G-code, short for “Geometric Code” or “G-programming,” is a standardized programming language used in computer-aided manufacturing (CAM) and computer numerical control (CNC) machining. It consists of a set of instructions that control the movements and operations of CNC machines, such as milling machines, lathes, routers, and 3D printers. These instructions are typically alphanumeric codes that convey specific commands to the CNC machine, guiding it through the manufacturing process.
Each G-code command represents a particular operation, movement, or function. G-codes are essential for translating design specifications from Computer-Aided Design (CAD) or Computer-Aided Engineering (CAE) software into tangible, machined products. Here are some common aspects of G-code:
- Motion Commands (G0, G1, G2, G3):
- G0 (Rapid Move): Moves the tool or machine rapidly to a specified position without cutting.
- G1 (Linear Move): Moves the tool or machine in a straight line to a specified position, typically used for cutting.
- Coordinate System (G90, G91):
- G90 (Absolute Programming): Specifies that the coordinates in subsequent motions are absolute, referenced from the machine’s origin.
- G91 (Incremental Programming): Specifies that the coordinates in subsequent motions are incremental, referenced from the current position.
- Tool Changes (M6):
- M6 (Tool Change): Initiates a tool change, where the machine stops to allow for the replacement of cutting tools.
- Spindle Control (M3, M4, M5):
- M3 (Spindle On – Clockwise): Activates the spindle in a clockwise direction.
- M4 (Spindle On – Counterclockwise): Activates the spindle in a counterclockwise direction.
- M5 (Spindle Off): Deactivates the spindle.
- Feed Rate (F):
- The F parameter specifies the feed rate, determining the speed at which the cutting tool moves.
- Dwell (G4):
- G4 (Dwell): Pauses the machine for a specified duration, allowing for a delay in the machining process.
- Program Control (M0, M2, M30):
- M0 (Program Stop): Pauses the program for operator intervention.
- M2 (Program End): Indicates the end of the program.
- M30 (Program End and Rewind): Marks the end of the program and may include additional functions like program rewind.
G-code provides a standardized means for communication between CAD software and CNC machines, enabling precise control over tool movements, spindle speeds, and other parameters.