B axis backlash elimination

[Ewood42]

One of the machines I program had a pretty serious crash a few years back, and needs to be programmed to move 1 deg past, then back when moving in the positive direction in B. Is there any straight forward way to change the post to do this? Afraid it's beyond my entry level post editing abilities, and the company will not pay for post work from MCAMNW for these older machines... so I'm on my own either editing this in by hand after post, or figuring out the post edits myself.

[MIL-TFP-41]

Make point toolpath to a plane that is 1 deg beyond your index location...then your regular toolpath, so your table will reposition the way you want? No post edit necessary.

 

Just a thought

[civiceg]

Or set the backlash on the machine?

[Ewood42]

Or set the backlash on the machine?

Maintenance said they've already tried adjusting the backlash parameter but the control can't compensate for it. From what I hear, it was a pretty spectacular crash, messed up the ring gear bad.

[ahaslam]

I would recommend building a macro in the machine. Editing the post would be kind of a pain in the butt to do. You will still want to make changes to the post so that it will use the macro... Come to think of it, getting the post to do that might not be too bad. You can do math in a post so just find the post block that calls up your B move and add in a new string variable such as saxisprep = what ever your axis is$ +1. Then output that string and an EOB then maybe a dwell? and then it should output your actual zero location. it's a starting point but check out the MP_documentation from the reseller. There is info in there on how to perform math functions in a post. Hope that helps a little. If you are still having trouble then let us know. 

[Ewood42]

Looks to be in the encrypted portion of the post file (Generic Fanuc 5X Mill from mcam was what I started with). Guess I'll stick with hand editing for now.

 

Thanks anyway, everyone!

[Jayson Kramer]

Sounds like you want something like this we do for our customers Makino post?

M11 (UNLOCK
G90 G00 B90.
G00 G91 B5.
G01 G91 B-5. F100.
G00 G90
M10 (LOCK
M251
G05.1 Q1

[Ewood42]

Yeah, pretty much. Could just add in string literals for the b movement using incremental like that... if it weren't in the encrypted portion of the post. So much of the 5 axis post that I can't see, pick apart, reverse engineer, and learn from!