Bubbles below PEI-sheet
Does anybody else have these bubbles below the PEI-sheet?
They appeared all over the Buildplate. On both sides.
At first they seemed to disappear over night after printing during the day.
But soon they just kept beeing there.
During a print they keep getting bigger. Espescially below the spots where the objects are beeing printed (as you can see on the picture).
The picture is from this morning after no printing yesterday.
I'm printing for a week now. Although printer statistics say total printing time is over 51 days.
However, I think I can feel the bigger bubbles to make the sheet uneven.
As far as I can see, the spring steel sheet ist brushed. It doesn't seem unlikely to me that bubbles appear after applying an adhesive sheet on a brushed surfaces. But I was wondering if that is a common issue and if Prusa is aware of it.
Re: Bubbles below PEI-sheet
Yes, I'm starting to see these too. my steel sheet also isn't flat when i look at it with a straight edge.
Re: Bubbles below PEI-sheet
it's probably the 3M adhesive under the PEI, becoming displaced during a print where the model grips well and then warps a little
ABS is a possible issue, high bed temperature, high propensity to warp
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Bubbles below PEI-sheet
Those bubbles come and go... i usually see them where a print was stuck but they go away eventually. 😀
Re: Bubbles below PEI-sheet
My sheet was covered in these prior to printing anything. It definitely gets worse after printing, though.
Re: Bubbles below PEI-sheet
It is the glue that is under the pei sheet. It is normal and does not affect adhesion or first layer quality.
It will dissaper ar move after one or two prints.
Re: Bubbles below PEI-sheet
When things get hot, they expand. When things cool down, they contract. Adhesive is not immune from this so bubbles will appear and dissappear over time as the bed cools. Shouldn't be an issue.
Re: Bubbles below PEI-sheet
got these aswell, cant wait for the powder coated plates to be available! going to order 10. Only had my MK3 for three days and I already want to buy a second! but will wait to see if they work out all the octoprint and serial comm bugs first.
Re: Bubbles below PEI-sheet
I've just completed a first print and notice these mainly under where the brim was. I think I can mitigate this with a higher live Z. Went through that routine and have moved it up from -0.612mm to -0.584mm.
Bubble morale will improve!
Re: Bubbles below PEI-sheet
I believe the bubbles are more related to shrinkage than Live Z level, trying to tune the bubbles out with LiveZ is likely to lead to disappointment
you will probably suffer a adhesion failure and resultant Blob... which often results in need for careful extruder recovery surgery, and possible need for premature thermistor, / heater replacement...
I have no idea what your settings are, but High Print speeds, high infill percentages, lots of perimeters and extrusion temperatures towards the top of the permissible ranges, tend to make shrinkage and PEI bubbling worse.
Often High infill percentages, lots of perimeters and high extrusion temperatures are un necessary! you may be trying to use them to combat problems caused by other issues...
perhaps reduced print speeds will help reduce the need for higher temperatures etc...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Bubbles below PEI-sheet
Bubbles below my PEI sheet started to come with bed temp 85 C printing PETG.
It started at the undersite. (side facing the heatbed). It will inflict the temp on your sheet. airbubbles at that side wil not give the right temp on the topside