The following is a representative part of professional PCB manufacturing enterprises in the test process of some special practices for PCB colleagues for reference:
1. Secondary test
Some PCB manufacturers adopted the "secondary test method" to improve the rate of finding the defects after the first high-voltage breakdown.
2. Dap test system
More and more PCB manufacturers have installed the "good plate marking system" and "bad plate error box" in the light plate tester to effectively avoid artificial leakage.The good board marking system identifies the tested PASS board for the testing machine, which can effectively prevent the tested board or bad board from flowing to the customer.The fault protection box of the fault plate is the signal that the test system output the box to open when the PASS plate is tested during the test.On the other hand, when the fault board is tested, the box is closed, allowing the operator to place the tested circuit board correctly.
3. Establish PPm quality system
At present, the quality system of PPm (Partspermillion) has been widely used in PCB manufacturers.Among many of our customers, HitachiChemICal of Singapore is the most valuable reference for its application and the results achieved.In this factory, there are more than 20 people who are responsible for the statistical analysis of online PCB quality and returned goods.The SPC production process statistical analysis method was used to classify each bad plate and the returned defective plate for statistical analysis, and the auxiliary tools such as microsection were combined to analyze which manufacturing process produced the bad and defective plate.According to the statistical data results, there is a purpose to solve the problems in the process.
4. Comparison test
Some customers adopt two models of different brands for different batches of PCB to conduct comparative testing, and track the situation of PPm corresponding to the batches, so as to understand the performance status of the two test machines, so as to choose a better performance test machine for testing the PCB used in cars.
5. Improve the test parameters
Select higher test parameters to strictly detect such PCB.PCBA OEM OEM materials because, if higher voltage and threshold are selected to increase the number of high-voltage read leakage, the detection rate of the PCB defect board can be improved.For example, a large taiwanese-owned PCB enterprise in suzhou used 300V, 30M, and 20 Europe to test PCB for automobile.