Abstract
In the strength test of polymer materials by the flexual test, evaluation was made using the SN ratio with load andspecimen thickness as the input signals. Traditionally, the quality of such materials kes been evaluated mast of the time by the strength at break. ln this study, SN ratios were odtained from the load/displacement, curves after defining the elastic and plastic deformation domiains. The optimum conditions were obtained from a molding experiment using molding conditions as control factors. lt was clarified that the results of verificaton experiments varied depending on how the SN ratio was obtained. Based on the abobe result, conclusion was made that it is quite adequate to use the SN ratios from the load/displacement curves which is proposed by quality engineering.
