The metal conductor inside the terminal block is the core part of the terminal, which transmits the voltage, current or signal from the external wire or cable to the contact part corresponding to the connector it matches. Therefore, the contact must have excellent structure, stable and reliable contact retention and good conductive properties. Due to unreasonable contact structure design, material selection error, mold instability, processing size is poor, surface roughness, heat treatment electroplating, such as surface treatment process unreasonable, improper assembly, storage and use of poor environment and improper operation, will be in contact with the parts and the contact site caused by poor contact. The plastic insulating materials and conductive components of the terminals are directly related to the quality of the terminals, which determine the insulation and conductive properties of the terminals respectively. Failure of any one terminal will result in the failure of the whole system engineering.
The bitter lessons that have taken place at home and abroad are profound. The function of the terminal insulator is to keep the contact part in the correct position, and to insulate the contact and the contact between the contact and the shell. Therefore, the insulating parts must have excellent electrical properties, mechanical properties and process molding properties. Especially with the high density and the wide use of the small terminal terminals, the effective wall thickness of the insulator is becoming thinner. Terminal blocks this has made more stringent requirements for insulating materials, injection mold precision and molding process.
Because there is metal excess on the surface or inside of the insulator, surface dust, flux, such as pollution, moisture, organic materials and harmful gas adsorption membrane and surface water membrane fusion to form ionic conductive channel, tide, long mold, insulation materials aging, etc., will cause short-circuit, leakage, breakdown, insulation resistance, such as low insulation phenomenon. Terminal insulator not only plays an insulating role, but also usually provides accurate alignment and protection for the protruding contact parts, and also has the function of installing and locating, locking and fastening on the equipment.
Fixed bad, light influence contact reliable cause instantaneous power loss, serious is the product disintegration. Disintegration refers to the terminal block in the plug state, due to materials, design, technology and other causes of the structure is not reliable caused by the plug and socket between the pin and the hole between the normal separation, will cause the control system power transmission and signal control interruption of serious consequences. Because the design is not reliable, wiring terminal material error, improper molding process selection, heat treatment, mold, assembly, welding and other process quality is poor, assembly is not in place will cause fixed bad. In addition, due to the coating of the skin, corrosion, touch, plastic shell flying edge, rupture, contact pieces of rough processing, terminal deformation and other reasons caused by poor appearance, due to positioning lock matching size of the poor, poor consistency in processing quality, total separation is too large and other causes of the exchange of bad, but also common, frequently-occurring. These kinds of failures can be found in the inspection and use of the process in time to remove.