Sand filling and deformation of patterns in the lost foam casting process

摘要

In the lost foam casting process foam patterns embedded in the flask might be deflected or even fractured due to sand flow in a vibrating flask. This in turn affects significantly dimension accuracy of the produced castings and increases the overall production costs. Sand bulk tends to rearrange in fabrications, hardening and flow during vibration. This study investigated experimentally the hardening behaviors of sand bulk in the vibrating flask and the factors that influence the foam pattern deformation after the finish of molding. Experimental results indicated the optimum sand filling conditions. After vibration, the hardening of sand bulk is closely related to the following factors: direction of vibration, exciting level, sand filling, the stratum depth of the sand bulk, the relative strength of the foam pattern respective to the flow field and duration of vibration. The force distribution in the flask changed both in directions and magnitudes with vibration time.