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Accuracy Standards

ISO 230-1 and 2 Guide

Use ISO 230-1 and ISO 230-2 as a procurement filter for geometric accuracy, positioning accuracy, and repeatability claims.

Reviewed: 2026-03-08Source: Reviewed against ISO 230, GB/T 17421, OEM documentation, and shop-floor calculator assumptions.

Direct answer: ISO 230-1 covers geometric accuracy; ISO 230-2 covers positioning accuracy and repeatability.

Use this guide to separate ISO 230-1 and ISO 230-2 methods and decide whether the evidence gap is geometric accuracy or axis positioning repeatability. Use the ISO overview for acceptance evidence and the ISO 230-2 guide when the report already contains axis positioning data.

ISO Acceptance Decision Path

Follow this path from ISO overview to geometric-test method, axis reports, series selection, and GB/T 17421 mapping.

1. Acceptance evidenceDefine the proof set for buying, relocating, or accepting a CNC machine.Use first when the question is what evidence is required before sign-off.2. ISO 230-1 vs 230-2Separate geometric checks from axis positioning and repeatability reports.Use when the user needs to choose between geometric method and positioning method.3. Axis report interpretationRead positioning accuracy, repeatability, reversal behavior, and report limits.Use when a laser/interferometer report already exists and needs interpretation.4. ISO 230 selectorChoose the correct ISO 230 family before reading a detailed guide.Use when the series map matters more than a single test explanation.5. GB/T mappingMap GB/T 17421 reports to ISO 230 acceptance workflows for imported machines.Use when Chinese supplier documents must be compared with ISO-based contract language.

How to Use These Standards

  • Use ISO 230-1 when you need geometric checks such as straightness, squareness, and axis relationship.
  • Use ISO 230-2 when you need axis positioning accuracy and repeatability data.
  • Require the test report, not only a brochure number, when tolerances affect the buying decision.

Method Split Before Acceptance

Acceptance questionUse ISO 230-1 when...Use ISO 230-2 when...
What is out of tolerance?Straightness, squareness, parallelism, spindle alignment, or axis relationship.Commanded-vs-measured axis position, repeatability, or reversal behavior.
What evidence should be requested?Geometric inspection record with setup, instrument, reference surface, and measured deviations.Laser/interferometer report with target positions, approach directions, environment, and uncertainty statement.
What limit decides pass/fail?The signed acceptance sheet, builder declaration, or customer quality plan.The same contract source, not a generic ISO number copied from another machine.

Equipment Selection Handoff

Use the equipment selection calculator to connect ISO accuracy requirements with work envelope, process fit, budget, and support constraints.

Use the ISO 230 reference table when you need a compact comparison of accuracy terms and test-report fields.