Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: studysession on January 05, 2011, 09:50:16 AM
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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
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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
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Thanks Hood!
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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.
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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.
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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
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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.
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Ok, did you see Daniels post regards grounding laptops, it cured his issues.
Hood
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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.
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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
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I did that too. I grounded everything together to the CNC machine. I grounded the stepper driver and SS to the machine.
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I have ran a couple of small jobs today and it worked. But the problem has been so intermittent I am not sure if it is good or not.
The board I bought from Keling did not come with documentation but I found great documentation with screen shots of the mach settings that I downloaded elsewhere. Hoping it keeps chugging along like it has on these couple of small jobs.
Attached is a pic of one of the small jobs I ran.
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Well hopefully the new BOB will cure it.
Nice wee crab, used to make my living catching them and lobsters :)
Hood
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Cool -
I didn't make a living at it but I grew up in the Chesapeake Bay area in MD for most of my child hood. Loved going crabbing each summer. :)
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I am going to attempt my first inlay pattern. I have seen people do inlays on things, now it's my turn to try. :)
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I still kind of miss the fishing but when I think about the 40ft waves and getting soaked with icy water I soon realise the workshops a better place ;D
Hood
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Funny -
I have never been where there are 40ft waves. That has to be an experience all by itself.
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Ha ha even my workshop experiences them once or twice a year ;D
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Let's hope it keeps working like this and I don't have any more problems. :)
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Heres hoping, looking good so far :)