Fanuc 21i Retrofit-Constant Surface Speed 1

[bugnut]

Just completed a retrofit of a Fanuc 21i to a lathe. No encoder on lathe for spindle speed but control gets a calculated signal telling what the spindle rpm is running. I am trying to use constant surface speed-conditions g50 max 100rpm, g96 400 css, ipr .1"
My problem is that when the machine is running it is not calculating the ipr and adjusting based on the actual spindle rpm-seems to continue running at the .1 ipr and the programmmed CSS(400). Any idea what to do to correct? Fanuc says no encoder is required use the spindle calculated rpm.....Hummmm not working!!

 

[fantech]

Are you using a Fanuc spindle drive? or someone elses?

 

[milllatheguy]

The IPR never changes. It is not calculated. Only the RPM changes in CSS mode. The IPR is .1 no matter what speed you are running.

BTW - .1 is rather fast, more of a thread feed rate than a turning feed rate.

 

[bugnut]

Thanks for the input ! Found out I had to add another Fanuc module-up and running now working good!!
Thanks Again, Bugnut