ISO 230-7:2015

Overview

ISO 230-7:2015 - Test code for machine tools - Part 7: Geometric accuracy of axes of rotation specifies standardized methods to measure, specify and test the geometric accuracy of axes of rotation in machine tools. Published as the second edition in 2015, it covers spindle units, rotary heads, and rotary/swivelling tables and focuses on unintended motions (error motion) and speed‑induced axis shifts that affect machining accuracy.

Key Topics

• Scope and focus
  • Axis of rotation error motion and speed‑induced axis shifts.
  • Excludes thermal effects (handled in ISO 230‑3), angular positioning (ISO 230‑1/‑2), run‑out, balancing, noise, rotational speed accuracy, and other non‑geometric properties.
• Terminology and definitions
  • Comprehensive terms for error motion types, directional decomposition, polar plots, and compliance properties (see Annexes and Annex G).
• Test methods and procedures
  • Test setups and procedures for rotating sensitive directions and fixed sensitive directions.
  • Measurement of radial, axial and tilt error motions for spindles, rotary tables and heads.
  • Data analysis methods and guidance for eliminating artefacts (e.g., reference sphere roundness - Annex B).
• Measurement practice
  • Recommended instrumentation, environmental considerations, warm‑up procedures, and measurement units.
  • Guidance on structural error motion tests and estimation of measurement uncertainty (Annex F).
• Supporting information
  • Informative annexes on general concepts, static tests, sensor bandwidth vs rotational speed, and bibliography.

Applications

ISO 230-7:2015 is practical for organizations and professionals who need reliable, repeatable assessment of rotary axis geometry:

• Machine tool manufacturers - design verification, factory acceptance testing, and quality control.
• Metrology and test laboratories - standardized test procedures and uncertainty estimation.
• OEMs / integrators - acceptance testing during installation and commissioning of CNC machines with rotary axes.
• Quality, maintenance and process engineers - root‑cause analysis for machining errors caused by axis eccentricity, tilt or speed‑dependent shifts.
• R&D and academics - comparative studies, performance improvement and benchmarking of rotary components.

Use cases include acceptance tests, periodic performance checks, troubleshooting part‑location errors in 2D/3D sensitive directions, procurement specifications, and warranty validation.

Related Standards

• ISO 230 series (test code for machine tools): Part 1, Part 2, Part 3, Part 4, Part 5, Part 8, etc.
• Complementary standards referenced for specific measurements: ISO 1940‑1 (balancing), ISO 230‑3 (thermal effects), ISO 230‑1/‑2 (positioning/geometry), ISO 10791‑6 and ISO 13041‑6 (rotational speed specifications).

Keywords: ISO 230-7:2015, machine tools, axes of rotation, geometric accuracy, spindle error motion, rotary tables, speed-induced axis shifts, test code, metrology.