Additive Manufacturing Taxonomy — Family Index
Process-family map for additive manufacturing (AM), organised against ISO/ASTM 52900:2021. Each process category is named with its standard term, its common industrial synonyms, governing physics, dominant material classes, representative machine vendors and material specs, and where it sits in the comparison table and selection heuristics at the end.
1. At a glance
ISO/ASTM 52900:2021 defines seven process categories:
- VPP — Vat Photopolymerization
- PBF — Powder Bed Fusion
- MEX — Material Extrusion
- MJT — Material Jetting
- BJT — Binder Jetting
- DED — Directed Energy Deposition
- SHL — Sheet Lamination
Materials axis (orthogonal to process):
- Polymer (thermoset photopolymer; thermoplastic)
- Metal (Ti, Al, steel, Ni-superalloy, Cu, Co-Cr, refractory)
- Ceramic (Al₂O₃, ZrO₂, SiC, hydroxyapatite)
- Composite (CF/GF-reinforced polymer, MMC)
- Bio / living tissue (cell-laden hydrogels, decellularised ECM)
A given machine usually occupies one process-category × one or two material-class cells. The taxonomy below walks each ISO/ASTM family in turn, then adds three industrially-important sub-families that sit alongside (hybrid, bio-printing, cold spray).
2. Vat Photopolymerization (VPP)
UV / visible-light cure of a liquid photopolymer resin, layer-by-layer, in a vat. Resolution is set by optics and resin chemistry, not powder size — so VPP dominates the “fine detail” end of AM.
2.1 SLA — Stereolithography
Point-by-point laser scan over the resin surface (top-down) or through a transparent vat floor (bottom-up). Charles Hull’s 1986 patent (US 4,575,330) at 3D Systems started commercial AM. Spot ~50–150 µm; layer 25–100 µm.
Vendors: 3D Systems (ProX 800, Figure 4), Formlabs (Form 3, Form 4 2024 with LFD low-force display), DWS Systems, UnionTech.
2.2 DLP — Digital Light Processing
A DMD (Texas Instruments micromirror) projector flashes a full slice of UV image in one exposure. Faster than SLA for full-area parts; pixel size sets XY resolution (~25–75 µm).
Vendors: 3D Systems Figure 4, EnvisionTec (now ETEC / Desktop Metal) D4K Pro, Stratasys Origin One (P3 programmable photopolymerization, acquired 2020), Asiga Pro.
2.3 LCD / MSLA — masked stereolithography
Cheap LCD panel masks a UV-LED backlight. Killed the hobby SLA market by ~2018; sub-$300 desktop machines now common.
Vendors: Anycubic Photon Mono / M3, Elegoo Mars / Saturn, Phrozen Sonic Mighty / Mega.
2.4 CLIP / DLS — Continuous Liquid Interface Production / Digital Light Synthesis
Carbon Inc.’s oxygen-permeable “dead-zone” membrane lets the build draw upward continuously rather than peeling each layer. ~10–100× faster than batch DLP; uses dual-cure resins (UV + thermal post-cure).
Vendors: Carbon L1 / M2 / M3 / M3 Max (subscription model).
2.5 VPP resins
Standard rigid, tough (ABS-like), flexible / elastomer (Carbon EPU, Formlabs Elastic), high-temp (heat-deflection >200 °C), castable (zero-ash for jewelry investment), dental (Class IIa biocompatible, e.g. Formlabs Permanent Crown), bone / dental ceramic-filled, silica- and alumina-filled “green” parts for sinter (Lithoz, Tethon).
3. Powder Bed Fusion — polymer (PBF-LB/P, PBF-IR/P)
A thin polymer powder layer is fused by a thermal source. Whole-volume preheat to just below Tm, then localised fuse.
3.1 SLS — Selective Laser Sintering
CO₂ laser scans each layer. Classic vendors: EOS P-series (P 396, P 500, P 770), 3D Systems sPro, Farsoon FS200 / FS300 / FS621M, Sintratec, Formlabs Fuse 1+.
Materials: PA12 (the workhorse, ~80–90% of SLS production), PA11 (more ductile, bio-based), PA-GF / PA-CF (glass- / carbon-filled), TPU (Lubrizol Estane, BASF Ultrasint TPU), PEEK / PEKK (high-temp, EOS HT-23).
