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Mach3 question: the ratio between mach3 and cnc machine
« on: March 02, 2009, 07:39:30 AM »
When i command the mach3 from X0 to X1000
However, i found that the cnc machine just move 30mm

How can i setup the ratio to 1:1?

Offline Hood

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Re: Mach3 question: the ratio between mach3 and cnc machine
« Reply #1 on: March 02, 2009, 07:46:48 AM »
What typr of motors? If steppers what kind of drives and what microstepping if its adjustable, if Servos what is the encoder count?
What pitch ballscrews?
Any gearing between motor and ballscrew?
Hood

Offline jimpinder

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Re: Mach3 question: the ratio between mach3 and cnc machine
« Reply #2 on: March 02, 2009, 02:36:46 PM »
In Config/Motor Tuning, you need to set up each axis with the proper number of steps per unit. I assume, from putting in a command like X1000, then you must be in mm's.

This should be set first under Config/Native Units.

For each motor then you must tell the computer home many pulses it has to put out to move your table 1mm. This is not difficult. If you are using stepper motors, then they will probably need 200 pulses to turn one rev. Your drive units will be able to introduce micro steps, and for smoother use, you should choose 8 or 10, usually by adjusting the DIP switches on the card. Lets say is is 10. This now means that you need 2,000 pulses per unit.

If you have any gearing between your motor and your leadscrew then this must now be calculated - on my machine I have a step down belt drive of 3 to 1 - so in my case this would now be 6,000 pulses. If you have no gearing, then no multiplier.

The final thing is the pitch of your leadscrew - mine is 5 mm pitch therefore I DIVIDE by 5 to get the result - 1,200 pulses per mm.

Each axis might be different, so make sure you calculate each one.

Start your speed setting at a reasonable speed say 100 mm per min, (acceleration about 10mmpsps) and gradulayy increase this until the motor clearly start missing steps, then come back down until the run smoothly again.

Do the same with the acceleration.










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