Post-processing of FDM 3D-Printed Polylactic Acid Parts by CNC Trimming

Abstract

3D printing is the next industrial revolution which has brought many advantages over conventional methods. Fused deposition modelling (FDM) is a 3D printing process that prints products by extruding molten thermoplastic layer by layer. The process is highly capable to print different products but achieving smooth surface quality without layer structure is still challenging. Hence, post-processing techniques are useful to enhance mechanical properties and also surface texture. In this study, Computer numerical control (CNC) trimming was used as a post-processing technology to find out its effects on 3D printed Polylactic acid (PLA) products. In FDM process, samples were printed in different build orientations form 0o to 90o and analysed their surface texture to understand the influence of build orientation on surface quality. The goal of this study is to examine trimming parameters on printed PLA products. Furthermore, specimens were trimmed with a wide range of feed rates and spindle speeds. Surface roughness measurement (in this case average surface roughness (Ra) and average maximum peak to valley (Rz)) was conducted to determine the surface characteristics. Finally, it was found out that 1,200 mm/min feed rate with 3,500 rpm spindle speed reached the best surface quality. There was an extraordinary improvement in all samples after trimming reach to 97.18% compared to printing process. Also, results showed 0o had the lowest range of Ra and Rz among samples. This means the printing direction is highly effective in both printing and trimming processes.