EFFECTS OF MATERIALS AND PROCESSING ON DMC INJECTION MOULDINGS.

This paper reports the use of various measurement techniques to determine the effects of material and processing variables on molded DMC articles. Ultrasonic scanning is used to reveal internal defects. Full elastic moduli can be obtained from ultrasonic velocity measurements, and show the anisotropy arising from alignment of glass fibers during flow. The flatness of an article can be checked using a shadow Moire imaging technique. Instrumented impact testing gives not only a measure of toughness, but also indicates the proportions of energy absorbed prior to major cracking and after this occurs. Filler distribution can be checked by optical microscopy or by X-ray microradiography, but a more practical means will probably be use of X-ray fluorescent analysis.