Hi,
i'm planning to convert my zay7045fg benchtop mill machine to cnc. Because of constrained budget i need to it without buying expensive new servos, new ballscrews etc...
i want to start from Z axis because it will eat the biggest part of my funds.
in order to make Z axis drive:
i bought used aerotech 1000dc series, NEMA42 sized servo motor. it delivers 1.48Nm stall torque and 7.1Nm in peak and nominal speed of 2000rpm. Rated power 220W, continous current 6A, terminal voltage 80V (max about 130V).
motor manofacturer's specs (model 1210):
http://www.aerotech.com/products/motors/1000specs.html
i have also bought occasionally bosch rexroth 25mm dia, 10mm lead ball screw.
i have also calcutaled timing pulley gear ratio 6:1 assuming 50mm/sec jog speed. My calculations is based on CNCmechanics v1.2.pdf from this thread:
http://www.cnczone.com/forums/showthread.php?t=8129
With 6:1 geardown i'll achieve 8,88Nm continous torque on ballscrew and over 42Nm in peak.
My question now is how to make gears? the problem is that gear ratio is pretty big i think. Because of 16mm dia motor drive shaft timing pulley attached to it should be an approx 25mm dia. For T5 type pulleys this mean 16 teeth pulley. To get 6:1 ratio i need 6x16=86 teeth on ball screw. I can't find such a pulley so it seems i need to make a two stage gear down: 3:1 and 2:1. Is it good idea? how about accuracy on ballscrew with such a two stage gear?
And of course the most important question: is this motor strong enough to manage with zay7045 mill Z axis assembly (it weight over 100-120kg)?
I know that 10mm screw lead is not the best solution but i can't find 5mm lead screw for the price i can accept.
Please join this thread and write me what you think about it guys.
thx!!
8061