First Layer Adhesion: Can I get your help with an experiment?
 
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David
(@david-50)
New Member
First Layer Adhesion: Can I get your help with an experiment?

Something weird happened with my textured sheet and I'd like your help testing to see if it can help show whether a sheet is good or bad.

I was having problems with sticking after quite a while of successfully using a textured sheet for small parts and sharp corners. I rechecked surface calibration many times, ran experiments at different levels, used 91% alcohol, stepped up to dishwashing soap and then in desperation (and while looking at replacements for a sheet with no visible damage) hit one complete side with a very light touch of 300 grit sandpaper (I know, lots of people recoiling in horror now but it was this or toss the sheet so I had nothing to lose). While cleaning the finest bit of dust from the sheet I discovered something. On the untreated but clean side the water beaded rapidly and ran off. On the treated (barely sanded) side the water wetted the surface and did not just roll off. Beading is symptomatic of the presence of waxes, oils, or some materials, especially if they are high gloss. Water was sticking to one side of my plate but not the other! Does that indicate plastic might do the same thing?

The treated surface is being tested with different prints now (both PLA and PETG) but the initial results are excellent. 

What I hope you help with:

Take your cold sheet and put some water on it (note: Prusa does not recommend this, but many people do it when cleaning). Look to see whether it beads up or wets the surface. Dry it off. Post a response here with if water ran off, if your prints usually stick (especially small ones or fine features), and the type of sheet. A pattern might show us if water can show if a sheet is good or bad.

 

Incidentally if this is a widely known test and I just haven't found it for some reason please post that and I'll edit or remove the post.

This topic was modified 9 months ago by David
Posted : 02/03/2021 6:45 pm
Dan Rogers
(@dan-rogers)
Noble Member
RE: First Layer Adhesion: Can I get your help with an experiment?

call me skeptical.  How much hydrophobic (beading) on the plate is probably a statement more about the surface of the plate (think wear) than it is about how a plastic compound with very little water in it (or none) would react to the plate.  Your experiment with skuffing up the surface with sandpaper I think more proves my point - the more "rough" the surface, the less it will display hydrophobia.

If your prints aren't sticking to your plate on one side, and the other side is sticking fine, turn the plate over.  The plates are not permanent and are wear parts.  

Posted : 03/03/2021 4:19 pm
bobstro
(@bobstro)
Illustrious Member
RE: First Layer Adhesion: Can I get your help with an experiment?

You can definitely tell when a smooth PEI sheet is properly cleaned based on how water rolls off it. On the smooth sheet, the areas with grease will tend to stay wet, while the cleaned areas will sheet off quickly and evenly. I don't think filament reacts the same way, particularly at heat, but I do agree that how water rolls off can tell a lot about the consistency of cleaning.

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 : 03/03/2021 4:36 pm
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