From the use point of view, the function of the terminal should be: the conductive part of the contact part must be conductive and reliable. The place where the insulation part should not be connected must be reliably insulated. There are three types of common fatal faults of Terminal Blocks:
1. Poor contact The metal conductor inside the terminal is the core part of the terminal, which transmits the voltage, current or signal from the external wire or cable to the contact corresponding to its matching connector. Therefore, the contact must have excellent structure, stable and reliable contact retention and good conductivity. Due to the unreasonable structure design of the contact, wrong material selection, unstable mold, out of tolerance machining size, rough surface, unreasonable surface treatment processes such as heat treatment and electroplating, improper assembly, poor storage and use environment, and improper operation and use, poor contact will be caused at the contact and mating parts of the contact. 2. Poor insulation The function of the insulator is to keep the contacts in the correct position, and to insulate the contacts and the shell from each other. Therefore, insulating parts must have excellent electrical performance, mechanical performance and process shaping performance. Especially with the widespread use of high-density and miniaturized terminal blocks, the effective wall thickness of the insulator is getting thinner and thinner. This puts forward stricter requirements for insulation materials, injection mold precision and molding process. Due to the existence of metal residues on the surface or inside of the insulator, contamination and moisture of surface dust, welding flux, etc., the fusion of organic material precipitates and harmful gas adsorption film with the surface water film to form ionic conductive channels, moisture absorption, mold growth, aging of insulation materials and other reasons, short circuit, electric leakage, breakdown, low insulation resistance and other adverse insulation phenomena will be caused. 3. Poor fixation The insulator not only plays an insulating role, but also usually provides precise neutralization protection for extended contacts, and also has the function of installation, positioning, locking and fixing on the equipment. Poor fixation may cause instant power failure due to slight impact on contact reliability, or even product disassembly. Disassembly refers to the abnormal separation between plugs and sockets and between pins and sockets caused by unreliable structure due to material, design, process and other reasons when the wiring terminals are plugged in, which will cause serious consequences of interruption of power transmission and signal control of the control system. Due to unreliable design, wrong material selection, improper selection of molding process, poor quality of heat treatment, mold, assembly, welding and other processes, and improper assembly, poor fixation will be caused. In addition, poor appearance due to coating peeling, corrosion, bumping, plastic shell flash, cracking, rough contact processing, deformation and other reasons, poor interchangeability due to over tolerance of positioning locking fit size, poor consistency of processing quality, excessive total separation force and other reasons are also common and frequently encountered. These faults can generally be found and eliminated in time during inspection and use.
