Need a help

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Need a help

Postby MaxP00 » Sun Oct 27, 2019 7:49 pm


Basically I want to create a certain kind of Helix/Spiral for FDM 3D printing. The trick to make this work (to some degree at least) is to create a geometry that forces the slicer to use as long strokes as possible, which are then mostly parallel. That more or less means to have a profile that is extruded, rotated and moved up for each layer. Particularly it is an arc from the center of the Helix to its circumference, and a thickness that is a multiple of the nozzle diameter.

I have tried to define something like this through the Sweep tool in PartDesign, and I guess that can't work because I can't embed the rotation/translation information in a Path/Wire.

So, my next idea is to take a sketch, copy/transform the Wire for each layer and then somehow create a Loft. I've figured out that I can put multiple instances of the Wire shape into a Part.Compound shape. But then that doesn't really work for the Loft, because I can't select the individual parts.

So, what would be the best way to create a loft from a large number of algorithmically created wire profiles? Is there a way to do this without all the wires showing up as a top-level object in the tree? Is this maybe the time to use OCC directly?

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Re: Need a help

Postby usbhub » Sun Oct 27, 2019 8:12 pm

Please ask in German here or in English in the English forum.
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Re: Need a help

Postby chrisb » Sun Oct 27, 2019 9:12 pm

Moved from German to english Help forum.
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Re: Need a help

Postby freedman » Mon Oct 28, 2019 4:37 am

Many times you might think that's the only to do something. If you can give us a picture or made up drawing we might be able to give you what FreeCAD is capable to make and how to do it.
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Re: Need a help

Postby chrisb » Mon Oct 28, 2019 6:19 am

If I understand you right, you want to take from a spring...
Snip macro screenshot-026efe.png
Snip macro screenshot-026efe.png (23.11 KiB) Viewed 427 times
...such a slice indicated by the small rectangle:
Snip macro screenshot-4ce73c.png
Snip macro screenshot-4ce73c.png (3.75 KiB) Viewed 427 times
Then you want to take that slice and and stack+rotate copies of this (I colored them differently):
Snip macro screenshot-00020a.png
Snip macro screenshot-00020a.png (22.68 KiB) Viewed 427 times

I was myself surprised that this seems to work :) , but it will not help you any further with your printer. The final result of this would be a helix and if you fuse all slices together it will be the same helix solid you had in the beginning. What you want is something that only the slicer can do.

If you want to play with this, I can attach the file, but it is all done manually, because PolarArray doesn:t support this spiraling. So I created clones and placed them appropriately.

Besides: you may consider in editing your first post and change the subject to something more meaningful, which may help others to find this topic in case they search for something similar. Most people here ask for help, yet they don't use all the same topic.
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Re: Need a help

Postby pl7i92LCNC » Mon Oct 28, 2019 8:49 am

why not using the integreted cura module to print
i do that also on color prints
like here
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Re: Need a help

Postby chrisb » Mon Oct 28, 2019 12:54 pm

This video has nothing to do with FreeCAD nor with OP's question to generate strokes as long as possible.
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Re: Need a help

Postby papyblaise » Mon Oct 28, 2019 3:37 pm

I don't understand where is the problem, because any basic printer 3D know how to do the slicing by herself :!: Isn't it :?:
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Re: Need a help

Postby chrisb » Mon Oct 28, 2019 6:08 pm

From what I understand Max wants the slicer to to follow the curve as far as possible, i.e. one layer radial next layer circular.
My slicer (cure) usually uses a diagonal pattern. For this special case I could tell cura to make it circular, but it may not be possible for all shapes to make the plastic mini sausages as long as possible.