Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: III on June 23, 2006, 09:53:09 AM

Title: Using a stepper as a spindle motor
Post by: III on June 23, 2006, 09:53:09 AM: Newbie question here.
I am working on building a cnc lathe using Mach 2 for the controller and a Xylotex 3 axis kit. Since I only need 2 axis for the lathe and I don't need over 200 rpm on my spindle I want to use the extra motor that came with the kit as my spindle motor. It is a standard 200 step per rev motor with the board set for 1/8 micro stepping. In the motor set up screen I set the steps per unit for 1600 (200*8). When I do my dry run the motor rpm is no where close to being right. Any ideas of what I might be doing wrong?

Edit: I forgot to add that I am just using the Mach 2 demo right now. I did not want to buy the full package until I made sure I could make it work.
Title: Re: Using a stepper as a spindle motor
Post by: Brian Barker on June 23, 2006, 12:07:49 PM: under the motor tuning change the step per unit :) I think it is going to be about 96000 ..
Title: Re: Using a stepper as a spindle motor
Post by: III on June 23, 2006, 05:02:43 PM: Quote from: Brian Barker on June 23, 2006, 12:07:49 PM
under the motor tuning change the step per unit :) I think it is going to be about 96000 ..

Thanks but that did not work. However I did get it working by accident. I accidentally changed the max rpm on pulley 4 and noticed that it changed how fast the spindle motor ran. By changing it to 1000 rpm the motor rpm is now dead on. I don't know why that worked and have read the manual at least 50 times trying to figure it out. The X and Z were dead nuts the first time. Am I overlooking a check box somewhere?
Title: Re: Using a stepper as a spindle motor
Post by: Brian Barker on June 23, 2006, 05:47:26 PM: It didn't do the right speed because it didn't know the ratio to use. (just a thought)
Title: Re: Using a stepper as a spindle motor
Post by: III on June 23, 2006, 06:51:23 PM: Quote from: Brian Barker on June 23, 2006, 05:47:26 PM
It didn't do the right speed because it didn't know the ratio to use. (just a thought)

That is what has me confused. I see the 4 pulley choices in the logic section but I can't find how to set up the ratios anywhere in the book. Maybe I was just getting frustrated and overlooked the obvious. The X and Z were a snap.

Thank you for trying to help me understand this better.
Title: Re: Using a stepper as a spindle motor
Post by: Brian Barker on June 23, 2006, 10:05:50 PM: Look at it this way:
The Max speed (in the motor tuning) is the Max RPM of the stepper motor.

The Pulley settings tell the computer what speed it can do in each range (Like when you shift your car)

Is that any help?
Title: Re: Using a stepper as a spindle motor
Post by: III on June 24, 2006, 10:33:15 AM: Quote from: Brian Barker on June 23, 2006, 10:05:50 PM
Look at it this way:
The Max speed (in the motor tuning) is the Max RPM of the stepper motor.

The Pulley settings tell the computer what speed it can do in each range (Like when you shift your car)

Is that any help?

I figured I was overlooking something obvious. I understand how it works now. Thank you for helping.