This applies to both the PEI and new 3ntr Diamond print surfaces.
Either print surface is good for thousands and thousands of parts without the use of special coatings, sprays or tape.
From time to time, it may be necessary to return the surface to original performance levels. Each time a part is printed and removed, some exchange of polymer happens. Each time the print surface is handled or left out in the environment outside the printer, or in the printer when it goes unused, dust and oils may accumulate on the surface.
All of these things tend to degrade the ability of the surface to hold part rafts down while printing. They can impact part removal too, depending on what has happened.
The solution to these things is a quick refinish and clean to restore the surface to it’s default, standard, expected performance.
Here is a PEI surface with some dust, and oil from handling.
Remove dust with a blast of whatever compressed air you have handy. If this happens to be shop air, know that often contains oil and water, unless the system is filtered. Those computer duster type air cans work pretty well and are dry.
Next strong wipe with alcohol. High percentage is what you want. Water is also a light solvent, and the combination of mostly alcohol and water can be more effective than alcohol alone is. The stuff you get from the grocery or drug store is just fine.
And the result should be a fairly clean surface.
Follow that up with a second alcohol wipe down to remove grit and left over Scotch Brite. Notice the changed look of the alcohol. This is one way to tell you have impacted the surface sufficiently to perform.
Your result should be a matte, fairly uniform surface, ready for printing!
In general, it’s a very good idea to wipe the print bed down prior to each print job. Use alcohol and give it a quick wipe with a clean cloth. A paper towel can leave things behind, but some shop type cloth towels may work just fine too. A cloth can be washed and used again and again.
Fit the print bed back into the printer, and if bed heat is being used, heat the bed to evaporate all the cleaning fluid and bring it all back to proper temperature.
This is often a great task to perform during your pre-job print nozzle purge operations.