Community guideTips & tricks / Design for vapor smoothing
Designing internal channels for vapor smoothing
Internal channels are one of the best reasons to vapor smooth. The process seals internal surfaces as well as external ones: the SF2X page says it “also seals internal cavities”. AMT’s systems run under vacuum, which lets the vapor travel into hard-to-reach areas of the part.
A published example
Norden replaced a multi-component, machined assembly with a single vapor smoothed part with internal vacuum channels, according to AMT’s Norden case study (Nov 2025). The case study describes the result as a sealed, uniform surface.
Design so the channel can be cleaned first
A channel smooths well when it is clean, so design it so the loose powder can come out first:
- Give every channel an exit. Dead ends trap powder.
- Avoid sharp internal corners where powder packs in, where your design allows.
- Plan cleaning access. Can you blow air through it, or pass a brush or a wire?
- Check before you load. Shine a light through the channel, or flow air and check it comes out clear.
Test it
Channel diameter, length and shape all play a part, and AMT does not publish a single minimum channel size for every material. The fastest answer for your design is a test part: send it for a benchmark.