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Repeating Problems with Y Axis Stepper
« on: June 03, 2018, 11:53:40 AM »
As title indicates, i am having a repeating issue with motor control on y axis of my milling machine. Both x and y are using same motors and settings. I have never had any stalling issue on X, but for some reason, y stalls sporadically, at the worst of times. I have replaced the motor 2 times now and cant figure out what is causing the issue. I have troubled shot the machine itself and am not finding any binding or others issues that would cause this. I've tried changing velocity and acceleration. Any thoughts. Could it still be a motor issue? The motors i am using are used and i have a bunch of them. I find it odd only y axis has issue. It doe not happen in jogging.
It does only seem to happen during rapids.  Can i limit or set rapid speed within Mach4?
« Last Edit: June 03, 2018, 12:06:40 PM by rodm717 »
Re: Repeating Problems with Y Axis Stepper
« Reply #1 on: June 03, 2018, 01:30:47 PM »
I went back through cam and did find 1 issue with 2d adaptive feedrate, just to take that out of the mix, however, still trying to find issue with rapid. I've ran through jogging at 100% and have not been able to replicate. Still haven't found a way to set rapid to say 75% and see if that will fix it. I really dont see a problem decreasing rapids as a work around, for my use.

Offline ger21

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Re: Repeating Problems with Y Axis Stepper
« Reply #2 on: June 03, 2018, 01:41:10 PM »
Your velocity setting is the rapid speed.
Gerry

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Re: Repeating Problems with Y Axis Stepper
« Reply #3 on: June 03, 2018, 02:25:12 PM »
Thanks, Ger21. I have been trying to get this machine finalized. It's the things that are most simple, that can sometimes have you stuck. Lol.  I will try lowering velocity. Its just odd in most any other scenario, it seems fine.   Fusion360 and trying to get accustomed to how it outputs code with Mach4 post processor. Some of the initial code seems overly complex for what it needs to do.
 Any idea if Mach3 post running on Mach4 would be better? Or a bit more simple?

Lowering velocity down to 45 and still having issues. Looks like a motor swap is a must. Hopefully not a defective driver.
« Last Edit: June 03, 2018, 02:29:04 PM by rodm717 »

Offline ger21

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Re: Repeating Problems with Y Axis Stepper
« Reply #4 on: June 03, 2018, 04:25:43 PM »
It's highly unlikely that the motor is bad.

Accel usually has more of an affect than velocity. Try lowering the accel.

What kind of drives are you using, and what machine is it?


I'm not familiar with the Fusion 360 Mach3 post, but most of the Fusion posts I've seen have a lot of things in them that I'd remove.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Repeating Problems with Y Axis Stepper
« Reply #5 on: June 03, 2018, 04:43:51 PM »
Hi,
you say the X and Y axis motors are the same, but are the axes?. Is the Y axis heavier for instance?.

A heavier axis will require more torque to accelerate it.  If you can eliminate other potential causes like power supplies, driver settings,
control settings the you may need to increase the size of the motor.

What motors are you using?
What voltage power supply are you using?
What drivers are you using?
What microstepping regime are you using?

Craig
My wife left with my best friend...
     and I miss him!
Re: Repeating Problems with Y Axis Stepper
« Reply #6 on: June 03, 2018, 05:26:29 PM »
Be sure you have smoothing checked on your adaptive toolpaths.   
Chad Byrd

Offline mark4

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Re: Repeating Problems with Y Axis Stepper
« Reply #7 on: June 04, 2018, 06:39:48 PM »
Hello was there a time when it worked perfect and for how long. or have you had this problem from the begining. Then i would go after my machanicals check oilers especailly they can screw up allot. Can you swap drives X and Y. Might also be good to make sure the power going to each drive is up to spec i have had contactors go bad and deliver bad power when under load. More the exception but i have seen it.
Good luck
mark
Re: Repeating Problems with Y Axis Stepper
« Reply #8 on: June 08, 2018, 06:19:48 PM »
Thanks for the interest and info, and questions. Problem did turn out to be motor.
I am using a Pokeys57cnc controller, Pokeys 60-256 drivers, 2510 ballscrews, and a7.2a 48v power supply on a round column conversion mill. All but Z is on a 2-1 ratio, while z inherently with worm gear is 10-1 use same pulley. I was initially using 3nm nema 34 3a EAD motors i had bought used, but seemed to run well in all previous testing. I swapped out the Y axis motor for a 4nm 80mm 4a Sumtor motor that was brand new and had the light go off in my head. 110 velocity is so quiet and smooth in comparison. I will be switching out the other 2 axis with 3nm 66mm 4a  Sumtor motors that i already had on hand. Luckily, i had bought these over a year ago when the price was exceptional, literally less than half, compared to current pricing on these motors.
While the electronics and configuraion are usually the main suspect, used motors i have learned can be as well.
Re: Repeating Problems with Y Axis Stepper
« Reply #9 on: June 11, 2018, 08:59:12 PM »
Unfortunately i had to order an additional 22t pulley and for time being placed a 12t on Z and the old EAD motor, while I bored out the 22t to fit the new motors 14mm shaft for X. Doing this raised the resolution even higher on Z. Thinking that limiting micro stepping to 1/2 while still maintaining steps to under 8000 for mach 4 to be a good thing. However, i immediately realized velocity and acceleration issues once again. So, i have 10 to 1 on the worm gearing to Z, a 12t pulley on the motor and a 22t pulley on the worm.
 I changed to 1/4 stepping and roughly 14500 steps in mach 4 and immediately resolved the velocity and acceleration issues, while the motor also smoothed out quite a bit. What am i not understanding here?? By increasing micro-stepping and step count, am i not decreasing torque and motor stability??? I had always believed, from various posts, that keeping mach step count under 8000 to be recommended.