How to remove those traces made during first layer calibration?
 

How to remove those traces made during first layer calibration?  

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prusanewuser
(@prusanewuser)
Reputable Member

Hi, during first layer calibration, the nozzle moved across the PEI smooth sheet to print a series of rectangular traces. Sometimes when using PEI smooth sheet, the traces cannot be removed even with disk soap and alcohol. Sometimes the traces had very thin filament on it sometimes even the filament have been removed, the traces are still on the sheet. This caused problem when I used the sheet later on because I can see those traces at the bottom of my new prints. Is there any good way to remove those traces on the PEI smooth sheet?

Posted : 11/01/2021 5:53 pm
bobstro
(@bobstro)
Illustrious Member

You don't want to over-use it, but acetone is effective at removing such traces so long as they're not gouged into the surface. Acetone used to be recommended for infrequent use to restore the smooth PEI -- it removes oxidation -- although Prusa has removed that recommendation. Presumably, because over-use can make the PEI brittle. I use it every few months as needed and have no issues.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 11/01/2021 6:13 pm
prusanewuser
(@prusanewuser)
Reputable Member

@bobstro

Thank you. I tried but even Acetone could not remove those traces. What could be the reasons? 

Given that I cannot get rid of those tracks, what can I do to avoid having those traces being imprinted at the bottom of new prints?

Posted : 12/01/2021 3:07 am
Chocki
(@chocki)
Prominent Member

If you have not actually damaged the PEI (Printed too low and actually scuffed the PEI), then printing over the top of thin extrusions slowly will cause the filament to melt together allowing you to peel off the newly printed layer taking any residue up with it.

If you have damaged the PEI, then I'm afraid it's there for life!. I have one textured sheet like this when I changed nozzles and did not recalibrate 😞 

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet....
Posted : 12/01/2021 10:44 am
bobstro
(@bobstro)
Illustrious Member

You can try using a fine abrasive to remove the traces. 0000 steel wool or 1000+grit sandpaper might work. Don't be too aggressive with it though.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 12/01/2021 2:26 pm
prusanewuser
(@prusanewuser)
Reputable Member
Posted by: @chocki

If you have not actually damaged the PEI (Printed too low and actually scuffed the PEI), then printing over the top of thin extrusions slowly will cause the filament to melt together allowing you to peel off the newly printed layer taking any residue up with it.

If you have damaged the PEI, then I'm afraid it's there for life!. I have one textured sheet like this when I changed nozzles and did not recalibrate 😞 

Could this be due to the possibility that the nozzle was too low and perhaps scratched the smooth sheet?

Posted : 12/01/2021 6:57 pm
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