In today’s key PCB applications, automotive PCBs hold a crucial position. However, the unique operating environment, alongside safety and high current demands of vehicles, imposes stringent requirements on PCB reliability and environmental adaptability, necessitating a broad spectrum of PCB technologies. This presents a challenge for PCB manufacturers. For those aiming to penetrate the automotive PCB market, a deeper understanding and analysis of this emerging sector is essential.
Automotive PCBs place a strong emphasis on high reliability and low DPPM. Therefore, does our company possess the technological expertise and experience required for high-reliability manufacturing? Is this aligned with our future product development strategy? Regarding process control, can we effectively adhere to TS16949 requirements? Have we achieved a low DPPM? Each of these aspects needs thorough evaluation. Merely recognizing the attractiveness of this market without proper preparation could harm the enterprise.
Below are some specialized practices in the testing processes of representative companies dedicated to automotive PCB production, offered for the benefit of circuit board manufacturers:
1. The second test method.
1. Some PCB manufacturers utilize the “second test method” to enhance the detection rate of defective boards following the initial high-voltage electrical breakdown.
2. Fault-proof testing systems for defective boards
An increasing number of PCB manufacturers have integrated “good board marking systems” and “bad board error prevention boxes” into their light board testing machines to effectively minimize human error. The good board marking system labels the tested PASS boards, ensuring that only verified boards reach customers. Conversely, the bad board error-proof box is designed so that when a PASS board is tested, the system signals that the box is open; when a defective board is tested, the box remains closed, guiding the operator in correctly handling the tested circuit boards.
3. Implementation of the PPM quality system
Currently, the PPM (Parts Per Million defect rate) quality system is becoming increasingly prevalent among PCB manufacturers. A designated individual is responsible for the statistical analysis of quality abnormalities in production and the return of defective PCBs. By employing SPC (Statistical Process Control) methods, each defective and returned board is categorized and analyzed statistically. Additionally, techniques like microsectioning are used to determine which production processes contribute to defects. The insights gained from these statistical analyses allow for targeted problem-solving within the manufacturing process.
4. Comparative testing methods
Some clients conduct comparative tests using different batches of PCBs from two different brands, tracking the PPM of each batch. This helps them evaluate the performance of both testers and select the one that demonstrates superior performance for automotive PCB testing.
5. Enhancing testing parameters
Selecting higher testing parameters is crucial for the stringent evaluation of this type of PCB. By opting for increased voltage and threshold levels, the incidence of high-voltage leakage readings can be raised, thereby improving the detection rate of defective PCBs.
6. Regular verification of testing machine parameters
Over time, the internal resistance and other related test parameters of testing machines can drift due to prolonged use. It is essential to periodically adjust machine parameters to maintain testing accuracy. Many large PCB companies conduct maintenance every six months to a year, adjusting internal performance parameters accordingly. The pursuit of “zero defects” in automotive PCBs remains a key objective for the PCB industry. Nevertheless, due to limitations in processing equipment and raw materials, the top 100 PCB companies globally continue to seek methods to reduce PPM.
