Collapsibility studies of MJM acrylate patterns for investment casting

Abstract

Direct rapid investment casting (IC) is among the favorable and economical casting process due to its flexibility in fabricating any geometrical part features within a shorter lead time. Polymer based materials used in rapid prototyping (RP) technologies are exhibiting significant cost reduction for low volume production and are potentially replacing conventional wax materials as sacrificial patterns in IC process. This paper reports on the collapsibility characteristics of acrylate patterns during the burnout process for IC molds. The acrylate based patterns were fabricated by a Multijet Modelling (MJM) process with hollow internal structure. The MJM patterns were then Slurry procedure were introduced for producing toughest ceramic mould to prevent cracking occurrence. Results showed that the acrylate patterns start to decomposed gradually from the ceramic mold at 350°C and at 600°C, a total clean burnout without any residues and ash content was attained. This study shows that acrylate patterns built from RP technologies are suitable for fabricating ceramic molds and are highly potential in substituting conventional wax for IC process.