alchemyEngine
Need methodology for different active lengths
I'm trying to apply this to an i3 bedslinger style frame, where the gantry is supported by twin stainless steel leadscrews, and inside an enclosure. The deviation from expected Z position is going to be dependent on the thermal growth of the length of leadscrew that is supporting the gantry. When the nozzle is at z=0 there's about 50 mm of active leadscrew, so if the chamber was heated from 20C to 40C the leadscrews would grow thermally 0.0000173 mm/mm/C x 50mm x (40C-20C) = 0.017mm. But when the nozzle gets up to z=100mm there would be 100+50 = 150mm of leadscrew active, so the total growth would be 0.0000173 x 150mm x 20c = 0.052mm. So the compensation needs to know the active length of the support element, which may change from layer to layer as it does in the case of the i3. I don't think what you currently have set up here takes that in to account.
Ideally this would be implemented by allowing arbitrary equations in temp_coeff or an optional alternative equation config parameter. This would need to be parsed for Z height and temperature variables.
I will not be able to work on this for some time still, but feel free to submit a pull request!
