The post says it is a Generic Mill 5 Axis mill posts and under the edit notes it says it was setup for our machines by the dealer (axsys and barefoot CNC). Not sure we are going to get much help form Axsys at least from what I've been told by our engineer who is in charge of all of this he has already contacted/worked them and to my understanding they told him it is what it is and that is just the way it is with the BC and axis. Thanks for all the help so far, sounds like we need some help with the post, which is what I rather figured.

I've played with this further, one thing I did find out was that the machine definitions limits where not set for the B and C axis, so I have now set them to the min/max limits, this however did not make any difference. I have attached 2 files, just a "simple" around trim of a rectangle part with 1" radius, notice how the first part starts at C90 and goes up to C270 and then unwinds, while the second part also starts at C90 and goes around to C-90 and then unwinds, which it shouldn't be doing since the machine can go to -270. For the first program Mastercam in the preview shows C-90 and rotation around to C270, which is actually what I want, it just doesn't post that way. The second program Mastercam shows C starting at -90 and rotating to -450 (um the machine can only do -270???). test.nc test2.nc

I think I understand some of the misc ints, like I said still learning! 4 Try to start C negative, I've tried both ways on this one with no change (set to false), 5 Clamp Rotary Axii I have not done anything with (set to false); and 10 is max feed for pivot (set to 800)? For the post it says it is the generic 5 axis mill post and then under the rev log it says Axsys set it up. I searched for bias_null and nothing was found. We have a CMS PK and Athena both with OSAI controls

We are talking with the Mastercam reseller, and we are using a post processor that as far as I know was created for us by our dealer.

First off I am fairly new to Mastercam and creating 5 axis programs, been creating 3 axis programs for years now, but now I have taken over the part of creating 5 axis programs and I am struggling with 3 main problems (previous programmer had the same issues). We have been told/worked with our distributor that this is just the way it is and nothing there is we can do about these issues other than manually editing the g-code. Where I work we have 2 5 axis machines both head head type with B and C axis on the Z axis and using TCP to run the same programs on both machines, both machines have 270 degrees +/- of rotation on the C axis. We mostly trim out thermoformed production parts using CNC vacuum nests. 1. B and C axis randomly inverting themselves in a program say from B90 C90 to B-90 C-90. Basically the B and C axis will be trimming the feature and then the next feature 2 inches over in the same plane it will completely invert B and C. Currently having to manually go through the g-code and correct any "inversions." Of course Mastercam/Post Processor? doesn't pull the head out of the part when it randomly inverts B and C. I have noticed when previewing the program in Mastercam it does occasionally show B and C inverting, but other times it does not, so I'm guessing the Post Processor is causing some of the issues? One particularly aggravating part I had a bunch of holes and slots all in one plane on the front of a part, it inverted B and C a total of 4 times! WHY? Grrrr! For what it is worth Mastercam only showed one inversion in the simulation, where'd the other 3 come from? 2. Controlling the unwind of the B and C axis as well as very unnecessary unwinds. WHY! WHY! WHY! WHY! If Mastercam/Postprocessor?? would just wind the head up to start with it wouldn't need to unwind. We have an easy 360 degrees of rotation on the machine if it would just wind it up to say -180 and as it goes around the part unwind to +180. Sometimes it will have 2-3 unwinds in a program just to make it 360 degrees around a part! Next problem is the unnecessary unwinds, I declare it likes to put unwinds in the program just to aggravate me at times! The program will be trimming around at say C90 and it decides it needs to unwind to finish the last turn (another 90 degrees to C180). HELLO the machine has another 180 degrees it can rotate on C why the bleep does it think it needs to unwind?? Or even worse it will finish the last turn with just a straight X or Y left to go and it decides it needs to unwind! WHY?! It is a freaking straight cut! 3. Finally third being able to control B and C axis orientation in a cut Basically we have several parts where we need to the BC head to trim in a certain orientation so the head has clearance (say C-90 +/- 60 degrees), I declare in every incident where I have had this Mastercam/Postprocessor has put the orientation completely opposite of what it needs to be and I have had to spend hours manually changing the g-code. I have tried everything I know how to do to get the g-code I need from changing the machines definitions and postprocessor that the machine only has -180 to 0 degrees of rotation on C. Even with that it will still post the code out as +90 or -270 Any help on these issues would be greatly appreciated! Like I said our distributor just told us that is the way it is, in which case why even pay for this "steaming heap pile" when I end up having to manually program it anyway?