I managed to figure out how to change the firmware to deal with the non linearity of this type of delta (my fork of marlin on github). I haven't yet got bed leveling working, but it doesn't seem to be working on the normal marlin firmware either.
So far it prints very nicely at low speeds (30 mm/s, 0.1 mm layer height, pla, 0.5 mm nozzle, 3000 acceleration set in firmware) EDIT: Looking back it wasn't actually doing 200mm/sec, as the arduino couldn't calculate the moves fast enough.
At higher speeds the limitations of the design become apparent ( 200mm/s, 0.2 mm layer height, pla, 0.5 mm nozzle, 3000 acceleration set in firmware)
EDIT: Looking back it wasn't actually doing 200mm/sec, as the arduino couldn't calculate the moves fast enough.
The ratio between the steppers and the upper arms is 1:14. Ideally it would be in 1 to 20 - 50 range. As long as the machine runs slow and the microstepping can really make its effects apparent. I wouldn't say that there's any fatal design faults in the icepick, but that 1:14 ratio is a bit of a snag. I have some ideas about using braided fishing line and some very small pulleys, if used, the big pulleys could be much thinner. Another alternative may be to increase the size of the main pulley, and cut off a piece off the bottom which isn't required, but increasing the pulleys may make the design a bit too bulky.
Ideas are welcome! Leave them in the comments below :)