English Author: Site Editor Publish Time: 2026-01-09 Origin: Site
The commonly used G-code instructions for CNC milling machines include
1. Positioning and movement command
G00 : Quick positioning (point control), used for rapid movement to a specified position.
G01 : Linear interpolation, moving along a linear path at the specified feed rate.
G02/G03 : circular interpolation, G02 is a clockwise circular arc (CW), and G03 is a counterclockwise circular arc (CCW).
2. Plane selection command
G17 : Select the XY plane (default).
G18 : Select the XZ plane.
G19 : select the YZ plane.
3. Coordinate system and unit instruction
G20 : inch input (imperial unit).
G21 : millimeter input (metric unit, default state).
G90 : absolute coordinate programming (default state).
G91 : incremental coordinate programming.
4. Fixed loop instruction
G81/G82/G83 : drilling cycle (G81 normal drilling, G82 with pause drilling, G83 deep hole drilling).
G84/G85/G86/G87/G88/G89 : boring cycle (G84 tapping, G85 conventional boring, G86 reverse boring, G87 back boring, G88 forward boring, G89 finish boring).
5. Auxiliary function instructions
G04 : Pause command (delay or pause).
G27/G28/G29 : reference point instruction (G27 checks the reference point, G28 returns the reference point, G29 returns from the reference point).
6. Special function instructions
G16 : polar coordinate interpolation.
G33/G34/G35 : Thread cutting (G33 equal pitch thread, G34 increased pitch thread, G35 decreased pitch thread).
Note : G code is divided into modal (such as G01, G17) and non-modal (such as G04, G27) instructions. Modal instructions remain valid after taking effect in the current program segment, while non-modal instructions are only valid in the current program segment. After the CNC milling machine is turned on, the default state is G17 (XY plane) and G21 (metric unit).
