., the left test board 105 and right test board 107 with the first test via 108 in this application), and tightly attach a test paper, such as fax paper, to the top of the PCB board. During testing, the flux to be tested is sprayed according to the set parameters. After spraying, the penetration capability is confirmed by observing the area wetted by flux on the test paper. The percentage of the wetted area to the total area of each hole diameter is the penetration capability for that hole diameter. For example, a 90% penetration capability for a 0.6mm aperture means that 90% of the area under that aperture is covered by flux.
[0037] The second test via 109 measures the point deviation, which is the distance deviation between the actual point of flux application and the preset target point when spraying flux onto a specific point on a simulated PCB board. It reflects the positioning accuracy of the equipment; a small deviation indicates that the equipment's motion control system and nozzle positioning are highly precise. For small, isolated solder joints, precise application ensures that flux is sprayed only onto the target pad, avoiding accidental spraying onto adjacent pads causing short circuits or missed spraying leading to cold solder joints. In actual operation, a series of test points with precise coordinates (i.e., the second test via 109 of this application) are set in the middle area of the test fixture, and the nozzle is controlled to move to the preset point for spraying. After spraying, a microscope or high-precision testing tool is used to measure the distance between the center of each actual sprayed point and the center of the preset target point, and the deviation values of all points are recorded. The maximum deviation value is usually taken as the result.
[0038] The first test through-hole 103 and the third test through-hole 112 simulate the deviation between the sprayed straight line and the ideal straight line after linear spraying on the PCB board. This is used to test the motion control accuracy and nozzle positioning accuracy requirements of the spraying equipment. Small linearity deviations on both sides indicate stable and consistent performance of the equipment throughout the entire working area. In actual operation, spraying is completed based on the first test through-hole 103 and the third test through-hole 112. The difference between the sprayed straight line on the fax paper in the first test slot 101 and the third test slot 110 and the preset ideal straight line is observed, and the consistency difference in the straightness deviation of the trajectory is calculated.
[0039] In summary, this invention provides a selective wave soldering flux spraying performance testing fixture, comprising a substrate, a first cover plate, a second cover plate, and a third cover plate. The substrate has a first test slot, a second test slot, and a third test slot. The first cover plate is disposed in the first test slot to perform flux linearity testing; the second cover plate is disposed in the second test slot to perform flux penetration ability testing and pinpoint accuracy testing; and the third cover plate is disposed in the third test slot to perform flux linearity testing. Compared with existing technologies, this application achieves integrated multi-dimensional testing, enabling simultaneous evaluation of flux spraying stability, uniformity, spraying penetration on PCBs of different thicknesses and through-holes of different diameters, spraying pinpoint accuracy, and spraying linearity, significantly improving testing efficiency and data reliability.
[0040] This invention also provides a selective wave soldering flux performance testing method, which transforms traditional subjective visual observation into objective quantitative data. It also evaluates the stability, intermediate point accuracy, and linearity of the spraying process through CPK value, which meets the process control standards of the electronics manufacturing industry. This facilitates long-term monitoring and quality traceability of flux spraying performance and provides accurate data support for process optimization.
[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. A selective wave soldering flux spraying performance testing fixture, characterized in that, include: The substrate (1) has a first test groove (101), a second test groove (104) and a third test groove (110) spaced apart along the width direction of the substrate (1). The bottom wall of the first test slot (101) is the first test plate (102). Along the length direction of the substrate (1), the thickness of the first test plate (102) gradually increases and then gradually decreases. The first test plate (102) is provided with a first test through hole (103) that penetrates the substrate (1). The bottom wall of the second test slot (104) is, along the length of the substrate (1), successively formed by a left test plate (105), a middle test plate (106), and a right test plate (107). Along the length of the substrate (1), the thickness of the left test plate (105) gradually decreases, and the thickness of the right test plate (107) gradually increases. Both the left test plate (105) and the right test plate (107) are provided with multiple first test vias (108). Along the length of the substrate (1), the apertures of the plurality of first test vias (108) on the left test plate (105) and the right test plate (107) are the same. Along the width direction of the substrate (1), the plurality of first test vias (108) of the left test plate (105) and the right test plate (107) are divided into a plurality of first test via (108) groups at intervals. From the first test slot (101) to the third test slot (110), with the first test via (108) groups as nodes, the aperture of the plurality of first test vias (108) gradually increases, and the aperture of the first test vias (108) in each first test via (108) group is the same. The test plate (106) is provided with a second test via (109). The bottom wall of the third test slot (110) is a third test plate (111), and the third test plate (111) is provided with a third test through hole (112) that penetrates the substrate (1). A cover plate structure that snaps into the first test slot (101), the second test slot (102), and the third test slot (103).
2. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The cover plate structure includes a first cover plate (2), a second cover plate (3) and a third cover plate (4). The first cover plate (2) is hinged to the substrate (1) and inserted into the first test groove (101) to abut against the first test plate (102). The second cover plate (3) is hinged to the substrate (1) and inserted into the second test groove (104) to abut against the left test plate (105), the middle test plate (106) and the right test plate (107). The third cover plate (4) is hinged to the substrate (1) and inserted into the third test groove (110) to abut against the third test plate (111).
3. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The second cover plate (3) includes a left cover plate (31), a middle cover plate (32) and a right cover plate (33) arranged sequentially along the length direction of the substrate (1). Along the length direction of the substrate (1), the thickness of the left cover plate (31) gradually increases and the thickness of the right cover plate (33) gradually decreases.
4. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, Along the length direction of the substrate (1), each of the first test via (108) groups includes a plurality of spaced first test via (108) groups, and each of the first test via (108) groups includes at least two first test vias (108) spaced along the width direction of the substrate (1).
5. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The first test slot (101), the second test slot (104) and the third test slot (110) are all arranged in a long strip along the length direction of the substrate (1).
6. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The top of the first test plate (102) is provided with a first positioning pin (113), and multiple first positioning pins (113) are arranged sequentially along the edge of the first test plate (102). The first cover plate (2) is provided with multiple first positioning holes (201) that match and correspond one-to-one with the first positioning pins (113). The top of the left test plate (105), the middle test plate (106) and the right test plate (107) are provided with second positioning pins (114), and a plurality of second positioning pins (114) are arranged sequentially along the edges of the left test plate (105), the middle test plate (106) and the right test plate (107), respectively. The second cover plate (3) is provided with a plurality of second positioning holes (301) that match and correspond one-to-one with the second positioning pins (114). The top of the third test plate (111) is provided with a third positioning pin (115), and a plurality of the third positioning pins (115) are arranged sequentially along the edge of the third test plate (111). The third cover plate (4) is provided with a plurality of third positioning holes (401) that match and correspond one-to-one with the third positioning pins (115).
7. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The first cover plate (2) is fixedly provided with a first transparent glass (202) on the side away from the substrate (1), the second cover plate (3) is fixedly provided with a second transparent glass (302) on the side away from the substrate (1), and the third cover plate (4) is fixedly provided with a third transparent glass (402) on the side away from the substrate (1).
8. The selective wave soldering flux spraying performance testing fixture according to claim 1, characterized in that, The substrate (1) is provided with a locking member (5) for locking the first cover plate (2), the second cover plate (3) and the third cover plate (4). The first cover plate (2), the second cover plate (3) and the third cover plate (4) are matched with a set of the locking member (5). The locking member (5) includes a limiting shell (501), a limiting block (502) and a reset spring. The limiting block (502) is slidably disposed in the limiting shell (501) along the length direction of the substrate (1). A reset groove (506) is opened on the rear side of the limiting block (502). The reset spring is disposed in the reset groove (506) and abuts against the limiting block (502) and the limiting shell (501) respectively.
9. The selective wave soldering flux spraying performance testing fixture according to claim 8, characterized in that, At both ends of the rear side of the limiting shell (501), limiting hooks (504) are formed along the width direction of the substrate (1). The chamber (503) inside the limiting shell (501) is "convex" shaped. The limiting hooks (504) abut against the limiting shell (501). An operation protrusion (505) is further provided at the top of the limiting block (502).
10. A method for testing flux spraying performance using the selective wave soldering flux spraying performance testing fixture according to any one of claims 1-9, characterized in that, It includes the following steps: S1. Take multiple sheets of fax paper and weigh the initial weight of the fax paper using an electronic balance. Define the initial weight of the fax paper as W0; S2. Place the weighed fax papers into the first test slot, the second test slot, and the third test slot respectively. Rotate the first cover plate to make it abut against the first test plate, rotate the second cover plate to make it abut against the left test plate, the middle test plate, and the right test plate, and rotate the third cover plate to make it abut against the third test plate; S3. Install the test fixture on the carrier of the selective wave soldering equipment, and ensure that the test area of the fixture is accurately corresponding to the spraying range of the equipment nozzle; S4. Start the control system of the selective wave soldering equipment, call the preset spraying program, and spray flux on the first test slot, the second test slot, and the third test slot respectively from the bottom of the substrate. Spraying parameters such as spraying flow rate, spraying time, nozzle height, moving speed, etc. are consistent with the actual production conditions; S5. After spraying, remove the fax papers in the first test slot, the second test slot, and the third test slot, weigh their weights again using the same electronic balance, record it as W1, and calculate the weight difference ΔW = W1 - W0 of each fax paper before and after spraying. This weight difference is the actual spraying amount of flux in the corresponding area; S6. Record the wetting area generated by the flux spraying on the fax paper, evaluate the penetration ability of the flux on PCB boards with different thicknesses and different pore diameters, record the straightness and the actual spraying length of the flux spraying trajectory on the fax paper, evaluate the spraying linearity of the flux, and record the spraying landing point deviation of the flux on the fax paper to evaluate the spraying fixed-point accuracy; S7. Repeat the above steps S1 to S6 to complete multiple tests, and generate CPK results based on the collation of multiple test data. Generate a comprehensive evaluation report according to the quantitative analysis results and the generated CPK value to clarify the pass situation of the flux spraying performance.