---
title: "Formlabs SLS Parts with Vapor Smoothing | AMT PostPro"
description: "A study by Formlabs and AMT: vapor smoothing Formlabs SLS parts cut surface roughness by up to 81% for a consistent, semi-glossy finish."
canonical: https://amtechnologies.com/resources/whitepapers/enhancing-the-surface-quality-of-sls-3d-printed-parts-with-vapor-smoothing/
updated: 2026-10-06
type: whitepaper
---
Whitepaper · Formlabs SLS powders

# Formlabs and AMT: surface quality of SLS parts with vapor smoothing

Selective laser sintering (SLS) makes intricate, robust parts, but their surfaces come out rough and porous. This collaborative study by Formlabs and AMT applies AMT vapor smoothing to Formlabs SLS powders to bring the surface closer to injection molding.

[Read the whitepaper (PDF, opens in a new tab)](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2) [Test your parts](https://amtechnologies.com/test-your-parts/)

Published Oct 6, 2023 Free download, no form

![Cover of the whitepaper “Formlabs and AMT: surface quality of SLS parts with vapor smoothing”](https://amtechnologies.com/img/resources/wp-formlabs-sls-800.webp)

- **With**: Formlabs
- **Material**: Formlabs SLS powders
- **Printing**: Formlabs SLS
- **Published**: Oct 6, 2023

- 81% lower surface roughness, at most

Source: [Formlabs whitepaper, amtechnologies.com](https://amtechnologies.com/resources/whitepapers/enhancing-the-surface-quality-of-sls-3d-printed-parts-with-vapor-smoothing/) [PDF (opens in a new tab)](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2) published Oct 6, 2023

## How vapor smoothing works

The part’s surface is exposed to solvent vapor, which melts the surface layers for a smoother finish while preserving the core structure. The process is highly controlled, so the finish can be tailored.

## Advantages

- Surface quality: up to 81% reduction in surface roughness, with a consistent, semi-glossy finish
- Durability: better resistance to moisture and bacteria, useful in harsh environments and medical applications
- Uniform application: the vapor reaches all surfaces, so complex geometries get a consistent finish[PDF](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2)

## Mechanical integrity

Vapor smoothing has minimal impact on mechanical properties, preserving or slightly improving tensile strength and elongation at break.[PDF](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2)

## Process considerations

Part geometry, racking and avoiding solvent pooling all matter. Predefined profiles for specific SLS materials and part designs help reach the desired result.

## Applications and options

Vapor smoothing is used in automotive, medical and consumer products, on parts such as air intake manifolds, medical devices and electronic accessories. The study includes 3D Nation, an automotive and aerospace prototyping company that reaches injection-molded part quality without traditional tooling in prototyping. Options range from in-house equipment to [service partners](https://amtechnologies.com/production-partners/), depending on part size, complexity and volume.

Key finding

Up to 81% lower surface roughness, consistent semi-glossy finish[PDF](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2)

Full whitepaper

Method, data and charts in the PDF. Free, no form to fill in.

[Download the PDF (opens in a new tab)](https://6983077.fs1.hubspotusercontent-na1.net/hubfs/6983077/Website/Whitepapers/AMT_WP_%20FORMLABS%20SLS%20SMOOTHING.pdf?ver=2)

Related

- [Compatible materials lists](https://amtechnologies.com/resources/documents/)
- [What is vapor smoothing?](https://amtechnologies.com/learn/what-is-vapor-smoothing/)
- [All whitepapers](https://amtechnologies.com/resources/whitepapers/)

Test your parts

## Send us a part. See it smoothed.

We vapor smooth your own parts and send them back with the results. No cost to evaluate · Parts returned · Typical turnaround 2–3 weeks[1]

[Test your parts](https://amtechnologies.com/test-your-parts/) [See the systems](https://amtechnologies.com/products/vapor-smoothing/)

## Sources

1. [PostPro benchmarking: send us your 3D printed parts](https://benchmarking.amtechnologies.com/) · AMT · read Oct 6, 2026