WestNQ
Posts: 2
Joined: Thu Apr 09, 2020 12:27 pm

Force outer perimeter to single extrusion

Thu Apr 09, 2020 12:40 pm

Greetings,
So I'm trying to print off a couple replacement gears for a hand mixer. Near the top of the splines, they're printing as separate islands, as indicated in the image below. Anyone have any ideas on how to force the outer perimeter to be a single extrusion, as it does further down the splines?
(Also, before anyone calls me out on it, I know PLA isn't ideal for this, and if I can get it working, I'll certainly switch over ABS)

Unfavorable
Capture.JPG
Ideal
Capture2.JPG
Thank you,
-Phil
Attachments
Gear.factory
(347.47 KiB) Downloaded 254 times

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dkightley
Posts: 2270
Joined: Tue Mar 10, 2015 4:09 pm

Re: Force outer perimeter to single extrusion

Thu Apr 09, 2020 4:58 pm

I think you need to go back to the CAD of this gear. It appears not only to be made up of 767 separate elements, but the teeth, having been made separately, do not overlap the core of the wheel fully...and are seen by the slicer to have a very, very small gap between the tooth and the core of the gear.....as if they're placed butted together and not overlapped.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

greybeard
Posts: 178
Joined: Mon Mar 02, 2015 1:23 pm

Re: Force outer perimeter to single extrusion

Thu Apr 09, 2020 5:46 pm

I make lot's, lot's of gears. Using FreeCAD for past 5yrs and the two Gear macro's works great.

Example below.

Regarding printing them, suggest using 3 upper, 3 lower layers, and 1 shell.
Attachments
gears.jpg
gears.png
3D Print Parts
https://www.thingiverse.com/Still_Breathing/designs

WestNQ
Posts: 2
Joined: Thu Apr 09, 2020 12:27 pm

Re: Force outer perimeter to single extrusion

Fri Apr 10, 2020 11:05 am

dkightley wrote:
Thu Apr 09, 2020 4:58 pm
I think you need to go back to the CAD of this gear. It appears not only to be made up of 767 separate elements, but the teeth, having been made separately, do not overlap the core of the wheel fully...and are seen by the slicer to have a very, very small gap between the tooth and the core of the gear.....as if they're placed butted together and not overlapped.
Interesting, I certainly didn't design it that way. I'll take a look again though, perhaps it's something to do with the STL conversion. Thank you for the heads up!
How did you discern how many separate elements it is? That would probably be handy to know!

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