Papers by Keyword: Plastic Lens

Abstract: The processing conditions during the manufacturing have critical effects on the optical performances of the molded lenses including the refractive index, isochromatic fringe order, and the fringed pattern. The objective of this work is to investigate numerically some effects of the molding conditions on the residual stresses of injection molded lenses, and then to optimal the processing parameters for reducing the residual stresses using the Taguchi method. The results show the optimal method is able to improve the residual stress and to produce a good fringed pattern.

Abstract: This research aims to demonstrate Six Sigma methodology to reduce defective rate. A case of glass-mold defective reduction in plastic lenses manufacturing was studied. After applying systematic DMAIC steps and statistical tools suggested by Six Sigma approach, it was observed that the defective rate due to scratched molds was decreased from 2,512 ppm to 826 ppm, and the sigma level was improved from 4.31 to 4.65. In addition, the improvement could save the production cost up to 75,000 USD annually.

Abstract: In this paper, some molding process parameters such as injection time, packing time, packing pressure and process temperature etc. were optimized by the Computer Aided Engineering (CAE) simulation (Moldex 3D) for injection molding of a plastic lens. Some experimental trials were carried out for verifying of the CAE simulation results with checking of the lens shrinkage and birefringence etc. as well. The results showed that, the recommended molding process parameters from CAE simulation and the actual experiments were almost the same, hence the CAE is a established tool based on the scientific approach to reduce experimental works, to identify critical parameters and to save substantial costs. Lately, a perfect plastic lens was gained by the Injection–Compression Molding process with the optimized process parameters by a CAE simulation.