3.2 MJF — Multi Jet Fusion
HP’s process (since 2016 with Jet Fusion 4200, now 5200 / 5210): a thermal-inkjet bar deposits a “fusing agent” and a “detailing agent” onto each powder layer, then an IR lamp sinters the agent-soaked voxels. Fastest polymer AM by volume.
Materials: PA12, PA11, PA12-GB (glass-bead), TPU, PP, PA-CF (5210 Pro). ~80% un-fused cake is recyclable.
4. Powder Bed Fusion — metal (PBF-LB/M, PBF-EB/M)
4.1 LPBF — Laser Powder Bed Fusion
Also marketed as SLM (SLM Solutions trademark — now Nikon), DMLS (EOS trademark), DMP (3D Systems). One or multiple fibre lasers (1064 nm Yb, 400–1500 W) melt a 20–60 µm powder layer in inert atmosphere (Ar; N₂ for steels).
Vendors and flagship platforms:
- EOS M 290 (250×250×325 mm, single 400 W), M 300-4, M 400-4 (4×1 kW)
- Nikon SLM (ex-SLM Solutions) NXG XII 600 / 600E — twelve 1 kW lasers
- TRUMPF TruPrint 3000 / 5000
- Renishaw RenAM 500Q / 500S (four lasers)
- GE Additive Concept Laser M2 Series 5, M-Line Factory
- Velo3D Sapphire / Sapphire XC — non-contact recoater, claims “support-free” overhangs to <10°
- Aconity AconityMIDI+ / ONE / LAB
- 3D Systems DMP Factory 350 / 500
- AddUp FormUp 350 (open architecture)
Materials (ASTM specs in parentheses where defined):
- Ti-6Al-4V Grade 5 / Grade 23 ELI (ASTM F3001)
- AlSi10Mg, AlSi7Mg, Scalmalloy, AlF357, A205 (Aeromet)
- 316L, 17-4PH, 15-5PH, PH1 (EOS), 18Ni300 maraging
- H13, M300 tool steels for conformal-cooling injection mould inserts
- Inconel 718 (ASTM F3055), Inconel 625, Hastelloy X, Haynes 282
- Co-Cr (F75 / F1537) for dental and orthopaedic
- CuCrZr, pure Cu (1064 nm absorption is the historic problem — green / blue-laser machines from TRUMPF and IPG now solve this)
- Refractory: W, Mo, Ta, Nb (specialty)
4.2 EBM — Electron Beam Melting / PBF-EB
Originated at Arcam AB (Sweden, acquired 2016 by GE Additive). Vacuum chamber, ~60 keV electron beam, ~700 °C powder-bed preheat (vs ~80–200 °C in LPBF) — yields stress-relieved as-built parts, but rougher surface and only conductive materials.
Machines: Arcam EBM Spectra H / Spectra L, GE Additive Q10plus / Q20plus.
Materials: Ti-6Al-4V (orthopaedic acetabular cups — the canonical EBM application, with intentional porous-lattice for osseointegration), Ti-Al (TiAl, e.g. GE GEnx LPT blades — first FAA-certified EBM flying part), CoCr.
5. Material Extrusion (MEX)
Thermoplastic melt or paste extruded through a nozzle, deposited in roads layer-by-layer.
5.1 FFF / FDM — Fused Filament Fabrication
S. Scott Crump’s 1989 Stratasys patent (US 5,121,329) used the trade-mark FDM; ISO/ASTM and the open-source community use the generic FFF. Filament (1.75 mm or 2.85 mm) is unspooled, melted in a heater block, extruded through a 0.2–0.8 mm brass / steel / ruby nozzle.
Vendors:
- Stratasys Fortus 450mc / 900mc, F123-series, F900
- Markforged X7 / FX20 — continuous-carbon-fibre lay-in with separate fibre nozzle
- Ultimaker S5 / S7 Pro
- Prusa Research MK4, XL (5-toolhead)
- Bambu Lab X1 Carbon (2022), X1E, P1S — drove the consumer market from ~50 mm/s to 500 mm/s with input-shaping and active-flow control
- Raise3D Pro3 / RMF500
- Pollen Pam Series MC (granulate-fed)
Materials: PLA, PETG, ABS, ASA, PC, PA6 / PA66 / PA12, TPU, PC-ABS, PEEK, PEI (ULTEM 9085 / 1010) for aerospace cabin interiors (FAA FAR 25.853 compliant on Stratasys F900 + ULTEM 9085), CF-PA / CF-PEEK / GF-PA.
