Any mach 3 gurus on here

Facundus Cues

Facundus Cues

AzB Silver Member
Silver Member
I am a little confused on setting up a stepper as a spindle. I have the thing running but as far a setting rpm and motor tuning.

The manual states "Now move to Config>Motor Tuning for the “Spindle Axis.” The units for this will be one revolution. So the Steps per Unit are the number of pulses for one rev (e.g. 2000 for a 10 times micro-stepping drive or 4 x the line count of a servomotor encoder or the equivalent with electronic gearing).
The Vel box should be set to the number of revs per second at full speed. For example, a 3600 rpm motor would need to be set to 60"

I am using a 1.8 stepper with 10x micro steps so 2000 steps per revolution is correct. it says to input velocity at revs per second but the velocity box in the software says per minute . The motor says 1500 rpm "which may or may not have enough torque" but the velocity box will only let me enter up to 1050 at 2000 steps. According to the manual the correct vel should be 1500/60 = 25 and it runs way slow. Another layer to my confusion is pulleys. I have a 4:1 ratio so I have tried to set steps per rev to 8000 and still cannot enter a velocity # high enough. I have also played with putting the ratio into the spindle pulley setup. I can get this turning fast enough with enough torque to get the job done but I would prefer to have my math correct so that my dro will show me a realistic rpm for reference purposes.
I know this is a lot to type so feel free to give me a call
-Thanks
Chris two two five 241-900 eight
 
so before getting ahead of ourselves......

What is your target rpm? This just a turning center I'm guessing?

What type of hardware are you running as far as motion controller? Ethernet/USB or LPT?

If your trying to spin too fast and using the LPT, then the frequency might be restricted by LPT output capacity. (Which would explain why your velocity setting is maxed out in motor tuning, this is actually dictated by max freq.) You may be looking at a mandatory workaround with lying to the pulley settings and dealing with numbers that read incorrectly on dros.

This is the sucky thing about digital signals. If you have a micro stepping drive then this can be defeated by decreasing resolution thus requiring less pulses per rev

Jim will probably respond when seeing this, since it appears you have put in some work and not looking for spoon feeding. He is definitely going to be the best person on earth to answer
 
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I have searched a lot through cnczone and mach forums and the only things that I could find were questions being asked by Royce from OB (R.I.P) but just the questions with no real answers.
I am running LPT on this machine and after I posted I started thinking that the vel was limited by frequency which is set to 35k and then I upped it to 45k which seems to test out fine on my machine. I am guessing from the research that I have done that my target rpm will be somewhere between 150-300 at the chuck. I have a 10t pulley on the stepper and a 40t on the headstock so I am guessing max actual stepper rpm will be 600-1200. The machine is a Taig bed with a headstock driven by a stepper with a cnc x/y axis running along the length of the bed. I plan to use a pc laminate trimmer to cut tapers with what will probably end up being a 6 wing cutter. I was hoping to be able to dual purpose this machine to cut slots for ring billets and v groves for points by setting up a second profile in mach for an angular a axis.
As far as the spindle profile goes, I seem to be getting adequate rpm and torque for the tapering but I would like be able to use real numbers for reference since I do not have any sort of encoder or outboard tach.
 
Royce actually ended up talking with Art the creator of mach 3. Art explained how to set it correctly. I will try to contact you within the next few days. If i don't call me at 847-489-3904.
As a hint your spindle pulley needs to be set correctly. And Jake is dead on for the max speed issue.
Jim
 
That is similar to setup I have and maybe where I am confused is the gearing on the motor. I actually entered 8000 steps per unit to accommodate foe the 4:1 . So 2000 = 1 rev on the stepper but 8000= 1 rev on the headstock. Is this the correct method or should the gearing be compensated for in spindle pulley? Or would the 2 options be equal ?
 
its possible thats how they've defeated the issues with high resolution....keeping the motor set at 2000 and then giving real numbers to pulley settings. I'd be interested to see if it works for you.

I know that Royce was using g540s on a couple of turning centers but cant remember if he did it without smooth steppers
 
I have it pretty close by timing 60 rpm against my stopwatch. I wish I had a tach of some sort but I guess it is really not that critical as long as it is close. I ended up at 8000 steps per unit and with a 45k signal it capped me at 337.5 on velocity which seems to be accurate on the spindle rpm. Thanks for all you guys help
 
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