Study On Mixing Performance And Optimization Of Injection Molding Machine For LED Light Distribution

LED light distribution device is a kind of product with high requirement for injection molding equipment, and ordinary screw injection molding machine is generally difficult to produce high quality LED light distribution device. The improvement of the screw mixing performance of the injection molding machine can improve the quality of the LED light distribution device. The optimization of the injection molding machine mold closing mechanism can provide the guarantee for the production of high quality LED light distribution devices.Through the establishment of 3D model of chaotic elements and common screw element, using Polyflow software to simulate the distribution of flow field of two kinds of elements. It is found that chaotic unit can break the laminar flow state of the material in the ordinary screw, and chaotic mixing can be triggered. The distribution and dispersion mixing performance of chaotic units is stronger than that of ordinary screw unit. In simulating flow field of barrier unit and ordinary screw unit, it is found that the barrier have the has the ability to transfer the material in positive displacement, and the material in the flow field of barrier unit is strongly drawn, and the dispersion mixing performance of the material is stronger than that of the ordinary screw unit, and the mixing performance of the material is equal to that of the ordinary screw unit. Uniform size and build model of chaotic unit, barrier unit, vane unit. The flow field in three kinds of novel mixing units are simulated respectively, by comparison, the residence time expectation of the three novel mixing units are 4s, 5s and 6s respectively. The order of distribution mixing performance from strong to weak is vane unit, barrier unit and chaotic unit. In dispersion mixing performance vane unit is the most powerful, and chaotic unit and the barrier unit are the almost. But vane unit have high requirement for material of injection system, and barrier unit and chaotic unit have not the requirement. Take the barrier unit as a mixing unit for further study, and establish barrier assembly to compare mixing performance with composite assembly. It is found that stretching effect of the material is not even in the flow field of the composite assembly and near the entrance is relatively large. The stretching effect of material is more uniform in the flow field of the barrier assembly, and the residence time of particles in the flow field of the composite assembly is longer than that of the particles in the flow field of barrier assembly so that distribution mixing performance of composite assembly is better than that of barrier assembly. But the material in flow field of barrier assembly suffered shear and tensile effect is stronger than that of composite assembly so that dispersion mixing of the barrier assembly is better than that of composite assembly. Because the material is subjected to the shear action and the stretching action by a long time, transient mixing efficiency and time averaged mixing efficiency of the composite assembly to the material are relatively high.Based on the differential evolution algorithm, the influence factor is introduced into the optimization process, and the influence factor optimization differential evolution algorithm is obtained. The algorithm is applied to the optimization of mold clamping mechanism, and compare with result of traditional ideal point optimization method. It is found that stroke ratio and force amplification ratio of the clamping mechanism after optimized by influence factor optimization differential evolution algorithm are increased 10.73% and 21.42% respectively compared with the original parameters. The results after optimized by traditional ideal point optimization method are increased 9.93% and 20.91% respectively compared with the original parameters. The optimal result of the influence factor optimization differential evolution algorithm is better than that of the traditional ideal point optimization method.The mixing performance of chaotic elements was tested by experiment. By testing the mechanical property of the sample, it is found that when the screw speed is lower than 75r/min, the influence of residence time on mixing performance is higher than that of shear and tension. When the screw speed is higher than 75r/min, the influence of residence time on mixing performance is weakened, and the effect of shear and tension is increased;The periodic disturbance applied to the material caused by the periodic intermittent baffle made dispersed phase size of different channel is different. the dispersed phase size is rapidly decreased, and then is slowed down, and finally it is reduced to the lowest point.