Optimal Design Of Precision Double-colored Injection Mold For Auto Seal Housing

The content of this paper is the optimal design of precision double-colored injection mold for the auto sealed housing,the sealed housing is made up of three parts: metal,hard plastic and soft plastic,it demands that the mold life is more than one million times.Before injection,prefabricated metal part will be arranged in the hard plastic injection mold cavity,hard plastic material: nylon material(PA66+30GF)is used in the first injection,after forming,the hard rubber part completely wrapped the metal parts;then mold opens,the semi-finished products of the first injection will be moved to the second injection position by mechanical hand,soft material: thermoplastic elastomer TPE(TC6 ABZ)is used in the second injection,it will fill the slots and buckles for the first injection as sealing material.Considering the requirements of high dimensional accuracy,complex structure,long mold life,low price and so on,based on software NX 10.0 and ASM 2014,this paper presents a mold design method which widely use CAD/CAE Technology,and combines simulation and experimental analysis to carry out optimization design research.First,a three-dimensional solid sealed housing is created in software NX 10.0;then software ASM 2014 is applied to simulate the best gate and so on of the sealed housing,and the general injection plan will be set up;the NX 10.0 wizard is used to construct mold cavity layout,parting design,mold base system,gating system,cooling control system,slider and core pulling,standard parts and so on,at last the three-dimensional mold will be built.Then,the warp distortion of sealed housing is specified as optimization objective,the constraints of the gating system and the cooling system is set,the definition of the optimization variables are: cooling time,mold temperature,V/P switching,filling pressure,injection time,and melt temperature,six injection molding process parameters in all.The evaluation and optimization is carried out by orthogonal test,and the best molding process parameters are determined: the cooling times is 20 s,the mold temperature 45 degrees,the V/P switching is 8MPa,the filling pressure is 45 MPa,the injection time is 15 s,and the melt temperature is 280 degrees.The influence of the process parameters on the warpage of injection molding is: melt temperature(54.1035%)> mold temperature(26.9066%)> cooling time(9.20098%)> injection time(4.41402%)> filling pressure(3.28692%)> V/P switching(2.90396%).Finally,according to simulation,the optimization of injection molding parameter is input in the injection molding machine,and the tests are carried in the workshop.Five groups of samples were extracted,and the overall yield of the sealed housing was 100%.The conclusion is obtained and verified that the orthogonal test method was applicable to optimize the injection molding process and reduce warpage.The research helps enterprises to avoid the traditional design that repeatedly modify the mold process,and provides a theoretical and practical guidance for optimal design of precision injection molding of double color mold,greatly improves the competitiveness of enterprises in the market.