Evaluation of ABS Patterns Produced from FDM for Investment Casting Process Mohd. Hasbullah Idris †1 and Safian Sharif 2 Faculty of Mechanical Engineering, Universiti Teknologi Malaysia 81310 UTM Skudai, Johor, MALAYSIA Email: hsbullah@fkm.utm.my 1 safian@fkm.utm.my 2 Wan Sharuzi Wan Harun 3 Faculty of Mechanical Engineering, Universiti Malaysia Pahang 26300 Kuantan, Pahang, MALAYSIA Email: sharuzi@ump.edu.my Abstract. The paper presents the investigation on Acrylonitrile Butadiene Styrene (ABS) pattern produced from Fused Deposition Modeling (FDM) for use as pattern for investment casting process. The investigations were carried out to establish the physical and collapsibility characteristics of H-shape pattern produced from 2 different construction methods, i.e. hollow and solid, using rapid prototyping FDM2000 machine. Surface roughness, dimensional accuracy and distortion were evaluated to establish the physical characteristics of the pattern constructed. Results on surface roughness show no significant variation between hollow and solid constructed patterns. As for dimensional accuracy, hollow patterns produced better accuracy as compared to solid patterns. However, result on distortion shows that hollow constructed patterns experienced 33.11% higher than solid constructed patterns. For collapsibility investigation, shell investment casting mould built from the 2 different pattern construction methods were fired to a temperature ranging from 300 °C to 600°C. The moulds were weighted at a predetermine temperature intervals to establish the collapsibility characteristic of the patterns. Experimental result shows that hollow pattern offers better mould cleanliness and no mould cracking at all temperatures. Keywords: ABS; FDM; Investment Casting 1. INTRODUCTION Investment casting process (IC) is a metal casting techniques capable of providing an economical means of mass production components with complex features such as thin walls, undercut contours and inaccessible spaces which are difficult or impossible to produce using other fabrication methods (Beeley 1995). Despite the wide range of applications in many industries, the standard (conventional) IC process practice in modern foundries has its drawbacks. High tooling costs and lengthy lead times are associated with the fabrication of metal moulds required for producing the sacrificial wax patterns used in IC (Sachs et al. 1991). The high tooling costs involved in conventional IC result in cost justification problems when small numbers of castings are required. Rapid prototyping (RP) techniques are fast becoming standard tools in the product design and manufacturing industries. With the capability of rapidly fabricating of 3D physical objects, RP has become an indispensable tool employed for shortening new product design and development time cycles (Hilton et al. 2000, Chua and Leong 1997, Wohlers 2000). RP techniques are unlimited neither by the geometry nor by the complexity of the parts to be fabricated. In addition, RP techniques involve no tooling or fixtures, resulting in simpler set up, lower overhead cost and shorter production lead times compared to other fabrication methods. With RP, parts that were previously impossible or extremely costly and time-consuming to fabricate can be built with ease. The application of RP-fabricated patterns as substitutes for the traditional wax patterns employed in IC stems from the fact that RP materials can be melted and ________________________________________ † : Corresponding Author 129 9