Among the key applications of PCBs today, automotive PCBs occupy an important position. However, due to the special working environment, safety and high current requirements of the automobile, it has higher requirements on PCB reliability and environmental adaptability, and the types of PCB technology involved are also wide. This is a challenge for PCB companies, and for manufacturers who want to develop the automotive PCB market, more understanding and analysis of the new market is needed.
Automotive PCBs place special emphasis on high reliability and low DPPM. So, do our companies have accumulated technology and experience in high reliability manufacturing? Is it consistent with the direction of future product development? In terms of process control, can it be done in accordance with the requirements of TS16949? Has the low DPPM been achieved? These are all to be carefully evaluated, and blindly entering this tempting cake will hurt the company itself.
The following is a representative part of the professional production of automotive PCB companies in the testing process, some special practices are provided to the majority of PCB colleagues for reference:
1, the secondary test method
Some PCB manufacturers have adopted the "secondary test method" to improve the rate of defects found in the first high-voltage electrical breakdown.
2, bad board foolproof test system
More and more PCB manufacturers have installed "good board marking system" and "bad board error prevention box" in the bare board testing machine to effectively avoid human error. The good board marking system identifies the tested PASS board for the test machine, which can effectively prevent the bad board from flowing to the customer. The bad board error prevention box will output the signal that the box opening when the PASS board is tested during the test, otherwise, when the bad board is tested, the box is closed, allowing the operator to correctly place the tested circuit board.
3. Establish a PPM( parts per million) quality system
At present, PPM quality system has been widely used in PCB manufacturers. Among the many companies, the application and achievements of Hitachi Chemical in Singapore are the most worthy of reference. More than 20 people in the factory are responsible for the statistical analysis of online PCB quality, using the SPC production process statistical analysis method, each piece of bad board and each piece of defective board returned are classified and statistically analyzed, and combined with auxiliary tools such as micro-slices to analyze which manufacturing process produces bad and defective boards. According to the statistical data results, the problem occurred in the process is purposefully solved.
4, comparative test method
Some customers use two different brands of test machine for comparison testing different batches of PCBs, and track the PPM of the corresponding batches to understand the performance of the two test machines, so as to select a better performance test machine to test the automotive PCB.
5, improve test parameters
Select higher test parameters to rigorously detect such PCBs, because if you choose a higher voltage and threshold, increase the number of high-voltage read leakage times, you can increase the detection rate of PCB defective boards. For example, a large Taiwan-funded PCB company in Suzhou uses 300V, 30M, and 20 ohms to test automotive PCBs.
