Injection Molding Defects
“Injection molding is a complex technology with possible production problems. They can be caused either by defects in the molds or more often by part processing (molding) Common defects include blisters, burn marks, color streaks, delamination, flash, embedded contaminates, flow marks, jetting, knit lines, polymer degradation, sink marks, short shot, splay marks, stringiness, voids, weld lines and warping.”
(Wikipedia, Injection Molding/Defects, 12/4/2010)
Injection Molding
Injection Molding Warping
Processing
Splaying
Recent Journal Articles
Determination of the transition temperature at different cooling rates and its influence on prediction of shrinkage and warpage in injection molding simulation
(1162–1168)Journal of Applied Polymer Science 123 #2 (2012)
Lucyshyn et al of the Montanuniversitaet Leoben and the PCCL Polymer Competence Center Leoben, Austria measured the transition temperatures of several amorphous and semicrystalline polymers using DSC-runs at different cooling rates. The transition temperature was described as a function of cooling rate. The obtained transition temperatures of the semicrystalline polymers were used in injection molding simulations with the commercial software package Autodesk Moldflow Insight 2010 to calculate the shrinkage and warpage of box-shaped test parts. The simulation results were compared with the experimental values of optically measured injection-molded boxes. The results showed a strong influence of the transition temperatures on the simulation results of a 3D model and a very low influence for a 2.5D model. Transition temperatures obtained at higher cooling rates improved the 3D simulation results for several dimensions. (RDC 10/12/2011)