x axis motor randomly stalling GRRR

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    Default x axis motor randomly stalling GRRR

    I have a DIY 48x96 router table. I drive all axis with 570in/oz steppers with 2 on the X axis. I set my max speeds and max acceleration numbers with the following procedure.
    I set the acceleration to a low number then set the max rate to some number and ran that axis back and forth far enough for the axis to get up to max speed like 10 times. I ramped up the speed and did it again. I kept doing this until I got the axis to stall then I reduced that speed by 20%. I then set to ramping up the acceleration in a likewize manner until it stalled again then reduced that acceleration by 20% again.
    Doing this I have had no issues with my Y or Z axis but my X will randomly stall when in a program.
    My max speed on the X axis is 800 IPM not cutting. Today I was happily running a table surfacing program at 400 IPM with a 2 inch diameter surfacing bit. I made several complete dry runs with no issues and made one complete run with the spindle on with no issues. When going for another run at .02 inches deeper the X axis stalled after going up and back twice just after it made the turn to start cutting again. I reran the program and it stalled in exactly the same place. I went to manual control using UGS and the axis moved at 800IPM at that point with no problem. I ran the program again and the axis stalled at the other end of the table when the bit was in AIR and not really cutting at all.
    At that point I discovered I had a broken limit switch so I took some time to replace that. I then ran 2 cycles of the same program cutting air with no issue.
    I am at a loss. What can cause RANDOM stalls of an axis running at half its max speed and according to the power curve at 400 IPM it should be at peak power.
    I did not feel the motors when they stalled. Can over heating cause a problem?? If so, how hot is to hot?
    What else can cause random stalls.
    Getting real frustrated. I fixed a problem yesterday where I accidentally had one of the motor wires shield touching one pin on the connector. It was making a lot of noise. Had stalling problems before fixing that so I was hoping that was it but no joy.

    BTW I am running an Arduino/GRBL set up. All Automation Technologies PS drives and motors.

    Help
    Thanks

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    Default Re: x axis motor randomly stalling GRRR

    It is very unlikely that the motors are too hot. Most stepper motors are rated for something like 100 deg C case temperatures (212 F).

    If it is stalling during acceleration it probably has nothing to do with the max feed rate. I like the way you did your determination for max rate and accel. It is exactly how I do it and I used to use 80% of the maximum achieved as well, but have since decided that about 60% is more appropriate. So, you may want to slow them down a bit more, especially acceleration because on a reversal of direction there is a lot of "jerk", and Grbl doesn't implement a s-curve type of acceleration. So it is pretty easy to exceed the accel capability of a system due to the jerk created especially at direction reversals. See this for a brief explanation: S-Curve Acceleration and Deceleration - National Instruments

    Which stepper drivers are you using?



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    Default Re: x axis motor randomly stalling GRRR

    If the stalling is on the axis with two motors and it's only happening under a cutting load sounds like its a flexing issue that is showing a mis-meshing alignment of the two motors. Is the axis with the two motors dead square to the travel? If it's a R+P drive did you engage the R+P gears with motor power energised when you squared the axis?



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    Default Re: x axis motor randomly stalling GRRR

    Update
    Now I am getting random stalling on every axis. Usually not accompanied by cutting. Sometimes just on a move to begin cutting with or without the spindle running.
    Drivers are Kl-5056E
    The X and Y axis are running an Everman Belt drive.
    IMG_20190513_144203382.jpg

    I think you may have something with the acceleration. It does seem to happen at the beginning of a move even if the move is not a direction reversal.
    I may lower my accel numbers to 60% and give it a try.



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    Default Re: x axis motor randomly stalling GRRR

    Are those the 3.5 amp motors, or the 5 amp?
    What voltage are you running them at?
    What microstep settings are you using?

    I don't think 800ipm would be a reliable max number.
    And I'd reduce the accel another 20%. Do you know what the accel is set at in in/sec/sec?

    Gerry

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    Default Re: x axis motor randomly stalling GRRR

    they are the 5 amp motors.
    I am running them at 48 volts with 1/8 microstepping.
    As far as acceleration numbers goes I had them at 800 for the x and y and 1000 for the z.
    I have lowered them to 200 for each. then I had to lower the z max rate to 300 in/min.
    After that It all seemed to keep working but it does accelerate really slow.
    Not sure where to go from here.
    Thanks



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    Default Re: x axis motor randomly stalling GRRR

    Do you think the axis could be binding? When I got my machine I was having a mechanical binding problem. post some pics of the router and see if anything jump's out at anyone.



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by Ntl View Post
    Do you think the axis could be binding? When I got my machine I was having a mechanical binding problem. post some pics of the router and see if anything jump's out at anyone.
    I dont think it is binding. Before I put the motors on I manually moved it all over and had no issues and it seems to stall at random areas.
    I lowered the acceleration numbers to 200 and all seems well for now.
    router table complete.jpg



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    Default Re: x axis motor randomly stalling GRRR

    ok now it is getting weird.
    I finished the surfacing of my table at these very slow accelerations and when I went to home it at the end the Z axis stalled during the very slow homing cycle.
    Frustration is mounting. Looking for any suggestions.
    Thanks



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    Default Re: x axis motor randomly stalling GRRR

    Can you post your Grbl settings and your Grbl version info?



