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IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > 21i - Finish bore does not cut oversized rough pass, comp or no comp
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  1. #1
    Join Date
    Oct 2014
    Posts
    2

    21i - Finish bore does not cut oversized rough pass, comp or no comp

    The machine is a Colchester storm a90. It has been sitting since it was bought used. I manage to get it making parts now.
    I am making pulleys and all is well except for smallest profile, which is where the bearings are pressed into.
    What is happening is that the rough pass bores oversize only on that profile, again for the smoothing pass then it 'cuts' to size for the finish. everything cleans up except that bearing bore which can be oversized. If i change the second U value that bore dimension deviates more as I increase U.
    I have tried g41, g40, tool nose 0, 2, 3 for a left hand bore bar. TNR .032"
    This is the second part with a bore profile where this has happened.
    These controllers aren't the most intuitive. lol. Am I misunderstanding something, coding wrong?

    Here is the code:
    Code:
    T0303;
    S600 M4;
    G00 X.93;
    Z.15;
    G71 U.025;
    G71 G41 P210 Q280 U.015 W.002 F.005;
    N210 G01 X8.1;
    N215 X8.054 Z0;
    N220 X7.572 Z-.051;
    N230 G02 X7,338 Z-.174 K-.022 I.062 R.15;
    N240 G01 X7.09 Z-.958
    N250 G03 X6.25 Z-1.317 R.425 K.066 I.42;
    N260 X2,138 C.065
    N270 Z1.88;
    N280 X.93;
    G70 P210 Q280 F.002;
    G00 Z8;
    M30;
    N260 seems to be the problem bit.


    Thanks

  2. #2
    Join Date
    Aug 2011
    Posts
    2517

    Re: 21i - Finish bore does not cut oversized rough pass, comp or no comp

    I'm not sure the C on line N260 is even legal.
    anyway, if that profile is a bore the U on the G71 line should be minus. Something like U-0.005
    it cuts oversize on the roughing because the U tells it to leave this amount on the part and moves (offsets) the tool in the plus direction, therefore leaving nothing for finishing.
    Make U a minus value.
    also you should probably remove line N270 because you are cutting in the opposite direction which doesnt make sense.

  3. #3
    Join Date
    Oct 2014
    Posts
    2

    Re: 21i - Finish bore does not cut oversized rough pass, comp or no comp

    Thank you!

    I made a couple typos. it should be
    N260 x2.138 c.065
    N270 z-1.88

    I'll give it a go.

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