Views: 150 Author: Site Editor Publish Time: 2021-02-06 Origin: Site
As a common product of connectors, wiring terminals appear more and more frequently in industrial production and life, and the safety of the terminals will follow. Common problems of terminal blocks include three major problems: poor insulation, poor fixing, and poor contact. In order to ensure the quality and reliability of the terminal blocks and prevent the occurrence of the above-mentioned fatal failures, SUN strongly recommends that users study and formulate corresponding requirements in accordance with the technical conditions of the products, and carry out the following targeted reliability tests to prevent failures. In this article, we will introduce 3 inspection methods to prevent terminal block failure.
At present, the general terminal blocks manufacturers' product acceptance test does not have this item, and users generally need to conduct continuity testing after installation. Therefore, it is recommended that buyers conduct conduction testing on some key models of products.
Some terminal blocks are used in the dynamic vibration environment. The experiment proves that only the static contact resistance is qualified, but it cannot guarantee reliable contact in the dynamic environment. Since the connector with qualified contact resistance is still undergoing instantaneous power failure when undergoing vibration, impact, and other simulated environmental tests, it is best to conduct dynamic vibration tests on the contact reliability of some terminals with high-reliability requirements assessment.
The single-hole separation force refers to the separation force of the contact member in the inserted state from being stationary to moving, which is used to characterize the contact between the pin and the socket. Experiments show that if the separation force of a single hole is too small, the signal may be interrupted when subjected to vibration or shock load. The method of measuring the separation force of a single hole is more effective than measuring the contact resistance. It is found that jacks with a particularly poor single-hole separation force are often still qualified when measuring contact resistance. Therefore, this requires manufacturers not only to develop a new generation of flexible mating, stable and reliable contacts but also not to use automatic insertion force testing machines for multi-point simultaneous testing of key models. The finished product should be 100% point-by-point single-hole separation force inspection to prevent instantaneous interruption of signals due to the loosening of individual jacks.
The quality of raw materials has a great influence on the performance of the body. Therefore, for raw materials, the choice of manufacturers is extremely important, not to blindly reduce costs and lose material quality. You should choose materials from a reputable manufacturer, and carefully check the batch number, material, and other important information for each batch of materials, and do a good job of traceability information for the use of materials.
At present, some manufacturing plants require that the electrical performance be tested after assembly into a finished product. As a result, the entire batch of finished products was scrapped due to the different resistances of the connectors themselves. The correct process should be 100% process screening in the state of the parts to ensure that the electrical performance is qualified.
The interchangeability check is a dynamic check. It requires that the plugs and sockets of the same series can be mated and connected to each other. From this, we can find out whether there is a phenomenon that cannot be inserted, positioned and locked, or even disintegrated under the action of rotating force due to the poor size of the edge body, contact parts and other parts, missing parts, or improper assembly. Another function of the interchangeability check is to detect in time whether there is any metal excess that affects the performance through the thread, bayonet and other plug connections. Therefore, 100% of the wiring terminals for some important purposes should be checked for this item to avoid such major fatal failure accidents.
Torque inspection is a very effective inspection method to assess the reliability of the terminal structure. For example, the US military standard MIL-L-39012 standard stipulates that according to the standard, samples should be sampled for each batch for torque resistance inspection.
In the electrical installation, it is often found that individual crimped wires cannot be delivered in place, or cannot be locked after delivery, and the contact is unreliable. The analysis reason is that there are burrs or dirt stuck at the screw teeth of the mounting holes. Especially when using the last few mounting holes that the factory has installed on a plug seat, if the defect is found, the crimping wires of the other holes that have been installed have to be removed one by one, and the plug seat is replaced. In addition, due to the improper selection of the wire diameter and the crimping aperture, or the incorrect operation of the crimping process, it will also cause the crimping end to be weak. For this reason, the manufacturer must conduct a thorough test on all the mounting holes of the delivered plug (seat) sample before the finished product leaves the factory. That is, the wire with crimped pins or sockets can be sent to the place by an assembling and dismounting tool to check whether it can be locked. According to the product technical conditions, check the pull-off force of each crimped wire.
The connection of the terminal is related to the safety of the entire control circuit and signal flow. The best way to ensure the correct operation of the system engineering is to ensure the performance of the terminal block above the relevant standards. Through the reliability screening of terminal blocks, various failure modes and failure mechanisms are discovered, which can lead to a lot of experience and lessons and eliminate various hidden dangers. To provide a scientific basis for improving design, process, inspection and use, it is also an important basis for revising and formulating the technical conditions of the terminal. Finding measures to prevent failures and realizing the transformation from failure to reliability is the ultimate goal of failure analysis of terminal blocks. SUN is China terminal blocks manufacturers, providing professional terminal block information. Contact us to know more information!