The enameled wire manufacturer tells you the detection of the flexibility of the enameled wire

Everyone must be familiar with enameled wire. It is very common in electrical appliances, motor instruments and telecommunications industries. Because it is used in these industries, the performance of enameled wire should meet the design requirements, processing requirements and operation requirements of electrical products, and require The unit using the enameled wire requires that the quality of the enameled wire can be guaranteed by a serious system and scientific means. If the wire is not sufficiently tough and the elongation is too small, the thin wire may be broken during winding, and the toughness is excessive. If the ratio is too large, it is easy to thin the section and cause the resistance to increase.

Today we will verify its flexibility test. Flexibility and adhesion tests include 1. Winding, 2. Tensile, 3. Sudden breaking, 4. Peeling and twisting tests. The enameled wire is subjected to two external forces when winding the coil: 1. Tensile force, if the elasticity of the paint film is insufficient, the elongation of the paint film after being stressed cannot keep up with the elongation of the conductor, and the paint film will crack. 2. Bending force, if the paint film on the outer edge is stretched after it is bent, the paint film on the inner edge is compressed, and if the elasticity is not good, the paint film will also crack. In addition, it is necessary to pay attention to the difference in materials. Thin wires are easy to be stretched and tested by the elongation method. Thick wires are greatly affected by bending and tested by the winding method.

The elongation of the paint film increases with the decrease of the winding diameter. Factors affecting the elasticity of the paint film, the flexibility of the paint film. The shape of a polymer chain is constantly moving, and there are many cases of curling during the movement. When curling, the polymer can expand and contract within a certain range under external force. The stronger the curl, the greater the stretching range, the higher the flexibility, and the better the elasticity. The elongation of the paint film itself is very small, and it has adhesion when it is applied to the wire, which is caused by the mutual diffusion of molecules between the paint and the metal. Wire enamel is a polar polymer, which has good compatibility with conductors, is conducive to molecular diffusion, and has good adhesion. If the wire surface is contaminated with non-polar substances or dirt, it will reduce the adhesion of the paint film.

The flexibility of the polymer chain is related to its main chain composition. Two single-chain combinations of carbon atoms can rotate freely around their central axis. Increasing the degree of cross-linking of the polymer can increase the rigidity of the polymer, but reduce the flexibility. When the molecular chains are cross-linked, they become a whole and restrain the movement of the molecular segments between the cross-linking points. The crosslinking of the material loses its flexibility and increases its brittleness. For a certain paint, the change of the elasticity of the paint film is mainly due to the crosslinking of the lacquer resin. If the enameled wire is not baked enough, the lacquer resin has not reached a certain degree of crosslinking and has not formed a proper body structure. At this time The elasticity and adhesion of the paint film are poor. If the baking is excessive and the cross-linking is too high, the elasticity will also decrease. Here, the particles on the surface of the paint film will cause stress concentration during winding, which will also affect the elasticity of the paint film.