5.2 Pellet extrusion / BAAM
Direct from pellet (granulate) — bypasses filament cost. BAAM (Big Area Additive Manufacturing) — ORNL + Cincinnati Inc. demo’d a Shelby Cobra-sized print in 2014; LSAM at Thermwood; Caracol Heron series; JuggerBot 3D Tradesman; Massive Dimension. Build volumes to ~6×2×2 m, deposition ~50 kg/h.
5.3 DIW — Direct Ink Writing
Pneumatic / screw-driven paste extrusion: silicones (Wacker Aceo, Lynxter), clays (LUTUM, WASP), graphene / metal-particle inks (Aerotech, Hyrel), and bio-inks (see §11). No melt — flows by shear-thinning, sets by cure or evaporation.
6. Material Jetting (MJT)
Drop-on-demand inkjet of a build material; ~16–32 µm layers.
6.1 PolyJet (Stratasys, ex-Objet, acquired 2012)
UV-cure photopolymer drops. Multi-material (multiple printheads + grayscale mixing) → full-colour, multi-Shore-A in one part — unique among AM processes. Soluble or breakaway gel support.
Machines: Stratasys J55 / J35 Pro (office-friendly), J750 / J850 Prime / J850 Pro / J850 Digital Anatomy (medical models), Objet260/500 Connex.
6.2 Wax pattern jetting
Solidscape T76+ / Max² / S500 — pure wax pattern for lost-wax / investment casting (jewelry, medical). Sub-25 µm layer, near-zero ash.
6.3 Nanoparticle metal / ceramic jetting
XJet Carmel 1400M / 1400C — nano-particle inks (steel, IN718, alumina, zirconia) jetted then sintered. Spritam (Aprecia) launched the first FDA-approved 3D-printed drug via inkjet AM (2015).
7. Binder Jetting (BJT)
A liquid binder droplet bonds powder; “green” part is then debound and sintered (metal / ceramic) or infiltrated (sand).
7.1 Sand BJT — foundry cores and moulds
ExOne S-Max / S-Max Pro / S-Print, voxelject VX1000 / VX2000 / VX4000 (the 4×2×1 m VX4000 is the largest production AM machine of any kind), Loramendi Reborn. Furan- or phenolic-bound silica, ceramic, or zircon sand. Used by automotive (cylinder-head cores), aerospace, art casting.
7.2 Metal BJT
Cold “green” part → solvent / thermal debind → high-temp sinter in H₂ / vacuum. Final part is ~95–99% dense (sometimes HIP’d to closing porosity).
Vendors: Desktop Metal Production System P-1 / P-50 (Single Pass Jetting), ExOne X1 25Pro / X1 160Pro (now Desktop Metal), HP Metal Jet S100, GE Additive Series 3 (formerly H2), Digital Metal DM P2500, Sandvik Osprey.
Materials: 316L, 17-4PH, 4140, 4340, IN625, Ti-6Al-4V (sinter-sensitive), Cu (excellent — no laser-absorption problem), Co-Cr.
7.3 Ceramic BJT and CJP
Lithoz CeraFab (technically lithography-based ceramic — sits between VPP and BJT), 3D Systems ProJet CJP (ColorJet — gypsum-based full-colour models). Bio-ceramic hydroxyapatite scaffolds (ExOne Innovent+).
8. Directed Energy Deposition (DED)
Feedstock (powder or wire) is melted at the deposition point by a focused energy source. No powder bed → larger envelopes, repair on existing parts, multi-material in-deposition.
8.1 Laser DED — powder (LMD / DMD / LENS)
Coaxial powder nozzles + fibre laser. Vendors: TRUMPF TruLaser Cell 7040, BeAM / AddUp Magic 800 / Modulo 400, Optomec LENS CS / LENS 860, Meltio M450 (wire+powder hybrid). Used for high-value repair (turbine blade tip restoration, die / mould repair, oil & gas valves).
8.2 Laser DED — wire
Meltio M600 (six-laser wire-fed system), Mazak Hybrid VC-500, TRUMPF TruLaser Weld 8000. Standard MIG-grade wire → 100% material utilisation (vs ~70% for powder DED).
