[MadPickinSkills]

Can someone give me a refresher on how the I and J codes are used or point me to a website that explains it?

[jpgdesigns]

the I & J define the center of the arc... Just keep in mind that the I & J could be relative or absolute depending on your controller... They are not controlled by G90 or G91... so find out what your controller is set to...
an example:
Absolute X & Y, Absolute I & J, Center of Arc 2,2, Radius 1, Clockwise Motion
G02 X3 Y2 I2 J2
Absolute X & Y, Relative I & J, Center of Arc 2,2, Radius 1, Clockwise Motion
G02 X3 Y2 I-1 J0

Hope this helps

[Torsten]

Can someone give me a refresher on how the I and J codes are used or point me to a website that explains it?

Besides been absolute or relative depending on Controller, I have seen different Controllers sometimes use opposite signs for relative addressing.
Most common when relative addressing is used it will be the distance from the tool start position to the centerpoint.
Where I = X direction, J = Y direction and K = Z direction.
Any IJK-Address amounting a Zero value may be omitted.
So for example

G17 (XY-Plane Selection)
G03 I-2.

Will drive a full circle with the center been 2 inches to the left of the current position.
Or use

G17 G03 J2.

This time the center of the 4 inch diameter circle will be 2 inch above the current position.
Hope this helps, good luck

[valmet58]

go see http://www.etec.wwu.edu/faculty/McKell/nccnc_prog3.pdf