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velocity setting
« on: January 05, 2011, 09:50:16 AM »
What determines the max velocity setting for the motors?

I am using Keling Nema 23 KL23H286-20-8B BIPOLAR STEPPER MOTOR 425  oz-in
http://www.kelinginc.net/NEMA23Motor.html

What I usually do is jog the motors to see if everything works smoothly after I enter in a number. Keep increasing the number until things aren't smooth any more and then go back to the last smooth number.

Thanks

Offline Hood

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Re: velocity setting
« Reply #1 on: January 05, 2011, 10:09:12 AM »
Not an easy question to answer for steppers as there are so many variables, what you are doing is really the only way, all trial and error and also you need to figure out the accel.
Way I did it was set accel low and increased the Vel until I found the max by motor stalling. Dropped that by half then did the same with accel. Then just found a happy medium between Vel and Accel. Personally I think Accel is more important than Vel. As an example I could get 2500mm/min with 40mm/s/s but if I dropped the Vel to 2200mm/min I could get the accel up to 120mm/s/s

With the latter real life machining is faster and much less chance of issues with  corner rounding in Constant Velocity.
Hood
Re: velocity setting
« Reply #2 on: January 05, 2011, 10:14:28 AM »
Thanks Hood!
Re: velocity setting
« Reply #3 on: January 05, 2011, 10:16:03 AM »
Jogging is different than a G0 move.  I can set speed and acceleration at 900IPM/200 and jog no problem, but the motors stall every time on a G0 move.  You can rough tune it by jogging, but fine tune it by running G-Code commands.  It might also depend on your mechanics.  I'm moving a 300lb gantry on a 9 foot table.
Re: velocity setting
« Reply #4 on: January 05, 2011, 10:19:14 AM »
I am running the 2x3 table from here -
http://www.finelineautomation.com/

So far other than the SS problems I like everything I have setup. Been making guitars on it when SS doesn't crash.

Offline Hood

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Re: velocity setting
« Reply #5 on: January 05, 2011, 10:44:49 AM »
rrc
Really shouldn't be difference between Jog and G0 unless you have a Slow Jog% set, then that may be why you would see that.

study
regards your SS problems, do you  have a parallel port you could try?
Hood
Re: velocity setting
« Reply #6 on: January 05, 2011, 10:48:13 AM »
No -
All my computers were stolen so I bought a netbook as a replacement. If I had a parallel port then I would of never bought the SS and saved some money.

Offline Hood

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Re: velocity setting
« Reply #7 on: January 05, 2011, 10:51:13 AM »
Ok, did you see Daniels post regards grounding laptops, it cured his issues.
Hood















Re: velocity setting
« Reply #8 on: January 05, 2011, 10:55:02 AM »
Which one? Was that the one where they posted about replacing the USB cable? I have been reading a lot in the SS section.

I am going to drive up and get me a new 1/8" bit and then come back and try some small items on the machine since I am off work today.

I installed a new driver board last night to see if it helps with my SS problem. I leave mach just sit there then come back jog something, enter some gcode and make it run and then just sit again. I close mach and come back and reopen mach etc... So far so good. We will see when I run some real jobs through it today.

Offline Hood

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Re: velocity setting
« Reply #9 on: January 05, 2011, 01:30:40 PM »
No, it was about connecting a Gnd wire from the SS to the power supply or something, will see if I can find it and post a link.
Hood