Lowering Fuse Sift Refresh Rate

Support & Troubleshooting Fuse 1
1

Hi everyone,

I’m looking for some guidance and shared experience regarding refresh rates when using the Fuse and Fuse Sift with Nylon 12 (PA12).

We’re currently running into an issue where excess recycled powder is accumulating over time. Based on our observations, this seems to be largely due to the fact that we rarely achieve the recommended ~30% mass packing density in our builds. In practice, even when the build chamber is fairly full of parts, we’re typically only reaching around 20% packing density.

Because of this mismatch, we’re consistently generating more recycled powder than we can reasonably reuse at the prescribed refresh rate, which is leading to an ongoing surplus of PA12 that goes unused.

This got me wondering:
Would it be reasonable to lower the refresh rate to ~20% to better match our actual packing density, in order to prevent excess recycled powder from accumulating?

I understand that reducing the refresh rate may negatively impact part quality, but in our case a moderate reduction in mechanical properties may be acceptable as long as it’s not catastrophic.

Has anyone here experimented with lowering refresh rates below Formlabs’ recommendations for PA12?

2

Yes, there are ways to reduce the refresh rate. I print from 0% to 100%. It all depends on what parts I’m printing and whether they are mechanically demanding or not. The only thing that is needed to prevent defects on the surface of the part is to increase the hardness of the armor around the part.

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We ran into this issue as well when we got our printer. We also end up in the 20-30% packing density range.
I have used as low as 20% in this scenario.
Once the excess was consumed, I vary the Refresh Rate up and down based on the Sifted Hopper levels. I usually use 30% but will go up to 40% and as low as 25% as the Used Powder levels accumulates or decreases to stay on top of this.

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