[mfpuller]

I am machining a very complex aluminum impeller, much more complex than the one mastercam shows in the tutorial. I had success programming it 5 axis, and was renting a 5 axis machine. The shop I work at only has a vf-3 with a 4th axis. So I am attempting to machine the wheels on the 4th axis now so i don't have to rent a machine. I was able to get my toolpaths to look pretty good in mastercam on my backplot by locking the axis limits on my xy plane to 10 degrees. So I tipped the rotary axis up in the machine on 10 degrees. My axis of rotation is the x axis.

My problem is what I post doesn't exactly look like my backplot. It appears that my post is posting out "A" codes that are about 8 degrees off from what my backplot is. I am using a protractor to figure out how much backplot is rotating. (Is there a way for the backplot to tell you where your rotation is at along with the xyz moves?) The "X" moves are identical from the backplot to the post. The "Y" moves seem to vary slightly from the backplot to the post.
My parts are keyed and were previously roughed out on the 4 axis, so there are rough blades on them. It appears that there is about an 8 degree difference to the existing roughed blades when I try to start running to toolpath on the machine, just as I suspected after looking at the post compared to the backplot. I am definately located correctly on the wheels as I went around and checked random points and they looked good.

I am using a multisurface path. My WCS is the top plane. My Tool plane is a custom 10degee plane. My output is set to 5 axis, but as I previously stated I have the axis limits locked at 100 degrees on the xz plane.

I am using the generic haas 4axis machine defintion. Any help would be greatly appreciated.

[Ydna]

I had the same problem with a much more simple part. It was basically a turned bar with 5 helix slots on it, that had varying angles on their slot walls. It only consisted of two toolpaths, a rough and a wall finish, but would yield completely different A values when posted.
I tried to get it to work for about a day but eventually I just manually programmed the finishes. Never figured it out.