Effect of Vibration Condition of Flask on Dimensional Accuracy of Casting in Expendable Pattern Casting Process

The effect of the vibration condition of flask on the appearance and dimensional accuracy of the casting in the expendable pattern casting (EPC) process was investigated experimentally. The aluminum alloy casting of the simple shape with the rib was cast by EPC process using the natural silica sand and artificial sand, and the dimensional change of the casting from the model was measured. As the vibration frequency increased, the fluidity of sand was better. When the artificial sand was used, the fluidity of sand due to the vibration of flask was considerably higher than the case of the natural silica sand. When the vibration frequency was sufficiently high, the appearance and dimensional accuracy of casting were good independent of the sand materials. When the vibration frequency was low, the leaching of the molten metal due to cracks in the coat wall was observed, and the positive different dimension of casting from the model was caused. However, when the artificial sand was filled, even at slightly low vibration frequency, the casting appearance was relatively good, and the different dimensions of the casting were small.