A study of the effect of thickness variation on shear heating for CAE analysis of injection molded thin plate

  Recently, several defects in injection molded products have been accompanied because being lighter and smaller than before. In the case of thin plate injection molding, high speed is required due to rapid formation of frozen layer. This processing condition generates high shear rate which develops a steep gradient in velocity. A Heat source so called shear heating is generated by high shear rate and viscosity of the polymer. In this paper, the effect of thickness variation on shear heating in cavity were investigated using injection molding simulation program Moldflow^TM. The results were shown that internal velocity and shear rate magnitude were reduced by thickness thickening in the same injection molding process condition. Also, thin products exhibited higher internal temperature distribution than thick products. During the injection molding of light guide plate(LGP) with thin thickness, difference of replication ratio of micro-pattern caused by this effect of shear heating was observedand verified withexperiments.