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warped PETG prints

Posted: Tue Jun 30, 2020 4:06 pm
by jferguson
I'm using the MakerGear Forum recommended PETG setup for Simplify3D with my M2/E. The printer is not enclosed and the ambient temperature in the shop is 75F.

Setup above calls for turning fan on after printing the first layer, using 87C for bed and 247C for extruder. I'm used to getting a little lift in the corners of prints which are more than 4 inches on a side, and if it matters, I use more elmer's stick glue and add a centimeter of brim.

Latest print showed warping half way up the print which was new for me.

Esun recommends no fan for their PETG.

I could turn off the A/c and let temperature in room rise into the mid 80s F, or turn off fan for all layers, or both.

What would you do?

Re: warped PETG prints

Posted: Tue Jun 30, 2020 4:50 pm
by ednisley
jferguson wrote:
Tue Jun 30, 2020 4:06 pm
turn off fan for all layers
Do that thing, along with mouse ears on the corners, and it'll be as good as it gets.

You may need more brim / mouse ears for difficult geometries, like a thin-bottom + thick-walled box. Don't be afraid to apply more brim, perhaps with two layers, in those cases.

I've been running a 90 °C platform and 250 °C hot end (indistinguishable from your settings) with no cooling, atop hairspray, and getting consistently fine results: parts stick like they're glued and automatically pop free from the cooled platform.

A few millimeters of the outer perimeters at the corners of box-shaped parts with thick walls may lift off the platform enough to be visible in light reflected from the bottom layer, but I can't measure the actual deformation, so it's Good Enough™ for my simple needs.

A few degrees of room temperature won't make any difference at all. My Basement Laboratory temperatures range from 10 °C in the winter to 25 °C in the summer, with no effect on anything I can see.

Re: warped PETG prints

Posted: Tue Jun 30, 2020 4:54 pm
by jferguson
thank you sooooo much.

Re: warped PETG prints

Posted: Tue Jun 30, 2020 9:37 pm
by jferguson
the M2 is at the shop about a mile from home. i use Octopi and can monitor the printing via the webcam which watches what's going on. I use VNC so can watch it from home. If there is a problem, I can shut down the print, which then does a soft shutdown on the printer.

my 20 hour print has about 4 hours on it and has passed the part where I was having warping problems.

I wonder why the recommended PETG setup called for fan after first layer.

thanks again, Ed.

Re: warped PETG prints

Posted: Wed Jul 01, 2020 3:52 am
by airscapes
PETG should never need a fan.. I think some folks print it way to hot and add the fan rather than dropping the temp ..