PCBA warping degree detection method

Abstract

The invention discloses a PCBA (Printed Circuit Board Assembly) warping degree detection method, which comprises the following steps of: 1, manufacturing a matched PCBA bearing jig according to the structure of a PCBA to be detected; 2, providing a detection system, making a to-be-detected PCBA warping degree test point map according to the structure of the to-be-detected PCBA, generating test point coordinates, formulating a to-be-detected PCBA warping degree standard, and inputting the test point coordinates and the warping degree standard into the detection system; step 3, placing the PCBA to be tested on the PCBA bearing jig for positioning; 4, the detection system controls the photoelectric distance measurement module to measure the distance of the corresponding test point according to the coordinate information of the test point of the PCBA to be tested, so as to obtain the data of each test point; and step 5, the detection system processes the obtained data to obtain height data of each test point location, obtains warping degree data by combining the distance between any two test point locations, compares the obtained warping degree data with a warping degree standard, and judges whether the warping degree of the PCBA to be detected is qualified or not. Compared with the prior art, the method has the beneficial effects that a machine testing mode is adopted, the error problem of manual testing can be avoided, the testing efficiency is greatly improved, full inspection of the PCBA warping degree can be realized, and loss caused by poor FOB bonding due to the fact that the warping degree exceeds the standard is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a method for detecting warpage of a PCBA. Background Art

[0002] At present, the warpage detection of PCBA (printed circuit board) is carried out manually at the time of incoming materials or before going online, and the number of samples is sampled and tested manually according to 5%-10%. During the test, the PCBA to be tested is placed on a platform covered with anti-static leather, and plug gauges of different thicknesses are manually inserted from the warped side of the PCBA. Finally, the thickness of the plug gauge can be seen to fully fill the gap between the PCBA and the anti-static leather. The thickness of the plug gauge is the warpage of the PCBA. This method has the following disadvantages: 1. The manual testing method has subjective intentions. Different testing techniques and testing habits of different personnel often result in a difference of at least one plug gauge thickness, which affects the R&D and process judgment of material performance; 2. This test method can only test the warpage of the left and right sides or the upper and lower sides of the PCBA, and cannot test the warpage of the middle wave line, which has a test loophole; 3. This test method is time-consuming and cannot be fully tested. Finally, the uneven PCBA causes abnormal bonding of the back-end FOB, and the defective ratio is about 1.7% to 3.5%.

[0003] Therefore, the prior art has defects and needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a PCBA warpage detection method.

[0005] The technical solution of the present invention is as follows: The present invention provides a PCBA warpage detection method, comprising the following steps: Step 1: according to the structure of the PCBA to be tested, a matching PCBA bearing fixture is manufactured;

[0006] Step 2: Provide a detection system, prepare a warpage test point map of the PCBA to be tested according to the structure of the PCBA to be tested, generate the test point coordinates, and formulate the warpage standard of the PCBA to be tested, and input the test point coordinates and the warpage standard into the detection system;

[0007] Step 3: Place the PCBA to be tested on the PCBA carrier fixture for positioning;

[0008] Step 4: The detection system controls the photoelectric distance measurement module to measure the distance of the corresponding test points according to the test point coordinate information of the PCBA to be tested, so as to obtain the data of each test point;

[0009] Step 5: The detection system processes the acquired data to obtain the height data of each test point, and obtains the warpage data by combining the distance between any two test points. The warpage data obtained is then compared with the warpage standard to determine whether the warpage of the PCBA to be tested is qualified.

[0010] Furthermore, in the step 1, when manufacturing the PCBA carrier jig, corresponding air-avoidance areas are set according to the device area, bonding area, and ZIF connector of the PCBA to be tested.

[0011] By adopting the above scheme, the beneficial effect of the present invention is that: by adopting the machine testing method, the error problem of manual testing can be avoided, and the testing efficiency is greatly improved, and the full inspection of PCBA warpage can be realized, avoiding the loss caused by poor FOB bonding due to excessive warpage. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of a PCBA test point of the present invention. DETAILED DESCRIPTION

[0013] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0014] Please refer to Figure 1 In this embodiment, the present invention provides a PCBA warpage detection method, comprising the following steps: Step 1: According to the structure of the PCBA to be tested, a matching PCBA carrier fixture is manufactured. Specifically, a corresponding air-avoiding area is set on the PCBA carrier fixture according to the device area, bonding area, and ZIF connector of the PCBA to be tested, to ensure that the board surface of the PCBA is at the same level as the contact surface of the carrier fixture, so as to avoid interference of the device and the like on the test.

[0015] Step 2: Provide a detection system to make a test point map of the warpage of the PCBA to be tested according to the structure of the PCBA to be tested, and the test point is preferentially selected at the position directly below the bonding area to ensure the smooth progress of subsequent bonding. Figure 1 Taking the PCBA board in as an example, 16 test points are selected, namely #1 to #16, and the test point coordinates are generated according to the test point map, and the warpage standard of the PCBA to be tested is formulated. The test point coordinates and the warpage standard are input into the detection system to ensure that subsequent detection and comparative judgment can be carried out.

[0016] Step 3: Place the PCBA to be tested on the PCBA carrier fixture for positioning. At this time, the detection system will adjust the alignment to obtain the coordinate information of the coordinate origin and test points #1 to #16 of the PCBA to be tested.

[0017] Step 4: The detection system controls the photoelectric distance measurement module to measure the distance of the test points #1 to #16 according to the coordinate information of the test points #1 to #16 of the PCBA to be tested, so as to obtain the data of each test point.

[0018] Step 5: The detection system processes the acquired data to obtain the height data of each test point, obtains the warpage data in combination with the distance between any two test points, and then compares the obtained warpage data with the warpage standard to determine whether the warpage of the PCBA to be tested is qualified. For example, there are 16 test points from test point #1 to test point #16, and there are 120 warpage data in these 16 test points. For example, the maximum warpage of the PCBA is set to 0.75% of the length. If the distance between the two test points is 5mm, the maximum height difference between the two test points cannot exceed 5*0.75%=0.0375mm. If these 120 warpage data meet the standards, the warpage of the PCBA to be tested is qualified, otherwise it is unqualified.

[0019] In summary, the use of machine testing can avoid the error problems of manual testing, and the testing efficiency is greatly improved. It can achieve full inspection of PCBA warpage and avoid losses caused by poor FOB bonding due to excessive warpage.

[0020] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A PCBA warpage detection method, characterized in that: The following steps are involved: Step 1: Make a matching PCBA bearing fixture according to the structure of the PCBA to be tested; Step 2: Provide a detection system, prepare a warpage test point map of the PCBA to be tested according to the structure of the PCBA to be tested, generate the test point coordinates, and formulate the warpage standard of the PCBA to be tested, and input the test point coordinates and the warpage standard into the detection system; Step 3: Place the PCBA to be tested on the PCBA carrier fixture for positioning; Step 4: The detection system controls the photoelectric distance measurement module to measure the distance of the corresponding test points according to the test point coordinate information of the PCBA to be tested, so as to obtain the data of each test point; Step 5: The detection system processes the acquired data to obtain the height data of each test point, and obtains the warpage data by combining the distance between any two test points. The warpage data obtained is then compared with the warpage standard to determine whether the warpage of the PCBA to be tested is qualified.

2. The PCBA warpage detection method according to claim 1, characterized in that: In the step 1, when making the PCBA carrier fixture, corresponding air-avoidance areas are set according to the device area, bonding area, and ZIF connector of the PCBA to be tested.

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