Community guideTips & tricks / Design for vapor smoothing
Press-fits, snap-fits and assemblies after smoothing
Smoothed parts often end up in assemblies. Two things change that you can design for: size, a little, and mechanical behavior, often for the better.
Size
AMT whitepapers measured dimensional change after vapor smoothing of 0.39 mm (0.4%) on HSS PA12 and a maximum of 0.4% on SLS PA2200. Details in Will vapor smoothing change my part’s dimensions?.
Mechanical behavior
The same whitepapers measured:
- Elongation at break: +38.1% (XY)12024 on HSS PA12 (Feb 2024). More stretch before breaking is good news for snap-fits and clips.
- Burst pressure: up to +7%22024 on SLS PA2200 (Jan 2024).
These are results for specific materials and test pieces. Treat them as a reason to test, not as design values.
Good practice for fits
- Design the fit, then validate it on smoothed parts. Prototype the mating pair through the same route you will use in production.
- Mark the critical faces when you send parts for a benchmark, and ask for them to be measured.
- Keep contact points off mating faces when racking. See How part orientation and fixturing affect results.
- Change one thing at a time. If a fit is off, first check whether the printed part was already out before smoothing.