G81 - Drill Cycle: Drill

Drill cycle.

The G81 drill cycle initiates drilling operation at defined XY position at defined height and for defined depth. G81 cycle can be repeated at any given XY position until cycle is cancelled with G80 or with any other motion command(G01/G00).

Single drill operation can be divided into following phases:

Phase 1: XY position
The drilling XY position is determined by the active distance mode and optional XY parameters.

When the cycle code does not include optional XY parameters, the drilling process will occur at the current machine position. This applies regardless of whether the active distance mode is G90 or G91.

If G90 is active and the cycle code includes XY parameters, the drilling process will take place at the position specified by the XY parameters.

If G91 is active and the cycle code includes XY parameters, the drilling process will take place at the position defined by the XY parameters, taking into account the G91 distance mode.

Phase 2: R level
R level is Z height where drilling starts. R level is set with parameter R. Machine Z axis travels to R plane with traverse speed.

Phase 3: Spindle (ON)
Spindle behavior can be determined by current spindle mode and/or with optional parameter S.

If spindle is already ON and cycle code does not use parameter S, spindle speed remains as set with preexisting S value.

If spindle is already ON and cycle code uses parameter S, new spindle speed is set with parameter S value.

If spindle is OFF and cycle code uses parameter S, spindle is turned ON and spindle speed is set with S value.

Phase 4: Plunge to bottom Z
From R plane machine descends to bottom Z level, defined with parameter Z.

If cycle uses F parameter, machine travels to bottom Z level at set F speed.

If cycle does not use F parameter value, machine travels to bottom Z level at F speed set prior of cycle execution.

Phase 5: Bottom Z and retract
Once machine reaches bottom Z level position, it retracts at traverse speed to pre-defined retract height. If cycle code used F parameter, then F value set prior of cycle operation is restored.

Retract height is defined with G98/G99, which can be either R plane or init height value.

If G98 is active, retract height is init height.

If G99 is active, retract height is R plane.

Phase 6: Spindle (OFF)
If S parameter is used, spindle is turned off at retract height.

If S parameter is not used, spindle state remains unchanged.

G81 <X> <Y> R Z <F> <S>

G00 X0 Y0 Z10
G98 G81 X0 Y0 R5 Z-15 F2100 S750
X10
X20
X30
G80

G00 X0 Y0 Z10
G99 G81 X0 Y0 R5 Z-15 F2100 S750
X10
X20
X30
G80

G82, G73, G83