# Overhangs lift up

My printer is exhibiting a problem wherein it's as if the nozzle pulls up on layers. I don't think it used to do this - it seemed like it manifested after I replaced the broken x-carriage with a printed one, but I don't see how that could have caused the issue. It's possible something else I did or replaced caused it; not sure. Allow me to give an example:

I'm trying to print a worm gear, with a tooth size of about 2mm. The teeth, as they appear in the stl, look kinda like

 ____________
<            >
>        <
<            >
>        <
<____________>


However, when printed, the edges are pulled upwards, looking more like

____________
\          /
_\        /_
\          /
_\        /_
\          /
\________/


I originally noticed the pull-up in the surface finish of flat things - there was a grid of raised bumps on the top layer, I believe corresponding to the empty points between infill walls. That wasn't an effect that mattered to me, though. The effect on the worm gear is much more significant.

Anybody know why my printer is pulling up on layers, or whatever it's doing?

• props for amazing ascii art. Does this happen when printing larger overhangs as well? – Nach0z Jun 5 '19 at 18:15
• @Nach0z Yes it does, you see this effect many times, e.g. at the bow of the Benchy, myself I experienced this with X-axis idler mounts with 45º slanting slopes. – 0scar Jun 5 '19 at 18:39
• @Nach0z Haha, thanks. Mine seems to happen primarily with thin layers - but on the other hand, I don't usually print large overhangs, anyway, so that may just be data I don't have. – Erhannis Jun 6 '19 at 14:56