1. Poor contact

The metal conductor inside the terminal block is the core component of the terminal, which transmits voltage, current or signal from external wires or cables to the corresponding contact of the connector that matches it. Therefore, the contact piece must have excellent structure, stable and reliable contact retention force, and good conductivity. Due to the unreasonable design of the contact structure, incorrect material selection, unstable mold, processing size deviation, 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 can be caused at the contact and mating parts of the contact.

2. Poor insulation

The function of an insulator is to keep the contacts in the correct position and to insulate them from each other, as well as from the housing. Therefore, insulation components must have excellent electrical, mechanical, and process forming properties. Especially with the widespread use of high-density and miniaturized terminal blocks, the effective wall thickness of insulators is becoming thinner and thinner. This puts forward stricter requirements for insulation materials, injection mold accuracy, and molding processes. Due to the presence of metal residues, surface dust, solder flux, and other contaminants on or inside the insulator, as well as the fusion of organic material precipitates and harmful gas adsorption films with surface water films to form ionic conductive channels, moisture absorption, mold growth, insulation material aging, etc., all of these can cause insulation defects such as short circuits, leakage, breakdown, and low insulation resistance.

3. Poor fixation

Insulators not only serve as insulation, but also provide neutralization protection for protruding contacts. They also have the functions of installation positioning, locking and fixing on equipment. Poor fixation can cause momentary power outage due to poor contact reliability in mild cases, and product disassembly in severe cases. Disassembly refers to the abnormal separation between plugs and sockets, as well as between pins and sockets, caused by structural unreliability due to material, design, process, and other reasons when the wiring terminal is in the plugged in state. This will result in serious consequences such as interruption of power transmission and signal control in the control system. Due to unreliable design, incorrect material selection, improper selection of molding processes, poor quality of heat treatment, molds, assembly, welding and other processes, and inadequate assembly, poor fixation can be caused.

In addition, appearance defects caused by coating peeling, corrosion, collision damage, plastic shell flying edge, cracking, rough processing of contact parts, deformation, and other reasons, as well as poor interchangeability caused by positioning locking fit size deviation, poor processing quality consistency, and excessive total separation force, are also common and frequently occurring diseases. These types of faults can generally be detected and eliminated in a timely manner during inspection and use.