Powder bed fusion

A 3D-printing process that uses a laser or electron beam to melt each layer of a part into a thin bed of metal or plastic powder.

• A blade spreads a powder layer 20–100 micrometres thick, the beam fuses the part's cross-section, the bed lowers, and it repeats.
• Thousands of layers build the part, each tiny melt pool solidifying in milliseconds, giving fine detail and near-full density.
• It is the most widely used metal-printing method, making rocket injectors, turbine parts and medical implants.
• Rapid heating and cooling leave internal stress that can warp parts, and poor settings cause pores, so builds need careful tuning and inspection.