8.3 Electron Beam DED — wire
Sciaky EBAM 110 / 150 / 300 — vacuum chamber, wire feed, deposition rates 3–9 kg/h Ti-6-4 (the highest in metal AM). NASA, Lockheed Martin, Airbus use for large Ti-6-4 near-net-shape forgings.
8.4 Plasma / arc DED
- Norsk Titanium RPD (Rapid Plasma Deposition) — plasma-transferred-arc Ti-6Al-4V wire; Boeing-qualified aerospace structural parts (787).
- WAAM (Wire Arc Additive Manufacturing) — repurposed MIG / TIG / Plasma robots (Cranfield University, Wayland Additive Calibur3 — actually EB-PBF, but Cranfield runs WAAM), MX3D (Amsterdam stainless-steel pedestrian bridge, 2018, twelve metres, built by ABB IRB 2600 + robotic MIG). Best for large, low-complexity structures at ~1–10 kg/h.
DED is also the only category that meaningfully does functional grading (composition gradient through the part) and repair / cladding on existing parts.
9. Sheet Lamination (SHL)
Foils or sheets cut to shape and bonded.
9.1 UAM — Ultrasonic Additive Manufacturing
Fabrisonic SonicLayer 1200 / 4000 / 7200 — Al / Cu / Ti foils ultrasonically welded at ~20 kHz, solid-state (T < 0.5 Tm). Unique capability: embed fibre-optic / thermocouple / electronics mid-build. Used by NASA on the Mars-2020 thermal-tile carrier.
9.2 LOM — Laminated Object Manufacturing
Original 3D Systems / Helisys process (paper-stack with adhesive, knife-cut) — largely obsolete for production but lingers in CAM-LEM ceramic (Lone Peak) and Mcor paper-colour systems (discontinued).
10. Hybrid / multi-process systems
DED or LPBF combined in one work envelope with 5-axis subtractive milling — single-fixture build & finish.
- DMG MORI LASERTEC 65 / 125 DED hybrid — laser-DED head + full 5-axis mill-turn
- Mazak VC-500 AM / Integrex i-400 AM — Ambit DED head swap into a Mazak machining centre
- Optomec LENS-CS — DED + mill
- Hermle MPA — cold-spray on 5-axis Hermle C-series, deposits embedded copper conformal channels in steel tool inserts
- Hybrid Manufacturing Technologies Ambit retrofit DED head — drops into any HAAS / DMG / Mazak / Mori platform
11. Bio-printing
Extrusion or inkjet of cell-laden hydrogels for tissue engineering, drug screening, regenerative medicine.
Vendors: CELLINK BIO X / BIO X6, Allevi 3 / 6, RegenHU R-Gen 200 / 3DDiscovery, Aspect Biosystems RX1, Inventia Rastrum, Organovo NovoGen (early commercial liver tissue, now wound down).
Bio-inks:
- GelMA (gelatin methacryloyl) — UV-crosslink
- Alginate — Ca²⁺ ionic crosslink
- Collagen Type I — thermal gel
- Decellularised ECM (dECM) — tissue-specific
- Pluronic F-127 — sacrificial / fugitive ink for vasculature channels
- PEG-DA, hyaluronic-acid methacrylate, fibrinogen
12. Cold spray (kinetic deposition)
Not strictly in ISO/ASTM 52900, but treated as solid-state AM by ASTM F42. Powder accelerated to >500 m/s in supersonic N₂ / He jet, deposits by plastic-deformation impact bonding. No melting → no HAZ, no oxidation, no microstructural change.
Vendors: Plasma Giken PCS-1000 / PCS-800, Impact Innovations ISS 5/11, Titomic TKF1000 (largest cold-spray system, ~9×3×1.5 m), VRC Metal Systems. US Navy + US Air Force (Tinker AFB, NAVAIR) use for aircraft skin and corrosion-pit repair on legacy airframes.
