Injection Molding Microfeatures

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

The objective of this research project is to develop a novel technology for successful micro injection molding with respect to lower cycle time and better replication as compared to the existing technology. This will be accomplished by rapidly heating the mold surface so that the melt can fill the cavity isothermally and yet be processed within the normal injection molding cycle time. Plastics have so far played only a subordinate role in the multibillion-dollar microsystem industry. A commercial breakthrough strongly depends on means of low cost mass fabrication with dimensional accuracy and good part quality. Widely used mass-production methods involving polymeric materials such as injection molding, however, require significant modification to adapt to micro molding applications. One of the hurdles limiting the current technical capability in micro injection molding is that the molten polymer in a tiny cavity instantaneously freezes upon contacting the relatively cold cavity wall. The problem gets worse when micro features with higher aspect ratio are to be molded. The three phase research plan includes an experimental component devoted to creating a flexible micro molding fixture, the second phase will be to conduct processing experiments with several thermoplastics, and the final phase will be the characterization of micro scale flow behaviors for this micro injection molding process. This research project will also yield much needed experimental data regarding the effect of microscale phenomena on the flow behavior of polymeric materials. It is expected that development of the integrated technology will push the current technical envelope of micro injection molding further into those areas that have so far been predominated by etching- and lithography- based fabrications. This can lead to 3-D microfabrication of structurally designed parts.