1. Poor contact
The metal conductor inside the terminal is the core part of the terminal, which transfers the voltage, current or signal from the external wire or cable to the corresponding contact with its matching connector. Therefore, the contact parts must have excellent structure, stable and reliable contact retention force and good electrical conductivity. Due to the unreasonable structural design of the contact parts, the wrong selection of materials, the instability of the mold, the abnormal processing size, the rough surface, the unreasonable surface treatment process such as heat treatment and electroplating, the improper assembly, the poor storage and use environment and the improper operation and use will cause poor contact in the contact parts and the matching parts.
2. Poor insulation
The function of the insulator is to keep the contacts in the correct position, and to insulate each other between the contacts and the contacts, and between the contacts and the shell. Therefore, the insulation parts must have excellent electrical properties, mechanical properties and process forming properties. Especially with the widespread use of high-density, miniaturized terminal blocks, the effective wall thickness of insulators is getting thinner and thinner. This puts more stringent requirements on insulation materials, injection mold accuracy and molding processes. Due to the existence of metal residues on the surface or inside the insulator, surface dust, flux and other pollution by moisture, organic material precipitates and harmful gas adsorption film and surface water film fusion to form ionic conductive channels, moisture absorption, mildew, insulation material aging and other reasons, will cause short circuit, leakage, breakdown, low insulation resistance poor insulation phenomenon.
3. Improper fixation
Insulators not only act as insulation, but also usually provide precise neutralization protection for extended contacts, but also have the function of installation positioning, locking and fixing to the equipment. Poor fixation, light impact contact reliable cause instant power failure, serious is the disintegration of the product. Disintegration refers to the abnormal separation between the plug and socket and between the pin and the jack caused by the unreliable structure of the terminal in the plugging state due to the material, design, process and other reasons, which will cause the serious consequences of the interruption of the power transmission and signal control of the control system. Due to unreliable design, wrong material selection, improper selection of forming process, poor process quality of heat treatment, mold, assembly, welding, assembly is not in place, etc., will cause poor fixing.
In addition, due to coating peeling, corrosion, bruises, plastic shell flaring, cracking, rough processing of contact parts, deformation and other reasons caused by poor appearance, due to positioning lock size is poor, poor processing quality consistency, total separation force is too large and other reasons caused by poor interchange, is also a common disease. These faults can generally be found and eliminated in time during inspection and use.
