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Homing without limit switches

Discussion in 'CNC Mills/Routers' started by badlizard, Oct 21, 2024.

  1. badlizard

    badlizard New
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    As the title implies, I'm curious about homing without limit switches. I have an Onefinity basic machine that does not use or have (and I don't want to bother with installing) limit switches. I'm thinking about using my Blackbox X32 with Openbuilds controller software.

    That said, is it possible to manually set home after I jog my machine into position? This is basically how I do it now with my Acorn controller. Jog to hard stops & 'Reset Home'. I'm wondering if I can do similar with the X32.
     
  2. badlizard

    badlizard New
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    I believe I found my answer when poking around, thanks to @David the swarfer
    Sounds like all I need to do is manually move my machine to home, then hit Reset on the X32. Couldn't be easier!

    "no need to remove anything, just raise Z to the top and reset the blockbox there. That is the simplest 'fake the home' move of all since 'home' is where the blackbox turns on or resets and we want Z home to be a high as possible.
    After that the G53 move will raise the Z to a safe height before moving to the start position, as intended."
     
  3. Giarc

    Giarc OpenBuilds Team
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    That should work. I did it for years, but when I rebuilt my machine I added homing switches. I prefer them because of something happens during a job, I can be home the machine, then jog to where I set the xy zero, edit the g code to remove the lines that were already cut, then resume the job. This has saved me on a couple of long jobs.
     
  4. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Just do it :) repeatability, jigging, job recovery, easy to understand offsets. Worth the couple bucks every time
     
  5. badlizard

    badlizard New
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    Definitely not a cost issue. I know that limit switches are preferred to hard stops, but the Onefinity doesn't really lend itself (easily, anyway) to installing homing switches. Their Buildbotics controller uses stall homing, which is essentially what I'm doing without limit switches. With 2 Y axis motors, I'm quite confident in dead-square homing against my hard-stops. I have less confidence in trying to square and maintain 2 Y axis homing switches within .002" or better accuracy and repeatability. That said, I have rehomed & continued jobs on a few occasions with no loss of realignment when picking back up on a job.

    At times, I do consider installing switches. It's one of those things I may do at some future point if I can configure almost micrometer-level of switch adjustment on the Y axis without it being too cumbersome.
     

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