FDM vs SLA vs SLS vs MJF: A Plain-Language Comparison
Ask three print services for a quote on the same part and you can get back three different acronyms with no explanation of what any of them mean for your part. Here’s the plain version, technology by technology.
FDM is the cheapest and most common. A nozzle extrudes melted filament layer by layer; most desktop printers use it, and it’s what most online services default to for a low-cost quote. The tradeoff is layer adhesion: strength along the layer direction is fine, strength across layers is the weak point, and parts can delaminate there under load. Finish is the coarsest of the four unless you pay for post-processing. Good for prototypes, brackets, jigs, and anything where cost matters more than surface finish.
SLA cures liquid resin with a laser, layer by layer, and the jump in surface quality over FDM is immediate: smooth surfaces, sharp edges, fine detail. What you give up is toughness. Depending on resin, SLA parts run more brittle than FDM plastics, so it suits presentation models, dental and medical models, and anything where how it looks matters more than what load it carries.
SLS fuses powdered nylon with a laser. No supports needed, since unsintered powder holds the part up as it prints, which is part of why it handles complex geometry well. It’s a step up in cost from FDM and SLA, and it’s the one most often chosen for functional end-use parts that actually have to survive mechanical stress in a small production run.
MJF is HP’s powder-bed process: same general idea as SLS, but inkjet arrays and printing agents do the fusing instead of a laser, and it prints noticeably faster in raw throughput. Cost sits around SLS or slightly above it. Where SLS and MJF actually differ on strength, density, and consistency is not a one-line answer, and we’ve written the sourced version of that comparison separately rather than compress it into a bullet here: SLS vs MJF: what the published research actually shows.
| Technology | Cost | Best for |
|---|---|---|
| FDM | Lowest | Prototypes, brackets, jigs, cost-sensitive parts |
| SLA | Mid-range | Presentation models, dental/medical models, fine detail |
| SLS | Higher | Functional end-use parts, complex geometry, small runs |
| MJF | Comparable to SLS | Same as SLS, plus higher-volume orders where print speed matters |
None of this tells you what a specific provider will charge for your part; that depends on volume, complexity, and the vendor’s own pricing model, which is what we’re building the comparison tool for. If you’ve already got quotes using different technologies and want a check on whether the tech actually fits your part’s requirements, that’s worth asking before you order, not after.