Page 1 of 1

PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 4:49 pm
by Katwitch
Can I please have some suggestions that work for some of you using PETG regularly? I've newly starting working with PETG and it looks like I'm having build surface adhesion problems. I've got / tried both the standard glass and the polymide coated version. I've tried hairspray on the glass and most recently glue sticks which is working the best. I'm still seeing the occasional peel up or bubble up for a few areas on a print with a larger base.

The PETG manufacturers (currently using Overture) scared the hell out of me about setting the first layer high enough to prevent smush. I was getting a little of that so I currently have the following settings in S3D: First layer Height 110%, first layer speed 50%, default printing speed 1800 mm/min, .35 nozzle with 1mm retraction, extrusion multiplier set to 0.9mm. Temps are set to 80 on the bed and 235-240 on the nozzle.

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 5:10 pm
by Mach
I print PETG on buildtak. First layer is definitely "smushed". If I'm worried about adhesion, I'll throw some magigoo on the buildtak. I print push plastic PETG (10KG rolls) at 255c and 90c bed. I back down the bed temp to 80 after the 3rd layer and turn the fan on. I was getting too much sagging without the fan. I was able to print without a fan in the winter. First layer 97, width 100, speed 40%. Printing at 40mm/sec. .4mm nozzle (e3d v6) with 1.2mm retraction. Printing 0.25 layer height.

Edit:Forget what I said above about buildtak and magigoo. Airscapes advice regarding bare glass is 100% better. If PETG stops sticking, wash the glass with Dawn and keep printjng. Once the bed cools down, you can hear prints breaking free from the bed. Wish I would have used bare glass from the start.

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 5:53 pm
by Katwitch
Thank you. I've not heard of buildtak. As I just researched, it looks like my Overture PETG came with a little square of it. You have to recalibrate your nozzle height once you stick that on your your bed right? If I switch materials a lot (I do) looks like I might need to just get another piece of borosilicate for this, but then there's the constant height adjustment issue...

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 8:00 pm
by airscapes
If petg is not sticking to your glass or polymide tape, your Z offset is not set correctly, or you are printing way to fast. I have had PETG remove a chunk of glass from my stock glass plate when not using tape..

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 9:10 pm
by Katwitch
airscapes wrote:
Thu Jun 11, 2020 8:00 pm
If petg is not sticking to your glass or polymide tape, your Z offset is not set correctly, or you are printing way to fast. I have had PETG remove a chunk of glass from my stock glass plate when not using tape..
Thanks.

I've had nozzle clogs from printing at 90% first layer (where ABS and PLA work perfectly at this Z setting). This is why I moved to 110% first layer. It could be because I was moving too fast. I've also seen a lot of people and filament manufacturers warn "never to smush PETG" as mentioned here https://rigid.ink/blogs/news/175700615- ... ing%20fan..

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 9:42 pm
by airscapes
Setting your Z offset correctly with a calibration square with each and every layer height change.. i.e a .15 layer height requires a different offset than .3mm layer .. A 70 degree bed vrs 110 degree bed will require a different z offset. Just so you can see what is very possible these parts are printed sequentially using a .75mm nozzle and eSun PETG at 14mmS . They are on .8mm wall thickness, that is all that is on the bed .8 wide on wall.
Covers and more covers.jpg

Re: PETG build surface adhesion advice

Posted: Thu Jun 11, 2020 9:50 pm
by airscapes
Here is a post that explains how to set the z offset
viewtopic.php?f=7&t=7959&hilit=M206

This stl should be 3mm tall when printed and the thickness of the wall should be .8mm +.01-02 if extrusion multiplier and Z offset is correct
2 walls at .4 EW 3mm tall.stl
(1.64 KiB) Downloaded 93 times

Re: PETG build surface adhesion advice

Posted: Mon Jun 15, 2020 1:26 am
by Gwhite
I've had really good results using hair spray on glass with PETG. I use thsi stuff:

https://www.amazon.com/gp/product/B0177F8FM0

Once the job cools, a light tap & it just pops loose.