CNC machining involves hundreds of commands, formulas, and machining parameters that programmers and machine operators must remember during daily production work. Instead of searching through manuals, machinists often rely on quick-reference cheat sheets containing the most important programming commands, machining formulas, and cutting data.
This CNC machining cheat sheet compiles essential programming commands, cutting formulas, chip load tables, and safety rules used by professional machinists. It is designed as a single reference page that can be bookmarked and used during real machining operations.
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SECTION 1 — MOST IMPORTANT G-CODES
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G-codes control machine movement and machining operations.
Common motion commands
G00 — Rapid positioning
G01 — Linear interpolation (cutting move)
G02 — Clockwise arc
G03 — Counterclockwise arc
Example
G00 X0 Y0
Rapidly moves the tool to the specified coordinates.
Linear cutting example
G01 X50 Y25 F200
Moves the tool in a straight cutting path using feedrate.
Drilling cycle commands
G81 — Standard drilling
G83 — Peck drilling
G84 — Tapping cycle
These commands automate repetitive drilling operations.
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SECTION 2 — MOST IMPORTANT M-CODES
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M-codes control machine functions such as spindle rotation, coolant flow, and program execution.
Common M-codes
M03 — Spindle clockwise rotation
M04 — Spindle counterclockwise rotation
M05 — Spindle stop
M06 — Tool change
M08 — Coolant ON
M09 — Coolant OFF
M30 — Program end and rewind
Example
S2500 M03
Starts the spindle at 2500 RPM in clockwise direction.
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SECTION 3 — FEEDS AND SPEEDS QUICK CHART
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Typical cutting speed ranges for carbide tools
Material Cutting Speed
Aluminum 200 – 600 m/min
Mild Steel 120 – 250 m/min
Stainless Steel 60 – 120 m/min
Titanium 40 – 90 m/min
Plastics 200 – 500 m/min
These values vary depending on tool coating, coolant usage, and machine power.
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SECTION 4 — CHIP LOAD REFERENCE TABLE
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Chip load determines how much material each cutting edge removes per revolution.
Typical chip load ranges for carbide end mills
Tool Diameter Chip Load
3 mm 0.02 – 0.03 mm
6 mm 0.03 – 0.05 mm
10 mm 0.05 – 0.08 mm
12 mm 0.06 – 0.10 mm
Maintaining correct chip load improves tool life and cutting efficiency.
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SECTION 5 — CNC MACHINING FORMULAS
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Feedrate Formula
Feedrate = RPM × Flutes × Chip Load
Example
RPM = 12000
Flutes = 4
Chip Load = 0.03 mm
Feedrate = 1440 mm/min
Spindle Speed Formula
RPM = (Cutting Speed × 1000) ÷ (π × Tool Diameter)
Surface Speed Formula
Surface Speed = (π × Tool Diameter × RPM) ÷ 1000
Material Removal Rate
MRR = Width of Cut × Depth of Cut × Feedrate
These formulas allow machinists to calculate proper machining parameters.
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SECTION 6 — SAFE START BLOCK TEMPLATE
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Every CNC program should start with a safe initialization block.
Example
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O1001
G90 G17 G40 G49 G80
G54
T1 M06
S3000 M03
G00 G43 Z100 H01
This structure resets modal states and prepares the machine safely.
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SECTION 7 — SAFE RAPID MOVE RULES
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Rapid moves must always occur at safe clearance height.
Safe movement structure
G00 Z100
G00 X50 Y50
Never move horizontally while the tool remains inside the workpiece.
Safe programming rule
Vertical retract first, horizontal move second.
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SECTION 8 — COMMON CNC PROGRAMMING MISTAKES
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Typical programming mistakes include
- missing feedrate commands
- incorrect tool offsets
- wrong work coordinate system
- unsafe rapid movements
Avoiding these mistakes significantly reduces crash risk.
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SECTION 9 — PRACTICAL CNC PROGRAM EXAMPLE
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Example milling program
%
O2001
G90 G17 G40 G49 G80
G54
T1 M06
S3000 M03
G00 G43 Z100 H01
G00 X0 Y0
G01 Z-5 F200
G01 X40
G01 Y40
G01 X0
G01 Y0
G00 Z100
M30
This simple example demonstrates safe program structure and toolpath control.
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FINAL PRINCIPLE
CNC machining efficiency depends on understanding programming commands, machining formulas, cutting data, and safety principles. By using quick reference guides and standardized programming practices, machinists can improve machining accuracy, reduce programming errors, and maintain reliable machine operation.
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