Abstract
Abstract Flow marks in injection moulding is quite often encountered on different type of polymers. This defects is known as successive and periodic bright and dull bands oriented perpendicular to the flow direction. Their appearances meanly depend on processing and observation conditions. This study was lead on two industrial polypropylene polymers with a simplified polished rectangular mould geometry. We show that this defect appears during the filling stage and comes from a local change of morphological and molecular orientation along the filling direction on the surface. An instability of the flow front due to a limited sliding at the contact combined to the strong changed of molecular orientation before and after the stagnation point are invoked to explain this instability.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
