G54

G54 is a G-code designation used in CNC machining to select a work coordinate system. In most controls, G54 designates the first of several user-defined work offsets, typically labeled G54 through G59. When G54 is active, the controller interprets subsequent position commands in terms of the chosen work coordinate system rather than the machine’s fixed origin.

G54 defines the translation between the machine coordinate system and the work coordinate system used for a specific program or setup. The offset values are stored in the controller and can be set in different ways depending on the control system. Common methods include using a dedicated offset screen or issuing a command such as G10 L20 P1 to define X, Y, and Z offsets. A typical purpose is to place the workpiece zero at a reliable feature on the part, enabling repeatable operations without re-establishing the origin each time.

Activation and switching between work offsets are done by selecting the desired offset, for example by issuing G54 to use the first offset, or G55, G56, etc., to switch to others. The active work offset remains in effect until another work offset (G55–G59) is selected or the machine is returned to machine coordinates with G53. Some controls also allow cancellation of work offsets with specific commands or through a reset procedure.

Practical considerations include ensuring that offsets use the same unit system as the program (millimeters or inches) and that the correct work offset is active for the operation. The number of available work offsets and the exact method to set them can vary by controller and machine.