Abstract:
Production of plastic items using the injection molding process has become technologically
advanced with the advent of both newer technology and newer materials. Setting of
machine control parameters play a major role in the ultimate product quality and the
machine efficiency. Control of machine and mould parameters is complex task, because
behavior of the material inside the machine and the mold, is effected by a range of
contributing factors. This results in machine control becoming very difficult and one has
to overcome this problem either by trial and error procedures, which cost time and
material, or employ advanced microprocessor controlled programming methods and
advanced automated machines with very high capital costs. In Sri Lanka, injection molding machines with highly advanced features are not very
common. Conventional methods are used to determine the appropriate machine settings
such as clamping force, charging stroke, barrel and injection pressure. Adjustment of these
parameters to correct a fault in the product or to achieve maximum output rates, while
manufacturing product quality is done experimentally, often relying on operator
experience. This project was aimed at building up some simple mathematical models to
determine the optimum settings taking into consideration the basic rheological equations
and experimental data that are readily available in the literature. The correctness of these
models was checked for validity on a medium scale injection molding machine and very encouraging results have been obtained. The applicability of this method for further
investigation is critically assessed.
