Selection of Micro Switch Materials

Micro switches are electromechanical devices commonly used in various applications for their precise switching capabilities. The selection of materials for micro switches is crucial to ensure their performance, durability, and reliability. Here are some key considerations for micro switch material selection:

1. Contact Materials: The contact materials used in micro switches should have low electrical resistance, high conductivity, and excellent wear resistance. Common contact materials include silver alloy, gold alloy, or silver-nickel (AgNi) composites. Silver alloys offer good conductivity but may wear faster, while gold alloys provide excellent reliability but are more expensive.

2. Housing Materials: The housing or casing of micro switches should be made of a sturdy and durable material to protect the internal components and withstand mechanical stress. Thermoplastics like polyamide (PA), polybutylene terephthalate (PBT), or polycarbonate (PC) are commonly used due to their good mechanical properties, high temperature resistance, and ease of molding.

3. Actuator Materials: The actuator is the component that receives the external force to initiate the switching action. The actuator material should have good mechanical strength, wear resistance, and be able to withstand repeated actuations. Common actuator materials include stainless steel, phosphor bronze, or thermoplastics such as PBT or PC.

4. Spring Materials: Springs are critical for the proper functioning of micro switches, providing the necessary force to maintain contact or switch positions. Spring materials should have good elasticity, fatigue resistance, and corrosion resistance. Materials like stainless steel or beryllium copper are commonly used for micro switch springs.

5. Terminals and Contacts: The terminals and contacts in micro switches should have good electrical conductivity and corrosion resistance. Common materials for terminals and contacts include brass, phosphor bronze, or silver-plated materials.

6. Environmental Considerations: The choice of materials should also consider the operating environment of the micro switch. Factors such as temperature, humidity, chemical exposure, and mechanical stress should be taken into account to ensure the selected materials can withstand the specific conditions.

When selecting materials for micro switches, it's important to consider the specific requirements of the application, such as electrical load, operating environment, expected lifespan, and cost constraints. Manufacturers of micro switches often provide guidelines and specifications for the suitable materials to use in their products, and it's recommended to consult these recommendations and conduct appropriate testing and validation before finalizing the material selection.