Injection Molding Simulation And Process Parameters Optimization Of Resin Liner For Ⅳ Hydrogen Storage Vessel

Hydrogen storage,as an intermediate part of the hydrogen energy industry,plays a pivotal role.The resin-lined type Ⅳ hydrogen storage vessel has lower manufacturing cost,lighter weight and longer service life than the aluminum-lined type Ⅲ hydrogen storage vessel,so it has become the focus of energy vehicles and other fields.The resin liner of typeⅣ hydrogen storage vessel contains a metal bottle mouth,which is connected with the resin liner and the metal bottle mouth by injection molding.Due to the existence of metal bottle mouth,the structure of resin liner is complicated,and the forming problems such as short shot and warping deformation occur in the process of injection molding,which affect the forming quality of resin liner and then affect the service life of hydrogen storage vessel.Therefore,the molding process was simulated before injection molding,and the possible forming defects in the actual production process were shown from the simulation results.According to the problems,some process parameters that can be controlled and adjusted in the injection process are optimized,so that the resin liner can meet the molding quality requirements.In this paper,the resin liner of type Ⅳ hydrogen storage vessel(referred to as injection parts)Moldflow was used to simulate the injection molding process and optimize the molding process parameters by multi-objective process parameter optimization method.The research content is divided into the following aspects:(1)Firstly,the three-dimensional model of injection parts was imported into Moldflow,gate position analysis and setting of the model were carried out,and the pouring system was established,so as to conduct the initial injection molding simulation and obtain the simulation results in the initial state.(2)Then,taking the filling amount under the pressure of the speed/pressure switch of injection parts as the test index,the process parameters such as the temperature of the molten plastic entering the mold cavity,the pressure required for the molten plastic entering the mold cavity,the pressure required to supplement the molten plastic and the time required to supplement the molten plastic were selected as the test factors to design the orthogonal test.Taking warpage deformation,volume shrinkage and residual stress in the cavity in the first main direction as test indexes,the Taguchi orthogonal test was designed by adding six factors on the basis of the above four test factors,such as the cooling time of injection parts after the completion of replenishment and mold temperature.The results of two orthogonal experiments were analyzed by range and variance.(3)Finally,two multi-objective process parameter optimization methods were used to optimize the process parameters of temperature,pressure,time,etc.which could be controlled during the molding process,taking each test index of injection parts tended to optimize,that mean the highest comprehensive performance of injection parts as the test index.Under the two methods of optimization results of the test index is compared,the experiment in injection molding process parameters combination are obtained,and the injection molding experiment.After the injection molding,the profile tolerance of the injection molding was measured.The results showed that the profile tolerance of the injection molding was 0.4475 mm,which was similar to the warping deformation obtained in the simulation of 0.4978 mm.The results show that it is feasible to optimize the performance of injection parts by optimizing some process parameters in the injection process.