The automotive electronics market is the third largest application area for PCBs after computers and communications. As automobiles have gradually evolved from mechanical products in the traditional sense to become high-tech products that are intelligent, informatized, and mechatronics, electronic technology has been widely used in automobiles, whether it is an engine system or a chassis system, Electronic products are used in safety systems, information systems, and in-vehicle environment systems. The automotive market has clearly become another bright spot in the consumer electronics market. The development of automotive electronics has naturally driven the development of automotive PCBs.
In today’s key applications for PCBs, automotive PCBs occupy an important position. However, due to the special working environment, safety and high current requirements of the car, its requirements on PCB reliability and environmental adaptability are high, and the types of PCB technology involved are also relatively wide. This is a major issue for PCB companies. Challenges; and for manufacturers who want to develop the automotive PCB market, more understanding and analysis of this new market is needed.
Automotive PCBs emphasize high reliability and low DPPM. So, does our company have the accumulation of technology and experience in high-reliability manufacturing? Is it consistent with the future product development direction? In terms of process control, can it be done in accordance with the requirements of TS16949? Has it achieved a low DPPM? These all need to be carefully evaluated. Just seeing this tempting cake and blindly entering it will cause harm to the enterprise itself.
The following provides a representative part of some special practices in the production of automotive PCB companies during the testing process for the majority of PCB colleagues for reference:
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 foolproof test system
More and more PCB manufacturers have installed a “good board marking system” and a “bad board error-proof box” in the optical board testing machine to effectively avoid human leakage. The good board marking system marks the tested PASS board for the testing machine, which can effectively prevent the tested board or bad board from flowing into the hands of customers. The bad board error proof box is that during the test, when the PASS board is tested, the test system outputs a signal that the box is opened; otherwise, when the bad board is tested, the box is closed, allowing the operator to place the tested circuit board correctly.
3. Establish a PPm quality system
At present, the PPm (Partspermillion, parts per million defect rate) quality system has been widely used in PCB manufacturers. Among the many customers of our company, the application and achievements of Hitachi ChemICal in Singapore are the most worthy of reference. In the factory, there are more than 20 people who are responsible for the statistical analysis of online PCB quality abnormalities and PCB quality abnormal returns. Using the statistical analysis method of the SPC production process, each broken board and each returned defective board are classified for statistical analysis, and combined with micro-slicing and other auxiliary tools to analyze in which manufacturing process the bad and defective board is produced. According to the statistical data results, purposely solve the problems in the process.
4. Comparative test method
Some customers use two models of different brands for comparative testing of different batches of PCBs, and track the PPm of the corresponding batches, so as to understand the performance of the two testing machines, and then choose a better performance testing machine to test automotive PCBs.
5. Improve test parameters
Choose higher test parameters to strictly detect such PCBs. Because, if you choose a higher voltage and threshold, increase the number of high-voltage read leakage, can improve the detection rate of PCB defective board. For example, a large Taiwanese PCB company in Suzhou used 300V, 30M, and 20 Euros to test automotive PCBs.
6. Periodically verify the test machine parameters
After long-term operation of the testing machine, the internal resistance and other related test parameters will be deviated. Therefore, it is necessary to periodically adjust the machine parameters to ensure the accuracy of the test parameters. The testing equipment is maintained in a large part of large PCB enterprises for half a year or a year, and the internal performance parameters are adjusted. The pursuit of “zero defect” PCBs for automobiles has always been the direction of the efforts of the majority of PCB people, but due to the limitations of process equipment and raw materials, the top 100 PCB companies in the world are still constantly exploring ways to reduce PPm.