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by 109jb View Post
    Can you post your Grbl settings and your Grbl version info?
    Here are my current GRBL parms
    Grbl 1.1g ['$' for help]
    [MSG:'$H'|'$X' to unlock]
    $0=10
    $1=25
    $2=0
    $3=0
    $4=0
    $5=1
    $6=0
    $10=1
    $11=0.010
    $12=0.002
    $13=1
    $20=1
    $21=1
    $22=1
    $23=0
    $24=25.000
    $25=3000.000
    $26=250
    $27=2.000
    $30=24000
    $31=0
    $32=0
    $100=60.000
    $101=60.000
    $102=125.984
    $110=17000.000
    $111=20000.000
    $112=7620.000
    $120=200.000
    $121=200.000
    $122=200.000
    $130=2539.000
    $131=1252.220
    $132=161.925


    Right after I did the motor tuning I had
    $112 at 9144
    $120 at 800
    $121 at 750
    $122 at 1500

    and I ran a couple small programs at those settings.
    All these issues started showing up when I ran my spoil board surfacing program.

    It was running at a feed rate of 400 IPM so nowhere near the numbers I had set.

    I first lowered 120 and 121 to 600 and still had stalling
    then 400 and still had stalling then went to 200 and managed to finish the surfacing passes without issue on the X and Y axis but when I went to home the machine the Z axis stalled going up
    Tried again homing and it stalled again. Shut off the PS and manually moved the axis then the home cycle completed.

    I just dont get why it ran for several days and MANY tests at the high rates with no issues and now I can hardly get it to run at all.

    I have 20mm profile rails on the X axis and CNCRP skate bearings on the Y and Z.

    Dont know of that matters. When an axis stalls I can always shut off the PS and move the axis by hand.

    Help



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by tkms002 View Post
    Here are my current GRBL parms
    Grbl 1.1g ['$' for help]
    [MSG:'$H'|'$X' to unlock]
    $0=10
    $1=25
    $2=0
    $3=0
    $4=0
    $5=1
    $6=0
    $10=1
    $11=0.010
    $12=0.002
    $13=1
    $20=1
    $21=1
    $22=1
    $23=0
    $24=25.000
    $25=3000.000
    $26=250
    $27=2.000
    $30=24000
    $31=0
    $32=0
    $100=60.000
    $101=60.000
    $102=125.984
    $110=17000.000
    $111=20000.000
    $112=7620.000
    $120=200.000
    $121=200.000
    $122=200.000
    $130=2539.000
    $131=1252.220
    $132=161.925


    Right after I did the motor tuning I had
    $112 at 9144
    $120 at 800
    $121 at 750
    $122 at 1500

    and I ran a couple small programs at those settings.
    All these issues started showing up when I ran my spoil board surfacing program.

    It was running at a feed rate of 400 IPM so nowhere near the numbers I had set.

    I first lowered 120 and 121 to 600 and still had stalling
    then 400 and still had stalling then went to 200 and managed to finish the surfacing passes without issue on the X and Y axis but when I went to home the machine the Z axis stalled going up
    Tried again homing and it stalled again. Shut off the PS and manually moved the axis then the home cycle completed.

    I just dont get why it ran for several days and MANY tests at the high rates with no issues and now I can hardly get it to run at all.

    I have 20mm profile rails on the X axis and CNCRP skate bearings on the Y and Z.

    Dont know of that matters. When an axis stalls I can always shut off the PS and move the axis by hand.

    Help
    Are you using a Ballscrew for the Z Axes what are the gear ratios that you are using with your drive system Pinion teeth and Gear Ratio

    Mactec54


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    Default Re: x axis motor randomly stalling GRRR

    Settings look fine, but I would suggest $1=255 which will keep the stepper drivers powered all the time.

    At this point, I would check basically everything. Wiring for loose connections, PS voltage, binding, etc. Diagnosing can be tough not being there.



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by mactec54 View Post
    Are you using a Ballscrew for the Z Axes what are the gear ratios that you are using with your drive system Pinion teeth and Gear Ratio
    z is a 1/2 10 5 start lead screw that is driven directly.
    x and y axis are 3-1 belt reduction
    16 tooth pulley on the motor to a 48 tooth pulley and that drives another 16 tooth pulley that drives the belt.
    IMG_20181213_175857907.jpg



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by 109jb View Post
    Settings look fine, but I would suggest $1=255 which will keep the stepper drivers powered all the time.

    At this point, I would check basically everything. Wiring for loose connections, PS voltage, binding, etc. Diagnosing can be tough not being there.
    can you explain the $1=255 please?



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    Default Re: x axis motor randomly stalling GRRR

    Quote Originally Posted by tkms002 View Post
    can you explain the $1=255 please?
    $1 setting is stepper enable time in milliseconds. For example after a command completes, Grbl keeps the stepper driver enabled for the number of milliseconds this is set for and then turns the drivers off (disabled). The max value of this setting is 255, and if you set it for that, then Grbl knows to NEVER disable the stepper drivers.

    In my opinion, there is no reason to ever disable the motors during normal operation, and if there is it means I can turn off the power switch. I prefer to let the stepper drivers take care of reducing current draw without totally disabling them by using the idle current feature built in to most modern drives these days.



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    Default Re: x axis motor randomly stalling GRRR

    At the moment I am thinking I had 2 issues. An excessive acceleration parm and issues with the Y and Z axis skate bearing set up. They seem very intolerant of dust accumulation.



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