When performing roughing and other such operations during turning, these functions permit to command in a single block the machining program which is normally commanded in several blocks. In other words, they simplify the machining program. The following types of fixed cycles for turning are available.
G-code:-
          G90    or      G77    = Longitudinal Turning Cycle  
          G92    or      G78    = Threading Cycle 
          G94    or      G79    = Transverse Turning Cycle.
Programming Format:-
          G90 X__ Z__ R__ F___ ;
          Or
         G77 X__ Z__ R__ F__ ;
Same for G92, G94 
X        =  X cutting point 
Z        = Z turning length 
R        = Taper Value (Radial)
F        = Feed Rate.
Longitudinal turning cycle G90 or G77:-
1.   Straight turning 
2.   Taper turning 
Threading cycle G92 or G78
1.   Straight turning  
2.   Taper turning 
Transverse turning cycle G94 or G79
1.   Straight turning 
2.   Taper turning




