Core terminology

• Additive manufacturing (AM): manufacturing that creates physical geometry by successively adding material from digital model data.
• 3D printing: a widely used term for AM; often associated with equipment or part creation, while “additive manufacturing” more often implies an industrial production system.
• Additive system: the machine, auxiliary equipment, software and controls used to perform an AM process.
• Build: one complete production cycle in which one or more parts are manufactured inside a defined build volume.
• Build envelope: the maximum usable three-dimensional region in which the system can manufacture.
• Feedstock: material supplied to the process, such as powder, wire, filament, pellets, liquid resin, sheet or slurry.
• Near-net shape: a geometry close to the final part but still requiring machining, finishing or other downstream operations.

The seven AM process categories

Category	Definition	Typical examples
Binder jetting	A liquid binder selectively joins regions of a powder bed.	Sand molds and cores; metal green parts followed by debinding and sintering.
Directed energy deposition (DED)	Focused thermal energy fuses material as it is deposited.	Laser-powder DED, laser-wire DED, wire-arc AM and electron-beam wire deposition.
Material extrusion	Material is selectively dispensed through a nozzle or orifice.	FFF/FDM polymers, pellet extrusion and bound-metal filament.
Material jetting	Droplets of build material are selectively deposited.	Photopolymer jetting, wax patterns and nanoparticle inks.
Powder bed fusion (PBF)	Thermal energy selectively fuses regions of a powder bed.	Laser metal PBF, electron-beam metal PBF and polymer laser sintering.
Sheet lamination	Sheets of material are bonded to form a part.	Ultrasonic metal lamination and laminated sheet processes.
Vat photopolymerization	Liquid photopolymer in a vat is selectively cured by light.	Laser SLA, DLP, MSLA/LCD and continuous interface processes.

Process notation and commercial language

• PBF-LB/M: laser beam powder bed fusion of metals.
• PBF-EB/M: electron beam powder bed fusion of metals.
• LPBF: widely used abbreviation for laser powder bed fusion; context should clarify whether the material is metal or polymer.
• DMLS: Direct Metal Laser Sintering; a widely used commercial or historical term for metal laser PBF.
• SLM: Selective Laser Melting; another common historical or commercial term for metal laser PBF.
• SLS: Selective Laser Sintering; most commonly associated with polymer powder bed fusion and not a universal synonym for metal LPBF.
• DED-LB/M: laser beam directed energy deposition of metal, using powder or wire feedstock.
• DED-Arc/M: arc-based directed energy deposition of metal.
• WAAM: Wire Arc Additive Manufacturing; a common industry term within arc-based metal DED.
• FDM: Fused Deposition Modeling, a Stratasys trademark commonly used for polymer material extrusion.
• FFF: Fused Filament Fabrication, a generic term for filament-based material extrusion.
• SLA: stereolithography; commonly refers to laser-based vat photopolymerization.
• DLP: vat photopolymerization using projected digital light to expose an area of each layer.
• MSLA/LCD: masked vat photopolymerization using an LCD mask and light source.
• MJF: HP Multi Jet Fusion, a commercial polymer powder-bed process using selectively applied agents and thermal energy.
• PolyJet: a Stratasys commercial material-jetting platform for photopolymers.

Digital design and build preparation

• CAD: computer-aided design data defining the intended geometry and engineering features.
• STL: a tessellated surface format made of triangles; simple and common but unable to represent rich product information.
• 3MF: a modern 3D manufacturing format that can carry units, color, materials, lattices and other metadata.
• Slicing: converting a 3D model into layers or exposure/deposition instructions.
• Build processor: software that converts prepared geometry and process settings into machine-specific instructions.
• DfAM: design for additive manufacturing; designing around process capability, supports, thermal behavior, material removal, inspection and economics.
• Topology optimization: computational redistribution of material to meet structural objectives and constraints.
• Lattice: a repeating or spatially varying cellular structure used for weight, stiffness, energy absorption, heat transfer or biological integration.
• Part orientation: the position of a part in the build; affects supports, surface, anisotropy, distortion, time and powder removal.
• Nesting: arranging multiple parts in the build volume to improve capacity, cost or thermal behavior.
• Support structure: temporary geometry used to anchor, conduct heat, resist distortion or support overhangs.

Production route and post-processing

• Powder lot: a traceable quantity of powder produced under defined conditions and released against specified requirements.
• Recoating: spreading a new powder layer across the build area in a powder-bed process.
• Depowdering: removing loose powder from the build and internal passages.
• Green part: a weak, unsintered part whose particles are held by binder after binder jetting or bound-material shaping.
• Debinding: controlled removal of binder before sintering.
• Sintering: furnace densification of particles below the bulk melting temperature, normally accompanied by shrinkage.
• Stress relief: heat treatment intended to reduce residual stress generated during manufacturing.
• HIP: hot isostatic pressing; simultaneous high temperature and isostatic gas pressure used to reduce internal porosity and modify microstructure.
• Support removal: mechanical, thermal, chemical or machining operations used to separate supports from the part.
• Surface finishing: processes such as blasting, machining, polishing, chemical treatment or coating used to achieve functional surface requirements.

Quality, defects and industrialization

• Anisotropy: direction-dependent material or part behavior caused by process history, geometry or microstructure.
• Lack of fusion: incomplete bonding between adjacent melt tracks or layers.
• Keyhole porosity: pores associated with an unstable deep vapor cavity produced by excessive or poorly controlled energy input.
• Porosity: internal void volume; its type, size, shape and location can matter more than one bulk density number.
• Process window: the controlled range of inputs that can produce acceptable output.
• In-situ monitoring: collection of data during the build, such as optical, thermal, acoustic or machine-state signals.
• NDT: nondestructive testing used to examine a part without impairing its future use.
• CT: X-ray computed tomography, producing volumetric data for internal features, porosity and dimensional analysis.
• Qualification: documented demonstration that a material, process, machine, facility or part can meet specified requirements.
• Validation: evidence that a process or method consistently achieves its intended result under defined conditions.
• Traceability: ability to reconstruct the history of material, equipment, software, parameters, operators and downstream operations.
• Digital thread: connected data relationships spanning requirements, design, manufacturing, inspection and service life.
• MES: manufacturing execution system used to schedule, track and document production operations.
• First-pass yield: proportion of units accepted without rework, repair or repeated processing.
• Takt time: production pace required to meet demand; in AM it must include the entire accepted-part route, not only print time.

Continue with The Seven Additive Manufacturing Process Categories, LPBF vs DMLS vs SLM vs SLS, or the Research Hub.

Primary terminology reference: ISO/ASTM 52900:2021. Standards should be verified in their current controlled editions before contractual, regulatory or certification use.