Inverse Time Feedrates - How do I get it to work

[speedybass]

I deal occasionally with parts that need full simultaneous 4axis milling, and I know that inverse-time feedrates are the way to go. I know that the machine must be able to work with it. What I am wondering is how to enable it in Mastercam. When I go to the generic posts to enable the switch to output in inverse time, it doesn't put the feedrate code out the way I would expect it to. I try editing the control def for the machine to get it to output, but that doesn't get it either. What is involved in getting it to work? Is there extra code needed in the post?

[Guest CNC Apps Guy 1]

How are you "expecting" it to come out?

[speedybass]

I would expect it to be in seconds or minutes, and constantly varying from line to line, based off of how much distance it is from line to line and how far from the center of rotation on the 4th axis.

[Bruce Caulley]

Be VERY careful setting this up. I am assuming that it is an ISO control, so you will need to make sure your post spits out a G93 on all moves that include that rotary axis. You will also need to make sure that the post reverts back to G94 for linear moves.

 

Bruce

[Guest CNC Apps Guy 1]

Ok, that sounds like you're looking for the right thing.

 

In your Control Def, make sure you have something like this...

 

[speedybass]

The picture in the previous post doensn't show up for me. Can you email that to me?

 

Thanks,

[Guest CNC Apps Guy 1]

You've got mail.

[speedybass]

I'm sorry, but I didn't seem to get that in my email. Can you send that to [email protected]

 

Sorry & Thanks,

[Guest CNC Apps Guy 1]

You've got mail.

[speedybass]

Wow, I'm still not getting the email. I've checked my spam filter and nothing shows up at all. What is this thing that I should have in my control def?