Selective Laser Melting in Powder Bed

Metallic 3D printing at high precision

Selective laser melting (SLM) is based on the so-called powder bedding process. In a build chamber whose size varies depending on the machine, metal powder is deposited layer by layer onto a build plate and melted in a highly localized fashion, based on a CAD model. With each layer, the plate holding the part is lowered, allowing it to gradually grow in height. Once the building process is complete, the unmelted powder is suctioned off and then prepared for reuse. Increasing adoption of the technology has already led to a wider range of materials being available, including various steels and aluminum, cobalt chrome and nickel alloys, as well as copper and titanium.

The size of the build chamber permitting, multiple workpieces can be produced simultaneously. This method of 3D printing becomes even more productive when multiple lasers are used simultaneously. The precision of powder bed machines depends on various factors, including the laser’s focal diameter, the material used, the layer thickness, and the structure of the component. A focal diameter of 80 µm can, with steels, for example, achieve a web width of 0.15 mm. With aluminum, it’s 0.3 mm. Selective laser melting can also achieve extremely fine structures, such as internal cooling channels in tools. Where even higher accuracy is required, specific areas of the component can be post-processed using conventional methods.

The right powder bed machine for every application

DMG MORI’s range of powder bed machines includes the LASERTEC 12 SLM, which features a build volume of 125 × 125 × 200 mm. It has a focal diameter of just 35 µm, allowing for the creation of extremely fine structures. The LASERTEC 30 DUAL SLM has a build volume of 300 × 300 × 350 mm and is equipped with two lasers. As a result, productivity increases by up to 80 percent. With both models, rePLUG makes material switchover fast and uncomplicated. The powder module makes zero-contamination changeover possible in under two hours.