Plasticating Process in an Injection Molding Machine

Abstract

A theoretical analysis is presented of a heat conduction problem in which a solid plate is melted by both external heating and frictional heat in the polymer melt, which is a physical model substituted for the plasticating process of solid polymer in a screwless injection molding machine.
A few examples of numerical results for low-density polyethylene are shown concerning the temperature distributions within the melted and solid polymer and about the relationship between dimensionless complete melting time and modified power-law Brinkman number. The latter is confirmed by observation of molten features of polymer extruded under various machine variables. Furthermore, it is shown that such data as the maximum value of pressure in stuffer chamber are also correlated by a theoretical maximum extrusion rate, which is defined by the correspondence between the real machine and the physical model for complete melting.