Limiting 4th Axis Rotation between 100 and -100

[socaled]

I have a 4th axis ro-tab with a trunnion table. due to the size of the part sitting on the trunnion I can not have it rotating passed 100deg in either direction. So when I'm @ A90 and I need to go to A270, I need it to rotate back thru A0 to get there. It's easy enough to do this by using A-270, but I can't get it to post that way. I've tried using the limits and axis positioning settings in the MD with out success. I'm using the Generic Fanuc 4X Mill post. 

[Rstewart]

This must be modified in your post from what I've been told...

[Elmer Fudd]

As a workaround I will do a dummy tool path at 0 degrees so that the rotary goes in the right direction.

[Elmer Fudd]

look for this in your post.

 

 

sec_limlo$   : 0   
sec_limhi$   : 135

[socaled]

look for this in your post.

can't find this in the post.

[Elmer Fudd]

Hmmmm, that's from my 5 axis post. I will se if I can find something in my 4 axis post when I get a second. What post are you using?

[Elmer Fudd]

Try this:

lim_hi       : 0     #Upper rotary axis limit      
lim_lo       : 0     #Lower rotary axis limit

[Colin Gilchrist]

There are no 4th Axis Rotary Limits available in the "Out-of-the-box" 4-Axis Post Processors from CNC Software. I don't believe that MPMaster has this either.

[AMCNitro]

what if you just edit the program and make it go back to A0. and then A100?  Is the transition a rapid move?

[socaled]

There are no 4th Axis Rotary Limits available in the "Out-of-the-box" 4-Axis Post Processors from CNC Software. I don't believe that MPMaster has this either.

That's what I've found, but I was hoping I was missing something.

 

what if you just edit the program and make it go back to A0. and then A100?  Is the transition a rapid move?

I can dummy move or hand edit and make it work, but I'm lazy. I want to program and post without the extra work. I also don't want to worry about anyone else forgetting that these things are necessary.  

Looks like I'll be editing a 5th axis post to work or trying to add limits to the 4th Axis. You know in my free time

[Elmer Fudd]

I do a dummy toolpath (drill to a point above the part) so that it is not forgotten later on. You could also do a manual entry toolpath.