If I program to use control for cutter compensation I have a couple of issues. The first is that when the program first starts to run it will drive the z axis below the set Z zero. The second is if I put a diameter in the tool chart it will give an offset error or make mickey mouse ears. I have also tried enter a small value in wear and still get a cutter comp error.

This is the second program I have written with the same issue.

Another problem I had after stopping the program is I entered MDI command of G0X0Y0 and the received an error the cutter comp was still active. So I entered G40 on the first line and the G0X0Y0 on the second line. Pressed cycle start and the x and y axis moved as expected but the z axis also moved to -0.06 which was well below the top of the part (note the spindle was about 2.5" above the part when I pressed cycle start). Good thing there was a hole there already.

Mach 4 Ver 4612

Programming in mastercam using a generic Fanic post processor

Did you find a solution to the Mickey Mouse ears? I have a similar problem trying to use diameter wear compensation in Mach 4 for the first time. I am using Fusion 360 for CAD/CAM to create an open pocket in a soft vice jaw to hold a part.

Using the Fusion 360 "In control" option in a 2D contour finishing toolpath Fusion 360 adds a G41 like this "G1 G41 X135.654 Y-6. D1" to fetch the diameter compensation from the Mach4 tool table however this adds a big ear to the toolpath displayed by Mach4.

Keith

No I have received any responses. It has to be something in the Mach software. I have tried the same program on another machine running a different control software and it worked fine.

Most of the time when you don't receive any responses is because others are not having the issue you are having or there isn't enough information for anyone to even to start to help.  I will say that we have thousands upon thousands of machine running Mach4 and cutter compensation without issue, so you are definitely not the only one using cutter compensation.  And don't take this the wrong way, as I'm not telling you that you are "not having a problem".  I'm simply stating that there is something unique that is happening that we have to solve.  With that in mind, the rest is dedicated to that end. 

1. We use Fanuc type C cutter comp.  The rules for cutter comp entry and exit are given Chapter 4 of the Mill G Code Programming manual and I believe them to be correct.
2. Have you tried a later build?  I don't remember any cutter comp issues with 4612, but that doesn't mean something isn't amiss with that build specifically. 
3. What other machine operate to your expectations?  Could it be they use a different style of cutter compensation? 

Most G code includes a safe start line similar to "G40 G80 G90" to put the machine into a known state.  if you stop the machine when in cutter comp mode, the machine is still in G41/G42.  Simply entering something in MDI does not magically clear that.  The reset button should be used to put the machine into a know state.  Look at any Fanuc control and you will see that the reset button is the most worn button on the machine!    Anyway, if you stop the machine when in cutter comp mode, the machine is still in G41/G42 unless you do something to change it (reset, MDI G40, etc..).

Also, please provide the G code program that you are trying to use, as it is impossible for me or anyone else to guess why you are getting the results you are getting.  Someone may spot an issue right away.  Otherwise, create a ticket with support and give them the G code file and tell them the results you expect.

Steve