Newbie- Can't get 4Axis Rotary to work properly

[Snarfty]

Hi
I am trying to get Mastercam V9.1 to create a 4axis Rotary toolpath. Everything looks like its working ok in backplot except I notice that the Z and Y axis move as the part rotates and as the tool stays vertical so this should not be so. After posting and looking over the co-ordinates it is obvious that this is what is happening. I'm guessing that it has something to do with my WCS but I can't work out how to stop it.
I have looked through my post-processor I think this is all setup correctly.
It is for a full-rotary axis on a Vertical Mill.
Any help would be appreciated.
Thanks

[ObrienDave]

What it is trying to do is keep a constant angular relationship between the cutter centerline and the point of contact with the surface.
This is to prevent the center of the cutter from doing most of the work or to prevent a climb cut becoming a conventional cut on a downward slope or visa-versa.
So, yes, there will be Y and Z axis movements.
If you can ZIP and attach a copy of your file and post processor with the .txt file, I will be happy to look at it for you.
Can't promise a really quick turnaround, but, I will try.

[Snarfty]

Hello Dave
Ok sorry I didn't explain myself very well. I know the Y and Z are supposed to move but they are rotating with the part ie. As though the spindle is turning around the part and not the part turning in relationship to the spindle. At 0 degrees the Z coordinates are a positive values of approximently the correct distance from center however at 180 degrees they are negative of about the same. So in the real world the cutter is going to embed itself through the body of the job as its trying to put the tip of it below the job. I noticed this first in the program and after going through backplot a few times I noticed the Y and Z axis are rotating even though the "Tool" remains vertical and the part rotates.
I've included the MC9 file and my post processor.
Let me know if there is anything else you need.
Thanks
Snarfty

[ObrienDave]

Ok, after looking at it for a while last night, I am under the impression there is something not set correctly in your post file.
I posted your program using the generic mpfan post and the output code was consistent with what we should expect to see.
Have you used this post file on other rotary type parts before?

[Snarfty]

No I havn't used this post file for rotary parts before. In the past we create programs for the rotary axis-semi manually in saying that we havn't done anything complex. I created that post from our generic one that we have been using just for normal 3 axis machining. I know it was eigther MPFAN or RPFAN. I will check it out on Monday at work and I'll let you know how I go.
Thanks

[ObrienDave]

In that case I would seriously suggest you start over with the original mpfan post.

Please don't ever use rpfan.
That is for REVERSE posting a nc file back into a nci file that you could load into Mcam.
AFAIK, that has not properly worked since V6.
Maybe newer versions of rpfan work better.
I don't know.

I will be happy to assist you with any post modifications that you don't feel comfortable doing yourself.
Forum rules dictate that you must attach a copy of your post file (please include the appropriate .txt file) to a message.

[TheBigJW]

Originally Posted by ObrienDave AFAIK, that has not properly worked since V6. Maybe newer versions work better. I don't know.

That can be said about almost all of Mastercam... Don't worry. Just pay your maintenance and they will fix it in the next version.

John

[Snarfty]

Thanks alot Dave, I have the problem sorted I'm not sure what happened but I deleted the post that I created. I then posted with MPFAN and it worked minus B-axis being my rotary, so I copy and pasted to make a new post then went through and changed the horizontal machine to vertical and indexing to full rotary and B-axis to A-axis just like I did the first time and it still works.
So in short I have no idea how it ended up doing what It was doing but It doesn't do it anymore.

Also where can I find these forum rules.
I'll let you know how I go when I actually get a chance to run the program.
Thanks Snarfty

[ObrienDave]

Glad you got it figured out.
And by all means, please let us know how it worked out.
Not sure where the forum rules are but if you ask one of the moderators they can point you in the right direction.
Good Luck