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A project log for Linux CNC Mill

A CNC Milling Project using the LinuxCNC software and Nema 34 Stepper Motors

qasim-doveQasim Dove 01/03/2016 at 06:340 Comments

So I was doing some calculations regarding my mill's speed, and I figured I needed to calculate the "theoretical speed limit" of my motors.

First, I needed to figure out the maximum rpm of my motor. For this, I needed to figure out the amount of hertz my stepper driver gave off and the pulses per rotation for my motor.

Hertz are pulses per second (pps) , so dividing the pulses per rotation (ppr) by the pulses per second (pps) should give us the rotations per second (rps).

Max Speed = (pps) / (ppr) * (micro-steps)

= 300,000 pps / 200 ppr * 1

= 1,500 rps

1,500 rps is the maximum speed of my motor. However, motor speeds are usually measured in inches per minute (ipm).


Here's how I converted it:

1,500 rps * 60 secs = 90,000 rpm (Converting seconds to minutes)

90,000 rpm * 5mm = 450,00 mm/min (Converting rpm to millimeter per minute)

450,000 mm/min / 25.4 mm = 17,716.5 ipm (Converting millimeters per minute to inches per minute)

Theoretically, that would give me about 17,716.5 ipm on my CNC machine.

Theoretically.

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