Which process should you use?
Seven process families, and the right one depends on the part. Start from what the part actually needs — material, size, detail, strength, budget — and the choice usually makes itself. Here is the comparison, the shortcuts, and the questions that decide it.
The seven families, side by side
| Process | Resolution | Speed | Cost | Isotropy | Typical parts |
|---|---|---|---|---|---|
| FDM / FFF Material extrusion | 0.1–0.3 mm layers | Moderate–fast | $ (lowest) | Poor (Z ≈ 30–70% of XY) | Prototypes, jigs and fixtures, low-volume functional parts, large tooling |
| SLA / DLP / MSLA Vat photopolymerization | 0.01–0.05 mm layers | Moderate (fast on MSLA/CLIP) | $$ | Good (chemical bonding) | Dental and jewellery masters, miniatures, hearing aids, fine functional prototypes |
| SLS / MJF / DMLS Powder bed fusion | 0.06–0.12 mm layers | Moderate (whole layer on MJF) | $$$ | Best (of the polymer processes) | End-use functional parts, complex ducting and manifolds, low-volume production, metal aerospace and medical parts |
| PolyJet / MJ Material jetting | 0.014–0.03 mm layers | Moderate | $$$$ | Good | Realistic full-colour prototypes, medical and anatomical models, over-moulding mock-ups, investment-casting patterns |
| Binder jetting Binder jetting | 0.05–0.2 mm layers | Fast (no melting) | $$$ | Good (post-sinter) | Sand casting moulds and cores, high-volume small metal parts, full-colour figurines and architectural models |
| DED / WAAM Directed energy deposition | 0.5–5 mm beads | Very fast (deposition) | $$$$ | Moderate (weld-like) | Repair of turbine blades and dies, large aerospace/defence structures, cladding, near-net-shape titanium |
| LOM / UAM Sheet lamination | 0.05–0.2 mm sheets | Fast (per layer) | $$ | Poor (between sheets) | Concept and architectural models (LOM), embedded-electronics and smart metal structures (UAM) |
Cost is relative ($ cheapest → $$$$ industrial). Resolution is the layer thickness — smaller is finer but slower.
Pick by what matters most
Lowest hardware and material cost, everything from PLA to PEEK, and affordable large build volumes.
Light cures finely and layers bond chemically — miniatures, dental, jewellery masters.
The strongest, most isotropic polymer parts; the powder bed supports every overhang.
Jets several photopolymers per pass — colour, transparency and shore-hardness gradients together.
Sinter-based, tooling-free and fast — the cost-competitive route to high-volume metal and direct foundry moulds.
Very high deposition rate onto existing parts — turbine repair, metres-scale structures.
Ultrasonic welding is cool enough to trap fibres and electronics between metal foils.
The five questions that decide it
- 1What material?
This narrows it fastest. Engineering thermoplastic → FDM or SLS. A fine detailed model → resin. Metal → powder-bed (SLM), binder jetting or DED. Full colour → material or binder jetting.
- 2How big — and how many?
Palm-sized and one-off → resin or desktop FDM. Large → FDM or DED. Dozens to hundreds of durable parts → SLS/MJF or binder jetting. Above ~10,000, stop printing and injection-mould.
- 3Detail vs strength?
You usually trade them. Resin wins detail and surface; powder-bed wins strength and isotropy; FDM is the cheap middle. Decide which the part actually needs.
- 4Supports and post-work?
Powder and sand processes need no supports and little cleanup; FDM, resin and jetting need supports removed and (resin) washing and curing. Budget the finishing time.
- 5Budget?
FDM is cheapest end to end; resin is cheap to buy but messy to run; powder-bed, jetting and metal processes are industrial-cost. Match the process to the part's value.
Then pick a material, read the design rules, or go back to the 3D printing guide. For high volume, compare with the moulding processes.