Studies On Precision Injection Molding Technology Of Imaging Optical Plastic Lens

With the rapid application and development of plastic lens in imaging optical system,the optical industry has a more and more pressing need on the manufacture of imaging plastic lens.Precision injection molding technology,as the main production technology of imaging optical plastic lens,has been paid more and more attention by the industry because of its high precision,high benefits and high efficiency.At present,there are still some disadvantages in studies on precision injection molding technology of imaging plastic lens.For example,the parameter of injection molding process parameters could only be determined by simple experiments,resulting in the fact that the plastic lens could not meet the form accuracy requirements of imaging optics;the form accuracy requirements of imaging optics for large aperture plastic lens with severe shrink could not be met by only adjusting the injection molding process parameters.This article mainly studied the affecting factors of the form accuracy of imaging optical plastic lens,put forward a compensation method for the form accuracy errors of plastic lens and formulate a precision injection molding process scheme for imaging optical plastic lens with different aperture.First,the principle and process engineering of precision injection molding were studied thoroughly,and the influence of each injection molding process parameter on the molding process in different stages was analyzed,which could provide theoretical basis for the subsequent optimization experiments of process parameters.Second,the plastic materials,the injection molds and the experimental devices were selected reasonably.PMMA was adopted as the plastic material of injection molding.The flow channel system,the cavity numbers and the drive-out system of mold design scheme and the experimental scheme of the combination of simulation experiment and the actual injection molding were formulated,which could provide guiding scheme for the optimization experiment of process parameters.Third,based on Taguchi-RSM method,the method of hierarchy optimization was adopted to determine the optimal processing parameters.In the first stage,the initial optimized process parameters and the process parameters which could affect significantly the form accuracy of plastic lens were determined based on Taguchi method.In the second stage,regression model was established for the process parameters which could affect significantly the form accuracy of plastic lens based on response surface method to determine the optimal processing parameters.Finally,to order to further improve the form accuracy of plastic lens,the deformation degree of the mold core in the injection molding process was studied at first,and the method to reduce the deformation of mold core in heat treatment was put forward.After the injection molding,the form error of heat-treated mold core increased 0.3502?m,and the form error of the unheat-treated mold core increased 1.5702?m,it could be seen that the deformation of heat-treated mold core decreased significantly.Second,the error compensation model for the material shrinkage error and the machining error of mold core was established,which was verified with compensation equation.The form accuracy of compensated plastic lens was 1.0127?m(P-V).Compared with the plastic lens which was uncompensated,the form accuracy increased 1.0966?m,which met the form accuracy requirements of imaging optics.