简体中文
When studying the quality assurance of wiring terminals, various environments they face are considered. Therefore, when designing terminals, all material issues, including metal materials and housing materials, will be considered. The material will affect the quality of the terminal blocks, and these issues should be considered by designers when designing terminals.
metallic material
The main metal components of the terminal include conductive strips, screws, and clamping parts, among which the key is the copper content of the conductive strip. In the national standards "Plugs and Sockets for Household and Similar Purposes" (GB 2099) and "Switches for Fixed Electrical Installations for Household and Similar Purposes" (GB 16915), the copper content is clearly specified to be at least 58%. Copper has excellent metal processing properties and high corrosion resistance; Copper has excellent conductivity, second only to silver. Therefore, copper is particularly suitable for forming electrical and mechanical connection components such as combination terminals. Copper metal parts and copper wires have almost the same coefficient of thermal expansion, avoiding varying degrees of thermal expansion in the event of significant temperature fluctuations, thus avoiding mechanical stress in the terminals and resulting connection loosening. The materials for screws and clamping parts are generally copper alloy or steel with surface electroplated rust resistant materials. The key is to have anti-corrosion performance and sufficient mechanical strength. In principle, steel without surface electroplated rust resistant materials should not be directly used, which can avoid the battery effect of steel metal parts and copper wires in wet conditions, and avoid unreliable electrical connections caused by electrical corrosion and the occurrence of screw rust. Usually, the surface of steel components needs to be treated with nickel plating, which can have a certain anti-corrosion effect.
Shell material
There are high requirements for the quality and performance of the combined terminal insulation shell, just like for its metal components. The vast majority of insulation shells are made of plastic such as PA66, PC, PP, etc. Regardless of the type of material, the shell must meet the corresponding requirements of flame retardancy, heat resistance, environmental protection, insulation, and mechanical strength.
A common material is PA66, which has a compressive strength of up to 600 kV/cm and can work continuously at a temperature of 100 ℃. It can withstand 200 ℃ for a short time and has a melting point of 250 ℃. It can still maintain elasticity at a low temperature of -40 ℃. PA66 generally does not breed various organisms and can effectively resist the erosion of microorganisms, bacteria, molds, enzymes, and ants. Gasoline, oils, lipids, aliphatic and aromatic compounds, chlorinated compounds, esters, ketones, and alcohol do not corrode these materials. Carbonate PC is also a common material, and polycarbonate combines multiple advantages, such as high hardness, good impact toughness, transparency, dimensional stability, good insulation performance, and good thermal stability. This non crystalline material only absorbs an extremely small amount of water and is therefore used to manufacture larger, stable shaped electronic component shells. Transparent polycarbonate is particularly suitable as a cover or marking material.
