G68.2 is associated with tilted-working-plane functions on certain FANUC-style implementations. Its availability, parameters and required surrounding commands are controller- and machine-specific.
The problem a tilted plane solves
An angled face has its own useful coordinate system. A tilted-work-plane function lets the program describe features relative to that plane rather than manually converting every point to the original work axes. The control and machine kinematics must agree about the plane’s origin and orientation.
Conceptually, a point in the local plane is transformed by rotation and translation into the work coordinate system. Rotation order matters: rotating about X and then Y generally produces a different orientation from rotating about Y and then X. Angle values cannot be interpreted without the controller’s convention.
| Function | Question it answers |
|---|---|
| Tilted working plane | In what oriented local frame are these coordinates expressed? |
| TCP control | How do machine axes preserve the intended tool-point motion? |
| G93 inverse time | How is the commanded block duration represented? |
| Work offset | Where is the part reference located? |
Details to verify in the exact manual
Confirm the control series, software options, machine-builder implementation, supported plane-definition method, angle order, work-offset behavior and cancellation sequence. Check how tool-length compensation, cutter compensation and canned cycles interact with the function. Verify whether an additional orientation operation is needed.
Do not paste a G68.2 example from a different machine into production. Other controllers may use different commands for related functions; for example, Haas documents G268/G269 for specified feature-coordinate-system applications. Similar concepts do not make those commands interchangeable.
A safe validation deliverable
Before running, require a proven postprocessor for the exact machine configuration, a checked tool/holder model, fixture clearances, calibrated kinematics and the machine’s normal program-proving process. Inspect the intended plane origin and axis directions in simulation.
This page intentionally omits runnable code and universal parameter addresses because the exact control implementation has not been specified. Its purpose is to help a programmer ask the right questions and separate plane orientation from feed mode and TCP compensation—not to replace the machine manual.
A 30-degree coordinate example without runnable G-code
Take a deliberately defined right-handed mathematical rotation about the global Y axis: x = u cos θ + w sin θ, y = v, and z = −u sin θ + w cos θ. Here (u,v,w) are local coordinates and θ = 30°. This convention is an explanatory model, not a declaration of how a particular control interprets its angle words.
A local point (10,0,0) maps to approximately (8.660,0,−5.000) mm. If the local origin is then located at global (100,20,30), the same point becomes (108.660,20,25.000) mm. Rotation establishes orientation; translation locates the feature. Reversing that order generally changes the answer.
What must be resolved before converting this to a program?
Record the exact controller series, machine kinematics, installed option, plane-definition method, rotation order and cancellation behavior. FANUC’s function catalog describes several tilted-plane definition methods. A postprocessor must implement the method supported by the actual machine; one mathematical example cannot supply its syntax or safe motion sequence. Check coordinate orientation at safe clearance in the approved proving workflow, and verify tool-length/TCP behavior separately.
Content updated October 8, 2026. Sources and numerical examples are explained above; examples are not production test results. Editorial method · Report a correction.
References and verification
Original explanations and worked examples by MfgWorkbench. Sources below support the stated concepts or selected reference data; they do not certify every example or a production application.
- FANUC — CNC function catalog, tilted working plane and G68.2
- FANUC America — advanced five-axis machining concepts
- Haas — G268/G269 feature coordinate system, a different implementation
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