Abstract: Due to the high vapor pressure and low melting boiling point of the Mg element in the Selective Laser Melting (SLM) forming process, it is easy to burn and produce a large amount of smoke under the action of high energy laser. To restrain element burning loss in SLM forming of the magnesium alloy, a method for modeling the relationship between the burning loss rate and the process parameters was proposed. First, by simulating the SLM temperature field, the relationship between process parameters and temperature model was established. Second, based on the theory of gas dynamics and thermodynamics, an analytic relation model between the burning rate and temperature was built. Finally, the relationship model between process parameters and element loss rate is developed. It was found that the burning rate is small when the laser power was 70-90 W and the scanning speed was 300-500 mm/s. SLM molding experiments were carried out to verify the window, and it was found that in this window, the amount of smoke was significantly reduced, and the performance of the molds was improved. When the laser power was 85 W and the scanning speed was 400 mm/s, the average tensile strength of the specimen was 324.1 MPa, and the elongation was 10.12%.

Key words: magnesium alloy, temperature, process parameter, element burning rate, saturated vapor pressure