printing bones, bottom knuckle curls up, how to fix?

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macmccaskie
Posts: 10
Joined: Sat Jun 09, 2018 6:19 pm

printing bones, bottom knuckle curls up, how to fix?

Post by macmccaskie » Sat Dec 01, 2018 8:30 pm

Details:
M3-ID v1, S3D 4.0.1
MG ABS natural, 250 Hotend, 110 bed
Layers Bottom/Top/Sides: 4/4/7, infill 25%
Nozzle .35, .2 layer, 53.3 mm/s
support 25%, dense support 70% w/7 layers, horz offset 0.3mm
skirt 2 layers with 8 outlines, offset .15mm
I think the rest is pretty much default
TIA - mac

Hey, I'm attempting to print the leg of this Woolly Mammoth Skeleton from thingiverse:
d60cc442a7538e01cdf7034fa0162bae_preview_featured.jpg
This part, the left front foreleg:
4e736a27c141f10e4a10cfdf7c420c81_preview_featured.jpg
Starts the print but bottom knuckle starts to curl upwards and eventually gets knocked off the build plate, hopefully these prints are clear enough to see what I'm trying to say:
280.JPG
282.JPG
283.JPG

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sthone
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Re: printing bones, bottom knuckle curls up, how to fix?

Post by sthone » Sat Dec 01, 2018 9:55 pm

I would probably split the tip off so it prints on a flat area then just print the tip separate and glue them together.

You could probably do this right in S3D but dropping the part below the print surface. (z offset) Just import two of the same part and flip one over. You just have to make sure they both line up correctly at the split.
.
Split.jpg
This is just an example I'd probably split it right in half and print one at a time.

As an alternative you can use a Program like Meshmixer to get a more accurate split.
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macmccaskie
Posts: 10
Joined: Sat Jun 09, 2018 6:19 pm

Re: printing bones, bottom knuckle curls up, how to fix?

Post by macmccaskie » Sun Dec 02, 2018 12:39 am

Thanks, I guess that will work, i'd have to use mesh mixer. This is not the only piece I would have to do this with.

But quit honestly I was hoping for more of a "how come it's doing this" tip.

ie:
too many side/ bottom layers?
reduce extrusion multiplier?
decrease part / support offset?
try to calibrate for filament thickness?
decrease support overhang from 60deg?
flip it upside down?

most other parts have printed fine, it is just the small convex surfaces on the bottom that do this. I even tried laying another piece horizontally with the same result.

-mac

airscapes
Posts: 260
Joined: Wed Jan 31, 2018 11:36 pm

Re: printing bones, bottom knuckle curls up, how to fix?

Post by airscapes » Sun Dec 02, 2018 1:10 am

well ABS is problematic at best.. PLA would be better.
But, there is how I would set supports for D&D miniatures (would also be using .25mm nozzle with a .25 extrusion width calibrated on the under extruded side.. by 1

support infill 40%
Dense 0
Extra inflation 0
base layers you are fine 5 or more
combine support 1
over hand 45
support resolution 1mm
Horizontal offset .12 You may want to try .
upper vertical separation 1
Lower 0
support infill angles 0 (this is an area you can play with adding 45 -45 90 0 etc.

where you have curves add extra manual support after you add the default
also with curves you will see that a horizontal offset of .1 get bigger where the support meats the part may want to try 0

Print speed 30 - 35mmS (I am guessing your speed is causing you the most issue.. )
if I was using abs bed temp 110 (Takes freaking forever) nozle 235
Enclosure CLOSED (really needed for abs)
No fan

ALSO raise that part so it is about 3mm off the plate so the support can fully encompass it

Or cut the part as has been suggested.

macmccaskie
Posts: 10
Joined: Sat Jun 09, 2018 6:19 pm

Re: printing bones, bottom knuckle curls up, how to fix?

Post by macmccaskie » Sun Dec 02, 2018 4:33 pm

Thanks airscapes:
I changed Horz. Offset to .1 due to last comment
base layers to 5
kept extra inflation at .9 since some of those towers are very high and I thought I needed extra support
lower vertical separation layers to 0
support infill angles to 45/-45 from 90 (thanks, I looked that up and learned something)
max overhang angle from 60 to 45 deg

question: what is over hand 45? was that a typo?

printing now, we'll see

-mac

airscapes
Posts: 260
Joined: Wed Jan 31, 2018 11:36 pm

Re: printing bones, bottom knuckle curls up, how to fix?

Post by airscapes » Sun Dec 02, 2018 5:33 pm

yes over hang..
extra inflation causes the support to go up and around the part.. Never found it helpful but may help.. you should be able to play with that and see exactly what it does in the preview.
You did not say you raised the part, that can help as well. Gives more room for the support to build under it..
Good luck and keep at it you will figure it out, this is the ART part of 3D printing..

macmccaskie
Posts: 10
Joined: Sat Jun 09, 2018 6:19 pm

Re: printing bones, bottom knuckle curls up, how to fix?

Post by macmccaskie » Sun Dec 02, 2018 6:42 pm

Thanks, I did raise the part, unfortunately no change with the cupping. I have switched to the RF_Foot and rotated it so the foot is down.

That foreleg is a b****, I've tried as designed, laid it down horz., rotated it, etc.

Without an enclosure I've printed the rib-cages, pelvis, tail and LF foot without issue. Maybe the forelegs are my tipping point?

I'll keep at it and thanks for your help, I learned a lot in the process.

-mac

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