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[turbocnc] More homing worries

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  • Roland Jollivet
    Hi Today I came across a new? problem. I would set up to drill a pcb, drill one hole, abort, reset, and repeat the process, but almost everytime there was an
    Message 1 of 1 , Oct 1, 2007
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      Hi

      Today I came across a new? problem.

      I would set up to drill a pcb, drill one hole, abort, reset, and repeat the
      process, but almost everytime there was an offset. I was desperately
      looking for backlash and sticking problems, but none found.

      The error is in the homing procedure. I have all three switches set on
      'positive' trigger, and;
      X -home negative (normal)
      Y -home positive (moves table away from tool because of fixtures)
      Z -home positive (normal, up)

      I jog the tool into the work envelope, then..
      If I press Alt-S, H, again and again, the axis will home, but like this;

      X approach
      Y approach
      Z approach
      - X backoff
      - Y backoff
      - Z backoff

      then again,

      X approach
      Y approach
      Z approach
      - X backoff (Y and Z don't backoff)

      then again,

      X approach
      - X backoff (Y and Z don't approach)
      - Y backoff
      - Z backoff

      then again,

      X approach
      Y approach
      Z approach
      - X backoff (Y and Z don't backoff)


      This might sound confusing, but there's a toggle function going on. X will
      always approach and backoff, but Y and Z make a single move following on
      from the previous one.

      It looks like the workaround for now, before running a job, is to move the
      tool out, do manual home, then run prog without any further manual homing
      or G28 operations.

      I'd appreciate it if one or two other members would perform a few 'homes'
      in sequence and note if all three axis do indeed back off. I'm using 4.01
      I don't recall seeing this in known bugs, and may explain offset errors
      some were having since there'll be and alternate error on Y and Z, between
      homes, being the distance between the open and close on the microswitches.
      The error is also easily missed since the all the motors move in quick
      succession

      Regards
      Roland
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