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(UBACKCUT OPERATION SEQUENCE) 
G21 (Set units to mm) 
G17 (Select XY plane) 
G90 (Absolute programming) 

(Define parameters) 
#SPINDLE_SPEED = 1000 (Spindle speed in RPM) 
#COOLANT_WAIT = 2 (Coolant wait time in seconds) 
#Z_SAFE = 1 (Safe height) 
#FL = 17 (Feed length) 
#SPOT_DEPTH = 10 (Spotface depth) 
#HOLE_DEPTH = 20 (Hole depth) 
#RAPID_FEED = 3000 (Rapid feed rate)
#MACHINE_FEED = 200 (Machine feed rate)
#ENGAGE_FEED = 80 (Feed rate for controlled moves)

(Start Spindle) 
M3 S#SPINDLE_SPEED 
G4 P#COOLANT_WAIT (Wait for spindle to stabilize)

(Step 1: Initial Position A - Tool above workpiece) 
G0 Z#Z_SAFE 

(Step 2: Position A - Coolant ON, insert retracts) 
M8 (Coolant ON) 
G4 P#COOLANT_WAIT 

(Step 3: Moving to Position B – With Rapid Feed) 
G0 Z[#HOLE_DEPTH + #FL] F#RAPID_FEED (Rapid move to pilot hole depth) 

(Step 4: Position B - Coolant OFF, insert retracts) 
M9 (Coolant OFF) 
G4 P#COOLANT_WAIT 

(Step 5: Moving to Position C - Below the workpiece) 
G1 Z[#HOLE_DEPTH + #Z_SAFE] F#ENGAGE_FEED (Controlled move to Position C)


(Step 6: Moving to Position D - Insert touches workpiece, Coolant ON) 
M8 
G1 Z[#HOLE_DEPTH] F#ENGAGE_FEED (Controlled approach to workpiece)

(Step 7: Position E - Machining spotface) 
G1 Z[#HOLE_DEPTH - #SPOT_DEPTH] F#MACHINE_FEED 

(Step 8: Moving back to Safe Position B - Coolant OFF) 
M9 
G0 Z[#HOLE_DEPTH + #FL] F#RAPID_FEED

(Step 9: Position B - Coolant ON, insert retracts) 
M8 
G4 P#COOLANT_WAIT 

(Step 10: Moving to Position A With Rapid Feed) 
G0 Z#Z_SAFE F#RAPID_FEED (Rapid retract to safe height) 

(End Spindle and program) 
M5 (Spindle OFF) 
M9 (Coolant OFF)
G4 P#COOLANT_WAIT 
M30 (End of program) 
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