Optimized Design Of Injection Mould For Automobile Sunroof Parts Based On CAE Warpage Analysis

In recent years,the engineering plastics have been used more and more in the automotive industry because of the great improvement in the precision and strength of engineering plastics.In order to ensure the quality of plastic products,warp must be paid close attention to by designers and users.The warp of the product quality problem is the most common,because in the plastic molding process,the plastic product is influenced by various factors,such as product design,mold structure and injection process parameters.It is difficult to control the warp,in the past,mold production design department mostly rely on experience,after repeatedly adjusting the process parameters and die design in the test mode,and then the required products are obtained.This design pattern does not adapt to the development of the mold industry and automobile industry.This paper uses Moldflow numerical simulation software to systematically study the warp deformation trend of the automobile sunroof.Thus we can modify the product model using pre-deformation and according to the analysis result,select the optimization scheme of mold design,in which,the filling is uniform;cavitation and weld line position is more reasonable;after packing,volume shrinkage is less;cooling is even and warp is small.Thus this would provide scientific basis for the mold design.First of all,we analyze in-depth the product materials,product monitoring requirements and structural shape,combined with Pro/E software.The results show that:Petra 230 BK-112 PET belongs to thermoplastic engineering plastics and has a good performance.So molding should pay attention to increasing injection pressure,select the large tonnage injection machine,use hot runner mold.Molding temperature does not exceed 300 degrees.The injection speed must be faster.The preliminary scheme of layout,which is one mold to one cavity,is adopted in the design of the mold.Both sides need side core.There should be 6 side holes in the middle of the parts.There should be inclined roof.And mold insert should be assembled with insert blocks.Secondly,the car roof components were analyzed by using CAE,including filling time,injection pressure,clamping force,weld line,cavitation,fiber orientation,mold temperature,cooling time,shrinkage and warp,so as to study the trend of the warp.The results show that the fiber orientation is not the main reason for the warp of skylights,and the influence of cooling conditions is not obvious.The problem is the differences mainly resulted from the warp value of the local shrinkage.After the product model is processed by reverse pre-deformation,the ideal warp value can be obtained and the problem can be solved.Finally,the die design is carried out by using Pro/E software,and the sample of the die is selected by trial mold.The warp value of the work piece is measured and analyzed.The results show that the actual work piece warp values are basically consistent with the simulation results.According to the theoretical analysis of the initial scheme,warp value is 2.2mm.After the product model is processed by reverse pre-deformation,and the mold design is optimized,warp deformation is less than ±1mm.Warp is improved.So the problem,in which the product warp can be solved after the product model is processed by reverse deformation,is verified.And this does not affect the accuracy of the product outline.