SLS material changeover sounds simple until you do it. In an r/AdditiveManufacturing thread where a shop asked for opinions on buying SLS, one operator was blunt: switching materials “is possible. Not practical.” They said cleaning the printer and sift station is a full day’s job before you even clean the vacuum, and that it takes several prints to make sure the old powder is gone. Their advice: choose one material and stick with it.
Why is it so much work?
Powder gets everywhere: printer, build chamber, sifter, vacuum and blaster. Any leftover powder of one type can contaminate the next. Formlabs notes that its Nylon 12 White Powder is sensitive to cross-contamination and recommends a dedicated depowdering station and media blaster so parts don’t look dirty.
What do vendors recommend?
For its Fuse series, Formlabs recommends buying one Fuse Depowdering Kit per powder if you change powder types. Otherwise, you need to clean the tools and the sieve. For TPU 90A, it says switching a Fuse printer is possible but recommends a dedicated Fuse, Sift and build chamber.
Do refresh rates change with the material?
Yes, which is another reason changeovers aren’t trivial. Formlabs’ published recommended refresh rates for printing in air include 30% for Nylon 12, 50% for Nylon 11, 50–70% for Nylon 12 GF and 20% for TPU 90A. Each material needs its own stock of used powder at the right mix.
When does an SLS material changeover make sense?
- When a customer program justifies a long run in the new material.
- When you can batch jobs so the changeover happens rarely.
- When dedicated equipment isn’t affordable yet and demand is occasional.
When should you dedicate equipment?
If you run a material regularly, the labor and scrap from repeated changeovers can add up quickly. That’s why both the operator and the vendor point toward dedicated machines and post-processing gear per material.
How do you price it?
Time your first few changeovers, including test prints, and treat that as a real cost. If a one-off job needs a changeover, either price that labor into the job, batch it with others, or send it to a partner already running that material.
Related on the Solvi blog: SLS TPU: How to Print and Depowder Flexible Parts; Depowdering SLS and MJF Parts: When Is Automation Worth It?; SLS Powder Cleanup: How to Keep Dust Under Control.
Sources: r/AdditiveManufacturing “Opinions on SLS” thread; Formlabs Fuse Depowdering Kit support page; Formlabs Nylon 12 White Powder; Formlabs TPU 90A.