AUTOMOTIVE


Electronics in Vehicles: The Reliability Challenge and the Crucial Role of Cleaning


The automotive industry has evolved dramatically, with electronics now integral to vehicle functionality.


by Elizabeth Norwood, senior chemist at MicroCare M


odern vehicles are sophisticated networks of electronic systems controlling everything from engine management to safety features and infotainment. While these advancements have significantly improved vehicle performance and convenience, they also present new challenges in ensuring the long-term reliability of these electronic systems. A critical aspect of maintaining reliability is proper electronics cleaning during manufacturing.


The Rise of Automotive Electronics Electronics are now vital in various vehicle applications:


Engine Control Units (ECUs): ECUs manage engine performance, fuel efficiency and emissions, enabling real-time adjustments that enhance overall vehicle performance. Safety Systems: Electronics are crucial for features like anti-lock braking systems (ABS), electronic stability control (ESC), airbags and advanced driver assistance systems (ADAS), which significantly improve vehicle safety. Infotainment and Connectivity: Modern infotainment systems rely heavily on electronics for navigation, entertainment and connectivity, ensuring a seamless user


experience.


Reliability Risks in Automotive Electronics


As vehicles incorporate more electronics, ensuring reliability becomes increasingly challenging. Key factors contributing to reliability risks include: Environmental Exposure: Automotive electronics face harsh conditions, including temperature extremes, humidity, dust and vibration, which can degrade components over time.


Manufacturing Defects: Even minor defects, such as residual contaminants left on printed circuit board assemblies (PCBAs) or improper soldering, can cause significant reliability issues, including short circuits and corrosion. Thermal Stress: Electronic components endure thermal cycling due to engine heat and varying external temperatures, leading to mechanical stress and potential failures.


Importance of Cleaning in Ensuring Reliability


To address reliability risks, proper PCBA cleaning during manufacturing is crucial. Cleaning removes contaminants that can


Automotive Electronics: Cleaning removes contaminants that can compromise electronic part performance and longevity.


compromise electronic part performance and longevity. The following points highlight its importance:


Removal of Contaminants: Cleaning cuts flux residues, solder splashes, dust and oils that can cause short circuits, corrosion and other failures, ensuring long-term reliability. Enhanced Solder Joint Integrity: Clean solder joints are free from residues that could weaken their integrity, essential for the mechanical and electrical stability of components. Improved Adhesion for Coatings: Cleaning ensures protective coatings adhere properly, safeguarding components from environmental factors like moisture and dust. Prevention of Electrochemical Migration: Cleaning removes ionic residues that can cause electrochemical migration, preventing short circuits.


Reliability Testing and Quality Assurance: Thorough cleaning is vital for accurate reliability testing. This helps manufacturers find weaknesses early, ensuring only high-quality products reach the market.


Cleaning Techniques in Automotive Electronics Manufacturing


Aqueous cleaning and solvent vapor degreasing are common methods in PCBA cleaning, each with advantages and limitations.


Aqueous Cleaning: Aqueous cleaning uses water-based solutions, often with detergents, to effectively remove a wide range of contaminants from PCBAs, but it requires multiple wash cycles and thorough drying, which can be time-consuming and energy-intensive


10 OCTOBER 2024 | ELECTRONICS FOR ENGINEERS


Aqueous Cleaning: This method uses water-based solutions, often with detergents, to remove contaminants from PCBAs. It is effective for removing a wide range of contaminants, particularly with ultrasonic


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