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This boolean subtract with offset is not solving - help!
tom_auger
Member Posts: 129 ✭✭
Hi friends, it's been a while but now I'm back and as always I have questions......
One of my most standard things for making 3D printed parts that fit into each other is to use Boolean Subtract with a small (eg: 0.3 mm) offset to create a bit of gap to account for the tolerances of FDM printing. Typically works a charm. I use it for things like threaded parts or even press-fit parts.
Well, here's my latest very simple threaded part - the inner part ("male") needs to subtract from the outer part to create the relief threading. However, if I apply a positive offset, even a tiny one, the boolean feature doesn't solve. Surprisingly, the opposite (negative offset) does work, but that's precisely the opposite of what I'm looking for.
Screen shot below and then a link to the doc if anyone wants to take a quick gander. As always, so greatly appreciated!
https://cad.onshape.com/documents/510bb745140070d8d7d5ce3a/w/83a9ab501d6696ead04ac9c6/e/4b95368fb7fda514f494f445?configuration=List_IWpyc5fQoT6y5H=Default
One of my most standard things for making 3D printed parts that fit into each other is to use Boolean Subtract with a small (eg: 0.3 mm) offset to create a bit of gap to account for the tolerances of FDM printing. Typically works a charm. I use it for things like threaded parts or even press-fit parts.
Well, here's my latest very simple threaded part - the inner part ("male") needs to subtract from the outer part to create the relief threading. However, if I apply a positive offset, even a tiny one, the boolean feature doesn't solve. Surprisingly, the opposite (negative offset) does work, but that's precisely the opposite of what I'm looking for.
Screen shot below and then a link to the doc if anyone wants to take a quick gander. As always, so greatly appreciated!
https://cad.onshape.com/documents/510bb745140070d8d7d5ce3a/w/83a9ab501d6696ead04ac9c6/e/4b95368fb7fda514f494f445?configuration=List_IWpyc5fQoT6y5H=Default
0
Best Answer
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tom_auger
Member Posts: 129 ✭✭
I was able to solve the issue using three separate "Move Face" features - one for each "side" of the thread (upper and lower side of the "V") and then I had to offset the top face of the collar (in blue) as the inverse operation on the cap was not solving. Dimensionally I'm not pleased with that last piece but I like knowing that my approach is still more-or-less viable.
But I'll probably remember that thread FS tool next time
0
Answers
It generally creates pretty well-behaved threads.
Here's how you could modify your design to make use of it (reducing the feature count a lot:
https://cad.onshape.com/documents/1c6c17d4576d0f7553bba4a6/
General tips:
- Fully define your sketches whenever possible--this helps a lot with complex geometry
- Watch out for tiny sliver faces--these make offsets not work as well
- There is generally a custom feature available to automate anything annoying
Hope this helps!@alnis is my personal account. @alnis_ptc is my official PTC account.
Thanks for the reminder Alnis! I have it installed but sometimes forget to use it. I also like doing things the "manual" way when I can because I always learn something new!
I was able to solve the issue using three separate "Move Face" features - one for each "side" of the thread (upper and lower side of the "V") and then I had to offset the top face of the collar (in blue) as the inverse operation on the cap was not solving. Dimensionally I'm not pleased with that last piece but I like knowing that my approach is still more-or-less viable.
But I'll probably remember that thread FS tool next time