Investigations for surface roughness and dimensional accuracy of biomedical implants prepared by combining fused deposition modelling, vapour smoothing and investment casting.

Abstract

Fused deposition modelling (FDM) is one of the most commonly used additive manufacturing (AM) processes to obtain 3D prototypes/patterns with compromised surface roughness and dimensional accuracy (mainly due to stair case effect). Some studies have been reported on use of vapour smoothing (VS) as post process (which has been applied post-production of FDM patterns) with the aim of enhancing its surface quality for biomedical application The patterns of thermoplastic, wax etc. obtained through FDM and VS can be further used as sacrificial patterns in investment casting (IC) applications (which is a renowned process for its capabilities of producing dimensionally accurate and highly finished casts). But hitherto little has been reported on combining FDM, VS and IC for controlling surface roughness and dimensional accuracy of biomedical implants. In this paper, two controlling parameters of each process (FDM, VS and IC) were utilised with Taguchi’s parametric approach and their effects on dimensional accuracy and surface roughness of final casts of implants were evaluated and studied using analysis of variance (ANOVA). The results specified that the combined process is highly capable and thus, prepared biomedical implants are statistically approved according to ISO UNI EN 20286-I standard for assembly purpose.