AiVibeMachine Tool Positioning Accuracy and Repeatability
Positioning accuracy describes how closely a CNC axis reaches commanded positions, and repeatability how consistently it returns to them. ISO 230-2 defines how both are measured and evaluated.
ISO 230-2 specifies a test in which an axis is driven repeatedly to a series of target positions in both directions while a laser interferometer or similar instrument measures the actual position. From the deviations it derives parameters including bidirectional accuracy, unidirectional and bidirectional repeatability, the reversal value caused by effects such as backlash, and the systematic positional deviation.
These values are used in machine acceptance tests, periodic verification and diagnosis of problems such as worn ball screws or incorrect compensation. Laser measurements also provide the data for pitch error compensation tables that the control uses to correct systematic errors along each axis.
Positioning tests describe single axes under the stated conditions; overall part accuracy also depends on geometric errors such as squareness and straightness, covered by ISO 230-1, and on thermal effects, covered by ISO 230-3, as well as on cutting forces and tooling. Values measured under different standards or methods are not directly comparable, so the test standard and conditions should always accompany a quoted figure.
Key points
- Accuracy is closeness to target; repeatability is consistency of return
- ISO 230-2 defines the bidirectional test and its parameters
- Laser interferometer data feeds pitch error compensation
- Figures from different standards are not directly comparable
Where AiVibe comes in
AiVibe designs and manufactures the AiAmbA AI Factory: edge devices plus AI agents that let people talk to CNC, PLC and robot controllers in plain language. Agents only propose changes, and a trained operator confirms each one.