Effect of process parameters on dimensional accuracy of fiber-reinforced thin-walled micro moulded part

Micro injection moulding is one of the most established processes for precise manufacturing of 3D complex micro components; however, the achieved precision varies greatly with respect to the process parameters. Production of micro connectors is one of the applications where high precision is demanded due to the complexity of features and strict tolerances. In addition, the use of fiber-reinforced polymers affects the desired accuracy, which is attributed mainly to the orientation of fibers in the final part. In this work, the effect of the processing parameters on shrinkage, fiber orientation and dimensional accuracy of glass fibre-reinforced micro injection moulded parts was studied with reference to a simplified geometry. The results indicated that micro injection moulding parameters affect the dimensional accuracy of the moulded parts, by changing the skin-core morphology within their thickness. Moreover, the fiber orientation analysis of the parts showed that the reduced thickness of mould cavity lead to the disappearance of the core layer, in favour of the predominant skin layers.