13. Comparison table
| # | Process | Typ materials | Min feature | Layer thickness | Build envelope | Typ deposition rate | Post-process | Typical use |
|---|---|---|---|---|---|---|---|---|
| 1 | SLA (VPP) | photopolymer resin | 50 µm | 25–100 µm | 145×145×185 mm (Form 4) → 1500×750×550 mm (3DS) | 10–60 mm/h (Z) | wash + UV post-cure | high-detail prototypes, dental, jewelry pattern |
| 2 | DLP (VPP) | photopolymer | 25–50 µm | 25–100 µm | up to 192×108×370 mm (Origin One) | 50–100 mm/h | wash + UV post-cure | dental aligners, hearing aids, end-use polymer |
| 3 | LCD/MSLA (VPP) | photopolymer | 35–80 µm | 25–100 µm | ~200×120×250 mm | 20–60 mm/h | wash + UV post-cure | hobby, desktop prototype |
| 4 | CLIP/DLS (VPP) | Carbon dual-cure | 50–75 µm | 25–100 µm | 189×118×326 mm (M2) | 100–500 mm/h | wash + thermal cure | end-use polymer (Adidas 4DFWD) |
| 5 | SLS (PBF-LB/P) | PA12, PA11, TPU, PEEK | 200–400 µm | 80–120 µm | 340×340×600 mm (EOS P 500) | 1–4 kg/h | de-powder, bead-blast | end-use polymer, low-mid volume |
| 6 | MJF (PBF-IR/P) | PA12, PA11, TPU, PA-CF | 200 µm | 80 µm | 380×284×380 mm (HP 5200) | 4–5 kg/h | de-powder, bead-blast, dye | end-use polymer high-volume |
| 7 | LPBF (PBF-LB/M) | Ti, Al, steel, IN718, IN625, CoCr, Cu | 100–200 µm | 20–60 µm | 250×250×325 mm (M 290) → 600×600×600 (NXG XII) | 5–150 cm³/h per laser | support cut, stress-relief, HIP, heat-treat, finish | end-use metal aerospace / medical |
| 8 | EBM (PBF-EB/M) | Ti-6-4, TiAl, CoCr | 200–400 µm | 50–100 µm | 350×350×380 mm (Spectra L) | 50–80 cm³/h | de-powder, HIP optional, finish | orthopaedic Ti implants, TiAl turbine blades |
| 9 | FFF/FDM (MEX) | PLA, ABS, PC, PA, ULTEM, PEEK | 400 µm | 100–300 µm | 200×200×200 mm desktop → 914×610×914 mm (Stratasys F900) | 50–300 cm³/h | support removal, anneal (PEEK) | prototypes → end-use polymer brackets |
| 10 | Markforged CFR | Onyx + continuous CF | 400 µm | 100 µm | 330×270×200 mm (X7) | mod | none | structural polymer + Al replacement |
| 11 | BAAM pellet MEX | ABS-CF, PETG-CF | 4 mm | 4 mm | 6×2×2 m | 20–80 kg/h | CNC-finish | tooling, mould, large fixture |
| 12 | DIW (MEX) | silicone, clay, bio-ink | 200 µm | 200 µm | varies | low | cure / sinter | soft robotics, ceramics, tissue |
| 13 | PolyJet (MJT) | photopolymer multi-mat | 14–28 µm | 14–28 µm | 490×390×200 mm (J850) | 5–20 mm/h | water-jet support removal | full-colour medical models, multi-Shore parts |
| 14 | Wax MJT (Solidscape) | wax | 25 µm | 12–76 µm | 152×152×101 mm | slow | melt support | investment casting patterns |
| 15 | XJet NPJ | steel, IN718, Al₂O₃, ZrO₂ | 30 µm | 8 µm | 500×280×200 mm | mod | debind + sinter | fine metal / ceramic functional parts |
| 16 | Sand BJT | silica / zircon sand | 300 µm | 280 µm | 4000×2000×1000 mm (VX4000) | 100–300 L/h | bake | foundry cores & moulds |
| 17 | Metal BJT | 316L, 17-4PH, IN625, Cu | 100 µm | 50–100 µm | 800×500×400 mm (P-50) | 1000 cm³/h (green) | debind + sinter (+ HIP) | mid-high volume metal end-use |
