The short version
FDM (Fused Deposition Modelling) builds objects by melting and depositing a plastic filament layer by layer. It's fast, versatile, produces strong and durable parts, handles large objects well, and is straightforward to run daily. Resin (MSLA) cures a liquid resin using UV light layer by layer, producing surface quality and fine detail resolution that FDM physically cannot match at any price point. Both technologies have a place — what determines which is right for you is almost entirely the nature of your projects.
If you can walk into our Somerset West showroom and hold a finished print from each, the decision usually becomes obvious within five minutes. If you can't visit, this guide should get you there.
FDM printing — the functional workhorse
FDM melts a thermoplastic filament (PLA, PETG, ABS, ASA, TPU) and deposits it layer by layer on a build plate to construct a solid object. The layers are visible on the finished surface — not as a flaw, but as a characteristic of the technology that becomes less noticeable at finer layer heights.
Where FDM leads:
- Large objects — build volumes up to 500×500×500mm on the Neptune 4 Max
- Strong, functional parts — replacement components, brackets, enclosures, jigs
- Wide material range — including flexible TPU, heat-resistant ABS and ASA, and outdoor-stable ASA
- Lower ongoing consumable cost — filament is significantly cheaper per kg than resin per litre
- Simpler post-processing — remove supports, done. No chemical wash or UV cure required.
- More forgiving for beginners — failures are less messy and less costly
Where FDM falls short:
- Surface detail — visible layer lines limit achievable fine detail
- Small intricate objects — at miniature scale, FDM layer lines become prominent
- Dimensional accuracy on very small features — sub-millimetre features are difficult to resolve cleanly
Resin printing — the detail specialist
Resin printing cures a liquid photopolymer resin using a UV light source through a high-resolution LCD screen, hardening each layer with exceptional precision. The result is a surface quality that is genuinely in a different category from FDM — smooth, fine-featured, and capable of resolving detail at a scale where FDM layer lines would be larger than the feature itself.
Where resin leads:
- Surface finish — smooth, professional-quality surfaces with no visible layer lines at standard resolution
- Fine detail — facial features, jewellery filigree, miniature texturing, dental anatomy
- Dimensional accuracy at small scale — tight tolerances achievable on small parts
- Presentation quality — prototypes and display models that look finished rather than printed
Where resin falls short:
- Smaller build volumes — resin printers have smaller build plates than equivalent FDM printers
- Post-processing — every print requires a chemical wash (IPA or water-washable solution) and UV curing before use
- Resin handling — liquid resin requires gloves, adequate ventilation, and careful disposal. Not suitable for environments without proper handling conditions.
- Higher consumable cost — resin is more expensive per volume than filament
- Brittleness — standard resin prints are more brittle than FDM prints in the same size, though ABS-like and tough resin formulations improve this significantly
Choosing by project type
FDM. Material strength, build size, and lower cost per part all point to FDM for functional applications. PETG for general functional parts, ABS or ASA for anything near heat or outdoors.
Resin. The detail level FDM produces on miniatures is noticeably inferior to resin at any price point. If detail is the point, resin is the technology.
Resin. Specifically castable or standard resin for lost-wax casting. The surface finish and edge definition of a resin jewellery model eliminates hand-finishing steps before casting.
Resin for presentation quality, FDM for functional testing. If the prototype is going to be photographed or handled by someone who will judge it visually, resin. If the prototype needs to be tested under load or in real conditions, FDM in the right material.
FDM. Resin printers have fundamentally smaller build volumes. Large prints are an FDM use case without exception.
Resin — specifically dental resin. Biocompatible dental resin formulations are available from our showroom. The dimensional accuracy and surface quality required for dental applications is only achievable in resin.
Full comparison at a glance
| Factor | FDM | Resin |
|---|---|---|
| Surface quality | Visible layer lines | Smooth, layer lines invisible |
| Fine detail | Limited by layer height | Micron-level resolution |
| Build volume | Large — up to 500mm³ | Smaller — typically 200mm or less |
| Material strength | Strong, impact-resistant options | Standard resin brittle — tough/ABS-like better |
| Material variety | PLA, PETG, ABS, ASA, TPU, more | Standard, dental, tough, water-washable |
| Post-processing | Remove supports only | Wash + UV cure required every print |
| Consumable cost | Lower — filament cheaper per kg | Higher — resin more expensive per litre |
| Beginner-friendliness | More forgiving | More setup and handling steps |
| Best for | Functional parts, large prints, versatility | Detail, jewellery, dental, presentation models |
Not sure after reading this? Visit our Somerset West showroom and hold a finished print from both technologies. That 10-minute visit answers the question more definitively than any comparison guide — including this one.
Frequently asked questions
Want to see both technologies running before you decide? Visit our Somerset West showroom — walk-ins welcome during business hours. Or get something printed without buying a machine through our print-on-demand service.
Print-on-Demand Service → Shop 3D Printers →