Brief Discussion on the 6 Ways to Reduce PCB Defective Rate for Vehicles

The automotive electronics market is the third largest application area for PCBs after computers and communications. With the traditional mechanical products of automobiles, they gradually evolved and developed into high-tech products that integrate intelligence, information, and mechatronics. Electronic technology has been widely used in automobiles, both as engine systems and chassis systems. Safety systems, information systems, and automotive interior systems all use electronic products without exception. The automotive market has obviously become another bright spot in the electronic consumer market. The development of automotive electronics has naturally driven the development of automotive PCBs.

In today's PCB applications, automotive PCBs occupy an important position. However, due to the special working environment, safety, and high current requirements of automobiles, their requirements for PCB reliability and environmental adaptability are relatively high, and the type of PCB technology involved is also relatively wide. This is a case for PCB companies. Challenges; For manufacturers who want to explore the automotive PCB market, more understanding and analysis of this new market are needed.

Automotive PCBs emphasize high reliability and low DPPM. Then, does our company have accumulated technology and experience in high-reliability manufacturing? Is it consistent with future product development? In the process control, can it be done in accordance with the requirements of TS16949? Have you achieved low DPPM? All of these must be carefully evaluated. Simply seeing this tempting cake and blindly entering will hurt the company itself.

The following provides representative of some professional production of automotive PCB companies in the testing process of some special practices for the majority of PCB colleagues to prepare reference:

1, the second test method

Some PCB manufacturers adopt the "secondary test method" to increase the rate of finding the first high-voltage breakdown defect plate rate.

2, bad board foolproof test system

More and more PCB manufacturers have installed "good board marking system" and "bad board error prevention box" on the light board tester to effectively avoid man-made leakage. The good board marking system identifies the tested PASS board by the testing machine, which can effectively prevent the tested boards or bad boards from flowing into the customer's hands. The bad board error proof box is the signal that the test system outputs the box open when the PASS board is tested during the testing process; otherwise, when the bad board is tested, the box is closed, allowing the operator to correctly place the tested circuit board.

3, establish PPm quality system

Currently PPm (Partspermillion, defect rate per million) quality system has begun to be widely used in PCB manufacturers. Among the many customers of our company, the application of Hitachi ChemICal in Singapore is the most worthwhile reference. There are more than 20 people in the plant responsible for the statistical analysis of online PCB quality anomaly and PCB quality return. Using the statistical analysis method of SPC production process, each bad plate and each defective plate returned were classified and statistically analyzed, and combined with microslicing and other auxiliary tools to analyze which manufacturing process produced bad and defective plates. According to the statistical data, there is a purpose to solve the problems that arise in the process.

4, comparative test

Some customer's different batches of PCBs use two different brand models for comparison testing, and track the corresponding batch of PPm conditions to understand the performance of the two test machines, so as to select a better performance tester to test the automotive PCB.

5, improve the test parameters

Select higher test parameters to rigorously investigate such PCBs. Because, if you choose a higher voltage and threshold, increase the number of high voltage read leakage, you can improve the detection rate of PCB defects. For example, a large Taiwan-funded PCB company in Suzhou uses 300V, 30M, and 20 Euro for testing automotive PCBs.

6, regular calibration test machine parameters

After the tester operates for a long period of time, the internal resistance and other related test parameters will deviate. Therefore, the machine parameters need to be adjusted regularly to ensure the accuracy of the test parameters. The test equipment maintains and adjusts the internal performance parameters in a large part of the large-scale PCB companies for half a year or one year. The pursuit of "zero defect" automotive PCB has always been the direction of efforts for the majority of PCB people, but is subject to various restrictions on process equipment, raw materials and so on, and so far PCB World Top 100 companies are continuing to explore ways to reduce PPm.