Study On The Injection Molding Process Of Polyurethane Non-Pneumatic Tire

With the progress of science and technology,the tire industry is facing great challenges and opportunities.Traditional bias tire and radial tire have safety risks due to explosive tire and easy deformation,so it is necessary to carry out air pressure and breakage check frequently.The emergence of non-pneumatic tire(NPT)in this century has completely broken the traditional technology,so that the development of the tire industry into a new era.Among them,the manufacturing and molding technology of non-pneumatic tire greatly affects the product quality,so it is of great significance to study it.In this paper,the NPT injection molding process of polyurethane material was analyzed by simulation method,and the NPT molding process was explored from the aspects of flow channel design and process parameter optimization,and the relevant process simulation optimization method was established.The specific work contents are as follows:(1)The material properties of injection molding materials were tested and the rheological constitutive equation parameters were determined to provide data support for the simulation.Combined with the injection molding experiment,the simulation accuracy was verified by comparing the cavity temperature and pressure field between the actual injection experiment and the simulation results.The results show that the comprehensive simulation accuracy can reach more than 80%.(2)Based on the simulation analysis method established in(1),the injection molding process of UPTIS tire was simulated in Moldflow to optimize the injection gate and flow channel of the tire.The results show that compared with the three product quality indexes of injection time,front flow temperature difference and warpage deformation,considering the time and material composition comprehensively,the design scheme of four sprains on the top side of UPTIS tire forming is more reasonable,which is the optimal scheme.(3)Focusing on UPTIS and Honeycomb NPT,CAE technology and orthogonal test method were used to study the influence of forming process parameters on NPT volume shrinkage and warpage deformation,and orthogonal test method was used to compare the influence degree of each process parameter.The results show that the quality of injection molding is mainly controlled by melt temperature and holding time,followed by mold temperature,holding pressure and cooling time.The influence degree of NPT process parameters of different structures is slightly different.(4)Based on the neural network prediction model and genetic algorithm,multi-objective optimization was carried out for the quality of non-pneumatic tire forming products.A multi-objective optimization model of honeycomb tire injection molding was established by using machine learning algorithm.The multi-objective optimization model was solved according to the genetic algorithm,and compared with the results obtained from the orthogonal experiment,the results show that:Compared with the process parameters optimized in the orthogonal experiment,the warpage deformation increased by 5.0%after using the genetic algorithm,but the volume shrinkage decreased by 14.8%,which was a larger reduction.Therefore,the combination of process parameters obtained through the genetic algorithm was corresponding to the forming NPT products with better quality.