Learn · Selective laser sintering
Vapor smoothing for SLS parts.
SLS vapor smoothing reflows the rough, porous surface of a selective laser sintered part into a smoother, sealed skin, with very little dimensional change: ≤ 0.4%12024 on SLS PA2200 in AMT’s published test. PostPro systems vapor smooth SLS parts in PA12, filled PA12, PA11 and polypropylene.2
No cost to evaluate · Parts returned · Typical turnaround 2–3 weeks3
Why SLS parts need finishing
Laser-sintered nylon, with an open surface.
SLS nylon parts are tough and need no supports, from desktop systems to industrial machines. Their surface is grainy and porous, which limits them wherever a part must seal, clean or look finished.
Sealed
Reflowing the surface closes its pores, so parts take up less water and dirt and can hold more pressure: up to +7%12024 burst pressure on SLS PA2200.
Accurate
The skin reflows, not the whole part: dimensional change was ≤ 0.4%12024 on SLS PA2200.
Desktop to industrial
The SFX and SF2X sit beside desktop SLS printers; the SF50 and SF100 take industrial build volumes.
Studied on desktop SLS
AMT and Formlabs published a joint study of vapor smoothing on Formlabs SLS powders.
Published results
What vapor smoothing measured on SLS parts.
Each result names the material it was measured on. Results depend on material, printer and recipe.
Dimensions
≤ 0.4%12024
Dimensional change PA2200 · SLS
Sealing
up to +7%12024
Burst pressure PA2200 · SLS
SLS PA2200 whitepaper Formlabs SLS study Arkema PA11 SLS whitepaper
Materials
SLS materials by finishing agent.
Nylons run with PostPro Pure or FA326; polypropylene with FA9202.
| Material | PostPro Pure | FA326 | FA9202 |
|---|---|---|---|
| PA 122 | Listed | Listed | Not listed |
| PA 12 Filled2 | Listed | Listed | Not listed |
| PA 112 | Listed | Listed | Not listed |
| Polypropylene2 | Not listed | Not listed | Listed |
Listed by AMT— Not listedPostPro Pure runs in every PostPro system; FA326 on the SF50 and SF100; FA9202 for polypropylene.
PartnerIn April 2026, Raise3D announced a partnership with AMT to offer PostPro vapor smoothing to its RMS220 SLS customers in Europe.4
Which PostPro
Which PostPro for your SLS printers.
Desktop systems next to desktop SLS, production systems for industrial builds. Every PostPro system lists PA12 and PA11.5
Questions
SLS vapor smoothing: questions.
Short answers from AMT’s published tests and material lists. Anything else, ask an engineer.
Can SLS nylon parts be vapor smoothed?
Yes. SLS PA12, filled PA12 and PA11 run with PostPro Pure or FA326, and SLS polypropylene with FA9202.2
How much do SLS parts change dimensionally?
Very little: ≤ 0.4%12024 on SLS PA2200 in AMT’s published test.
Do filled SLS powders smooth?
Filled PA12 grades from SLS are listed with PostPro Pure and FA326.2 Send a part in your grade to confirm the finish.
Which PostPro suits a desktop SLS printer?
The desktop Desktop vapor smoothing for R&D and low-volume production.5 The SF2X doubles its chamber; the SF50 and SF100 take industrial volumes.
Next step
See the price. Run the numbers. Hold the part.
List prices are public and the cost-per-part math is yours to check, with no email needed for either. The free benchmark puts your own parts, vapor smoothed, in your hands.
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01Quote
Build your quote
Pick a system and its options and get an itemized total on screen, from AMT’s published list prices.
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02ROI
Calculate your ROI
Compare your cost per part with manual finishing, using your own labor rate and volumes. Every assumption is editable.
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03Benchmark
Test your parts, free
Ship us your parts with a prepaid label. We vapor smooth them and send them back with before-and-after photos and a benchmark report.
No cost to evaluate · Parts returned · Typical turnaround 2–3 weeks3
Prices: AMT list prices, excluding tax and shipping; confirmed in your formal quote.
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