1st layer non sticking issue  

RE: 1st layer non sticking issue

Almost always is bed contamination and/or insufficient layer one calibration.

Soap and water wash the bed, keep hands away from the surface: fingerprints will destroy a PLA print, and alcohol doesn't clean them off well, and is just as likely to take oil from your fingers and move it to the bed in an ultra fine film that's great for printing PETG, but makes an absolute mess with PLA.

Here's a bed cleaned with alcohol:

Here's a bed washed with soap and water (it's like pulling tape off the bed). Note the tweezers and my fingers are nowhere near touching.

A few cleanings procedures:

Alcohol rinse: every few prints

• Gloves recommended.
• Once in a while, an alcohol rinse is helpful to remove PLA residue. It does not remove finger oils well.
• Pour a 5 cm puddle of 91%+ alcohol in the middle of the bed, with clean hands use a fresh paper towel to scrub the bed. Wipe up all the alcohol.

Acetone wash: infrequent (DO NOT USE on Powder Coated sheets)

• Pour a 2 cm puddle of acetone on the bed, scrub it around with a fresh paper towel. It will evaporate fast as you clean. This step removes PEI oxides that form over time and with heat, and improves PLA adhesion to a like new state.

Hot Water wash: often, as needed, and after any of the above

• Handle the bed only by the edges.
• Wash the bed in hot water, use a fresh paper towel as a wash cloth, with a few drops of plain dish soap (Dawn, unscented, no anti-bacterial, etc.).
• Rinse well in hot water - if you have very soft water, rinse a bit longer.
• Dry the bed with a fresh paper towel.
• Handle the bed only by the edges.
• Place bed on printer.

Streak test: when contamination is suspected

• With a fresh piece of paper towel, and very clean fingers, dampen the towel with 91%+ alcohol, and wipe the bed side to side moving back to front, like you're painting it with alcohol. The alcohol should be thin enough on the towel it quickly evaporates. If you see any streaks, the bed is dirty and needs a wash.

RE: 1st layer non sticking issue

Thank you for your thorough answer!
I will do the soap bath and let know if the issue appears, this is great help to other newbies in print!

RE: 1st layer non sticking issue

Worked indeed!

I did exactly what you wrote - soap bath alone helped. You saved me another hours of troubleshooting 😉

RE: 1st layer non sticking issue

Tim,

Great article for cleaning the smooth PEI sheets.  But did you know that it's not a good idea to clean the Powder Coated sheets with water?

Just and FYI.

Robin

RE: 1st layer non sticking issue

Posted by: RAHRAH

Tim,

Great article for cleaning the smooth PEI sheets.  But did you know that it's not a good idea to clean the Powder Coated sheets with water?

Just and FYI.

Robin

Well, if water is bad, then anything but fresh 99.9% alcohol is also unusable.  Acetone is bad, causing cracking, but so far, I never heard of issues with water.  Have you personally had issues using soap and water to clean a powder coated sheet, or repeating information from Prusa?  Or is this lore you've heard somewhere else?

Acetone wash: infrequent (DO NOT USE on Powder Coated sheets)

Answered my own question: you are correct:

Acetone, in particular, must not be used on the powder-coated sheet! Using acetone makes the surface (Ultem) crack, and eventually, it peels off. Also, the powder-coated sheet is not waterproof. When exposed to high humidity, it corrodes and loses its properties. Therefore, do not clean the sheet with water. It is possible to do that only if you have truly tried everything mentioned and your objects still don’t stick to the surface. It could mean that you have sugar-based compounds on your sheet that can’t be dissolved with IPA.

RE: 1st layer non sticking issue

As an aside, who'd have thought Ultem and water is a no-no?  From the Ultem website:

 Ultem® is resistant to hot water and steam and can withstand repeated cycles in a steam autoclave. FDA compliant grades ofUltem® are available.

RE: 1st layer non sticking issue

i bet the problem is the areas between the Ultem droplets on the surface

RE: 1st layer non sticking issue

Posted by: Tim

As an aside, who'd have thought Ultem and water is a no-no?  From the Ultem website:

 Ultem® is resistant to hot water and steam and can withstand repeated cycles in a steam autoclave. FDA compliant grades ofUltem® are available.

Tim,

The warning may have been from the production process issues that Prusa had getting the sheets made.  At least until recently, they could only get a few to pass the tests reliably.  I thought it was related to the process not so much the ULTEM material.  But it was me repeating the Prusa mantra as you cited above.  I really liked your article and wanted to help improve it.  😉

I am looking for ways to clean those sheets.  Mine has lost some sticky and I am reticent to wash them in water.  I do handle them carefully but I am open to some suggestions.  I wonder if repeated heating causes some issues.

Robin

RE: 1st layer non sticking issue

@Robin,

Thanks ... a compilation of personal experience and others work.

If I make some gross assumptions about the PC sheet; if it is spatter coated, the bonds between spats may be weak and permeable so water can get in and make contact with the spring steel.  Steel being what it is, and water, don't mix well and oxides form. Moisture could creep under the spatter and cause chipping. But this is all conjecture.  

Seems cleaning has limited options.  Perhaps wash & dry the sheet, then bake on the printer at 110c for a few minutes?  Or maybe only 95c just in case the water gets trapped, to avoid steam damage.

With PEI, repeated heating does oxidize the surface, and acetone is handy to remove the oxides. No clue with Ultem, but guessing, an autoclave is pretty warm, and the material is rated for hundreds of cycles, I doubt it oxidizes much.   So probably just plastic residue build up is affecting adhesion.  

Some folk have used Scotch-Brite pads as they try to abrade the surface; but on texture, not sure it works well.  A caveat: the non-mar variety of pads are the only thing I'd even try to use. 

In any case, this is Prusa's problem to solve for users.  Have you asked them for suggestions beyond alcohol mentioned in their Care and Feeding blog?