Finite Element Analysis on Rapid Prototyping Pattern with Different Internal Structure for Investment Casting

Manufacturing a metal product with complex geometry usually will related to Investment Casting (IC) process as the process has the highest capability to deliver the intended objective. But producing the wax pattern for the process has already consumes half of the time of overall process. Rapid Prototyping (RP) is considered to be a solution as it capable to reduce the time in a large margin. Compared to wax patterns traditionally made for IC, RP patterns mainly built from polymer based material. Polymer may react differently than wax when it comes to the burnout process which is a critical part in IC that determines the quality of the final cast product. By considering both strength and collapsibility, cube pattern with different internal structure designs were developed using SolidWorks software and analysis by ANSYS software. All designs were tested for total deformation and equivalent Von Misses stress within the temperature range from room temperature of 27oC up to 700oC. The result from the simulation indicates that most of the shell cracking takes place in the initial steps of the burnout stage which is before the glass transition temperature of thermosetting patterns. Shells cracking are strongly related to the internal structure of the Multi-Jet Modeling (MJM) patterns. The study shows the possibility and places of mould cracking during the burnout