Effect of Process Parameters of Fused Deposition Modeling and Vapour Smoothing on Surface Properties of ABS Replicas for Biomedical Applications

Abstract

In spite of numerous applications, the functionality of FDM patterns is severely influenced by poor surface finish which must be maintained as it would be further inherited by castings. The impact of process parameters of an advanced finishing technique i.e. Vapour Smoothing (VS) has been investigated on surface roughness, hardness and dimensional accuracy of hip implant replicas. The Taguchi L18 Orthogonal Array and ANOVA statistical tools were used to scrutinize the significant parameters. The exposure of hot chemical vapours tends to melt the upper surface of ABS parts which are immediately cooled. This led to improvement in surface finish and surface hardness as layers settle down as smooth surface. The shrinkage in FDM parts has been noticed due to layer re-settlement. Based on significant parameters, the mathematical models for each response were formulated using Buckingham Pi theorem. The multi-response optimization study was performed to endorse a single set of process parameters to attain best surface characteristics. The Differential Scanning Calorimetry tests were performed which reveal that VS process enhanced thermal stability of material due to increase in bonding strength.