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Essential G Codes in CNC Programming

While all G codes have specific uses and functions, a few are used more frequently due to their importance in machining processes. Here are some of the most commonly used G codes:

G00 – Rapid Positioning

G00 quickly moves the machine to a specified location using the shortest possible path. All axes move simultaneously to reach the target coordinates in a straight line, but this movement is not done at a cutting feed rate—it's designed for speed rather than precision cutting.

G01 – Linear Interpolation

G01 directs the machine to move in a straight line at a controlled feed rate, which is set using the F function. Before using G01, define the target X, Y, and Z coordinates to guide the linear motion. The machine then calculates and follows this straight path at the specified feed speed.

G02 – Clockwise Circular Interpolation

G02 commands the machine to move in a clockwise arc. To use it, specify the arc’s center (usually via I and J values) and the endpoint of the arc. The starting point is automatically taken as the end of the previous motion command, ensuring a continuous path.

CNC G Codes list

G01 Linear interpolation using a feed rate

G02 Circular interpolation clockwise

G03 Circular interpolation, counterclockwise

G04 Dwell

G10 Set working datum position

G17 Select X-Y plane

G18 Select Z-X plane

G19 Select Z-Y plane

G20 Imperial units

G21 Metric units

G27 Reference return check

G28 Automatic return through reference point

G29 Move to a location through reference point

G31 Skip function

G32 Thread cutting operation on a Lathe

G33 Thread cutting operation on a Mill

G40 Cancel cutter compensation

G41 Cutter compensation left

G42 Cutter compensation right

G43 Tool length compensation

G44 Tool length compensation

G50 Set coordinate system (Mill) and maximum RPM (Lathe)

G52 Local coordinate system setting

G53 Machine coordinate system setting

G54~G59 Set Datum

G70 Finish cycle (Lathe)

G71 Rough turning cycle (Lathe)

G72 Rough facing cycle (Lathe)

G73 Pattern Repeating Cycle

G74 Left hand tapping Mill

G74 Face grooving cycle

G75 OD groove pecking cycle (Lathe)

G76 Boring cycle

G76 Screw cutting cycle (Lathe)

G80 Cancel cycles

G81 Drill cycle

G82 Drill cycle with dwell

G83 Peck drilling cycle

G84 Tapping cycle

G85 Bore in, bore out

G86 Bore in, rapid out

G87 Back boring cycle

G90 Absolute programming

G91 Incremental programming

G92 Reposition origin point

G92 Screw thread cutting cycle (Lathe)

G94 Per minute feed

G95 Per revolution feed

G96 Constant surface speed (Lathe)

G97 Constant surface speed cancel

G98 Feed per minute (Lathe)

G99 Feed per revolution (Lathe)Enter topic text here.