Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: joestefano on May 16, 2011, 06:48:58 AM
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My set up: HD X2 mill with 20 tpi axis screws, Y axis 269oz Xylotex belt driven 28 tooth gear on both motor and axis screw, My Mach 3 motor tuning settings are 32000 steps per, velocity 7, 1.5 accel. I am getting a small amount of motor stall. Does anyone know if this setting is what others are running?
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Try sherline mode and see if that helps. Usually motors dont stall a small amount, so to me sounds more likely your pulse width is not enough for your drives, setting Sherline will make it a wide pulse which some drives require.
Hood
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Where do I find this setting?
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Config menu then Ports and Pins and it is to the right on that page.
Hood
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Hood,
I tried what you suggested, no difference. Does the setting that I described seem odd? If I increase the velocity to 10 and the accell to 3 I get quite a bit of stall about a 1/4" in 2" of movement. Is it the belt drive setup? Why dont I get it on my X axis which is direct drive?
Thanks
Joe
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Your velocity and accel sound very slow even at the increased rate but all will depend on the individual machine and its hardware.
Check the axis in question is not binding.
Might also be an idea to swap drives around to see if the problem follows the drive, likewise the motor if possible.
Also check all wiring is secure.
Hood
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I rthink there is a problem here with terminology.
Motor Stall normally means that the stepper motor is either overloaded, or that the step rate is too fast and the motor is not able to generate enough touque. This does not preduce predictable results. It sounds more like you have something slipping. Motors either stall or they don't stall. at low speeds and accelerations your stepper motors should produce the most torque and be very reliable. If you are having problems getting reliable moves you should look at all the mechanical connections first. Are you sure the motor is turning? if so - is the leadscrew turning at teh same rate? Get a marking pen and put some marks on shafts and connectors and make sure they are not slipping relative to each other. Make sure that the belts are properly tightened. is this only happening on 1 axis?
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Yes only the Y axis it is belt driven (see my setup) the X axis is fine but it is direct drive. Your right about the terminology may it is not motor stall. I'm going to post a video of the problem on you tube I'll let you know when it's available. Thanks for all your help guy's.
Joe
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Guy's,
Here is a short video of what my motor is doing. Is this motor stall??? http://www.youtube.com/watch?v=3kQWmijRlmk My velocity is set at 7 and accel is 1.5
Please let me know what you think.
Thanks
Joe
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I am presuming that is a constant feed when the axis is going bad? If it is then I would say its a bad pulse stream, either from the computer or the BOB or bad drive.
Have you tried swapping drives around?
Hood
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yes, constant feed. Yes, I swapped drives and motors and no change. I even tried a 425oz motor, same result. I checked for binding seems smooth. I tightened the belt and loosened the belt. I wish I understood more about the relationship between Velocity and acceleration. I have my "steps per" set at 32000 is that correct?
Joe
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Have you checked the active state of the STEP pulses ?
Russ
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Where do you check these settings?
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Under Config/Ports and Pins/Motor Outputs
Russ
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If the active state doesnt help then swap wires on your breakout board so X is using the Y pins and Y using X.
Hood
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I'm having a similar issue. I turned my x axis into a belt drive and now the stepper stalls, which it didn't do when it was in direct-drive mode.
swapping the wires didn't do a thing. y kept moving on x driver and x stalled.
Have you found a solution? or a why is this happening?
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I had that problem with my crappy Chinese motors - "Smooth" brand LOL. In the beginning I had a Leashine drive. It required a pulse width of 8. The Leadshine drive could run the motor slow but when the speed got up (like in your video) it would just stall and scream (no load).
I changed to Gecko G203V drives which run fine with a pulse width of 2, and can run my rubbish motors up to speed.
Hope there's something in the above can help.
Keith.
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The Xylotex drive is very bad about harmonic resonence. Especially with 20 tpi screws. I delt with that for years before switching over to a G540. I finally had to build dampeners for the machine. When i watched your video, Especially at the end I could hear the motor lock up and whine.
https://www.youtube.com/watch?v=9RoOZs9LrYo
https://www.youtube.com/watch?v=ivDQTeGuduk
https://www.youtube.com/watch?v=8Am69_F93yA