3D Printing: How to print an overhanging arc? (7 Solutions!)
Channel: Roel Van de Paar
Date: 2019-06-24

3D Printing: How to print an overhanging arc?


The Question: I am designing a part that has to clamp around a 11mm bushing, and due to other
design constraints, it has to be printed with a semicircle-shaped overhang:
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This is proving very challenging to print. Two copies of this part have to
clamp tightly around the bushing in all directions. Support material is rather
hard to remove from the very top of the arc (where the overhang angle is the
highest) and I often end up removing just too little of the support material
(so the part doesn't fit around the bushing) or too much (and the bushing can
wobble around).
Is there any way I can modify the design of this part (bearing in mind that it
absolutely has to be printed in this orientation) to make it more tolerant of
my inaccuracy when removing supports, or is there perhaps some way to manually
design supports that are easier to remove (Simplify3D and Cura both don't quite
cut it)?

Solutions Sample (Please watch the whole video to see all solutions, in order of how many people found them helpful)

== This solution helped 6 people ==
If your printer is printing support material that is too strongly attached, you
can increase the space between the support and the part in some slicing
softwares. On Cura it is located in the "expert settings" menu (you can open it
by pressing Ctrl + E), under the "Support" text. Try fiddling with the "Z
distance" setting until you find the right setting. You can also change the
type of support and support infill amount and see if it have any positive or
negative effect.
Edit : I think you should also redesign your part : it seems that it cannot
lock the bushing on. The semicircle should be a bit smaller to have a bit of
space between your two parts. This way the bushing will be secured firmly by
the tightening force of the screws and precision should be less of an issue.

== This solution helped 9 people ==
I think a lot of this depends on the slicing engine you're using as to what
options you have. I use MakerWare (now MakerBot Desktop) which has many options
for the support scaffolding as well as other useful settings for your
situation. As someone else stated, adjusting the distance (even slightly) can
make a world of difference in how easy the supports are removed. Also bear in
mind that supports can be more difficult to remove with larger layer heights,
so try printing in a lower layer height.
Often times, you shouldn't need to use support structures for a feature like
this. I might suggest printing without supports at a reduced speed and lowered
nozzle temperature. This will help ensure that the material hardens quicker,
which becomes helpful higher along the arc.
Related to the suggestion above, you can focus your slicing setting on better
bridging. This should give better control on feeds/speeds while "bridging" a
gap between overhanging features. Some slicing engines allow you to specify a
different layer height for these areas on the print.
So, I would try printing with reduced print speed, nozzle temperature(s), and
layer height with supports. My machine has a range of 0.1mm to 0.3, but I've
had more success printing between 0.12mm and 0.15mm layer height with
scaffolding in mind.
Last suggestion (when absolutely all else fails) purchase some sort of
dissolvable filament (ie PVA - water soluble) and set your scaffolding-to-part
distance really close and print. Obviously this only works if you have a multi-
extruder head or a lot of time on your hands to swap the materials and adjust
the nozzle temperature for each layer (please don't do that...)

With thanks & praise to God, and with thanks to the many people who have made this project possible! | Content (except music & images) licensed under cc by-sa 3.0 | Music: https://www.bensound.com/royalty-free-music | Images: https://stocksnap.io/license & others | With thanks to user Tormod Haugene (https://askubuntu.com/users/115), user Tom van der Zanden (https://askubuntu.com/users/26), user tjb1 (https://askubuntu.com/users/233), user Tinkerer (https://askubuntu.com/users/240), user the third dimension (https://askubuntu.com/users/10), user TextGeek (https://askubuntu.com/users/40), user tbm0115 (https://askubuntu.com/users/98), user SusanW (https://askubuntu.com/users/895), and the Stack Exchange Network (https://3dprinting.stackexchange.com/questions/250). Trademarks are property of their respective owners. Disclaimer: All information is provided "AS IS" without warranty of any kind. You are responsible for your own actions. Please contact me if anything is amiss at Roel D.OT VandePaar A.T gmail.com.