ISO 230-2:2014

Overview - ISO 230-2:2014 (Test code for machine tools, Part 2)

ISO 230-2:2014 specifies standardized methods for testing the accuracy and repeatability of positioning of numerically controlled (NC) machine tool axes by direct measurement of individual axes. The methods apply equally to linear and rotary axes and are intended for type testing, acceptance tests, comparison testing, periodic verification, machine compensation and similar uses. Tests are based on repeated approaches to selected target positions and include defined parameters and uncertainty estimation practices.

Key technical topics and requirements

• Scope and test conditions: environmental requirements, machine warm-up and preparation, and responsibilities of manufacturer/supplier and user for thermal conditions.
• Test programme: mode of operation, selection of target positions and measurement travel; repeated measurements at each target (unidirectional and bi-directional approaches).
• Measured parameters: positioning deviation (actual minus target), mean unidirectional/bi‑directional deviations, reversal errors, repeatability estimators and axis-level metrics.
• Evaluation rules: procedures for axes up to 2 000 mm (and rotary axes up to 360°) and guidance for longer travels (segments for axes > 4 000 mm).
• Measurement uncertainty: estimation methods referenced to ISO/TR 230-9:2005 and provided in Annex A (simplified uncertainty estimation).
• Optional and informative annexes:
  • Annex B: optional step cycle (not for formal acceptance unless agreed).
  • Annex C: evaluation of periodic positioning error.
  • Annex D: positioning tests using calibrated ball arrays or step gauges.
• Presentation and reporting: standardized parameters, nomenclature (including additions in the 2014 edition), and items to be agreed between supplier and user.

Practical applications

• Acceptance and type testing: verify that NC axes meet contractual positioning accuracy and repeatability requirements.
• Commissioning and periodic verification: baseline and track machine performance over time for preventive maintenance.
• Machine compensation and calibration: provide measurement data for geometric and control compensation routines.
• Comparative testing and procurement: objectively compare machines or validate vendor claims.
• Metrology and quality assurance: produce traceable test reports including uncertainty estimates for QA, audits or dispute resolution.

Who should use ISO 230-2:2014

• Machine tool manufacturers and suppliers
• Production engineers and maintenance/service teams
• Metrology laboratories and calibration service providers
• Quality managers, OEM purchasers and acceptance inspectors
• Research and development teams working on NC control and compensation

Related standards and references

• ISO 230-1 (geometric accuracy), ISO 230-3 (thermal effects), ISO/TR 230-9 (measurement uncertainty).
  Using ISO 230-2:2014 ensures repeatable, traceable assessments of NC axis performance - key for reliable machining accuracy, process control and supplier-user agreements.