Testing of Plastic Moldings.

The testing of finished components can be of assistance to the design engineer in two areas: determination of deformations and stress/strain factors of complex moldings under extreme load; evaluation of the functional and practical performance of moldings. Permissible deformations and stress/strain factors are the basis for assessing moldings. In the case of plastics, they must often be determined with higher accuracy than for metallic materials. Plastics show comparatively low elasticity moduli and permissible stresses; therefore, they are more readily stressed to the limit. As analysis often does not permit the necessary accuracy, measurements must be made on models of prototypes which can even be made from model materials by low-cost methods. Often the evaluation of the functional and practical performance on the basis of calculated or experimentally determined stress/strain data is not possible with the required reliability, because the material properties depend on parameters of load and structure in a way difficult to express numerically. Here the testing of finished moldings can be of assistance where it is possible to prepare prototypes from the selected material by the method envisaged for commercial production.