G89 Cycle Introduction
G89 cycle is used in CNC turning machines for boring holes from the side to the workpiece. It is the same as the G85 cycle as a command format, the only difference is that it is used for boring holes in the X axis direction, not in the Z axis direction.
After the command is used, boring to the other coordinates is continued by positioning the Z axis or C axis. The G89 cycle continues to run until the G80 command arrives.
G89 Cycle Format
|G89 X(U)_ R_ P_ F_ K_ M_ ;|
|X_ or U_ : Final drilling depth (X for absolute, U for incremental)|
|R_ : The distance from the initial level to point R level|
|P_ : Dwell time at the bottom of a hole|
|F_ : Cutting feedrate|
|K_ : Number of repeats (When it is needed.)|
|M_ : M code for C-axis clamp (when it is needed.)|
After positioning, rapid traverse is performed to point R. Drilling is performed from point R to point X. After the tool reaches point X, it returns to point R at a feedrate twice the cutting feedrate.
G89 Cycle Examples
G89 CNC Program Example – 1
O1234; Program number
M51 ; Setting C-axis index mode ON
M3 S2000 ; Rotating the drill
G00 Z50.0 X50. C0.0 ; Positioning the drill along the Z- and C-axes
G89 X30.0 R10. P500 F5.0 M31 ; Drilling hole 1
C90.0 M31 ; Drilling hole 2
C180.0 M31 ; Drilling hole 3
C270.0 M31 ; Drilling hole 4
G80 M05 ; Canceling the drilling cycle and stopping drill rotation
M50 ; Setting C-axis index mode off
M30; Program end
Note: M31is used for C axis Clamp in this example. Could be change due to machine builder.