| 18 | Ceramic BJT / Lithoz | Al₂O₃, ZrO₂, HA, Si₃N₄ | 25–40 µm | 25 µm | 100×100×100 mm | low | debind + sinter | dental, surgical, RF / aerospace ceramics |
| 19 | CJP / ColorJet (BJT) | gypsum + binder | 100 µm | 100 µm | 508×381×229 mm | mod | infiltrate (CA / wax) | full-colour visual prototypes |
| 20 | Laser DED powder | Ti, IN, tool steel | 500 µm | 200–500 µm | 800–4000 mm reach | 0.5–4 kg/h | machine to final | repair, multi-material, gradient |
| 21 | Wire-DED laser | Ti, IN, steel | 1 mm | 0.5–2 mm | similar | 1–6 kg/h | machine | medium-scale near-net-shape |
| 22 | EBAM (Sciaky) | Ti-6-4, IN, Ta, refractories | 3–6 mm | 2–5 mm | 5800×1200×1200 mm (EBAM 300) | 3–9 kg/h (Ti) | HIP + machine | large Ti aerospace structures |
| 23 | WAAM | Ti, steel, Inconel, Al | 2–5 mm | 1–3 mm | robot envelope (5–20 m) | 1–10 kg/h | machine | bridges, propellers, large frames |
| 24 | UAM (SHL) | Al, Cu, Ti foils | 25 µm | 100–200 µm (foil) | 1200×600×600 mm (SonicLayer 4000) | mod | machine | embedded-sensor parts, dissimilar-metal |
| 25 | Cold spray | Al, Cu, Ni, Ti, Inconel | 1–3 mm | 0.05–1 mm | robot envelope | 5–20 kg/h | machine | corrosion repair, dimensional restoration |
14. Materials matrix
14.1 Polymers (thermoplastic + photopolymer)
- Commodity FFF: PLA, PETG, ABS, ASA
- Engineering FFF: PC, PA6 / PA66 / PA12, PC-ABS, TPU 95A
- High-performance FFF: PEEK, PEKK, PEI (ULTEM 9085 / 1010), CF-PEEK, CF-PA
- SLS / MJF: PA12, PA11, PA-GB, PA-GF, PA-CF, TPU (Estane, Ultrasint), PP, PEEK HT
- Photopolymer (VPP, MJT): rigid (standard, tough, durable), flexible / elastomer (EPU, Elastic 50A), high-temp (HDT 238 °C / Rigid 10K), castable (jewelry zero-ash), dental Class IIa (Permanent Crown, Surgical Guide), ceramic-filled green for sinter
14.2 Metals
- Titanium: Ti-6Al-4V Grade 5 / Grade 23 ELI (medical), CP-Ti, Ti-6Al-2Sn-4Zr-2Mo (aerospace), TiAl γ-aluminide (EBM only — too brittle for LPBF)
- Aluminium: AlSi10Mg, AlSi7Mg, AlF357, Scalmalloy (APWorks high-strength), A205 / A20X (Aeromet, copper-bearing high-strength), 6061-RAM2 (Elementum), 7075-derivatives (Hughes-Reduced/Nanoal)
- Stainless / PH steels: 316L, 304L, 17-4PH, 15-5PH, PH1 / GP1 (EOS proprietary)
- Tool steels: H13, M300 (1.2709 maraging), H11, S7, M2 — for conformal-cooled mould inserts
- Ni-superalloys: Inconel 718 (most common — ASTM F3055), Inconel 625, Hastelloy X, Haynes 282, MAR-M-247 and René 80 (cast-grade, difficult — cracking-prone in LPBF, EBM preferred)
- Co-Cr: F75 (cast composition, EBM), F1537 (LPBF, wrought-composition), CoCrMo dental
- Copper: pure Cu, CuCrZr (high-conductivity heat exchangers, NASA RS-25 nozzle, SpaceX Raptor injectors) — requires green / blue laser or e-beam
- Refractory: W, Mo, Ta, Nb — specialty research-grade
- Precious: Au (jewelry, Cooksongold via EOS), Pt, Pd
14.3 Ceramics
Al₂O₃ (alumina, electrical / RF), ZrO₂ (zirconia, dental crowns), Si₃N₄ (bearing rolls), SiC (research), hydroxyapatite + β-TCP (bone scaffolds), porcelain (Lithoz dental).
