Results 1 to 6 of 6

Thread: Circular G-code Cuts

  1. #1
    Join Date
    Dec 2011
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default Circular G-code Cuts

    I am writing code to do circular cut, and was going to use G02 (unless there is something easier than G02 to do a full circle) But I am having trouble putting it together. Im working on a part with a male and female side, two different pieces. But I am having issues with doing the male part, as I need to make circular cuts that get smaller and smaller to the desired radius / diameter, then to step down and repeat. I get how G02 works, but I dont think I get how I, J, and K work, or it could be my starting point thats killing me. So was wondering if someone could help with an example or explain what each part of G02 does.

    Thank you for any and all help.

  2. #2
    Join Date
    Dec 2011
    Location
    Illinois / Wisconsin border
    Posts
    190
    Thanks
    29
    Thanked 22 Times in 21 Posts

    Default Re: Circular G-code Cuts

    Quote Originally Posted by stephenj5 View Post
    I am writing code to do circular cut, and was going to use G02 (unless there is something easier than G02 to do a full circle) But I am having trouble putting it together. Im working on a part with a male and female side, two different pieces. But I am having issues with doing the male part, as I need to make circular cuts that get smaller and smaller to the desired radius / diameter, then to step down and repeat. I get how G02 works, but I dont think I get how I, J, and K work, or it could be my starting point thats killing me. So was wondering if someone could help with an example or explain what each part of G02 does.

    Thank you for any and all help.
    Think if the "I,J,K" as your "X,Y,Z" coordinates but, in a "delta" move.
    Always when you're programming a circle, you specify the END POINT and the CENTER of the radius.
    Now, the end points are always easy to calculate, it's the I,J that seems to be tricky for most.
    The I,J for any center is FROM YOU'RE AT. - that's the trick.
    So, if you need a full circle, let's say above your current position, the center of the circle would be in the Y+ direction, right?
    How far to the center (I,J) is actually your Radius. So, a simple code;
    G02 J1.0 F10.
    Would make a complete circle as if you were starting at the 6 O'Clock position, with a 2" diameter.
    If you are starting at the 3 O'clock position, the code would be;
    G02 I-1.0 F10.

    One last thing to remember, is to ALWAYS change back to a linear move (G00, G01) when your done circle interpolating. The G02 & G03 are "MODEL" and the control will assume you're still making circles if you don't.

  3. #3
    Join Date
    Dec 2011
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default Re: Circular G-code Cuts

    Very nice, I get it and seems to work. I did want to double check, if im using the same point, lets say the center of the circle that I need to make, if im making a larger or smaller hole, aside form changing the I / J, Do i need to move my starting point? I was playing with it in a simulator, and it seemed to make one circle, then make the second one, starting at the same point, so it was they both had that starting point, but the little circle was not in the center, but along the edge of the larger circle. I get it, but im not sure if if the radius is the starting point from the center of the circle, or if it thinks the edge of the radius is the center of the circle.

    I was also wondering if there was a canned cycle version of this, where I can set a radius, and have it make so many cuts in the z direction till hitting a certain point.

    Thanks for the help

  4. #4
    Join Date
    May 2008
    Location
    Great State of Wisconsin
    Posts
    1,211
    Thanks
    7
    Thanked 134 Times in 112 Posts

    Default Re: Circular G-code Cuts

    Quote Originally Posted by stephenj5 View Post
    Very nice, I get it and seems to work. I did want to double z direction till hitting a certain point.
    It depends on what type of control you are using. Some controls have pocketing routines and others do not. Fanuc will not unless the MTB wrote one for the machine. Most of them you are going to have to write yourself. The most common way is using macroB programming.

    Stevo
    (The opinions in this post are my own and not those of machinetoolhelp.com and its management)

  5. #5
    Join Date
    Dec 2011
    Location
    Illinois / Wisconsin border
    Posts
    190
    Thanks
    29
    Thanked 22 Times in 21 Posts

    Default Re: Circular G-code Cuts

    Quote Originally Posted by stephenj5 View Post
    Very nice, I get it and seems to work. I did want to double check, if im using the same point, lets say the center of the circle that I need to make, if im making a larger or smaller hole, aside form changing the I / J, Do i need to move my starting point? I was playing with it in a simulator, and it seemed to make one circle, then make the second one, starting at the same point, so it was they both had that starting point, but the little circle was not in the center, but along the edge of the larger circle. I get it, but im not sure if if the radius is the starting point from the center of the circle, or if it thinks the edge of the radius is the center of the circle.

    I was also wondering if there was a canned cycle version of this, where I can set a radius, and have it make so many cuts in the z direction till hitting a certain point.

    Thanks for the help
    What is the machine and the control? Do you know if you have Macro option?
    Try this; Enter in MDI, #160=123.456
    If you run this and don't get an error, I can help you with a simple code / sub routine.
    You'll have to give me some more information on what you're trying to do though.

  6. #6
    Join Date
    Jul 2011
    Location
    Texas
    Posts
    6
    Thanks
    0
    Thanked 3 Times in 2 Posts

    Default Re: Circular G-code Cuts

    Programming G02/G03 on a Fanuc Control, I,J,K is the incremental distance from the current position to the arc center with respect to your X,Y,Z Axis.

    So, as MMMMM has posted:

    G02 J1.0 F10 = Cuts a 1.0" Clockwise Arc/Radius, w/ the arc center 1.0" from the current position along the Y+ Axis. Without specifing an End Point for the arc, your machine will simply cut a full circle.

    For half an arc you program:

    G0 X1. Y-1. (POSITION TOOL TO START POINT FOR ARC)
    Z.1 (RAPID TO R PLANE)
    G1 Z-1.0 F10. (FEED TO Z DEPTH)
    G2 Y1. J1. (CLIMBCUT CLOCKWISE FROM Y-1. TO Y1., W/ A 1." RADIUS, Y1. = END POINT OF ARC, J1. = RADIUS AND DIRECTION FROM CURRENT POSITION TO ARC CENTER)
    G0 Z1. (RAPID TO CLEARANCE)

    Regards,

  7. The Following User Says Thank You to MarkC For This Useful Post:

    MMMMM (12-14-11)

Similar Threads

  1. Circular Interpolation on Fanuc Control
    By weiselma in forum Machine Repair & Troubleshooting
    Replies: 4
    Last Post: 08-01-14, 11:27 AM
  2. Circular Interpolation
    By BeezCNC22 in forum Programming / Applications
    Replies: 2
    Last Post: 02-15-12, 10:15 PM
  3. Need recipe for circular interpolation on gd2
    By MrS in forum Programming / Applications
    Replies: 0
    Last Post: 11-26-11, 06:46 AM
  4. 3 axis circular interpolation
    By mocol in forum Automation & Interfacing / Installation / Ladder logic
    Replies: 1
    Last Post: 07-22-10, 12:04 PM
  5. Circular interpolation problem
    By anjum in forum Machine Repair & Troubleshooting
    Replies: 3
    Last Post: 06-14-10, 10:32 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •