Selective laser melting (SLM) is one of the most popular advanced manufacturing techniques. SLM is an additive manufacturing (AM) technique that enables production of complicated metal products with high precision and flexibility and acceptable surface finish. It uses a high-intensity laser beam as the energy source to selectively melt metallic powder, which is dictated by 3D CAD data.
SLM enables production of critical parts which are impossible by various traditional metal forming techniques such as casting, forging, extrusion and metal cutting. Unlike the traditional manufacturing techniques, it manufactures 3D objects by gradually adding metal powder layer by layer according to the CAD model. With no need for any dies or tools, it may help to shorten design and production cycles and save time and costs for production.
SLM process parameters affect the multiple quality attributes of SLM-built parts. Thus, it is important to develop a new optimization methodology of SLM process parameters for improving the multiple quality attributes of SLM-built parts. It is a multi-objective optimization (MOO) problem. The multiple quality attributes are converted into a single overall quality index (OQI) using multi-attribute decision-making (MCDM) method, and the MOO problem is converted into a single objective optimization (SOO) one. The optimization results may differ according to the applied MCDM method.
In order to solve this problem, Yang Ji Yon, a post-graduate student of the Faculty of Material Science and Technology, proposed a reasonable process optimization methodology for improving multiple quality attributes of SLM-built parts using integrated OQI (I-OQI) combined with multiple OQIs obtained from multiple MADM methods.
She applied the proposed methodology to optimizing the process parameters such as laser power (LP), scan speed (SS) and overlap rate (OR) for improving five quality attributes of SLM-built AlSi10Mg alloy such as tensile strength, hardness, relative density, volumetric energy density and build rate.
The optimal values of the SLM process parameters obtained from Taguchi and grid search optimization methods were LP 320 W, SS 900 mm/s and OR 0.25.
The proposed methodology could be actively applied to the SLM process optimization of not only Al alloys but also various metal/alloys.
For further details, you can refer to her paper “Process Optimization for Improving Multiple Quality Attributes of AlSi10Mg Alloys Manufactured by Selective Laser Melting Based on Integrated Overall Quality Index” in “Russian Journal of Non-Ferrous Metals” (SCI).