[bb218]

I am an experienced programmer but my experience is with a Hardinge Conquest lathe and Fanuc controller. I am having trouble getting the Cutter comp to work as I think it should. I have made so many changes I am not sure what did what but The diameters are coming out wrong, if they are right then the shoulders are wrong,

I want to face to the center line of the part using G41 which programming X to zero I should see a -X value of 2times the Tool nose radius. Then I want to switch to G42 and travel back up the face and chamfer the Od then travel the od to a shoulder, up the shoulder and then off the part, G40 and home.

My experience has been with the lathe tool in the back side of the part so I am questioning my thinking on the G41 or G42 and also the quadrant number I should pick. I have gotten so many different values I am beginning to think maybe the parameters are set wrong in my machine. Is it possible that the Z axis is set for a lathe designed to have the tool in the rear and the X axis set for a front tool ? I have never been able to get both the faces and Od comps to both be correct?

Mike

[djm77]

The TL machines are back to front really. You have to think that the tool is coming from the back as it would on a traditional slant bed cnc lathe. Just use G42 for external and G41 for internal as you would normally.


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[Ydna]

I may be incorrect but I don't know if it's possible to program a profile that changes from G41 to G42 without moving anywhere. If I were you, I would face the workpiece like normal (with no compensation) then activate comp off the workpiece and carry on with the OD profiling that you described. The thing is, lathe tool comp won't make any difference with the facing pass, only when you cut the chamfer will the coordinates change, but it would need to cut G42 on the facing move then switch to G41 on the retract and OD profile. Like I said, the control might allow you to do it, but it seems kinda complicated for effectively what is a straightforward profile.
If you haven't already, you may wish to check the Haas lathe manual since it has some great explanations of the tool nose compensation codes along with examples and whatnot.