3D Printing Comparison

Resin or nylon?
SLS or MJF?
Each has its place.

Three dominant 3D printing technologies for functional prototyping and low-volume production. SLA uses photopolymer resin. SLS uses powder-bed nylon with laser fusion. MJF (HP Multi Jet Fusion) uses powder-bed nylon with inkjet fusing agent. Here's how to pick.

Get a Quote DFM guide

01 · At a glance

Side-by-side summary.

Option A

SLA (Stereolithography)

UV laser cures photopolymer resin layer by layer. Smoothest surface finish of any 3D print process. Resin-based — limits material properties. Best for cosmetic prototypes and visual models.

Option B

SLS / MJF (Nylon Powder)

Both fuse nylon powder into solid parts. SLS uses laser; MJF uses inkjet fusing agent. Production-grade nylon PA12 mechanical properties. Best for functional prototypes and low-volume production.

02 · Detailed comparison

Feature-by-feature breakdown.

Attribute	SLA	SLS / MJF
Material	Photopolymer resin (various grades)	Nylon PA12 (most common), PA11, PA12-GF
Mechanical (yield)	~60–80 MPa (tough resins)	~45–50 MPa (PA12)
Impact resistance	Poor to moderate	Excellent (nylon flexibility)
Drop test pass	Fails on standard resins	Passes (production-grade nylon)
Surface finish	Ra 2–5 µm (smoothest)	Ra 6–10 µm (slightly grainy)
Dimensional accuracy	±0.1 mm typical	±0.2 mm typical
Transparent/translucent	Yes (clear resins available)	No (nylon is white/grey)
Cost (per cc of material)	Moderate	Lower
Build volume	300 × 300 × 300 mm typical	380 × 284 × 380 mm (HP MJF)
Lead time	24–48 hours	48–72 hours
Post-processing	Support removal + UV cure	Depowdering + bead blast
Color options	Clear, colored resins, paintable	White (MJF), grey (SLS), dyeable
Chemical resistance	Poor	Good (nylon general-purpose)
Outdoor UV stability	Poor (most resins)	Moderate (nylon with UV)
Best use	Visual prototypes, cosmetic	Functional prototypes, low-volume production

03 · Decision guide

When to choose each.

Choose SLA (Stereolithography) when:

Visual/cosmetic prototypes for presentation
Transparent or clear parts
Small precise features (finer detail than SLS)
Smooth surface finish required
Fastest turnaround (24-hour possible)
Consumer product design review mockups

Choose SLS / MJF (Nylon Powder) when:

Functional prototypes requiring real nylon properties
Drop testing and mechanical abuse
Living hinges, snap fits, press fits
Production-intent parts (bridge production 100-1000 pieces)
Parts subject to flexing, impact, or outdoor use
Mechanical parts that will be thread-tapped or heat-insert installed

FAQ

Common questions.

Both fuse nylon powder using powder bed fusion. SLS (Selective Laser Sintering): uses laser to fuse powder point-by-point. MJF (Multi Jet Fusion, HP proprietary): inkjet deposits fusing agent, then heats entire layer. MJF is faster (40–60% less print time), slightly better surface finish (Ra 6 vs 8 µm), more consistent part density. SLS is more established, slightly better for glass-filled materials. For most nylon prototype work, MJF is the better modern choice.

Yes on all three processes, but effectiveness varies. SLS and MJF nylon: threads can be printed directly and hold adequately for low-cycle applications. Standard practice: print slightly oversized hole, then thread-tap after printing for reliable threads. Heat-set brass inserts also work well in nylon. SLA resin: threads are fragile and often strip — heat-set inserts recommended. For critical threaded connections, use inserts regardless of 3D print process.

Depends on part complexity. Simple part with no undercuts: injection molding typically cheaper at 100 parts once tooling amortizes ($3000 tool spread over 100 parts is $30/part tooling cost). Complex geometry impossible to injection mold without complex tooling: MJF can be cheaper because no tooling required. Also: MJF supports design iteration without tooling changes. For production parts that won't change, injection molding wins. For production parts that might iterate, MJF wins.

SLA: 24–48 hours typical for standard parts. Rush: 24 hours possible. SLS: 3–5 business days typical. Rush: 48 hours possible. MJF: 3–5 business days typical. Rush: 48 hours possible. All scale linearly with quantity — SLS/MJF batch many parts in one print, MJF slightly faster because single build cycle fuses entire layer at once.

SLA: ±0.1 mm typical on critical features, ±0.05 mm achievable with careful orientation. SLS: ±0.2 mm typical, ±0.1 mm on small features with careful orientation. MJF: ±0.15 mm typical, ±0.05 mm on features under 10 mm. For features below 1 mm or tight tolerances, consider CNC instead of 3D printing. For general prototype fits and clearances, 3D print tolerances are adequate.

Yes — common workflow. Example: functional parts in MJF nylon (durable, testable), visual trim parts in SLA (smooth cosmetic surface), combined into prototype assembly. Or: complex geometry in MJF (print difficult shapes), precision features in CNC (drill and thread holes to tolerance). We offer all three processes in-house plus CNC — combine on single PO for integrated workflow.