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Trouble with support material  

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leo
 leo
(@leo-3)
Active Member
Trouble with support material

Hi. I am looking to print the part below and I am having trouble with the support material. Depending on the settings, the support material is either too hard to remove, or the edge of the print bends and the print fails with a crash detection (see pic below). I tried a few different settings over 4 printing attempts including the Contact Z Distance, Pattern, Pattern spacing, Support on build plate only, and a few others without success. Here is my latest (failed) configuration:

Printer: Prusa MK3
Slic3r PE 1.41.2
Print settings: .15mm
Filament: PLA+ (using "generic PLA" in Slic3r)
Fill density: 30%
Overhang threshold: 0
Contact Z distance: 0.1 (this seems to be the critical parameter: 0 makes the support material too hard to remove, and the surface of the part look very ugly after removing the support; higher values tested so far make the print fail as the edge of the part bends while printing)
Pattern: Honeycomb (also tried rectilinear)
Pattern spacing: 1.0 (tried a few settings from 1.0 to 2)
Support on build plate only: checked -- seems like the best option to avoid support material inside the groove around the edge of the part (near the plate), which is too difficult to remove
Don't support bridges: unchecked

I used Meshmixer to generate the 'tree' supports you see under that little box at the top -- seems like a good combination when keeping 'Support on build plate only' checked.

I would appreciate any tips to print this part. Thanks a lot!

Posted : 11/04/2019 3:36 am
vintagepc
(@vintagepc)
Member
Re: Trouble with support material

Unfortunately that is a very tricky geometry to do on an FDM printer. You're going to have to play with orientation to get better results, i suspect. For example, see if you can orient it at an unusual (maybe 45) degree angle to the build plate with a large brim - then you won't have to print such a massive overhang. Or, find a way to print it as two pieces (split it in the large flat plane and glue it after the fact)

Of course, if you place it at an angle, you are now challenged with supporting it properly during the print....

Posted : 11/04/2019 4:26 am
gnat
 gnat
(@gnat)
Noble Member
Re: Trouble with support material

That is a massive overhang/bridge! If forget the setting, but there is one you can adjust to cause the support to be under 100% of the bridge/overhang. Have you played with that?

I have a part similar to yours where only one edge touched the plate and the overhang started about 1" off the plate. My test prints with Inland PLA ran just fine, but when I ran the final print with Prusa Black it was all kinds of terrible. I ran it again (no gcode changes) with Inland PLA+ Black and it came out perfect (other than being shinier than the rest of the parts that had run with the Prusa Black).

So I'd suggest playing with the overhang settings if you haven't, maybe up the bed temp before it starts the bridge to radiate a bit more heat up there, and possibly try a different filament.

MMU tips and troubleshooting
Posted : 11/04/2019 5:36 pm
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