Work offsets are how your machine knows where the part is.
Understanding them means you can set up multiple fixtures, run repeat jobs, or recover mid-cycle without losing zero.
The Concept
Every CNC has a Machine Coordinate System (MCS) — the absolute home — and multiple Work Coordinate Systems (WCS) defined by offsets like G54, G55, etc.
Each offset is a shift from machine zero.
How It Works
When you probe or manually set your part zero, the machine stores that position as an offset.
For example:
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Machine X home = 0.000
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Your part zero = X = 24.560
That offset (24.560) becomes your G54 X-value.
Using Multiple Offsets
You can fixture four identical parts side-by-side:
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Left-front part = G54
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Right-front part = G55
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Left-rear = G56
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Right-rear = G57
Each setup references its own offset, allowing one program to run all four parts in sequence.
Programming in Fusion 360
Set different Setups and assign unique WCS IDs (G54–G59).
Post all setups in a single NC file, and the machine will automatically shift coordinates between parts.
Pro Tips
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Always re-home before setting offsets.
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Use fixture datums like dowel pins for repeatability.
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Store offset data sheets with job documentation for consistent re-runs.
Lesson
Accurate offset management saves hours. Once you master G54–G59, you can scale to G154 P01–P99 (100 extra offsets) for production work — all while keeping perfect alignment.
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