4 axis polar geometry

Hi,

I'm building a large CoreXY printer (320x320x320), and its first task will be to print a real size BB-8.

The body will be build from a big PMMA sphere (or maybe stainless steel if I can find one), and 3D printed panels will be screwed on it. For these panels, which are parts of a sphere, I would like to make something smart: instead of print them with a lot of support, I would like to print them as if there where flat. The idea is to build a specific bed, with a vertical rotation axis. This axis combined with X (or Y) axis will make a standard 2D polar geometry. Then, adding another (horizontal) rotation axis, under the vertical rotation axis, will give the ability to bring back every location of the printed part horizontal. The range of this axis is plus/minus 37°.

The printed part will have to be designed flat, which is not very difficult. They will be sliced as if they where printed flat, but with the correct firmware, they will actually be printed as a sphere (on a spherical bed, of course)!

This config does not even require an extension board.

My question is: is it difficult to add the support of such geometry in dc42 firmware? Is it modular enough to do that without changing too much things in the core code? This config will require a good bed leveling procedure, as the spherical bed won't be a perfect sphere...

What do you think?

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Frédéric

In firmware version 1.19 I rewrote the kinematics code to make it highly modular, so that new machine architectures can be added easily. Already this new modularity has been used ot implement SCARA geometry and dual carriage CoreXY geometry. So it shouldn't be difficult to add your 4-axis polar geometry.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Great I will have a look at the code this week-end...

Thanks again.

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Frédéric

BTW, which branch/tag do you suggest me to use to implement this geometry? dev? Or the stable 1.18.1?

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Frédéric

The modular kinematics refactoring is in version 1.19, last time I checked it was in the dev branch.

Ok; 1.19 seems to be the next stable release...

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Frédéric

I've seen a Delta printer doing 5 axis milling. Seems easier to build to me...although pricey for sure

This will be my next one

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Frédéric