Glass Fiber/Polyphthalamide Composites for 3D-Molded Interconnect Devices Application: Structure and Properties

The research work was to demonstrate the feasibility of a three-dimensional molded interconnect devices concept using the injection-molding technique and to investigate the effects of weld/meld line types on the structure and properties. Two different polymers based on polyphthalamide/glass fiber composites (PA6 T/X and PA10 T/X composites) were produced by injection molding at the different processing conditions. A mold was designed in such a way that a weld and meld line can be produced at different angles by changing an insert inside the mold. The mechanical properties such as stiffness, tensile strength, and flexural strength were determined in tensile and flexural tests, respectively. The adhesive strength and electrical resistance were studied with the pull-off process and four-point measurement, respectively, and are discussed. The dispersion of the glass fiber and types of meld/weld line were inspected using scanning electron microscopy. The results were in-line with the expectation of a reduction in mechanical properties in areas where weld/meld lines occurred. The results of tensile tests clearly showed that the weld and meld lines showed a considerable influence on mechanical properties. It was found that the tensile and flexural strength of polyphthalamide/glass fiber composites with weld line type decreased approximately 58 and 62%, respectively, compared to the composites without the weld line. On the other hand, the effects of injection time and mold temperature on the tensile strength were marginal.