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OpenBuilds CONTROL: X-axis error after pause/resume?

Discussion in 'OpenBuilds Bug Report' started by Ed Tschoepe, Apr 6, 2020.

  1. Ed Tschoepe

    Builder

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    Hey, folks!

    Probably user error here on my part, but I ran into something odd today that I thought I should share. I'm using the OpenBuilds BlackBox with OpenBuilds Control (v1.0.215) and I had gotten 20 minutes into a 1.5-hour-long CAM operation (generated using Fusion360) on my CNC when my kids wanted to take a walk. So I waited until the tool had retracted above the work surface, hit the pause button and then turned off the router and vacuum.

    The computer stayed on (in presentation mode), as did power to the BlackBox and the stepper motors.

    When I returned a half hour later and resumed the job (having restarted the router and vacuum), it plunged into the MDF I was milling at an odd place and resumed. I heard that and almost shut it down but I thought I'd let it continue in case most of the parts were still salvageable. I soon realized that it was cutting through pieces at the wrong place and I can tell now by looking at the 2D profile it was following that it acted as if I had shifted the X0 point up (to the right) by about 3 inches.

    Anyone have any idea what the issue might be?
    Thanks!
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Project Maker Builder Resident Builder

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    Is your $1 settings in Grbl settings set to 255 to keep the motors locked while Idle? If not, could have been moved mechanically (bumped while walking past for example)?
     
  3. Ed Tschoepe

    Builder

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    Thanks for the tip, but I think this was due to the "user error" I mentioned and that the pause/resume was just a misdirection. :oops:

    My CNC is a homebrew design, basically a modified OX that uses ball screws that I already owned and didn't use on another project. I turned it on a few minutes ago so I could jog the gantry out of the way and I noticed a scraping sound while moving along the X axis. It turns out that two of the screws holding onto the ball nut have come loose enough to make contact with the aluminum extrusion holding up the Z-axis assembly.

    So although I don't remember hearing any scraping yesterday there must have been some going on that was masked by the router and vacuum sounds. I must have been missing steps ... lots of them.

    That does surprise me, given the reduction and the crazy torque that these motors provide, but it's the most logical explanation. I have to remove the Z-axis and fix everything.

    Thanks!!!
     

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