Taper threading is not a usual practice in cnc machine workshops, but sometimes customer want a component with taper threading, So here is the solution. Taper threading on a cnc lathe machine with Fanuc control is just easy with Fanuc G76 threading cycle. Fanuc CNC control threading cycle G76 gives us lot of flexibility.CNC Programming tapered threading with Fanuc threading cycle G76 is not that difficult, just one parameter have to add.
Normal Threading with Fanuc G76 Threading Cycle CNC Program
N5 G76 P010060 Q100 R0.05 N6 G76 X30 Z-20 P1024 Q200 F2
One G76 parameter which have to be added for tapered threading is R in G76 second block.
Tapered Threading with Fanuc G76 Threading Cycle CNC Program
N5 G00 X50 Z5 N6 G76 P010060 Q100 R0.05 N7 G76 X43 Z-45 P1024 Q200 R-14.5 F2
The R parameter in second block of G76 is the tapered value. Note that R is given as Radius value.
How to calculate R parameter for Tapered Threading on Fanuc with G76 Threading Cycle.
R = (Start Diameter – End Diameter) / 2