The company has now industrialized a low-temperature soldering process that employs a BiSnAg solder with a melting point of 138°C.
In the HARTING Mitronics division, this extends the plastics portfolio for AVT processes on laser direct structured (LPKF LDS) three-dimensional molded interconnect devices (3D-MID). Whereas, previously, only plastics with a very high heat deflection temperature could be used in conjunction with standard electronic solder, the new process enables the use of plastics with a low melting point, such as PBT (polybutylene terephthalate). The expansion of the process combinations also offers even better utilization of the potential of 3D-MID technology with regard to the more efficient use of space, integration and miniaturization. This means that HARTING 3D-MID solutions can be adapted with even greater accuracy to individual customer requirements.
The low melting solder joints have proven robust in environmental/mechanical endurance tests and, in shear tests, demonstrate retention forces comparable with those of conventional SnAgCu solders. The solder melts cleanly on the metal tracks and forms a cavity-free solder cone. In the AVT process, the solder can be applied according to an automated dispensing method.
Fielding its new colored PBT plastics for the LDS process for the manufacture of 3D-MIDs, HARTING is now also creating attractive components for visible use. PBT plastics have proven reliable base materials and are now available in many colors. Colored plastics are not only suitable for use in casings or other visible components but also for color-coding development stages or production series. In laboratory tests, the substrates have shown that they can be structured to optimum effect. In environmental/mechanical endurance tests, the metallization has delivered stable results on a level comparable with that of well-known production materials. In adhesion tests, this level has even been exceeded.