An experimental investigation of surface roughness effects on melt flow in micro-injection molding

Abstract

The purpose of this report is to facilitate the research of surface roughness effect in micro injection molding by studying the flow pattern of parts produced from a dual surface roughness mold insert. Injection molding process is a common process widely used in the industries in producing products. As surface roughness is one of the factor of influencing flow due to frictional factors, it is important to understand how it affects the flow of polymer melt in injection molding, especially micro injection molding, where the thickness of the cavity is of similar scale to the surface roughness value. Thus the injection molding process can be optimized to obtain optimum results. To carry out the project, firstly a rectangular insert with two surface roughnesses is first fabricated using EDM. The insert is to be fabricated to a distance of approximately zero between the two mean planes of the different roughness surfaces. This is to ensure a fair experimental process and results obtained will be accurate. Next injection molding process will be carried out to produce incomplete molding parts with micro thickness for the studying of flow pattern to be made. During this stage, injection molding parameters will be manipulated to aid in the study of the melt flow. A design of experiment will then be conducted to study on the flow of the polymer melt and how each factor affects the flow. Molding parameters include melt temperature, mold temperature, injection pressure and cavity thickness. Finally observations and conclusion will be made to study how surface roughness affects the plastic melt flow in the mold cavity.