Efficient enamelled-copper wire soldering

Due to tightening thermal requirements, enamelled-copper wires are continually being developed to guarantee optimum thermal resistance by means of improved insulation. Moreover, developments in wire technology minimize the structural shape and reduce costs

According to EUTECT, the  challenge is that soft soldering is used for the soldering process, which can be processed up to temperatures exceeding 450 °C without leaving oxide residue on the product or drastically influencing the soldering systems' service lives. The operator can use protective gases to prevent oxide formation.

Overall, the soldering system has to be adapted to the special requirements imposed by enamelled-copper wire soldering. Module components such as solder nozzles, pumps, and solder tanks are especially stressed in high-temperature applications exceeding 450 °C.

Tinning or contacting through soldering the most diverse materials that are used to insulate copper wires without prior stripping poses a special challenge. Besides polyurethanes, polyurethane plus butyral, polyesterimide, polyesterimide plus polyamide, esterimide, triple insulated Tex-E wires in modified polyester construction, and many more are used. Natural silk, nylon, or ketron are generally used as a sheathing material for flex based on enamelled wire. Without additional mechanical stripping, the machine investment is reduced on the one hand and on the other the processing time is reduced by a factor of 2 to 4, depending on wire thickness.

The most varied tasks are conducted during the actual soldering process. The insulating enamel is removed by dipping into the flowing solder wave. The solder wave also ensures that oxides, greases, and other impurities are removed at the positions to be soldered. At a temperature exceeding 450 °C, the solder wave constantly promotes oxide-free solder, whereby the process site is permanently washed, cleaned, and ultimately tinned or soldered. Since heat is transfer quickly, adjacent plastics and casting compounds may only be subjected to a light thermal load. This ensures that connections and pins remain in their intended positions. This process step must be done reproducibly. That's why EUTECT often deploys special grippers or masking techniques that are said to guarantee high, uniform quality standards.