Method for optimizing vehicle PCB defect rate

Among the various applications of printed circuit boards (PCBs) today, automotive PCBs hold a significant position. However, due to the demanding operating environment, stringent safety requirements, and high current demands in automotive applications, these PCBs must meet higher standards for reliability and environmental adaptability. The complexity of the required PCB technologies further intensifies the challenge for manufacturers. Companies seeking to enter the automotive PCB market must conduct thorough research and analysis to navigate this highly competitive sector successfully.

High reliability and low Defective Parts Per Million (DPPM) are critical in automotive PCB production. Therefore, companies must evaluate whether they have the necessary technological expertise and experience in high-reliability manufacturing. Does their expertise align with future product development trends? Can their process control capabilities meet the rigorous standards of IATF 16949? Have they successfully achieved low DPPM levels? These factors require careful assessment, as blindly entering this lucrative market without adequate preparation could be detrimental to a company's long-term growth.

Below are some specialized testing methodologies implemented by leading automotive PCB manufacturers to enhance product reliability, which may serve as a reference for PCB industry professionals:

1. Secondary Testing Method

Some PCB manufacturers adopt a secondary test method to improve the detection rate of defects that may not be identified in the initial high-voltage electrical breakdown test.

2. Foolproof System for Defective Board Prevention

To minimize human errors, many manufacturers integrate good board marking systems and defective board prevention mechanisms into bare board testing equipment. The good board marking system ensures that only tested and approved boards are identified as PASS, preventing defective boards from reaching customers. Additionally, the defective board prevention mechanism operates as follows: if a PASS board is tested, the error prevention box remains open, allowing normal workflow. However, if a defective board is detected, the box remains closed, prompting the operator to handle the defective PCB appropriately.

3. Establishing a PPM (Parts Per Million) Quality System

The PPM quality system is widely implemented in PCB manufacturing to enhance quality control. A notable example is Hitachi Chemical in Singapore, where over 20 specialists conduct real-time statistical analysis of PCB quality using Statistical Process Control (SPC) methods. Each defective board—whether identified online or returned by customers—is systematically categorized and analyzed using tools such as micro-sectioning. This allows manufacturers to pinpoint the specific production stage responsible for defects and implement targeted corrective measures based on statistical data.

4. Comparative Testing Method

Some customers conduct comparative testing by evaluating the performance of two different brands of testing equipment on various PCB batches. By tracking the DPPM rates for each batch, they can determine the more effective testing system for automotive PCB quality assurance.

5. Enhanced Test Parameters

To improve defect detection rates, manufacturers employ stricter testing parameters, such as higher voltage thresholds and increased high-voltage leakage readings. For instance, a major Taiwan-invested PCB manufacturer in Suzhou conducts automotive PCB tests at 300V, 30MΩ, and 20Ω to ensure rigorous defect detection.