Makerspace Staff Guide: Equipment Maintenance

From the Prusa Website:

• Clean with ~90% IPA (isopropyl alcohol) or denatured alcohol when cold. Apply on unscented paper towel and rub the sheet down. Do not use anything made for skin! It can contain oils that ruin adhesion!
• 1-2 times a month it can be cleaned the same way with acetone if IPA cleaning is not sufficient.
• After extended use (1-2 years) the surface can smooth out further, which affects adhesion. Using high-grit sandpaper (600-1000), the PEI can be revived by light sanding, bring fresh PEI to the surface. The sheet will have a very light texture after this treatment.
• The smooth PEI film on the steel sheet can be replaced in case of extensive damage.

Bubbles underneath the PEI

Over time, you might see some small bubbles underneath the PEI. This is nothing serious. These bubbles usually do not affect print quality and will disappear after a few days or weeks. Here are 2 tips that will make these bubbles disappear faster:

1. Swap the side of the steel sheet you were printing on. This will speed up the "recovery" of the PEI surface. 
   Bubbles appear around the spot where you print the most (center of the sheet), most often underneath the corners of your printed parts.
2. When slicing the models, vary your placement on the print surface. Don't use just one spot i.e. the center.

Bubbles under PEI sheet