Electric pressure cooker LCD industrial control circuit boards are exposed to high humidity, steam, and oily environments in kitchens for extended periods. Moisture corrosion can easily lead to component short circuits, solder joint oxidation, and insulation degradation, directly impacting device stability and service life. Improving moisture corrosion resistance requires coordinated optimization of multiple dimensions, including material selection, structural protection, coating processes, and environmental control, to create a systematic protection system.
Substrate materials are the foundation of circuit board corrosion resistance. Traditional FR-4 fiberglass boards have a high moisture absorption rate, which can easily lead to delamination or swelling in humid environments. Low-moisture-absorption polyimide (PI) or ceramic substrates can be used instead. These materials offer improved temperature resistance and strong chemical stability, effectively reducing moisture penetration. Furthermore, lead-free, environmentally friendly solder should be used for solder pads and component pins. Its corrosion resistance is superior to that of traditional lead-based solder, reducing the risk of solder joint oxidation in humid environments.
Structural protection requires sealing to block moisture intrusion. For areas prone to water ingress, such as the electric pressure cooker LCD's interfaces and buttons, silicone seals or waterproof rubber pads can be used, combined with ultrasonic welding to achieve a seamless enclosure. For the cables connecting the circuit board to the LCD, flexible printed circuit boards (FPCs) can be used and covered with waterproof film to prevent seal failure due to frequent bending. Additionally, when laying out the circuit board, placing sensitive components (such as chips and capacitors) away from steam vents or areas where condensation accumulates can reduce the risk of localized corrosion.
Coating is a key method for improving the circuit board's resistance to moisture. Conformal coating (moisture-proof, salt spray-proof, and mildew-proof) is a common industry solution. This method, applied by spraying or dipping, creates a 0.1-0.3mm thick transparent protective film on the circuit board surface, effectively shielding it from moisture and corrosive gases. Acrylic conformal coatings offer fast curing speeds and low cost, making them suitable for large-scale production. Silicone conformal coatings offer superior temperature resistance and are suitable for high-temperature cooking environments. Polyurethane conformal coatings offer both flexibility and abrasion resistance, protecting the circuit board from mechanical damage. For demanding applications, Parylene nano-coating technology can be used. This vapor deposition process creates a uniform, dense nano-scale coating on the circuit board surface. With a thickness of only 2-5μm, it provides 360-degree protection without affecting component heat dissipation or signal transmission.
Potting can further enhance the circuit board's protection level. Applying epoxy or silicone potting compound to the entire circuit board creates a completely sealed protective layer, isolating it from moisture, dust, and chemicals. Epoxy potting compounds offer high hardness and strong chemical resistance, but are difficult to repair. Silicone potting compounds, on the other hand, are elastic, cushion mechanical shock, and are easy to disassemble and repair. For electric pressure cooker industrial control circuit boards, a low-viscosity, self-leveling silicone potting compound is recommended. It penetrates into component gaps, eliminating blind spots.
Environmental control is an additional measure to extend the life of circuit boards. During the production of electric pressure cookers, circuit boards must be stored in a dry environment and sealed in moisture-proof bags to prevent moisture absorption during transportation. During the equipment's operational life, condensation can be reduced by optimizing the heat dissipation design. For example, adding temperature and humidity sensors near the circuit boards automatically activates the heating module for dehumidification when humidity exceeds the specified limit. Furthermore, regularly cleaning the circuit board surface from oil and dust can prevent it from absorbing moisture and forming a corrosive medium.
Process optimization is key to ensuring effective protection. Before coating, the circuit boards must be plasma cleaned to remove surface oxides and oil, improving coating adhesion. The potting process requires strict control of the glue curing temperature and time to prevent cracking of the protective layer due to insufficient curing. The sealing structure must pass airtightness testing to ensure IP65 protection or above. Through standardized process flows and strict quality control, the resistance of electric pressure cooker LCD industrial control circuit boards to moisture corrosion can be significantly enhanced.
