[Todd Zuercher]

I need to set up a way for offsetting the tool path an increment from the center of rotation of a C-axis, and am looking for the best options for doing it.
The machine in question is a large wood working machine with a big horizontal molder spindle mounted on a C-axis. The control is a Fanuc 310i, but it does not have Custom Macro installed (at least not yet.) Well the molder tooling is rarely perfectly centered on the center of rotation for the C-axis. What I want to be able to do is offset the tool path (which will be written for the center of the C-axis rotation) so that the tool will cut in the correct place regardless of the angle the C-axis. In other words if I make a cut with the C-axis at 0 degrees then turn the C-axis 180 degrees and cut in the opposite direction the two cuts would line up.

What are my options for doing this?

If the machine had Macro-b, I'd use a macro to calculate the sin and cos of the C-axis angle to calculate the amount to offset the C-axis, but that can't be done on this machine.

Would using a tool radius offset work? The offset initialization move would be a little scary, but as long as I was sure to always get it done above the material I think it could work.

[deadlykitten]

hy you need a corection inside the program, thus not an offset, that will adjust position among circumfereence

this can be added as a variable inside each position block of your code, and you can control it from your system variable input panel, thus there will be no need to recreate the code outside the machine, then reload/reselect, but simple panel operation

i can help with a simple application that will input the corection variable automaticall inside your program file; after that, you will need to build a table, that will help converting circumference corection to C axis degrees, or whatever is needed for your program to work properly / kindly

[deadlykitten]

i just remembered this post : it will be needed to keep the operation inside 0-359.999 degrees, thus it may not work, if, after a corection, the toolpath will shift from 359* to 2*

trying to go over/under 360 may leave to errors, especially for rad comp codes

is possible to handle them by using in code formulas that will restrain any degree value between 0-359, but this may increase cycle time, because many calculations will be added; another aproach is to shift C axis origin, in such a way that it will cover any 'normal' changes aplied : for example, if you have a groove between 170*-190* and another oposite one between -10*+10*, then, for the last one, change C axis origin with 180*, so to shift it at 170*-190*

in short, what you wish for, can be done / kindly