CNC Path along a 3D curve

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freecad-heini-1
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CNC Path along a 3D curve

Postby freecad-heini-1 » Sat Jan 13, 2018 11:00 am

Please can you answer me the question if it's possible to create a cnc path along the yellow curve as to see in this picture:
cnc_path_alonge_the_yellow_edge.png
cnc_path_alonge_the_yellow_edge.png (25.74 KiB) Viewed 1078 times
If possibe start with an 90° arc and at the end of the path 2mm longer drive out with a 90° arc.
The bottom face is not flat, it's 1mm concave on the deepest position.
It's important that the cnc path follow the curve and the bottom face. I know that because of the 2mm flat milling tool the face will have some unaccuracy, but that's not so much wrong, I guess max difference 0,01mm.

Here are my cad-file:
fc-017_path_edge.fcstd
(93.92 KiB) Downloaded 21 times
The milling tool should be a end mill cutter 2mm diameter with sharp edges.
It's a hardable steel and the edges are not sharp, there is a 0,1mm radius because of edm.
Wth this path I hope that we can mill away the radius.
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DeepSOIC
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Re: CNC Path along a 3D curve

Postby DeepSOIC » Sat Jan 13, 2018 11:48 am

There is a "path from shape" tool in Path menu. I wonder if it does what you want...

I have almost no clue how to use Path (I always use a slicer instead for my 3d printer). So my project is probably incorrect, but it gives some g-code, making it useful.
Attachments
path-from-shape.FCStd
(17.9 KiB) Downloaded 14 times
path-from-shape.png
path-from-shape.png (192.23 KiB) Viewed 1064 times
herbk
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Re: CNC Path along a 3D curve

Postby herbk » Sat Jan 13, 2018 12:34 pm

Hi Wilfried,
like that?
fc-017_path_edge_hk.jpg
fc-017_path_edge_hk.jpg (84.86 KiB) Viewed 1054 times
I keep the step over at 100% and step down at 2mm, i know to big steps, but on the pic you will only see a green cube if i set the parameters to a value it make sense to work with... ;)
I Made something like that a few weeks before with stepdown of 0,1mm and step over 50% with a very good result (expecting the milling time...).

You have to select both squares and use the "3D Pocket" operation. If i select only the inner square, FC crashes...?
Attachments
fc-017_path_edge_hk.fcstd
(184.35 KiB) Downloaded 26 times
Gruß Herbert
freecad-heini-1
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Re: CNC Path along a 3D curve

Postby freecad-heini-1 » Sat Jan 13, 2018 1:41 pm

Thanks Viktor, that goes into the right direction.

@Herbert, this part is ready machined, except for a small 0,1mm radius because of edm .
So I need just one toolpath along the yellow coloured curve with a soft ramp in and out, if possible.

Do I need a solid or is a shell also o.k. to create the cnc path?
chrisb
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Re: CNC Path along a 3D curve

Postby chrisb » Sat Jan 13, 2018 4:15 pm

freecad-heini-1 wrote:
Sat Jan 13, 2018 1:41 pm
Do I need a solid or is a shell also o.k. to create the cnc path?
You need a solid to use the Path workbench.
Last edited by chrisb on Sat Jan 13, 2018 10:42 pm, edited 1 time in total.
You need at least FreeCAD 0.19.23300 to edit my current sketches.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
freecad-heini-1
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Re: CNC Path along a 3D curve

Postby freecad-heini-1 » Sat Jan 13, 2018 5:57 pm

The part in my inquiry is just a demo part.
Is it possible to create a toolpath on parts like this with ramp in and out?
herbk
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Re: CNC Path along a 3D curve

Postby herbk » Sat Jan 13, 2018 6:48 pm

Ramp entry dosn't work on "path from shape" and "path from shape" ignores the tool diameter.

In my mind "3D Pocket" should do what you want if you select the inner square and set the start depht to something like 0,5 highter as the bottom is.
A prob.for you could be, that 3D Pocket respects the toll diameter and dos not remove material from the bottom.
Om ny installation FC crashes if i try it like descriebed, but FC on OpenSuse is a little bit difficulty... For that i don't know, is it a lokal problem or a general.
Gruß Herbert
chrisb
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Re: CNC Path along a 3D curve

Postby chrisb » Sat Jan 13, 2018 10:45 pm

freecad-heini-1 wrote:
Sat Jan 13, 2018 5:57 pm
The part in my inquiry is just a demo part.
Is it possible to create a toolpath on parts like this with ramp in and out?
Can the mill perform radius compensation on its own?
You need at least FreeCAD 0.19.23300 to edit my current sketches.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
mlampert
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Re: CNC Path along a 3D curve

Postby mlampert » Sun Jan 14, 2018 7:18 am

If I understand your question correctly all you want to do is create a path along the yellow line. The way to do that is to select the underlying face
Capture.PNG
Capture.PNG (12.2 KiB) Viewed 970 times
and then you want to create a "Profile based on face or faces" and only select the "Process Holes" in the Operation:
Capture1.PNG
Capture1.PNG (7.52 KiB) Viewed 970 times
herbk
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Re: CNC Path along a 3D curve

Postby herbk » Sun Jan 14, 2018 8:42 am

Hi Markus,
the squere you selected is not flat, better, the inner line is not at one Z level. Path by shape creates a G-code with this different Z levels, "Profile by Face" does the last round only at one level.
Gruß Herbert