Geometrical accuracy and optical performance of injection moulded and injection-compression moulded plastic parts

The manufacturing of optical components by injection moulding and injection-compression moulding is a serious challenge for tool and machine technology as well as for process control. To evaluate the quality of optical parts the accuracy of the moulded geometry as well as the resulting optical performance has been analysed. At present a geometrical moulding accuracy in the lower micron range has been achieved for the production of thick-walled lenses. Overall injection-compression moulded lenses showed a better optical performance than injection moulded lenses. To further improve the resulting geometrical quality, local material shrinkage can be compensated by precisely modifying the cavity contour.