The Research Of The Alluminum Casing Joint Low Pressure Die Casting Mould Design And Process Opotimization

As a kind of almost no machining allowance liquid metal forming technology,the LPDC is characterized by smoothing filling,compact inner microstructure,no design riser and high process yielding compared to other casting methods.It is widely used in the automotive,aerospace,military industry,mechanical and electrical areas,especially in the production of the thin-walled alluminium alloy complicate castings. The object of this study is a thin-walled complicate casting,is easily to produce misrun,cold insulation,shrinkage porosity and other defects when fast cooling process,because of hard to form top-down solidification sequence.So it is important to design and opotimize its process.This study apply the computer numerical simulation technolgy,study the process of filling and solidification,analyze the craft parameters effects on its forming quality,opotimize out reasonable parameters,solve the cold insulation problem in the process of gravity casting,provide the theoretical guidance and technical support for its practical produce.The main work and conclusions are as follows:(1)The division of FEM.Study three ways of the division of FEM, it proves that high quality mesh with UG, compared to Meshing and UG-Meshing ways.This improves the accuracy and efficiency for later simulation opotimization.(2)Design the mould and craft.Design the 3-D entity of the part and design three kinds of different gating systems according to the LPDC principle.Opotimize out resonable gating system and design its LPDC mould.(3)Pre-process of simulation. Choose out material and its thermal physical parameters, intial conditions, boundary conditions, performance parameters, with theoretical analysis, mathematical calculation and practical production.(4)Simulation opotimization of craft parameters.According to the simulation results, analyze its effects on part forming. The final study shows that the reasonable prameters are as follows: Filling temperature is 690℃, upper mould preheating temperature is 350℃, lower mould preheating temperature is 300℃, filling pressure is 5000 Pa, filling time is 2 s, holding pressure is 10000 Pa, holding pressure time is 40 s.(5)Process improvement.Design three improvement schemes, it shows that scheme III is more reasonable, with smaller shrinkage porosity rate.