Design Of Injection Compression Mould And The Injection Process For The Light Guide Plate

Light guide plate is one of main parts of back light module, As thedecreasing of the depth of the products due to the demand of people and thedownstream products, the application of injection molding for thin-wall lightguide plate is getting harder, and the defects of the products such as residualstress and warpage is getting more prominent, the dimensional accuracy,appearance and optical properties are seriously affected by the injectionmolding process parameters. Injection compression molding process waswidely used to solve the problems mentioned. For the sequential injectioncompression molding, injection compression mould was designed for the lightguide plate, and the injection process and injection compression process wasresearched through the warpage, residual stress, microstructures and opticalproperties of the products.The main content of the paper are as follows:(1) The EMX module of Pro/E was used in this paper to design theinjection compression mould of the light guide plate. The mould can alsorealize injection molding of the products. The minimum diameter of the microspheres structures which processed using mirror EDM is60μ m.(2) The software Moldflow6.1was used to simulate the one cavity lightguide plate with microstructures, Orthogonal Experiment method was used.The level of effects on residual stress of different process parameters is moldtemperature, packing time, packing pressure, melt temperature. And thesimulation results from the model without microstructures are almost thesame as the actual model.(3)The Orthogonal method and single factor analysis method were usedto simulate the injection molding and injection compression molding of themodel from the designed mould, for injection molding, the volume shrink rateand warpage were analyzed, for injection compression, the effects of differentprocess parameters on warpage was analyzed.(4) The one cavity mould was used to conduct the injection moldingexperiment, the filling state, warpage and optical properties was analyzed.Injection pressure was the main factor that affects the filling and warpage, andmelt temperature was the main factor that affects the optical properties.(5) The designed mould was used to conduct injection molding andinjection compression molding with orthogonal Experiment method. Throughthe contrast of the products got from the two molding methods, it was foundthat the residual stress of the products from injection compression molding issmaller than the injection molding, and the distribution of the residual stress isnear the compression print; The filling state of the microstructures of the injection compression molding has higher quality. And the experiment resultis almost the same as the simulation results for the warpage.