The Design And Simulate Optimize On Casting Technology Of The Large Thin-walled Aluminum Transmission Box

This paper takes the large complex thin-walled aluminum transmission box as theresearch object, which has complex shape. During the production process, there often appearssevere shrinkage hole, shrinkage porosity and deformation with distortion casting defects.Therefore transmission box casting process has to be verified before its actual production.However, the traditional method is validated through repeated experiments, which needs notonly long trial period, but also high cost of experiments. This article is mainly through theapplication of computer simulation technology, and focuses on preliminary design of thecasting process about the transmission box, thus to shorten the shrinkage trial period and toreduce production costs.Transmission box’s overall wall thickness is thin, whose parts are thick and large, and itsthin and thick walls are unevenly distributed, leading to uneven filling, too fast solidificationspeed and shrinkage porosity difficulties. So smooth filling process, the good performance ofshrinkage porosity methods with low-pressure casting should be selected. By analyzing thetransmission box structure, the casting process parameters have been design. For example, theminimum diameter of the casting is20mm, the minimum thickness of the cast is6mm,machining allowance of two side surface is5.5mm, the bottom surface is6.5mm, shrinkagerate is from1.18%to1.04%, and the curved surface of the amount of deformation adds2.5mm reverse distortion. According to low pressure casting method for designing castingsystem design and filling pressure during solidification process, its cross-sectional area runneris537cm2, its horizontal runner’s cross-sectional area is360cm2, its sprue cross-sectional areais172cm2, and its filling pressure is0.0315MPa, increasing pressure of0.0504MPa. Byanalyzing the distribution of the thermal section castings, according to the formula D Gch7.6S, to calculate the thickness of the thermal section of the cold iron and to designcasting solidification feeding system.Using casting simulation software can finish filling process, the solidification processand the stress and strain of the casting process.①Through the simulation on the fillingprocess of transmission box, filling stage by uniform pressure adjustment for variablepressure, to achieve smooth filling;②Based on the transmission box solidification processsimulation, will boost pressure to0.0567MPa, solidification feeding system to adjust,shrinkage decreased;③By simulating the transmission box stress-strain process, the antibending deformation of surface with0.5mm, curved surface deformation is obviouslyreduced.