The low pressure casting process of aluminum alloy volute was simulated by Viewcast software

and the position and size of defects in the volute were predicted.The result shows that the final solidification position is located at the thick and large part

and there exist defects such as shrinkage porosities（holes）in the volute.The origination of the defect was analyzed

and a optimization scheme was proposed by adding the sprue and ingate in the middle of the gating system to increase the feeding effect of the thick and large part.The optimized results show that the defects can be eliminated completely

meeting the production requirements.