The reliability standards of automotive electronic PCB(printed circuit board) assembly involve many aspects, the following is the summary and analysis of these standards:
1. Material standards
High and low temperature resistance:
Automotive electronic systems need to work normally under various climatic conditions, so PCB materials must have good high and low temperature resistance. For example, special FR-4 sheets with high glass transition temperatures (Tg) or high temperature nylon materials are selected to ensure stable circuit connections and normal functioning of electronic components at high temperatures (such as over 100 ° C in the engine compartment) and low temperatures (such as extreme cold conditions of minus 40 ° C).
Chemical corrosion resistance:
The operating environment of the car is complex, and the PCB may come into contact with various chemicals, such as oil in the engine compartment, coolant, salt on the road, acid rain and so on. Therefore, it is necessary to choose chemical corrosion resistant materials, such as special protective coatings, corrosion resistant substrates, to prevent chemical erosion of PCB, resulting in circuit damage.
Lead-free compliance and environmental requirements:
Comply with RoHS(Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment) and other environmental regulations to ensure lead-free and hazardous substances control in PCB materials and manufacturing processes.
2. Design and layout standards
Multi-layer PCB design:
Automotive electronic PCBS are typically designed with multiple layers to increase mechanical strength and electrical performance, adapting to complex circuit configurations and harsh operating conditions.
Reasonable layout partition:
The analog circuit, digital circuit, high frequency circuit and other fine division, using ground layer or shielding line isolation, to prevent mutual interference. For example, on the PCB of the automatic driving assistance system, the high-frequency circuit of the millimeter-wave radar is separated from the digital circuit of image processing to ensure the accurate capture of radar signals and the rapid processing of image data.
Redundant design:
Set a backup channel for key signal and power lines. If the main line fails, the backup takes over in time to avoid system crash. Taking the PCB of the engine control unit as an example, the key circuits that control fuel injection and ignition timing are equipped with dual redundancy design to ensure that the engine is always in a controlled state.
Thermal management Design:
For components with large heat output, such as power modules, the heat dissipation path should be fully considered in the PCB layout. The large area of copper foil heat dissipation, the installation of heat sink and even the use of liquid cooling structure to cooperate with it, to prevent performance degradation or failure due to overheating.
3. Manufacturing and assembly standards
Strict manufacturing process control:
The manufacturing and assembly process of automotive electronic PCBS requires strict process control to ensure that every step complies with standards and specifications. From the selection of raw materials to the final testing and quality inspection, comprehensive and strict management is required.
Component selection and quality control:
Strictly select automotive grade components that meet the AEC-Q series standards. These components have undergone a number of durability verification such as strict temperature cycling, humidity testing, and mechanical impact, and can stick to their positions for a long time under harsh automotive conditions.
Welding process and quality control:
Ensure that the welding process meets the requirements of lead-free welding and the welding quality is reliable. Strict appearance inspection, X-ray inspection, electrical testing, etc. are carried out on the welded PCB to ensure that the welding quality meets the requirements.
4. Testing and certification standards
Environmental adaptability test:
Includes salt spray tests to assess the corrosion resistance of PCBS in high salt environments; Humidity and high temperature aging tests to verify long-term reliability and stability.
Electrical performance test:
Including signal integrity, power supply stability, EMC/EMI(Electromagnetic compatibility/interference) tests. Through high frequency testing, signal crosstalk testing, electrostatic discharge (ESD) testing to verify that the PCB’s electrical performance meets the requirements.
Comply with international quality management system standards:
Such as IATF 16949(quality management system standard developed by the International Automotive Working Group), ISO 9001, etc. These standards put forward strict quality requirements for the design, development, production, installation and service process of automotive electronic PCBS.
5. Other standards
High mechanical strength and stability:
Automotive PCB needs to withstand long-term vibration and shock without damage. Mechanical properties are ensured through tests that simulate the actual operating environment of the vehicle, such as hot and cold cycle tests, vibration tests and drop tests.
Long life design:
Since the average service life of a car is 10 to 12 years, automotive PCBS must have a long life to match it to ensure stable operation throughout the life cycle of the car.
In summary, the reliability standards for automotive electronic PCB assembly involve many aspects such as materials, design, manufacturing, testing and certification. Only by strictly following these standards can we ensure the safe and reliable operation of automotive electronic PCBS in a variety of complex road conditions and environments.
