Selective Laser Melting (SLM) already offers the possibility to create individual implants from titanium- and cobaltchromium-alloys. Establishing magnesium alloys within the process will enable the manufacturing of biodegradable implants. The SLM process of magnesium is a non-standard process showing large evaporations of magnesium. The major issue for the behavior of magnesium is the high affinity for oxygen resulting in the fast formation of a ductile oxide layer during processing. Since liquid metal does not wet oxide layers the SLM process can only take place when the oxides are removed and re-oxidation is prevented during the melting process. A shock wave induced by evaporation of magnesium particles breaks the oxide layer, impurities are absorbed by evolving nanosize particles and dense parts can be produced. Using a MgCa0.8 magnesium alloy within the process, the composition of the alloy changed and cracks were found in the sample due to the evaporation of magnesium.