Issues With ASA Over-Adhesion
Hi!
I got my MK3S+ about 2 months ago, and have been enjoying using it since.
When I ordered my printer, I also got some Prusament ASA. I tested it by printing a replacement fan-shroud part, on the smooth PEI sheet. Even after the bed had cooled, I could not remove it from the sheet. I ended up using acetone to dissolve the bottom layers of the part to get it off.
After that experience with extreme over adhesion, I set the ASA aside. Later, I made a new steel sheet profile with a higher (more positive) live Z value, and tried again with the ASA. This time I got the part off, but the first layer was way too high, and it did leave a mark (seems permanent) on the PEI. I then tried glue stick, and it certainly worked in reducing adhesion but the first layer now seemed too squished with the same live Z.
Also, each time I've attempted printing with ASA, the smooth sheet gets TONS of small bubbles. I know that some are normal, but is is unusual to have lots?
It seems to me that ASA ought not to be printed on the smooth sheet, perhaps the textured sheet would be better? (lowers adhesion?)
So for me, it boils down to these questions:
- What can be done to prevent extreme adhesion to the smooth PEI sheet with ASA?
- How to do the above while getting good, consistent first layers?
- Are the amount of small bubbles I'm seeing after printing ASA normal?
- How can I prevent/cure the bubbles on my smooth PEI sheet?
- And finally, should you even print ASA on the smooth PEI?
Thanks in advance for any help!
RE: Issues With ASA Over-Adhesion
Sounds about right. Do use a release agent suitable for ASA/ABS - couple of choices
- The commercial kind - layerneer, bed goop - there are a bunch of these. Create a layer to print on top of.
- The non-commercial kind - - high volume hair spray, layered and layered across the sheet - the real sticky ones. This creates a printable layer that will last several prints.
About your smooth sheet - if the bubbles ripped open, you can buy spare PEI replacement part - each steel sheet has two, one on each side - under "spare parts" on the prusa store if you are a registered owner. Or buy another steel sheet - from Prusa or your favorite local market like Amazon.
If the bubbles aren't ripped, just press them back onto the glue layer that is underneath. Then heat it up, and use a plastic scraper to smooth them back into the glue layer - avoid making ripples (don't press too hard, but do press hard enough)
With a well applied release agent, you don't give up a smooth first layer - and so live z is still how you get that how you like. The trick is a thick, sacrificial release layer. Yes, you might have to clean up the first layer some - there will be traces.
RE: Issues With ASA Over-Adhesion
I want to do more printing with ASA as well. According to the material guide https://help.prusa3d.com/en/materials#_ga=2.240036547.1942451027.1615952384-224096729.1613260496 ASA shouldn't be printed on the powder coated sheets, but the table has been updated to include the satin sheet, and is approved for that. I have ordered a satin sheet which should be here in a couple of days as I also want to print spare fan shrouds in ASA. It looks like the shroud that came with my MK3S+ upgrade kit was printed on a satin sheet.
In the knowledge base for ASA https://help.prusa3d.com/en/article/asa_1809 , one sentence indicates "It is recommended to use a smooth PEI sheet for printing with ASA. The powder-coated TXT sheet might stick too well to your model and might get damaged when you remove the print." but in another sentence below, "ASA sticks very well to our print sheets (smooth and powder coated) but other print surfaces, like glass, might require a layer of acetone with dissolved ASA (or ABS)." Seems contradictory, but I have printed ASA on the power coat with no issues. In fact, I had to lower the Live Z to get better adhesion when I was printing the MK3S+ fan shroud because the supports would pop off. Take your chances I guess, but the fan shroud had a small surface area on the powder coated sheet, so may not have been an issue?
RE: Issues With ASA Over-Adhesion
@daryl-p, looking back at the fan shroud part on my MK3S+ it certainly looks like it was also printed on the satin sheet. That must be what they are using now on the farm. Maybe I should get one, but lately it seems like Prusa gets all of my money. 🙂
Hey, at least I would have an excuse to get more prusament, right?
So far, I’ve had a great experience with Prusa and am loving the MK3S+ but I wish they were more upfront about using ASA/ABS instead of just saying, “print on smooth PEI sheet.” I assume before the satin sheet they used smooth ones on the farm, so they must have a method of getting reliable prints that don’t ruin or stick too well to the smooth sheet.
@dan-rogers, thanks for your help. None of the bubbles have ripped so I will be able to push them back onto the adhesive. Right now I’ve been alternating printing on different sides but that only has a marginal effect on them.
As for the release agent, is glue stick an acceptable release layer? I know you mentioned hairspray and some 3D-Printing specific products, but I already have the glue stick on hand.
From what you said it sounds like I actually need to set my live Z to match the release layer, not the steel sheet, correct?
RE: Issues With ASA Over-Adhesion
ASA, ABS, PC Blend, and PETG are prone to over adhesion as a bed ages. The print gets stuck in the small holes in the print bed and it is difficult to remove them. I use small plastic razor blades or scrapers to remove the print and supports. Supports can be a booger to remove.
Release agents can be a must with some filaments if your bed is excessively sticky. Once the filament will no remove with my fingernails with ease, I start using a release agent. I really like hair spray because of the ease of application and removal.
--------------------
Chuck H
3D Printer Review Blog