---
title: "Vapor Smoothing voxeljet HSS PA12 | AMT PostPro"
description: "PostPro vapor smoothing on voxeljet HSS PA12: Ra 12.81 to 4.16 µm (XY), elongation at break +38.1% (XY), dimensional change no more than 0.4%."
canonical: https://amtechnologies.com/resources/whitepapers/vapor-smoothing-voxeljets-hss-pa12-with-amt-postpro/
updated: 2026-10-06
type: whitepaper
---
Whitepaper · PA12

# Vapor smoothing voxeljet’s HSS PA12 with AMT PostPro

AMT tested PostPro vapor smoothing on PA12 parts made with voxeljet’s High Speed Sintering (HSS). The focus was surface quality, mechanical properties and dimensional accuracy.

[Read the whitepaper (PDF, opens in a new tab)](https://amtechnologies.com/resources/whitepapers/vapor-smoothing-voxeljets-hss-pa12-with-amt-postpro/) [Test your parts, free](https://amtechnologies.com/test-your-parts/)

Published Feb 6, 2024 Free download, after a short form

![Cover of the whitepaper “Vapor smoothing voxeljet’s HSS PA12 with AMT PostPro”](https://amtechnologies.com/img/resources/wp-voxeljet-hss-750.webp)

- **With**: voxeljet
- **Material**: PA12
- **Printing**: voxeljet High Speed Sintering (HSS)
- **Published**: Feb 6, 2024

- +38.1% (XY)[1] elongation at break
- ≤ 0.4%[1] dimensional change after smoothing

## The process

PostPro uses a chemical vapor process to smooth and seal the surfaces of printed parts. It makes the top layer of material on the part mobile, so it reflows into a smooth, sealed finish with precise control over the final surface quality. It works on a wide range of thermoplastic polymers, PA12, PA11 and TPU among them.[1]

## Surface quality

Average roughness (Ra) fell from 12.81 µm to 4.16 µm in the XY direction and from 16.83 µm to 7.54 µm in the XZ direction, uniformly across the part surfaces.[1]

## Dimensions and mechanical properties

Shrinkage was minimal: no more than 0.22 mm (0.25%) after printing and 0.39 mm (0.4%) after vapor smoothing. Elongation at break rose by 38.10% in XY and 25.00% in XZ, with no significant change to Young’s modulus, so the structure keeps its integrity.[1]

## Conclusion

PostPro vapor smoothing improves the surface finish of HSS parts while keeping their mechanical and dimensional properties, for parts that need precise surface specifications and structural reliability.

Key finding

Elongation at break +38.1% (XY)[1]

Full whitepaper

Method, data and charts in the PDF. Free, after a short form.

[Download the PDF (opens in a new tab)](https://amtechnologies.com/resources/whitepapers/vapor-smoothing-voxeljets-hss-pa12-with-amt-postpro/)

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[2]

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

## Sources

1. [Vapor smoothing voxeljet's HSS PA12 with AMT PostPro (whitepaper)](https://amtechnologies.com/resources/whitepapers/vapor-smoothing-voxeljets-hss-pa12-with-amt-postpro/) · AMT · Feb 6, 2024
2. [PostPro benchmarking: send us your 3D printed parts](https://benchmarking.amtechnologies.com/) · AMT · read Oct 6, 2026