The belts are fixed at the ends and come up around some turnaround bearings and over the drive pulley.
The one on the stepper is 12 tooth and the jack shaft is 72 tooth for a 6:1 ratio. Then the small pulley to the long belts is a 10 tooth with a 3/8" pitch so each revolution of the jack shaft moves the carriage 3.75" . This gives you .625" of movement for each revolution of the stepper. So this means that at 800 rpm on the stepper I go 500 IPM. This keeps me in the better rpm range.
How fast? it will go 500IPM and accelerate at 300 inches per second per second.
I used a nema 23 stepper from automationdirect STP-MTR-23079 with gecko 203v drives on 64 volt. Control is EMC2. I'm quite pleased with the results.
Here is a closer look at one of the Y axis carriages.
John |