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PETG edges peeling off  

Active Member
PETG edges peeling off

Hi all,

Just looking for input if anyone can help. I am printing PETG and it's a bit tricky.

I am printing a very simple shape, just a box. But I want the corners to be rounded. It looks great, but the corners on the bottom are peeling off. Its like a layer all around that I can pull away. I tried sanding around the bottom edge and it helps a bit, but doesn't look as nice as Id hope. I just want a nice round edge, its jaggedy and peeling.... I was wondering if anyone had any ideas as to why this is happening? 


Ive tried playing with temperature settings and print speed. Also the PETG I am using is pretty cheap so maybe that is the reason? anyways any suggestions would be appreciated!!






Posted : 17/09/2021 5:15 pm
Dan Rogers
Noble Member
couple of thoughts

In the prusa slicer, on the layers and perimeters page, enable "add extra perimeters as needed".  Assuming (can't see clearly in the picture at all) that you have rounded the bottom-most corners, and you are sliced down to a very thin wall, there is an issue that can crop up on round profile surfaces where there is not enough supporting layers on the curved part.  Checking this setting will add extra lower perimeters until each layer is supported by at least 70ish % of a layer below it.

Another one to turn on is "detect thin walls".  This will account for any design that doesn't factor extrusion width into the wall width design equation.  It usually helps get rid of sliced out voids (visible in the post-slicing preview) where you don't want them.

Finally, for a sturdy corner do not print in vase mode - there is only one extrusion width holding everything together, and rounded bottom will nearly always fail.

Posted : 17/09/2021 8:41 pm
Noble Member

If you changed from PLA to PETG you need to do some extra purge, because the mixed stuff in the nozzle does neither stick to PLA nor PETG.

Posted : 18/09/2021 8:48 am
Noble Member

This is one of the constraints that everyone eventually encounters in 3D design.

A shallow curve, fillet or horizontal cylinder will always have an area of poor surface quality because there is always a point where the angle is too great for unsupported printing and also the space beneath the curve is too small for supports.

If at all possible use chamfers or invert the part so that important curves are printed on a top surface.



Posted : 18/09/2021 12:03 pm