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  1. #1
    Join Date
    Dec 2011
    Posts
    0

    out of round condtion

    i have a mori NL2500 that i am turing spindles on. Tolerances are tight +/- .0127mm. The bearing surface furtheset awa from the main spindle continues to have an out of round condition. Seeing about .050mm. Having a big problem figureing this one out. Part is not tapered, spindles are dead on. any suggestions.

  2. #2
    Join Date
    May 2004
    Posts
    4519
    Fix your work holding.

  3. #3
    Join Date
    Jun 2005
    Posts
    142
    Ask a vague question, get a similar answer.

    What dia is the bearing and how far out is it?
    Is the spindle stepped or basically the same dia along its length?
    Using a chuck or collet?
    What material is it?
    DOC?
    Finish allowance?
    Can you use a tailstock or subspindle?

    Answer some of these questions and we can help, you might even fix it yourself...

  4. #4
    Join Date
    Dec 2011
    Posts
    0
    no steps or taper. Part is not physically round. Egg shape increases the farther u get away from the main spindle and closer u get to the sub spindle.

    2 bearing diameters - 66mm & 44mm - the 44mm is the one giving fits.

    Material is 4140 45~48 RC

    Microcentric collets

    Finish is 1.25 micrometers

    machine has a full sub spindle. We use a dead center with the spindles synced. Cant use a live center because our machine doesn't accpet independent spindle M codes.

    had Ellison come in an do a full alignmnet after we did it. They said the machine was dead on and in better alignment than most in the field.

  5. #5
    Join Date
    Feb 2009
    Posts
    6028
    3 things come to mind...

    Bar is whipping in the main spindle-tighter liner
    or
    Hydraulic actuator is not aligned properly, causing the back of the spindle to walk(run out)
    or
    the rear support bearing on the spindle is loose/bad.

  6. #6
    Join Date
    Dec 2011
    Posts
    0
    not running bar stock - use cut to length stock

    yesterday i discovered that i can make test cuts all day long with no issues. But as soon and i unchuck the part on the sub spindle and rechuck on it, i see .030mm~.040mm of runout. Is this nornmal? Ellison says this is my problem. I can't say for sure. Sub chuck is brand new as is the collet.

  7. #7
    Join Date
    Feb 2009
    Posts
    6028
    So, when Ellison checked alignments, did they check spindle centerlines between the 2 chucks? Do you see collet marks on the transfer material?

  8. #8
    Join Date
    Dec 2011
    Posts
    0
    Chucks check true between each other.

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