How to adjust the CNC coordinate offset?

1. Preparations and Safety Specifications

  1. Equipment Status Check
    • Execute G28 to return to the reference point and ensure the machine coordinate system is reset
    • Inspect the firmness of workpiece clamping to prevent displacement during machining
    • Clear the tool compensation memory (if unnecessary)
  1. Tool Preparation
    • Edge finder/dial indicator (for workpiece origin positioning)
    • Test cutting tool (matched to the machining material)
    • Caliper/micrometer (for dimension measurement)

2. Core Offset Adjustment Methods

(1) Workpiece Coordinate System Offset (G54-G59/G54.1)

1. Test Cutting Method (Without Edge Finder)
Test Cutting Method (Without Edge Finder)
2. Edge Finder Method (High-Precision Positioning)
  1. After clamping the edge finder, set the spindle speed to 800-1000 rpm
  1. Touch the side of the workpiece in the X-direction, record the machine coordinate X1; touch the opposite side in the reverse direction, record X2
  1. Calculate the origin: X0=(X1+X2)/2, and input the value into G54-X
  1. Repeat the above operations for the Y/Z directions
3. G10 Command Programming Setting (Batch Machining)
N10 G10 P1 X250.0 Y300.0 Z0 ; P1=G54, set origin coordinates
N20 G10 P2 X450.0 Y300.0 Z0 ; P2=G55, multi-station switching
N30 G54 M98 P1000 ; Call subprogram for machining

(2) Tool Compensation Offset

1. Length Compensation (G43/G44)
  • In-Machine Tool Setting:
Touch the tool to the upper surface of the workpiece, press “TOOL OFFSET” → “Shape”, and input Z0
  • Off-Machine Measurement:
Measure the tool length L with a tool setter, and input it into the corresponding number (H1-H99)
2. Radius Compensation (G41/G42)
  1. Test cut an φ50 (50mm diameter) outer circle, with the actual measured diameter being φ49.8
  1. Enter the “Radius Compensation” interface and input +0.1 (to compensate for wear) into the corresponding number
  1. Use G41 for climb milling and G42 for conventional milling, following immediately after G01/G00

(3) Temporary Coordinate System Offset (G52)

  • Application Scenario: Machining repeated features on the same workpiece
N10 G54 G00 X0 Y0 Z50
N20 G52 X50 Y30 ; Temporarily offset origin to (50,30)
N30 M98 P2000 ; Machine the first feature
N40 G52 X150 Y30 ; Offset to the next feature position
N50 M98 P2000
N60 G52 X0 Y0 ; Cancel offset (or use G53)

3. Operation Differences Between Different Systems

System
Workpiece Offset Entry
Tool Compensation Path
FANUC 0i
Press “OFFSET SETTING”
“Shape” page in the same interface
SIEMENS 802D
“Parameters” → “Workpiece Offset”
“Tools” → “Compensation Parameters”
KND 1000T
Directly input No. 100 offset memory
Tool Compensation Page

4. Verification and Troubleshooting

  1. Verification Process
    • Dry Run: Disable Z-axis feed (G00 Z50) and execute the program to observe the trajectory
    • Test Cut Part: Perform a 10mm shallow cut; the machining dimension deviation ≤ 0.02mm is considered qualified
  1. Common Error Handling
    • Reversed positive/negative offset value: Verify the measurement direction (e.g., the X-direction away from the origin is positive)
    • Incorrect coordinate system call: Check if the G54/G55 command in the first line of the program matches
    • Unit confusion: Confirm the system uses the mm system (not inch)

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