A semi-empirical modelling of selective laser melting

• Main Author: Yap, Chor Yen
• Other Authors: Chua Chee Kai
• Format: Theses and Dissertations
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering::Manufacturing::Flexible manufacturing systems; DRNTU::Engineering::Mechanical engineering::Prototyping; DRNTU::Engineering::Materials::Material testing and characterization
• Online Access: http://hdl.handle.net/10356/69292
• Institution: Nanyang Technological University

Selective Laser Melting is a particular powder bed based Additive Manufacturing technology capable of producing metallic components from powders. There has been increasing research and industrial interests in this technology as it can achieve near-full density fabrication. Research has also shown that Selective Laser Melting is capable of producing components that are higher in strength and hardness compared to their cast counter parts due to the localised and rapid solidification that occurs during the process. As interests in Selective Laser Melting grows, more research has been focused on finding the optimal process parameters for different materials. However, current parameter optimization studies are usually carried out by trial-and-error, which is time consuming. This Ph.D. project aims to develop a semi-empirical model of the Selective Laser Melting process. This model will enable parameter optimization studies to be shortened by a providing a close estimation of the energy requirement of the process, by considering the thermal properties of the materials, the laser-material interaction and morphology of the melt tracks. The scope of this project is limited to metals and alloys as they are the most common materials used in industrial applications and some of the relevant information is available in scientific articles. A model of the process was developed and the energy requirement of the process was found to vary with the thermal conductivity values of the materials, in addition to their thermal capacities and melting temperatures. Applications and limitations of this semi-empirical model are also discussed. Through this work, optimized process parameters were also established for pure nickel and pure tin. These metals had not been successfully processed by Selective Laser Melting previously. The resultant microstructures of these materials have also been examined via various characterization techniques.