Six methods to reduce the defect rate of automotive PCB

Six methods to reduce the defect rate of Automotive PCB

Circuit board manufacturing, circuit board design and PCBA processing manufacturers explain the six methods to reduce the defect rate of automotive PCB

The Automotive electronics MARKet is the third largest applICation field of PCB after computers and communications. With the gradual evolution and development of automobiles from traditional mechanical products to high-tech products with intelligence, informatization and electromechanical integration, electronic technology has been widely used in automobiles, including engine systems, chassis systems, safety systems, information systems, and interior environment systems. The automotive market has obviously become another highlight of the electronic consumer market. The development of automotive electronics has naturally driven the development of automotive PCBs.

In today's key application objects of PCB, PCB for automobile occupies an important position. However, due to the special working environment, safety, high current and other requirements of automobiles, they have high requirements for PCB reliability and environmental adaptability, and involve a wide range of PCB technology types, which is a challenge for PCB enterprises; For manufacturers who want to expand the automotive PCB market, they need to do more understanding and analysis of the new market.

The PCB used in automobile especially emphasizes high reliability and low DPPM. Does our enterprise have the accumulation of technology and experience in high reliability manufacturing? Is it consistent with the future product development direction? Is the process control in accordance with the requirements of TS16949? Has a low DPPM been achieved? All of these should be carefully evaluated. It will hurt the enterprise itself to enter blindly just to see this attractive cake.

The following provides some special practices of some representative PCB manufacturers specializing in the production of automotive PCB in the testing process for reference to PCB colleagues:

1. Secondary test method

Some PCB manufacturers adopt the "secondary test method" to improve the rate of finding defective boards after the first high-voltage electrical breakdown.

2. Bad board anti fool test system

More and more PCB manufacturers have instalLED "good board marking system" and "bad board error proofing box" in the optical board testing machine to effectively avoid man-made leakage. The good board marking system marks the tested PASS boards for the testing machine, which can effectively prevent the tested boards or bad boards from flowing into the hands of customers. Bad board error proofing box means that during the test, when the PASS board is tested, the test system outputs the box opening signal; On the contrary, when a bad board is tested, the box is closed to allow the operator to correctly place the tested circuit board.

3. Establish PPm quality system

At present, the PPm (parts per million) quality system has been widely used in PCB manufacturers. Among our customers, Singapore's application and achievements are the most worthy of reference. There are more than 20 people in the factory who are specially responsible for the statistical analysis of the quality abnormalities of online PCB and PCB quality abnormal returns. The SPC production process statistical analysis method is used to classify and statistically analyze each piece of bad board and each piece of returned defective board, and analyze which manufacturing process produces bad and defective boards in combination with auxiliary tools such as microsection. According to the statistical data results, solve the problems in the process purposefully.

4. Comparative test

Some customers use two different brands of PCBs in different batches for comparative testing, and track the PPm situation of the corresponding batches, so as to understand the performance of the two testing machines, so as to select a better performance testing machine for testing automotive PCBs

5. Improve test parameters

Select higher test parameters to strictly detect such PCBs Because, if you select higher voltage and threshold value and increase the number of high-voltage leakage readings, you can improve the detection rate of PCB defective boards. For example, a large Taiwan funded PCB enterprise in Suzhou used 300V, 30M, and 20W PCBs for testing automobile PCBs

6. Regularly verify the parameters of the testing machine

After the tester operates for a long time, the internal resistance and other relevant test parameters will be biased. Therefore, the machine parameters need to be adjusted regularly to ensure the accuracy of the test parameters. Test equipment is maintained and internal performance parameters are adjusted half a year or one year in a considerable number of large PCB enterprises. The pursuit of "zero defect" automotive PCB has always been the direction of efforts of PCB people. However, due to the limitations of process equipment, raw materials and other aspects, the top 100 PCB enterprises in the world are still constantly exploring ways to reduce PPm. circuit board manufacturing, circuit board design and PCBA processing manufacturers will explain 6 methods to reduce the defect rate of vehicle PCB.