R notation for arcs is a little easier to program standing at the machine
for some types of parts. As you noted, you can't do full circles with it -
and at 180 deg exactly there's some interesting stuff that occurs with the
math as well.
From: jcc3inc [mailto:jccinc@...
Sent: Sunday, August 01, 2004 8:28 AM
Subject: [turbocnc] G02 Xnn Ynn R nn Type Arc Programming
I note that there are some programs where arcs are programmed with
an "R" instead of I and J in the codes. Why might this mode be
If I reason correctly, one cannot generate a complete circle using
the R code as only one point on the complete circle is defined! You
would have to do a circle in halves (or something like that).