ISO 6481:2019

Overview

ISO 6481:2019 - Test conditions for vertical surface type broaching machines - Testing of accuracy - specifies geometric accuracy tests and tolerances for vertical surface type broaching machines (machines whose main cutting axis, Z, is vertical). It focuses strictly on verification of geometric accuracy (acceptance, comparison, maintenance) and does not cover operational checks (vibration, abnormal noise, stick‑slip) or machining parameters (speeds, feeds). The standard is written with reference to ISO 230‑1 and uses metric units throughout.

Key topics and requirements

• Scope and terminology
  • Defines common configurations, axis designation and related terminology for vertical broaching machines.
  • Clarifies that tests relate to geometric accuracy only.
• Geometric tests (examples given)
  • G1 - Flatness of the table: test methods include straightedge + gauge blocks or precision level/optical instruments. Example tolerance: 0.040 mm for measuring lengths up to 1 000 mm.
  • G2 - Flatness of the broach‑holder surface: two‑step measurements (horizontal and vertical); example local tolerance 0.025 mm for lengths up to 500 mm; total tolerance example 0.040 mm.
  • G3 - Parallelism of Z‑axis movement to broach‑holder surface: examples include local tolerance 0.025 mm over 1 000 mm and total tolerance 0.050 mm.
• Measurement practice
  • Primary units: millimetres (linear) and angular deviations expressed as ratios (with microradian/arcsecond clarifications where useful).
  • Minimum measurable tolerance guidance: 0.010 mm when adapting measuring length.
  • Permitted instruments: dial gauges (DTI, LVDT, digital indicators), straightedges (granite, ceramic, steel), precision levels, optical instruments - provided their measurement uncertainty meets or is better than required (per ISO 230‑1).
• Testing process
  • Test order is flexible to ease fixturing; levelling per manufacturer’s recommendations (refer to ISO 230‑1).
  • For acceptance, the exact tests and agreed tolerances must be specified in purchase/acceptance agreements.
• Machining tests
  • Clause 7 provides guidance that machining/production tests are to be agreed between user and supplier (not prescribed in detail).

Practical applications and users

• Who uses ISO 6481:2019:
  • Machine tool manufacturers and OEMs for factory acceptance testing.
  • End‑users and purchasers for acceptance criteria and quality contracts.
  • Metrology and inspection teams, test laboratories, and maintenance engineers for periodic verification and troubleshooting.
• Practical value:
  • Standardizes geometric acceptance criteria and test methods for vertical broaching machines, enabling consistent verification, reduced disputes during acceptance, and improved traceability of accuracy checks.

Related standards

• ISO 230‑1:2012 - Test code for machine tools - Part 1: geometric accuracy (normative reference used throughout ISO 6481:2019).
• Prepared by ISO/TC 39, Machine Tools, SC 2 (Test conditions for metal cutting machine tools).

Keywords: ISO 6481:2019, vertical surface type broaching machines, testing of accuracy, geometric tests, broach holder, Z‑axis, flatness, parallelism, ISO 230‑1, machine tool acceptance.