Modeling of Linear Shrinkage in PLA Parts Fabricated by 3D Printing Using TOPSIS Method

3D printing is one of the most preferred rapid prototyping (RP) methods used for prototyping. However, for the functional use product, the part must be highly accurate and have good strength. The biggest constraint in the functional use of RP parts is the dimensional inaccuracies. These dimensional defects mostly happen due to the irregular surface profile and shrinkage of the part. The part fabrication process in RP is governed by many process parameters. In this study, selection of the process parameters which affect the shrinkage of PLA parts is determined by using TOPSIS. Part length (PL), layer thickness (LT) and printing speed (PS) were selected by applying TOPSIS method. Response surface methodology (RSM) has been used for the design of the experiment. ANOVA has been used to identify the significant parameters followed by regression to correlate the response with process parameters. A statistical model is developed for the shrinkage in PLA parts. It has been observed that shrinkage tends to increase with increment in PL and reduces with increment in LT and PS.