Theoretical determination of selective laser melting modes for the manufacture of parts with minimum porosity

Abstract

The subject of this article is the process of manufacturing parts of aerospace technology by selective laser melting (SLM) using metal powder of heat-resistant alloy Inconel 718. Objectives: to determine the reasonable size of the melt bath in relation to certain process parameters; to examine the level of porosity based on the obtained values of the melt bath; to determine the most acceptable mode of the SLM process. The methods used are mathematical models of optimization and methods for solving nonlinear problems. The simulation took into account such parameters as the power of the laser radiation, the scanning speed, the size of the laser spot, the temperature of the construction plate, the thickness of the powder layer and the hatch spacing. The following results were obtained. According to the obtained data, the optimal dimensions of the melt bath were determined, which ensure the stability and productivity of the SLM process, the minimum level of porosity, a high level of tightness and the reliability of aerospace parts. Conclusions. The scientific novelty of the obtained results is as follows: the values of the optimal parameters of the SLM process for the manufacture of parts with a minimum level of porosity for heat-resistant alloy material Inconel 718 were confirmed. LPBF methods, namely SLM. It was found that the optimal single track was formed at two combinations of scanning modes, namely: at a laser power of 100 W, and a scanning speed of 600 mm/s; at a laser power of 100 W, and a scanning speed of 700 mm/s. According to the simulation results, according to the criterion, the level of porosity (solids ratio) was less than 0.5%, the highest growth rate was detected at 100 W, scan speed 700 mm/s and hatch spacing 0.1 mm.

Keywords

• селективне лазерне плавлення
• пористість
• ванна розплаву
• закон фур'є
• моделювання процесу
• параметри процесу