3D printing processes
What is FDM 3D printing, and what is it good for?
FDM (fused deposition modelling) 3D printing melts thermoplastic filament and lays it down layer by layer to build a part. It suits large parts, jigs, fixtures, brackets and functional prototypes. On our service, FDM builds parts up to 1000 × 1000 × 1000 mm at ±0.5% (minimum ±0.3 mm), with lead times from 1 calendar day.
Reviewed by HenleyPrint3D engineers2 min readUpdated
Key takeaways
- Build volume up to 1000 × 1000 × 1000 mm; lead time from 1 calendar day.
- Tolerance ±0.5% with a minimum of ±0.3 mm; layers from 50 microns.
- Wide material range, from PLA to ULTEM on request.
- Layer lines show, and strength is lower across layers than along them.
Suits
Large parts, jigs, fixtures, brackets and functional prototypes.
Worth knowing
Not the best choice for fine detail or a smooth surface straight off the machine. Use SLA, or add a finish.
FDM key figures
| Property | FDM on our service |
|---|---|
| Build volume | Up to 1000 × 1000 × 1000 mm |
| Tolerance | ±0.5% (min ±0.3 mm) |
| Layer height | From 50 microns |
| Minimum wall | 1.0 to 1.2 mm |
| Self-supporting overhang | About 45° from vertical |
| Lead time | From 1 calendar day |
FDM strengths and limits
| Good for | Watch out for |
|---|---|
| Large parts, jigs, fixtures, brackets | Visible layer lines |
| Tough, heat-tolerant and flexible materials | Strength across layers is lower |
| Lowest cost per part among our processes | Nylon and long thin parts warp on cooling |
Common FDM materials
| Material | Use it for | Watch |
|---|---|---|
| PLA | Form-fit models | Softens above about 55 to 60 °C |
| PETG | General functional parts | Moderate heat limit |
| ABS / ASA | Impact loads; ASA for outdoor use | ABS warps on large parts |
| TPU | Seals, grips, bumpers | Low stiffness |
| Nylon | Wear and moving parts | Absorbs moisture |
FDM or another process?
| If you need | Choose |
|---|---|
| A part larger than 350 mm | FDM |
| The lowest cost per part | FDM |
| Fine detail and a smooth surface | SLA |
| Support-free nylon in batches | SLS |
Designing for FDM
For a tight fit, print the feature with a small allowance and ream it afterwards. For a smoother surface, specify a sanded and painted finish. Material grades, from PLA to ULTEM on request, are listed on our FDM materials page, and the FDM 3D printing service page covers ordering and build sizes.
To compare FDM with resin and powder processes, see FDM vs SLA vs SLS vs PolyJet. For why orientation matters, see layer orientation and part strength.
Frequently asked questions
How strong are FDM parts?
FDM parts are strongest along their layers and weaker across them. Correctly oriented nylon or ABS parts are routinely used as functional components, but loads across the layer lines should be avoided or designed for.
How accurate is FDM 3D printing?
Typically ±0.5% with a practical minimum around ±0.3 mm. Material, part size and geometry all affect the result, and critical features can be machined after printing.
What is the difference between FDM and FFF?
They describe the same process. FDM is a trademarked term from Stratasys, while FFF (fused filament fabrication) is the generic name used widely in the industry.
Can FDM parts be used outdoors?
Yes, if the material is chosen for it. ASA is formulated for UV stability, whereas PLA and some other grades degrade or soften in sunlight and heat.
What is the largest part FDM can print?
It depends on the machine. Desktop printers manage a few hundred millimetres, while our industrial FDM service builds up to 1000 × 1000 × 1000 mm, and larger assemblies can be bonded from sections.
Get started
Talk to an engineer about your part.
Send us your CAD or describe the problem. We recommend the process, material and finish, and quote with the lead time up front.
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