G-codes tell a CNC control how to interpret motion, planes, offsets and canned cycles. The same code can behave differently between controls, so this lookup is deliberately limited to selected Haas mill codes and the descriptions shown in Haas’s online reference. It is a quick index, not a replacement for the machine’s operator manual or a safe way to test unfamiliar code.

CNC milling G-code reference

Read the modal group

The group number in the table is the Haas reference’s modal-group identifier. Codes in one group generally select competing modes, so a later code from the same group changes the active selection. The table includes examples such as G00 and G01 in motion group 01, G17/G18/G19 in plane-selection group 02, and G20/G21 in unit-selection group 06.

That grouping is useful when reviewing a program block, but the group number does not explain every parameter, default, or exception. Open the linked Haas manual entry for the exact code and confirm how the control handles its address words and machine options.

Motion, planes and units

G00 selects rapid positioning and G01 selects linear interpolation. G02 and G03 select clockwise and counterclockwise circular interpolation in the active plane. G17, G18 and G19 select the XY, XZ and YZ planes on the Haas mill. G20 and G21 select inch and metric programming modes. Check the program’s unit mode before interpreting coordinate or feed values; a wrong assumption can make an otherwise valid-looking program unsafe.

G90 and G91 select absolute and incremental positioning. In absolute mode, an axis target is referenced to the active coordinate system. Incremental mode describes a move from the current position. A program may switch between them, so do not infer the active mode from a single line or from a CAM post setting.

Offsets and canned cycles

G54 through G59 select work coordinate systems in the Haas list. G43 applies positive tool-length compensation, while G49 cancels the listed tool-length compensation modes. G80 cancels canned cycles. G81 is a drilling cycle and G83 is a peck-drilling cycle in the Haas mill reference. The actual retract plane, depth, feed and return behavior depend on the full block, modal state and control implementation.

For example, when a program uses G83, inspect the cycle parameters and preceding setup blocks as well as the code name. The reference tells you that G83 is the normal peck-drilling canned cycle on this Haas mill list; it does not tell you whether the selected depth, peck, feed, tool, coolant or workholding is appropriate.

Controller and version limits

This article does not combine Haas, FANUC, Siemens, LinuxCNC or other control descriptions. Even familiar codes can have different options, syntax, defaults and alarm behavior. The reference list can also change as a control gains software features. Match the machine model and software version before applying a code to a real program.

Use graphics mode or the control’s approved simulation workflow to review unfamiliar programs. Verify tool offsets, work offsets, clearances, fixture locations, spindle and feed limits, and the machine’s safety procedures. Never use this lookup as a substitute for proving out a program safely.

Modal state can persist beyond the block where it was first selected. Review the program from its beginning and include subprogram calls, resets and tool changes in the review. A code description helps you identify a command, but the complete sequence and machine setup determine the resulting motion.

A related workflow

If your task is exporting a CAD model for machining, see the site’s SolidWorks to G-code guide. That article covers a file and CAM workflow; this table serves as a controller-specific code index.

Source

Descriptions and modal groups are selected from Haas Automation’s Mill G-Codes reference. Consult the control-specific manual for the complete behavior and current revision.