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First layer issues - Prusament PETG
 
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First layer issues - Prusament PETG  

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FlyingPete
 FlyingPete
(@flyingpete)
Active Member
First layer issues - Prusament PETG

Hi,

I am having issues with first layer printing a shown in image,  printing with PrusaSlicer and Prusament PETG profile, 0.2mm quality.

Not having many issues with other plastic types.

Thanks!

Peter.

Napsal : 17/10/2019 9:37 pm
Sharpee
 Sharpee
(@sharpee)
Active Member
RE: First layer issues - Prusament PETG

This thread may give you some idea of settings & trials of my experience with PETG on smooth PEI: https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/factory-reset-slow-extrusion-of-filament-95100-flow/#post-169463

It looks to me as if the nozzle is to close to the PEI plate & temperature of nozzle is to hot. What settings you printing at and what is the room temperature? I also found this article / guide to be helpful: https://www.simplify3d.com/support/print-quality-troubleshooting/ Prusa Research has one on the web to: https://www.prusa3d.com/print-quality-troubleshooting/

Napsal : 18/10/2019 2:31 am
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(@)
Illustrious Member
RE: First layer issues - Prusament PETG

When all else fails, clean the print bed.  Even PETG sometimes needs the surface to be free of oils and fingerprints. 

Live-Z is also a possibility.  But adhesion (or lack there of) looks to be the primary problem you have; fix that, then you can actually examine Live-Z with some level of confidence the layer is sticking the way it should and the proper amount is being extruded/adjusted

Napsal : 18/10/2019 2:56 am
bobstro
 bobstro
(@bobstro)
Illustrious Member
RE: First layer issues - Prusament PETG
It's always tricky trying to judge from a pic, but it looks to me like your Live-Z is too low. PETG doesn't like as much layer 1 squish as PLA, so the nozzle can drag and cause the filament to peel up like this. This is a common problem that can be caused or aggravated by two factors that need to work together well for successful prints. Here's mama's tried and true copypasta recipe to get you going...
 
Filament should lay down cleanly on the PEI print surface and hold throughout the print. There are 2 main causes of bed adhesion issues. Even if you're dubious that these are the cause of your problems, they're 2 fundamental troubleshooting steps that you need to complete to rule out the basics:
  • A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. If it's a smooth PEI sheet, take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails , and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. 
  • If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. It's much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers. 
Remember that the effectiveness of a solvent such as isopropyl alcohol is going to depend on concentration and volume relative to the amount of grease you're trying to remove. 71% pads work... on very tiny amounts of grease. A squirt of 91% works better, but if there's a lot of grease, you need a lot more alcohol. This is why the wash under the sink with Dawn is so effective: There's a much larger volume of Dawn-and-water rinsisng stuff away instead of just moving the broken-down grease molecules around.
  
And above all else, avoid touching the PEI print surface.
 
Try those 2 steps. If you're uncertain of the Live-Z results, post pics here of the 75x75 print bottom and you'll get quick help. If you want more detail, I've consolidated my notes on Prusa PEI adhesion, bed cleaning, and Live-Z calibration. PETG will require a release agent to reduce its tendency to over-adhere to the PEI print surface. You do still want an evenly clean print surface though. Just spray some Windex on the PEI print surface, or wipe your fingers around on it a bit before prints.
 
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

Napsal : 18/10/2019 3:14 am
FlyingPete
 FlyingPete
(@flyingpete)
Active Member
Topic starter answered:
RE: First layer issues - Prusament PETG

Thanks all, will have a play once current print is done 🙂

Napsal : 18/10/2019 6:04 am
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