Quote Originally Posted by CNCBlug View Post
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So i have this figure of 4000-5000mm/min in my head and i hope it is not unrealistic.

Saying that i'd also like to mention that i intend to use a DeWalt 2kw for a spindle and the gantry will be from extruded aluminium and profile rails. I dont know how that affects the speed, but i am sure a heavy gantry/Z has all sorts of influences.

Thanks
5000mm/min on a 5mm pitch screw is 1000rpm or 16.67rps = 3333 steps/sec. On 40v at that pulse rate those motors (~4.5Nm holding torque) are going to give approx 1.2Nm of useful torque (there is no exact way to work this other than actually measure it, but the datasheets for similar motors on 120V/5.5A show 2.7Nm at 3kpps its a rough extrapolation)

This useful torque is whats available to overcome the static inertia of the load (including friction loses etc) and, often forgotten, the ability to decelerate the load (remember it will push back on the motor as it can drive the ballscrew in reverse) and will determine the maximum gantry weight under cutting forces that can be sustained without losing steps...