This should not be difficult - Why is my circle so big?


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Thread: This should not be difficult - Why is my circle so big?

  1. #1
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    Default This should not be difficult - Why is my circle so big?

    So I have some code to cut a circle 1.339" in diameter (inside cut). Here's the code.

    %
    N10 G70 G17
    N20 G40 G90
    N30 S1000
    N40 T1 M06
    N50 G00 Z0.5
    N60 S1000 M03
    N70 X1.8954 Y0.4149
    N80 Z0.0197
    N90 G01 Z-0.06 F4

    (All is good until here)

    N100 G02 X1.3992 Y1.4519 I-0.2226 J0.5307 F12.0
    N110 X1.6702 Y1.5211 I0.2736 J-0.5064
    N120 X1.8954 Y0.4149 I0.0026 J-0.5755

    (Back to good again)

    N130 G00 Z0.5
    N140 M05
    N150 M02
    E




    I have two problems with it and both are equally disturbing.

    #1 - circle comes out to just over 3.75" in diameter.

    #2 - circle has a small (1/2" x 1/2") pac-man mouth in the 2 o-clock position


    Machine is a Hurco with Ultimax. Code comes up on the display after being dripped in and it's the same as shown above. Double checked that everything is in inches.



    Anyone have any ideas? This stopped being fun a few days ago.

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    Default Re: This should not be difficult - Why is my circle so big?

    Hi ecdez.

    Numbers are good.... assuming 3/16 tool diameter. It's odd that the "mouth" is at 2 o'clock. It simulates at 11. Perhaps a bogus code from the prior tool? Try adding G50 and G69 in the beginning.



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    Default Re: This should not be difficult - Why is my circle so big?

    In my frustration and desperation to figure this out I posted the question elsewhere too and one of the guys there took only that section of code and put it in a program for his machine and got the the same result. Someone else ran the math and the arc dimensions come out to the same size as what I actually cut. In the Cam program thought (SheetCam) the hole is the correct size and a perfect circle. Only thing I can figure is that SheetCam may have a bug in the post processor for Hurco Ultimax. Other than that the program is pretty simple to use and I like it. Another user here has a post he modified for his machine that he's going to send me when he gets a chance. I'm anxious to give that a try.



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    Default Re: This should not be difficult - Why is my circle so big?

    Why are you using 3 arcs, instead of a circle.?

    Make the following changes.

    Line N70 - Add G00, to this line.
    Line N80 - Add G00, to this line.
    Line N100 - Delete this line.
    Line N110 - Delete this line.
    Line N120 - Add G02 and F12.0, to this line

    %
    N10 G70 G17
    N20 G40 G90
    N30 S1000
    N40 T1 M06
    N50 G00 Z0.5
    N60 S1000 M03
    N70 G00 X1.8954 Y0.4149
    N80 G00 Z0.0197
    N90 G01 Z-0.06 F4
    N120 G02 X1.8954 Y0.4149 I0.0026 J-0.5755 F12.0
    N130 G00 Z0.5
    N140 M05
    N150 M02
    E


    good luck . Mike



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This should not be difficult - Why is my circle so big?

This should not be difficult - Why is my circle so big?