2010 Volume 18 Issue 3 Pages 67-74
Some switches and other automotive parts are made by welding together two separately molded parts. To reduce lead time and work-in-process, a method of welding the two parts together in the die was developed. In the development of this new method, plastic-to-plastic adhesion was evaluated with the objective of optimizing the molding conditions so as to obtain stronger adhesion. With reference to metal-to-metal adhesion evaluation methods, an attempt was made to evaluate plastic-to-plastic adhesion by a standardized S/N analysis of the force-stroke characteristic of the welded parts, but reproducible gain was not obtained even after repeated analysis of waveform data using several different patterns. A second attempt was then made, using a Cartesian product of an orthogonal array to which the molding conditions were allocated and an orthogonal array to which the data extraction conditions were allocated. As a result, a data extraction method with high objectivity and reproducibility was obtained,enabling an optimal method of evaluating the adhesion of the plastic parts to be found.
