sphere shape in path workbench?

[bbb]

Hi,

I would like to produce some G-code which can be used to mill out a sphere shape, but I don't know what do I wrong, it is simply not working for me.
My model is simple - a sphere with some inner cuts and it is sliced to fit to my final material (attached). My problem is that when I try to create the path, it is became straight on the outer side, it does not follow the face of the selected object. In my attachement there is the path I could generate, hope there is someone who can tell me what did I wrong and how to do it right

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 32-bit
Version: 0.17.13522 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 3bb5ff4e70c0c526f2d9dd69b1004155b2f527f2
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Hungarian/Hungary (hu_HU)

[chrisb]

There is a subforum dedicated to questions concerning Path. I moved the topic.

[chrisb]

Contour works as designed. It creates a path around the outer shape of the base object.

You should use the 3D Pocket if you want the path to follow the curved shape. You have to create one 3DPocket for each slice of the sphere, putting them all into one 3DPocket operation keeps all paths on the level of one slice.

[chrisb]

Sorry for the hint with 3D pocket. It looked very good, but the paths go through the solid part of the sphere. Only the bottom slice is handled correctly, as can be seen in wireframe display mode.

[chrisb]

And here we go again: Your job has only the bottom slice as base object. If you want to create paths for the whole sphere, make a Part->Union of all slices and use that as a base object for the job. Then you can add paths for each slice with 3DPocket. The image shows it (more or less) for the first two slices.

[bbb]

Thanks, but it is not working for me... My fresh installed FreeCAD throws an error sometimes, but I don't find a way to see a log file to trace the problem.

phpBB [video]

The slice thingy does not matter for me, it was just way simpler to model the object in whole and after that slice it for mill them one by one.

[chrisb]

Thanks, but it is not working for me...

Please try selecting the outside only.

[bbb]

I did, no luck, no path generated.

phpBB [video]

The file you have attached has the same problem, it does not follow the face, but uses the base (the widest thing) to make the pocket.

[GeneFC]

I did a quick test, and I think you can get the curved shape if the surface is *inside* an enclosed 3D pocket. Add a surrounding ring to make a "moat" around the outside spherical surface. You will probably need to add a thin plane at the bottom edge of your design to keep a contiguous solid with a defined bottom to the "moat".

The 3D pocket operation then faithfully follows the spherical shape. Of course there may also be extra junk in the path, depending on the shape of the "moat". I just used a simple ring, but you may be able to create more appropriate shapes.

Gene

[bbb]

I have tried this method as you suggested. Almost worked, but the tool path stops at around the middle of the face.

3dpocket-moat.png (164.79 KiB) Viewed 2019 times