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Mobile WebSiteWire harness welding methods include diffusion welding, high frequency welding, cold pressure welding, and ultrasonic welding.
1. Diffusion welding
A welding method in which the weldments are closely attached and held at a certain temperature and pressure for a period of time to allow atoms between the contact faces to mutually diffuse to form a joint. The main factors affecting the diffusion welding process and joint quality are temperature pressure diffusion time and surface roughness. The higher the soldering temperature, the faster the atomic diffusion. The soldering temperature is generally 0.5 to 0.8 times the melting point of the material. Depending on the type of material and the quality of the joint, diffusion welding can be carried out under vacuum, shielding gas or solvent, with vacuum diffusion welding being the most widely used. In order to accelerate the welding process, reduce the requirements for the roughness of the welding surface or prevent the occurrence of harmful structures in the joint, an intermediate interlayer material of a specific composition is often added between the welding surfaces, and the thickness thereof is about 0.01 mm. The diffusion welding pressure is small, the workpiece does not produce macroscopic plastic deformation, and it is suitable for precision parts that are not processed after welding. Diffusion welding can be combined with other thermal processing processes to form a combined process, such as heat dissipation-diffusion welding, powder sintering-diffusion welding, and superplastic forming-diffusion welding. These combined processes not only greatly increase productivity, but also solve problems that cannot be solved by a single process. For example, the various titanium alloy components on supersonic aircraft are the same as the base metal by the diffusion bonding of superplastic forming-diffusion welding. It is especially suitable for welding non-metallic materials such as dissimilar metal materials, graphite and ceramics, and dispersion strengthening. Superalloys, metal matrix composites and porous sintered materials. Diffusion welding has been widely used in the manufacture of reactor fuel elements, honeycomb structural plates, electrostatic accelerating tubes, various blades, impellers, dies, filter tubes, and electronic components.
Diffusion welding is to contact the welding surfaces of the material to be welded at a certain temperature and pressure, and expand the physical contact of the surface to be welded by microscopic plastic deformation or by generating a trace liquid phase through the welding surface, so that the distance is extended (1~5) A soldering method in which metallurgical bonding is achieved within x10-8 cm (so that the attraction between atoms acts to form a metal bond), and then the atoms are mutually diffused for a long time and mutually infiltrated.
Obviously, for ordinary wire harness welding, the cost of using diffusion welding is too high.
2, high frequency welding
High-frequency welding is based on solid resistance heat. The resistance heat generated by the high-frequency current in the workpiece during welding causes the surface of the workpiece weld zone to be heated to a molten or close plastic state, and then the forging force is applied (or not applied) to achieve metal bonding. Therefore it is a solid phase resistance welding method. High-frequency welding can be classified into contact high-frequency welding and induction high-frequency welding according to the way in which high-frequency current generates heat in a workpiece. When in contact with high frequency welding, high frequency current is transmitted to the workpiece through mechanical contact with the workpiece. In induction high-frequency welding, high-frequency current generates an induced current in the workpiece through the coupling of the external induction coil of the workpiece. High-frequency welding is a specialized welding method that requires special equipment according to the product. High productivity and welding speed up to 30m/min. Mainly used for the welding of longitudinal seams or spiral seams when manufacturing pipes.
Obviously, for small wire harnesses, high frequency welding is not suitable.
3, cold pressure welding
When the pressure is deformed, the oxide film on the contact surface of the workpiece is broken and extruded, and the welded joint can be cleaned. The applied pressure is generally higher than the yield strength of the material to produce a deformation of 60 to 90%. The pressing method can be used to slowly squeeze, roll or add impact force, or it can be pressed several times to achieve the required amount of deformation.
Because cold welding does not need heating, no need for packing, the equipment is simple; the main process parameters of welding have been determined by the size of the mold, so it is easy to operate and automate, the welding quality is stable, the productivity is high, the cost is low; without the flux, the joint will not cause corrosion. When the temperature of the joint is not increased during welding, the crystal state of the material is unchanged, which is particularly suitable for the welding of some metal materials and products which cannot be realized by dissimilar metals and heat welding. Cold press welding has become one of the most important welding methods in the electrical industry, aluminum products and space welding.
The working surface of the cold welder and its mold may accumulate metal debris and must be removed periodically. If there is compressed air, the compressed air can be used to blow off the debris. If the debris is to be completely removed, remove the mold from the welder, disassemble the four modules of the mold, and carefully clean each module with a magnifying glass to ensure that all debris on the surface of the module is removed. Care must be taken when removing the mold, especially small springs are easily lost. If the surface of the mold is not clean, it will cause the wire to slip easily in the mold, so that the welding fails. Note that no grease is allowed on the working surface of the mold after repair.
Cold pressure welding requires simple equipment, simple process and good working conditions. However, the pressing force required for cold-welding is large, and the equipment is large when welding large-section workpieces. The surface of the workpiece after lap welding has deep craters, which limits its application range to some extent.
Therefore, cold press welding is not a perfect choice for wire harness welding.
