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IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > X axis looses steps in the exact same line of code each time.
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  1. #1
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    X axis looses steps in the exact same line of code each time.

    Hi there,
    Im loosing steps on my X axis at a certain line in the code. I'm running mach3 on windows 7 with a printer port to a breakout board then to individual cards. My stepper motor will make a buzzing noise just like if you were to try to run you axis into an end stop. it lasts for a second or two. It doesn't do it every time but almost every time. I made 7 pieces and it did it on 5 of them.
    I have 1200 OZ motors, ball screws and linear rails. I removed the cars off of the rails and checked to make sure they were not clogged with sawdust the cars and the gantry head moves easily along the rails. the ball screw also rotates freely.
    I'm cutting slots with a 3/4" bit in Ash I plunge down 3mm at 190mm per minute, then it travels to the end of the slots and plunges again.. travel speed is 1800mm per minute. My acceleration is set to 120mm per second in ports and pins. It happens right after a plunge as it starts to travel it makes it about a 1/4 inch then hangs up. there are 9 slots and it only does it in one slot at the same depth and place. I dialed down my acceleration and speed. same thing.
    I run all shielded cable...…. power supply in in a separate box from the BOB and control cards...…

    This is what I'm cutting the circled slot is the trouble spot.




    And here is the lines of code where it happens.
    This is in mm

    Z-12. F190.
    X417.014 F2000.
    Z-15. F190.
    X436.014 F2000.
    Z-18. F190.
    X417.014 F2000.
    Z-21. F190.
    X436.014 F2000.
    Z-24. F190.

    Any suggestions would be great!

    Glen

  2. #2
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    Re: X axis looses steps in the exact same line of code each time.

    I've had the exact same thing happened with my first CNC machine (Mach3, parallel port, Chinese TB6560 driver/breakout board). I guess the "right" combination of X/Y/Z motor speeds caused some kind of a resonance. The solution was to replace the TB6560 board. The new board has been working fine ever since - 7 years and counting.

  3. #3
    Community Moderator ger21's Avatar
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    Re: X axis looses steps in the exact same line of code each time.

    There's also a bug in Mach3 where in certain instances, it will accelerate far above the acceleration rate.
    Try changing the F2000 to a lower feedrate and see if the stalling goes away?
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  4. #4
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    Re: X axis looses steps in the exact same line of code each time.

    Quote Originally Posted by CitizenOfDreams View Post
    I've had the exact same thing happened with my first CNC machine (Mach3, parallel port, Chinese TB6560 driver/breakout board). I guess the "right" combination of X/Y/Z motor speeds caused some kind of a resonance. The solution was to replace the TB6560 board. The new board has been working fine ever since - 7 years and counting.
    Thanks for the info, I had planned on finally swapping the parallel board out today to a new USB board I’ve had sitting around for a year. Was thinking about it last night.


    Glen

  5. #5
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    Re: X axis looses steps in the exact same line of code each time.

    Quote Originally Posted by ger21 View Post
    There's also a bug in Mach3 where in certain instances, it will accelerate far above the acceleration rate.
    Try changing the F2000 to a lower feedrate and see if the stalling goes away?
    Thanks Gerry, wasn’t aware of the bug. What I did do and it still failed was to override the feed speed in the Mach3 screen down to 1800mm per minute.Why don't they fix the bug????

    Going to swap out the BOB to a new USB and see if it still occurs!
    But before doing that I’m going to generate anew TAP. File in Fusion and just select that row of slots and repeatedly air cut that path and see if it happens again.


    Glen

  6. #6
    Community Moderator ger21's Avatar
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    Re: X axis looses steps in the exact same line of code each time.

    Why don't they fix the bug????
    Mach3 development stopped about 6-7 years ago.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  7. #7
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    Re: X axis looses steps in the exact same line of code each time.

    So today I reran the problematic code and it missed steps in the first try.
    So I went and redid the post processing and just slected the row of slotes that was problematic.
    I ran that TAP. file over and over and over and it never missed a step!?!?!?! I even turned up my acceleration and it was still good.
    Very confusing how the code will loose steps if I have all three rows of slots selected. But wont if I only select and runs the problematic row of slots.

    Now I'm not sure if I should bother changing out my parallel port BOB for the USB one ????

    Glen

  8. #8
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    Re: X axis looses steps in the exact same line of code each time.

    What happens if you try a pocketing cut with a smaller tool?Just a suggestion to see if that one slot is at a machine location where there may be a problem.A change of BOB will be sending the same number of pulses as the parallel version,are they all being received by the stepper?I would be carefully looking at any joints and terminals on that axis just in case there is a hint of movement or a crack in a soldered joint.

  9. #9
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    Re: X axis looses steps in the exact same line of code each time.

    Don't leave me wasting all my time,
    Don't leave me helpless in this cold world standard deviation calculator

  10. #10
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    Re: X axis looses steps in the exact same line of code each time.

    Quote Originally Posted by routalot View Post
    What happens if you try a pocketing cut with a smaller tool?Just a suggestion to see if that one slot is at a machine location where there may be a problem.A change of BOB will be sending the same number of pulses as the parallel version,are they all being received by the stepper?I would be carefully looking at any joints and terminals on that axis just in case there is a hint of movement or a crack in a soldered joint.
    Thanks for your reply! If it was a loose wire or cracked solder joint, I think the problem would be more random .It occurs at the exact same line in the code each time it happens.

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