The build unit has a felt seal around the edge of the print bed that prevents powder from leaking into the body of the build unit. If the felt seal is dirty or contaminated, the print bed may not move smoothly, or the contamination may melt during a print.

Clean the build unit felt seal if there is visible melted powder protruding from the felt seal, or if the Z-axis stalls intermittently, triggering a print error.

To clean the build unit felt seal:

1. Empty the build unit using a Fuse Sift X1. Make sure the print bed is at its top position.

2. Vacuum any powder on the top of the build unit.

3. Using a T20 Torx driver, loosen and remove the four screws securing the print bed to the build unit. Set the screws aside.

4. Use a prying tool to pry the print bed upwards until where it can be removed by hand.

5. Use a vacuum with a brush attachment to clean all powder and debris from the felt seal around the edge of the print bed.

6. Reinsert the print bed into the build unit, aligning the screw holes in the print bed with the corresponding ones in the build unit itself. Thread one print bed mounting screw into each of the four screw holes. Using a T20 Torx driver, tighten until snug.