In today's PCB key application objects, automotive PCB occupies an important position.
Due to the special working environment, safety and high current requirements of automobiles, the reliability and environmental adaptability of PCB are highly demanded, and the types of PCB technology involved are also wider.
This is a challenge for PCB enterprises, and for those who want to develop the automotive PCB market, they need to know more about and analyze the new market.
PCB for automobiles emphasizes high reliability and low DPPM. Does our company have the accumulation of technology and experience in high reliability manufacturing? Is it consistent with the future direction of product development? In terms of process control, can we do it well according to the requirements of TS16949? Has low DPPM been achieved? All of these should be carefully evaluated. Blind entry of this attractive cake will do harm to the enterprise itself.
Following are some typical practices of some automotive PCB enterprises which specialize in the production of automotive PCB in the testing process, which can be referred to by PCB colleagues.
1. Secondary test method
Some PCB manufacturers adopt the "secondary test method" to improve the rate of defect plate found by the first high voltage electrical breakdown.
2. Anti-dull Testing System for Bad Board
More and more PCB manufacturers have installed "good board marking system" and "bad board error-proof box" in the light board tester to effectively avoid human leakage. The good board marking system identifies the tested PASS boards for the tester, which can effectively prevent the tested boards or bad boards from flowing into the hands of customers. In the process of testing, when the PASS board is tested, the test system outputs the signal that the box opens. On the contrary, when the bad board is tested, the box closes, so that the operator can place the tested circuit board correctly.
3. Establishing PPm Quality System
At present, the quality system of PPm (Partspermillion, millionth defect rate) has been widely used in PCB manufacturers. Among many of our customers, Itachi ChemICal in Singapore is the most valuable reference for its application and achievements. In this factory, more than 20 people are specially responsible for the statistical analysis of online PCB quality abnormalities and PCB quality abnormalities returns. SPC production process statistical analysis method is used to classify each defective plate and each defective plate returned for statistical analysis, and combined with Micro-slicing and other auxiliary tools to analyze which manufacturing process produces defective and defective plate. According to the statistical data results, purposefully solve the problems in the process.
4. Comparative Testing Method
Some customers use two different brands of PCB to test in different batches, and track the PPm situation of the corresponding batches, so as to understand the performance of the two kinds of testers, so as to select better performance testers to test PCB for automobiles.
5. Improving test parameters
Select higher test parameters to strictly detect such PCB/PCBA OEM agent.
Because, if higher voltage and threshold are chosen, the detection rate of PCB defective plate can be improved by increasing the number of high voltage leakage reading. For example, a large Taiwanese-funded PCB enterprise in Suzhou uses 300V, 30M and 20Euro to test PCB for automobiles.
Method of Optimizing Defect Rate of Automotive PCB
2019 09/17
