Interface terminal development history and material selection

In 1928, Phoenix Contact invented the world's first modular terminal block. This is the prototype of modern terminals, and it is also the first invention patent that Phoenix Contact applied for and obtained. Since then, Phoenix Contact has been passionate about innovation, committed to the development of various connection technologies, and formed a complete electrical interface technology system, many of which have become industry application standards.

The choice of materials directly affects the performance of the entire product and is the key to the design. Take plastic materials as an example: if the design is based on UL94 and V-0 flame retardant, it is necessary to carefully review whether the technical parameters of each material property table can be used. To meet product standards, such as whether the impulse withstand voltage and aging resistance tests can be passed, in terms of hardware materials, the choice of sheeting materials, which is mainly TP, is especially important, because the sheeting must not only meet a certain electrical conductivity (current), but also have a certain The elasticity of the metal has brought difficulties to our engineers in the selection of materials. This is precisely the trend that connector manufacturers are pursuing in elastic components. Many manufacturers of hardware materials are working hard in this regard, and the conductivity directly affects When it comes to temperature rise and contact resistance, the quality of elasticity is related to the chemical elements, elastic modulus, hardness, and tensile strength of the material. The elastic modulus is calculated by the fourth strength theory formula of material mechanics. The greater the electrical conductivity of the material, the lower the contact resistance, the lower the temperature rise. The plug-in force and the contact resistance have a quadratic relationship. The contact resistance is mainly divided into: compression resistance, film resistance, and volume resistance (the resistance of the conductor itself) . Among them, the film resistance accounts for 70-80% of the total resistance, which is also the main factor affecting the life of the connector. Full attention should be paid to the terminal gold plating and silver plating. Although the conductivity of silver is higher than that of gold, its chemical Stability is not as good as gold, and the film resistance caused by it is much greater than gold plating. Therefore, understanding the relationship between the above is of guiding significance for our choice of materials and is a prerequisite for product design.