Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 10 2021 12 22 Optimization of Additive Manufactured Part Made by Ti6Al4V Alloy to Achieve Best Relative Density and Surface Roughness Optimization of Additive Manufactured Part Made by Ti6Al4V Alloy to Achieve Best Relative Density and Surface Roughness 5169 5184 4516 10.22060/mej.2021.19555.7051 FA Amir Hossein Ghasemi Department of manufacturing, Faculty of mechanical engineering, Teacher training shahid Rajai university, Tehran, Iran Valiollah Panahizadeh Department of Mechanical Engineering, Faculty of Mechanic, Shahid Rajaee Teacher Training University, Tehran, Iran Journal Article 2021 01 26 One of the most popular additive manufacturing techniques is called laser powder bed fusion. Several parameters are involved in this method and four of the most important factors are laser power, scanning speed, infill pattern angle, and hatch space. Change in this parameter has a direct effect on defects and fabricated parts quality. Post-processing treatment such as heat treatment was cared out in order to improve part property and applications. Built time and costs reduce significantly by suitable choice of process parameters and post-processing treatments. In this article genetic algorithm cared out to highest relative density and lowest surface roughness and best value of each parameter presented. The results showed that the best output could achieve by using 102-105 Watt of laser power, 623-630 mm.s^-1 scan speed, 73-76 µm of hatch space, and 638-640 °C of heat treatment temperature. One of the most popular additive manufacturing techniques is called laser powder bed fusion. Several parameters are involved in this method and four of the most important factors are laser power, scanning speed, infill pattern angle, and hatch space. Change in this parameter has a direct effect on defects and fabricated parts quality. Post-processing treatment such as heat treatment was cared out in order to improve part property and applications. Built time and costs reduce significantly by suitable choice of process parameters and post-processing treatments. In this article genetic algorithm cared out to highest relative density and lowest surface roughness and best value of each parameter presented. The results showed that the best output could achieve by using 102-105 Watt of laser power, 623-630 mm.s^-1 scan speed, 73-76 µm of hatch space, and 638-640 °C of heat treatment temperature. https://mej.aut.ac.ir/article_4516_573f7f25b7b1eb79a4ec6ba896debefd.pdf