The DMLS machine starts the 3D metal printing process by sintering each layer—first the support structures to the base plate, then the object itself—with a laser pointed at a bed of metallic powder. After micro-welding a cross-section layer of powder, the build platform lowers and a re-coat blade travels over the platform to deposit the next layer of powder into an inert build chamber. The method is continued layer by layer until the construction is finished. When the construction is completed, pieces are manually brushed to remove the bulk of loose powder, followed by the appropriate heat-treat cycle while still fixtured in the support systems to alleviate any tensions. Pieces are taken from the platform, and support structures are removed from the parts, before finishing with any bead blasting and deburring that is required. The final DMLS pieces are almost 100% dense.

The Process Methods Of DMLS

The DMLS process may be carried out in two ways: powder deposition and powder bed, which vary in how each layer of powder is deposited. The metal powder is held in a hopper in the powder deposition process, which melts the powder and deposits a thin layer onto the build platform. The powder dispenser piston elevates the powder supply in the powder bed technique (shown below), and a re-coat arm spreads a layer of powder over the powder bed. The powder metal layer is subsequently sintered using a laser. After completing a layer, the build piston lowers the build platform and the next layer of powder is placed. The powder deposition technique has the benefit of allowing the use of many materials, each in its hopper. The powder bed approach is confined to a single material but allows for speedier construction times.