Analysis of absorptivity for parameter optimization on metallic powder layer of Selective Laser Melting(SLM)

Abstract

With the mature advancement of science and technology application of the additive manufacturing is more and more widely Among them the metal material in selective laser melting (SLM) has a great potential in the future Because of high cost for manufacturing long production cycle and strict parameters in controlling etc these reasons cause the SLM not to be universal So this thesis studis on the optimized process on metal powders by absorptivity and scattering effect By the raining model any size distribution and the type of material for the deposition of metal powders can be simulated The information of metal powders is imported into Zemax by program coding of Macro and analyzing of the absorptivity of metal powders under high-energy laser beam Also galvanometric scanning system in SLS was simulated in Zemax to analyze absorptivity of energy from the metal powders The results between using galvanometric scanning system of SLM and without using the one of SLM are compared each other It is found that the effect of galvanometric scanning system to the absorptivity of metal powders can be neglected In order to analyze the effect of laser spot size powder particle size distributions powder material on the absorptivity of powder bed and the non-sequential ray tracing simulations were implemented in Zemax It is found that in the case of powder particles size with Gaussian distribution the suggested powder layer thickness is around the value of the mean size of powder particles In order to verify this simulation model the parts with different layer thickness were manufactured by SLM machine In experiments it is found that by using the suggested powder layer thicnkess from simulation the quality of final parts in terms of packing density and surface rougness is better than the other values of powder layer thickness

Date of Award	2016 Aug 30
Original language	English
Supervisor	Yu-Lung Lo (Supervisor)