LPBF

Laser powder bed fusion (LPBF) is a metal additive manufacturing process in which a laser selectively fuses regions of a bed of metallic powder to build parts layer by layer from a supplied 3D model. The build occurs inside a sealed chamber filled with an inert gas, typically argon, to minimize oxidation and contamination. After each layer is fused, a new layer of powder is spread across the bed, and the process repeats until the part is complete.

A typical LPBF workflow uses a fine, spherical metal powder and thin layer thicknesses, often in the range of 20 to 60 micrometers. The laser is scanned across the powder bed to melt along defined hatch lines, following the cross-sections of the part. The platform lowers by one layer thickness after each pass, and the powder bed is recoated for the next layer. Build support structures may be required for overhanging features and then removed after printing.

Materials used in LPBF include stainless steels, titanium and aluminum alloys, nickel-based superalloys, cobalt-chromium alloys, and copper alloys. Powder properties such as particle size distribution, flowability, and morphology strongly influence build quality. Equipment typically includes a sealed chamber, a fiber or diode laser, a controllable powder recoater, and an inert gas supply, with process parameters including laser power, scan speed, hatch spacing, and layer thickness.

Advantages of LPBF include the ability to produce complex geometries and near-net-shape metal parts with good mechanical properties. Limitations include high equipment cost, slower build rates for large parts, and potential defects such as porosity, cracking, residual stresses, and anisotropy, which often require post-processing like heat treatment or hot isostatic pressing. LPBF finds applications in aerospace, automotive, medical implants, and tooling, supported by various quality standards and inspection methods.