Investigation of micro-injection moulding: Factors affecting the replication quality

Micro-injection moulding is one of the key technologies for micro-manufacture because of its mass-production capability and relatively low component cost. The surface quality in replicating micro-features is one of the most important process characteristics and constitutes a manufacturing constraint in applying injection moulding in a range of micro-engineering applications. This research investigates the effects of three processing and one geometric factor on the surface quality of micro-features in three different polymer materials. In particular, the following factors are considered: barrel temperature, mould temperature, injection speed and distance between micro-features. In this investigation, the mould temperature was set in the conventional range. The study revealed that in general, increasing the barrel temperature, mould temperature and the injection speed improves the polymer melt fill in micro-cavities. However, the effects of these factors on the process replication capabilities are not consistent for different polymer materials, and could be adverse in specific conditions. Varying the distance between micro-features does not affect the melt fills.