PETG (PolyLite) Adhesion Poblems / Wobbly Brim

Already did. Is consistent

90°C was tried but did not help. But I will try it again with 90°C with the new calibration.

Printing with PLA is not causing any problems.

Update will come as soon as I did further testing.

What kind of temp does thermal camera show on the surface when you set it to 90 C?

What is the ambient temp in the room where you print? And is it well ventilated?

Yes if I set it to 90°C it is 90°C :joy:



To the edge the last 1cm is always about 5°C cooler but that seems more like normal for me.

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For me, print would warp and lift up from the bed whenever there is too much cooling. So you should look into it from that point of view - how you can reduce cooling, reduce airflow in that area and how to keep temps high enough so that the print stick.

Just recently I had a case when even PLA warped and lifted up from the bed. It was because I started printing in a very cold room (morning) and there was just too much cold air and print model was big. I reduced AUX fan, split print into more parts and reoriented it and then it was fine.

Well, you have lots of help on the other factors, but I’d like to point out some things not intuitive about drying.

  1. Brand new filament is often delivered damp!!! That it was sealed with desiccant is good, but it does not ensure it is dry, that’s a misunderstanding of the subject. :grin:

Why? Several reasons, but without writing a longer novel, one is:
During the extrusion in manufacturing, it goes through multiple reducing nozzles down to 1.75mm. It needs to be quickly cooled, so many companies run it though a water cooling process to set it!
They’re sure not going to bake it for hours to dry it, they just reel it and bag it.

  1. Not true. (Sorry! :stuck_out_tongue_winking_eye: :grin:)
    Desiccant is widely misunderstood. Desiccant will help prevent further uptake of moisture, but it will not dry filament. :astonished:
    It’s excellent that you keep it bagged right, thick aluminized bags are good, but watch out if it’s clear, they’re not as nonpermeable and can allow moisture in over time.
    Best is bagged and in a sealed box (I have a bunch of Dog/Cat food ones, thick, sealed lid and a large desiccant in it). Link if you wish.

However - on the AMS - Every time you open it you let in fresh air. It takes hours before the desiccant can drive the humidity down. Again, it can’t dry the filament. Period.

  1. Knowledge is power, and as you know there’s a hell of a lot to this 3D game. I know you’re a willing learner, that will serve you well. In that vein, I offer you this to read about drying, it’s a fairly good one:
    https://all3dp.com/2/how-to-dry-filament-pla-abs-and-nylon/
    and another that gives a good chart (but is dry as hell … Pun intended!)
    Drying filaments before processing | Fillamentum

Final thought - You can screw around trying different settings, speeds, whatever, but if you have not dried the filament it’s all useless motion except to learn the settings! PETG and others are known to be particularly hydroscopic (moisture loving) and print crappy when damp.

You want to print right? Dry the damn filament 1st!! :face_with_raised_eyebrow: :grin:
Said with love. LOL
Many people dry every new roll then store it properly to avoid issues.
/End Rant

Take a couple mins and read that article, K?
Cheers!

@ThanksForAsking Thanks for all the explaining about moisture and filament. I was aware that desiccant does not help if the filament has already absorbed moisture.
I may try drying but wanna add, that when the first layer is done, the print can continue and is flawless. And while calibrating printing was done with speeds up to 80mm/s with no problems in upper layers. Also these layer don’t show signs of wet filament so that is very unlikely. But I will give it a try to be sure cause I wanna elininate all possible causes for this problem to pin down the cause, so that other in the future know what to do.

I did read the whole article :joy:

@djeZo888 First layer has absolutely no cooling enabled. All other layer work well or at least just need fine tuning. But thanks for the hint.

It is also important what kind of cooling you have for other layers, not only first. Because cooling affects whole print, not only top layers. I am just going through warping issues with Spectrum PETG HT100, which is a bit different PETG that likes to warp, especially if the print is larger.

What helped me so far was using Wham Bam plate.

Now I am experimenting with various settings for cooling.

On one hand you need cooling for overhangs and on another, too much cooling can cause print to warp. So, a balance needs to be found.

So hello again guys.
An update after some testing:

Did that now.

I did some more calibration with the flow rate and set the first layer speed to 20mm/s.
The result is way better now.
For anyone interested:
PolyLite PETG:
Flow Ration: 0,9502, Temp is 255°C and Bed 70°C




As you can see on the left border I still had one bump and also when looking at the side which sticked to the print bed I could see some signs that it had problems sticking again there. But in the end it worked well so definitely going in the right direction.