14.4 Composites
- Chopped fibre in thermoplastic: CF-PEEK, CF-PA, GF-PA (FFF, SLS, MJF)
- Continuous fibre: Markforged CFF (continuous carbon, Kevlar, fibreglass, HSHT-glass lay-in inside a Nylon matrix)
- MMC: SiC-Al, TiC-Ti (research, DED + cold spray)
15. Post-processing
15.1 Support / powder removal
- Polymer FFF: water-soluble PVA / HIPS, breakaway, SR-30 / SR-110 alkaline-soluble (Stratasys)
- VPP: IPA / TPM wash → UV post-cure (Formlabs Form Wash + Form Cure)
- PolyJet: water-jet of SUP705 / SUP706 gel
- SLS / MJF: bead-blast + tumble + optional vapour-smooth (AMT PostPro 3D acetone vapour for PA12)
- LPBF: wire-EDM off build plate; cut supports; bead-blast / abrasive
15.2 Debinding + sintering (BJT-metal, MEX-metal, NPJ)
Solvent debind (acetone / heptane) → thermal debind in N₂ / H₂ → high-temp sinter (~1300–1400 °C for 316L, ~1080 °C for IN625, ~1250 °C for 17-4PH). Density 95–99.5%.
15.3 HIP — Hot Isostatic Pressing
100–200 MPa Ar at near-solidus temperature, 2–6 h. Closes gas-porosity in LPBF Ti-6-4, IN718, AlSi10Mg — mandatory for aerospace fatigue-critical parts. ASTM F3001 mandates HIP for Ti-6-4 implants.
15.4 Heat treatment
- AlSi10Mg: T6 (solution 530 °C / quench / age 160 °C × 6 h) → σ_y ~250 MPa
- 17-4PH: solution 1040 °C / age H900 / H1025 / H1150 depending on strength-toughness trade
- Ti-6-4: stress-relief 600–700 °C; β-anneal 1050 °C for fatigue
- IN718: solution 980 °C + double-age 720 → 620 °C
- Tool steels (H13, M300): solution + tempering / age-hardening
15.5 Surface finishing
Bead / shot peening, electro-polishing (especially for Ti / CoCr medical Ra < 0.4 µm), chemical polish (CMP, Hirtisation by Hirtenberger), abrasive flow Extrude Hone for internal passages, micro-machining of mating surfaces, DLyte electrochemical dry-electrolyte (GPAINNOVA).
16. Quality and inspection
16.1 In-situ monitoring (LPBF)
- Melt-pool monitoring: high-speed coaxial photodiode + camera — EOSTATE MeltPool, Sigma Labs PrintRite3D, SLM Solutions Melt Pool Monitoring (MPM)
- Layer-wise thermography: e.g. EOSTATE Exposure OT, Aconity AconityVISION
- Powder-bed imaging: before/after recoat, ML-classified anomalies
16.2 Post-build inspection
- X-ray CT: Zeiss Metrotom 1500 / 6 scan, Nikon XT H 225 / 320 / 450, GE phoenix v|tome|x m / s, North Star Imaging X25 / X50 — internal porosity to ~0.1% void fraction, complex internal geometry verification
- CMM: tactile + optical for external geometry
- Surface roughness: confocal (Sensofar, Bruker) vs stylus (Mitutoyo)
- Density: Archimedes for batch, CT-derived for spatial
- Mechanical: tensile, fatigue, fracture-toughness witness coupons per build
16.3 Standards
- ISO/ASTM 52900:2021 — terminology (replaces ASTM F2792)
- ISO/ASTM 52904 — LPBF process qualification
- ISO/ASTM 52911-1 — design rules for PBF metal
- ASTM F3001 — Ti-6Al-4V ELI by PBF (medical)
- ASTM F2924 — Ti-6Al-4V by PBF (general)
- ASTM F3055 — IN718 by LPBF
- ASTM F3318 — AlSi10Mg by LPBF
- NADCAP AC7110/14 — aerospace AM accreditation
17. Selection heuristics
| Need | Recommended process |
|---|---|
| Form-fit visual prototype, $ minimum | FFF (Bambu X1C, Prusa MK4) PLA |
| High-detail aesthetic prototype | LCD resin (Anycubic, Phrozen) or SLA (Form 4) |
| Functional polymer prototype, moderate batch | SLS PA12 (Formlabs Fuse 1+, EOS P 396) |
| End-use polymer, high volume | MJF (HP 5200) PA12 |
| Continuous-CF structural polymer (Al replacement) | Markforged X7 / FX20 |
