An Investigation of Form Errors Predicted Model for Injection Moulded Aspheric VCD Lens

The aspheric VCD lens is hard to fabricate by injection moulding due to its small volume and high precision requirement. The processing conditions have critical effects on the quality of the moulded lenses. An optic lens needs precisely controlled surface contours, so determination of the processing conditions for lens moulding becomes very complicated. This study’s purpose is to investigate experimentally some effects of the moulding conditions on the form errors of injection moulded lens. An aspheric VCD lens was moulded using polymethyl methacrylate. Different combinations of moulding conditions were used focusing on moulding process parameters of the ram speed, the mould temperature, the melt temperature and the packing pressure, The predicted model of form errors was formulated by orthogonal and regression analysis. Finally, the predicted model is proven to be valid based on the residual diagnostic plots.