Re: Tek Knob Project - scan and make


Yes, as I said, no more hair.
I would rather mill the knobs with a dividing head than put myself through that.


On Thu, Dec 21, 2017 at 6:59 AM, Kuba Ober <kuba@...> wrote:

Normal Marlin firmware will deal with the gcode of course; it doesn’t care much as long as you’re outputting gcode in coordinates of the printer’s axes. The issue is getting the non-Cartesian gcode. Since the knobs have simple shapes, a straightforward parametric gcode generator script can do the whole thing for output in cylindrical coordinates. I like vagrearg’s gcmc for that.

Another simple idea is to generate the 3D model unrolled onto the hub, i.e. using pseudo-cylindrical coordinates directly: X->axial position, Y->circumferential position, Z->radius. Then the gcode output from a slicer can control such a printer directly with no modifications!

If one were to generate the 3D model in true cylindrical coordinates (Y->angle), the slicer output will have to have the flow factor set at the beginning of each layer to a value proportional to the layer number, and the speed set to a value that’s an inverse of the layer number. That’s to accommodate the growing angle->circumferential position scale the radius increases.


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