DMLS

Step 1

Printing

Unlike polymer based Powder Bed Fusion technologies, DMLS requires support structures to anchor the object to the build plate. The metal powder material is spread across the build platform by a re-coater. A high-powered laser selectively sinters (melts) the metal powder in the cross-sectional slice of the CAD model. The build platform then lowers by the height of one layer and a new layer of metal powder is deposited. The process repeats until all slices are complete and the build is left to cool down inside the machine.

Step 2

Post Printing

The build chamber is removed from the printer and placed in the machine's de-powdering station. The build plate is raised to lift the part out of the chamber and all unsintered powder is brushed and blown away from the parts which are anchored to the build plate by the support structures. The unsintered powder is reclaimed and 100% of it can be used in future builds. The part(s) are then separated from the build plate either by a saw or wire EDM. The build plate is then resurfaced before it can be used again. With their supports still intact, the parts are then de-stressed in an inert furnace to release any metal tension.

Step 3

Support Removal

Manual Removal Support structures are typically part of the part and must be cut off with saws, grinders, or CNC machining. Soluble Support Removal Non-applicable Manual Cleaning Note: Removal often requires specialised tools or wire EDM due to the strength and density of metal supports.

Step 4

Surface Finishing

Sanding / Polishing Applied after support removal. Polishing can be performed in a vibratory finishing system. Chemical Smoothing / Coating Options include electropolishing or chemical etching to smooth and passivate surfaces. Painting / Priming Rare, but can be used for cosmetic purposes or corrosion protection. Gloss / Matte Control Controlled via polishing or coatings; untreated surfaces are typically matte / rough.

Step 5

Curing / Heat Treatment

UV / Thermal Curing Non-applicable. Annealing / Stress Relief Essential. Parts undergo thermal treatment (e.g., 2–4 hours at 600–800°C) to relieve internal stresses from the printing process.

Step 6

Assembly and Functional Finishing

Gluing or Bonding Rare; welding or mechanical fastening is most common. Drilling / Tapping / CNC Common and often necessary; tight tolerances and smooth fits are usually achieved through secondary CNC machining. Inserts / Fasteners Threaded inserts or direct metal threads are common for assemblies.

Step 7

Special Treatments

Infiltration / Sealing Non-applicable; parts are fully dense or nearly so post-sintering. Functional Coatings Options include anodising (aluminium), passivation (stainless), PVD/CVD coatings, and plating for wear, corrosion, or conductivity. Post-print Functionalisation HIP (Hot Isostatic Pressing) is frequently used to eliminate internal voids and improve fatigue resistance; surface treatments may also include shot peening or hardening.