| Complex Al aerospace bracket | LPBF AlSi10Mg → T6 → HIP |
| Ti orthopaedic implant with porous lattice | EBM Ti-6Al-4V (acetabular cup template) |
| Tool-steel injection mould with conformal cooling | LPBF H13 or M300, then HIP + heat-treat + EDM + polish |
| Large Ti landing-gear or wing-rib near-net-shape | Sciaky EBAM (1 t-class deposition) or Norsk Titanium RPD |
| Large stainless / IN large-scale structure | WAAM (MX3D-style) |
| End-use Ni-superalloy turbine vane / fuel-nozzle | LPBF IN718 (e.g. GE LEAP fuel nozzle, 19→1 part) |
| Copper combustion chamber / heat exchanger | LPBF CuCrZr (green or blue laser) |
| Foundry sand mould for one-off castings | Sand BJT (ExOne S-Max, voxeljet VX1000) |
| Mid-volume small metal parts ($ per part) | Metal BJT (Desktop Metal P-50, HP Metal Jet) |
| Investment-casting wax pattern (jewelry, surgical) | Solidscape wax MJT or castable SLA resin |
| Dental crown, biocompatible polymer / ceramic | DLP Permanent Crown (Formlabs / Dentsply) or LCD ceramic-filled |
| Turbine-blade tip repair | Laser DED powder (Optomec LENS, TRUMPF TruLaser Cell) |
| Aircraft corrosion-pit repair (Al / Ti skin) | Cold spray (Plasma Giken, Titomic, VRC) |
| Multi-Shore / full-colour anatomical model for surgical rehearsal | PolyJet J850 Digital Anatomy |
| Soft-robotics elastomer or silicone | DIW (Wacker Aceo, Lynxter) or Carbon DLS EPU |
| Bone scaffold or tissue construct | Bio-printing (CELLINK BIO X) with GelMA or dECM |
| Food-safe consumer polymer part | SLS PA12 (FDA-cleared) or MJF |
| Embed strain-gauge / fibre-optic inside an Al part | UAM (Fabrisonic SonicLayer) |
| Build & finish in one fixture | Hybrid (DMG MORI LASERTEC, Mazak VC-500 AM) |
| Fastest possible polymer build, support-free overhangs | Carbon DLS (CLIP) |
| Self-supporting LPBF metal (overhangs to ~10°) | Velo3D Sapphire (non-contact recoater) |
18. Cross-references
- additive-manufacturing — process overview tier-2 note
- aluminum-alloys — AlSi10Mg, AlSi7Mg, Scalmalloy, A205 wrought / cast / AM grades
- titanium-alloys — Ti-6Al-4V Grade 5 / 23 ELI, TiAl, CP-Ti
- steel-grades — H13, M300, 4140 tool & structural for AM
- stainless-steels — 316L, 17-4PH, 15-5PH heat-treats
- copper-alloys — CuCrZr, GRCop-42/84 (NASA)
- ceramics-taxonomy — Al₂O₃, ZrO₂, Si₃N₄, hydroxyapatite for VPP / BJT ceramic AM
- polymers-taxonomy — PA12, PEEK, ULTEM, PC for SLS / MJF / FFF
19. Citations
- ISO/ASTM 52900:2021 — Additive manufacturing — General principles — Fundamentals and vocabulary. (Supersedes ASTM F2792.)
- ISO/ASTM 52904:2024 — AM — Process characteristics and performance — Practice for metal PBF-LB to meet critical applications.
- ISO/ASTM 52911-1:2019 — AM — Design — Part 1: Laser-based PBF of metals.
- ASTM F3001 / F2924 / F3055 / F3318 — material-specific PBF specs (Ti-6-4 ELI, Ti-6-4, IN718, AlSi10Mg).
- Gibson, I.; Rosen, D.; Stucker, B.; Khorasani, M. — Additive Manufacturing Technologies, 3rd ed., Springer, 2021.
- Wohlers Associates — Wohlers Report 2025 — annual industry survey of installed-base and revenue across all seven categories.
- Frazier, W. E. — “Metal Additive Manufacturing: A Review”, JMEPEG 23(6), 2014 — foundational survey.
- DebRoy, T. et al. — “Additive manufacturing of metallic components — Process, structure and properties”, Prog. Mater. Sci., 2018.
- NIST IR 8005 — Measurement Science Roadmap for Metal-Based AM.
- America Makes — National Additive Manufacturing Innovation Institute reports.