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Author Topic: Motor tuning 166 Oz steppers motors  (Read 1970 times)

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Motor tuning 166 Oz steppers motors
« on: May 27, 2015, 10:28:20 AM »
Hey guys hoping to get  some help . I have an old Taig Micromill 2000 .  I believe  it has 166 Oz steppers motors on it .
 Recently I have re  adjusted machine calibrated adjusted gibs . And looking to maximize motor tuning . In past I have played around with motor tuning but not had much luck to get  both low toque and fast rapids . Where do you guys have your motor  tune  set  at?

 From my Old  notes I think  I ran machine in past at 8000 steps 30 velocity Accel 5 and step pulse 2.

 Now im trying to dial in motors with no such luck.   Here is where im at . I am running Mach3  software and have the Motors tuned somewhere in the 8000 steps 25-30 . Acc 4 step2
 Am I like WAY OUT OF THE BALLPARK???

   Now I do Suspect they may be running hot /  allot slower however I do have the torque.   I have played around with this but never able to have both worlds ( or the sweet spot)   either I have the torque  with slow acceleration or the acceleration  is a tad too fast and it looses position.

Where is the best setting  to get maximize  feed rapids  with decent torque  WITHOUT loosing positioning.?  looking for  low torque power power with best rapid speeds .  What setting would be best to achieve this?


 Thanks
Kenny V

Offline RICH

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Re: Motor tuning 166 Oz steppers motors
« Reply #1 on: May 27, 2015, 09:00:41 PM »
Find the max velocity for which you start skipping, then reduce that velocity by 30%.
Now start increasing the acceleration, increasing by a value of 1 until you start to skip,
reduce that accel value by say 30%.

So now you have a point by which you can refine the tuning. Depending on what you doing
you may want to allow more "headroom" to take care of machining harder to machine materials. 

Now that said, what you are after is power and that is torque x speed.

Have a good read of the info on the Gecko site as more than what you want to know is available.

RICH
 
Re: Motor tuning 166 Oz steppers motors
« Reply #2 on: May 28, 2015, 12:55:55 PM »

Ok thanks  and I do have a good base line and understanding  as far as motors running smoothly  been in range all along  by actual calibration method using indicators on axis and running jog or repeat increments  they sound/ run fine .However with a load they are skipping or loosing position .

 Where do I go from here?  let me explain
By not taking a cut  putting some resistance on a knob  lets say  a jog fast  ,  it does not take  much resistance  till motor skips... I have tried tweaking both  velocity and accelerate but haven't had much luck finding  low end Torque with the resistance test .

 Sorry to be PIA
When you say what you are after power and torque speed is it still  is it possible to have maximum  acceleration  or these motors are only capable  of setting  low torque  to remain accurate  w/out loosing positioning. If so how do I accomplish that ?
 thanks allot for all your help
Kenny v

Offline RICH

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Re: Motor tuning 166 Oz steppers motors
« Reply #3 on: May 28, 2015, 10:27:10 PM »
Quote
with a load they are skipping or loosing position

That's what i meant by headroom.....
Go back and look at all the stuff about steppers on the Gecko site for understanding stepper basics
as it's beyond what I can comment on here.

Probably at the velocity you don't have much motor torque left so as soon as it sees a load  
it starts to skip. Don't know how much your using just to move the axis ( it can be measured ) so if that is minimized you have more power left for machining. Frankly i changed out the motors on my Sherline from
...i think they were something like 160 in oz ...to 500 in oz and have plenty of power and velocity.
I use 500 in oz on the Atlas mill and can do 100 IPM and break end mills. The motors are only using 3 amps
 and the inductance is low and only using 36 volts.

Supply voltage, amp setting, gearing used, how wired can all make a difference in the motor / axis preformance. And understand that there are trade offs.  Increase voltage and velocity will  increase. As motor rpm increases torque decreases. More amps more torque ....but none of these are single change and single performance improvements. Manufactures provide motor curves based on different voltages providing a  torque to rpm / steps' rev plot.

Go to the gecko site and you will find some formulas to calculate and you will find that Gecko say's you want power = speed x torque!

So what i am basicly saying is that the "whole" thing is a SYSTEM and the system needs to be designed to meet YOUR needs.

Sorry, but this stuff is not just plug and play....but....having a look at what a lot of vendors provide and users use is still a good base to kick off from.

BTW, I think in the Members Docs i posted some basic design stuff for the 6" Atlas Lathe Conversion
thread.

RICH
 
« Last Edit: May 28, 2015, 10:29:28 PM by RICH »
Re: Motor tuning 166 Oz steppers motors
« Reply #4 on: May 29, 2015, 04:06:46 PM »
thank so much Rich  for all your help/ comments  I will have a better look a Gecko info  .  Even when ramping down the velocity they don't seem to have much torque esp in fast jog  s and somewhere with federate over 20IPM   My Guess is these motors are not  that sufficient less ya go slow .
thanks again
Kenny v
Re: Motor tuning 166 Oz steppers motors
« Reply #5 on: December 30, 2015, 11:16:49 AM »
WOW........all the stuff you two are talking about blows my mind.  I was going to ask about motor tuning also but it seems very complicated and I am very new to all this.  Im not sure if my motors are tuned correctly or not....all I know is that the machine works and cuts the small projects that I attempt.  I will look at the settings for the motors as they are and change things to see what changes.  I would like to get a bit more rapid speed if I could but have to be careful not to screw with my system to much.  Kenny if you get a satisfactory setting, please let me or us know and I will try it on my machine to see what the settings do for me.
thanks

Offline beefy

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Re: Motor tuning 166 Oz steppers motors
« Reply #6 on: December 30, 2015, 05:31:47 PM »
Kenny,

have you also checked your gibs to see how much resistance there is to the sliding motion. Can you disconnect the leadscrew nut and slide them by hand to ensure they are not binding.

Keith