Minimizing wax shrinkage in investment casting

a novel design for paste-form wax injection

Abstract

Investment casting refers to an industrial manufacturing process that involves dipping wax patterns into the slurry of refractory material to form a ceramic, plaster, or plastic shell. The wax pattern is further melted, and metal is poured into the shell to create a casting. This process is commonly used to manufacture complexshaped components that require tighter tolerances with a better surface finish. The quality of the final cast component mainly depends on the quality of the wax pattern and ceramic shell. The Quality of wax patterns produced mainly depends on the linear shrinkage, surface roughness, and hardness, so there is a need to remove these defects to improve the quality of the wax patterns and, in turn, the casted product. Among the challenges mentioned above, wax shrinkage plays a crucial role in producing precise components; wax shrinkage can be reduced if injected at a lower temperature or in its paste form, i.e., around 45°- 49°c. To address this shrinkage, a wax injection unit is designed and tested, capable of injecting wax at lower temperatures. The developed subsystem can be integrated with a wax injection moulding machine and can inject wax in its paste form.