I was asked this question again, and this was my reply:
Disclaimer: The calculations were done quickly on a calculator and may have slight rounding errors – but not to a factor of 10!
The large wheel radius is 75mm making circumference = 471mm The pulley on the motor is typically T2 20 or T2 16: 40mm or 32mm
Ratio is thus 11.78 or 14.72
Given a step size of 0.9deg, and 32uStep an electronic step is 0.028125 degree With the ratio, that becomes 0,002387521 or 0,001910666 degrees on the large wheel.
Lowest possible resolution would be at full arm extension 90degrees to the extended direction, which is less than 150mm+150mm from the SCARA tower, but for simplicity let’s make it 300mm.
Circumference of that symbolic circle would be 1885mm, making the single step lowest resolution movement 6.282mm*0,002387521 (40mm pulley) which is 0.015mm. This is smaller than the effect of filament variation or room temperature variation on your print…
Morgan Pro has a advertised specification of 100micron resolution – which means it will definitely pass the specification and will probably achieve more by a factor of 9 or 10 in terms of movement alone
Reprap Morgan is proud to announce that we are partnering with Robohand / Robobeast to help enable many more.
Morgan and RoboBeast will soon be manufactured in the same plant. This will be the driving force behind one of the largest bespoke print-farms in South Africa. Robohands, Robobeasts and Morgans will roll of the plant in harmony.
Richard van As (Robo Rich) is currently in the USA, setting up the largest print farm at the College of the Ouachitas. in Arkansas
They are fixing up and calibrating more than 50 (brand new) formerly troublesome makerbots to make Robohands… and other things while the opportunity presents itself
You may have noticed some changes on the Morgan Site… A certain good looking 3D printer seems to dominate the page…
Richard van As helped make this metamorphosis possible, by subtly suggesting material substitutions, hinting at colour choices, and not so subtly bugging Quentin to get his ducks into a row and redesign Morgan to be more robust, easier to build and manufacture and to be very easy on the eye… Every good wunderkind needs a good mentor.