ASME B89.4.10360.2-2008 — Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs) — Part 2, CMMs Used for Measuring Linear Dimensions

28 10 月, 2026
ASME Standards

📏 ASME B89.4.10360.2-2008, Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs) — Part 2: CMMs Used for Measuring Linear Dimensions, is a Technical Report issued by the ASME B89 Committee. Its main text reproduces verbatim the text of the ISO 10360-2 Final Draft International Standard (FDIS), and it is closely aligned with the International Standard ISO 10360-2 published in 2009. The report defines the methods, measuring equipment, test procedures, result processing, and conformance rules for acceptance tests and reverification tests of CMMs whose primary use is measuring linear dimensions. It is one of the most frequently referenced CMM performance documents in procurement acceptance, periodic calibration, and quality-system audits.

💡 Note how the report handles the ISO text: the ISO text is reprinted verbatim, while ASME-specific supplementary requirements are given in bordered text boxes. Wherever ASME normative text conflicts with the ISO text, the ASME requirements govern, and the conflicting ISO sentences are shown in strikeout font. Always read the bordered ASME boxes when using this document.

1. Nature and Scope of the Document 📌

This Technical Report, issued by the ASME B89 Standards Committee and effective July 11, 2008, follows an “overall length measurement performance” route — unlike the component-by-component philosophy of B89.4.1-1997. It directly assesses a CMM’s length measurement capability using calibrated length artifacts under the actual probing configuration, producing numeric metrics that buyer and seller can use for direct conformity decisions. This makes it much closer to the commercial acceptance scenario.

The report has nine chapters: Scope; Normative references; Terms and definitions; Symbols; Environmental and metrological requirements (environmental conditions, operating conditions, length measurement error E_L, repeatability range R₀, workpiece loading effects); Acceptance tests and reverification tests (principle, length measurement error with zero ram axis stylus tip offset E₀, R₀, length measurement error with a 150 mm ram axis stylus tip offset E₁₅₀, dual-ram machines in simplex and duplex modes); Compliance with specifications (acceptance criteria, data rejection and repeated measurements, thermal derating of specifications); Applications (acceptance, reverification, interim check); and Indication in product documentation and data sheets. Four annexes (A–D) cover interim checks, artifacts representing a calibrated test length, alignment of gauges, and mathematical adjustments.

⚠️ Part 2 applies only to CMMs used for measuring linear dimensions. Machines that also claim form measurement capability (ISO 10360-5 / ASME B89.4.10360.5) or scanning capability (ISO 10360-4) must be tested under those parts as well — linear-dimension results alone do not constitute a complete acceptance.

2. Terminology and Key Performance Metrics 🔧

Building on the ISO 10360-2 FDIS terminology, the report defines several core concepts with precision. Four metrics are essential to understanding the whole document:

Length measurement error E_L: the range of the CMM’s errors of indication for size measurement. The manufacturer states its permitted value as a maximum permissible error (MPE), usually a linear function of the measured length, e.g., MPE_E = A + L/K.
Repeatability range R₀: the range of repeated measurements of the same calibrated test length under identical conditions — the signature of the random error component.
Length measurement error with zero offset, E₀: the length measurement error when the ram axis stylus tip offset is zero (the stylus used in its standard orientation) — the most basic acceptance metric.
Length measurement error with a 150 mm offset, E₁₅₀: the length measurement error when the stylus tip is offset 150 mm in a specified direction, checking performance degradation in offset probing postures.

Metric	Meaning	Typical Test Points	Characterizes
E_L (length measurement error)	Range of indication errors for size measurement	MPE declared by manufacturer; measure multiple calibrated lengths in representative orientations	Combined systematic and random error
R₀ (repeatability range)	Range of repeated measurements of one length	Repeat a calibration length the prescribed number of times and take the range	Random error
E₀ (zero-offset length measurement error)	Length measurement error with standard stylus posture	Zero offset; measure calibrated lengths along the three axes and diagonals	Overall spatial indication consistency
E₁₅₀ (150 mm offset length measurement error)	Length measurement error with the stylus offset 150 mm	Offset the stylus as specified and repeat the representative measurements	Effect of probe posture on accuracy

💡 When a manufacturer states specifications, the test conditions must be given together: probe type, stylus configuration, temperature range, measured-length range, and placement orientations. An MPE number without conditions is meaningless — the same machine can differ by a factor of several between orientations and lengths.

3. Test Procedures for Acceptance and Reverification 📏

Chapter 6 gives the complete procedures for the E₀, R₀, and E₁₅₀ tests. The underlying logic is:

Measuring equipment: calibrated test-length artifacts. Annex B lists artifacts usable for bi-directional measurements — gauge blocks, step gauges measured bi-directionally, ball bars/ball plates measured bi-directionally, and laser interferometry with contact probing; uni-directional measurements must be supplemented with bi-directional measurements, and uni-directional artifacts require additional short-gauge-block measurements per Annex B.3.
Orientation layout: measure in several representative orientations where the calibrated length fits, typically the three axis directions and diagonal directions. Gauge alignment follows Annex C: parallel-face gauges and ball bar/ball plate gauges have different alignment requirements — the former need parallel measuring faces, the latter are aligned to the ball center line.
Number of measurements and data processing: repeat each orientation the prescribed number of times; derive the test results per Sections 6.3.4 and 6.5.3. If individual data points are anomalous, Section 7.1.2 permits rejection under documented rules with supplementary repeated measurements — but rejection must be recorded.
Dual-ram machines: Section 6.6 separately prescribes arrangements for simplex mode and duplex mode; the synchronization error of duplex operation cannot be replaced by single-ram data.

🚨 Common acceptance mistake: placing gauge blocks at the edge of the table, letting HVAC airflow blow directly over the blocks, or starting measurements before the machine has warmed up. These introduce thermal deformation of the blocks and machine thermal drift, so the E₀ data become both inflated and non-reproducible — a good machine is wrongly rejected, or real defects are masked.

4. Environmental and Metrological Requirements 🌡️

Chapter 5 states explicit environmental and metrological requirements:

Environmental conditions (5.1): temperature, temperature gradient and rate of change during the test, and permitted vibration and humidity ranges, normally set from the manufacturer’s declaration combined with site realities.
Operating conditions (5.2): the machine’s operating state during testing, including warm-up time, air supply pressure, and cleanliness.
Workpiece loading effects (5.5): consideration of workpiece weight on table deformation and indications, with supplementary loaded tests where necessary.
Thermal derating (7.1.3): if the actual ambient temperature differs from the specification reference temperature, the MPE specification may be corrected using the prescribed thermal derating method before the conformity decision.

⚠️ The environment is “part of the specification,” not “background noise.” The contract should state the test temperature range, permitted gradient and fluctuation, and the thermal-derating treatment outside that range. This avoids “invalid results due to environment” disputes at acceptance time.

5. Engineering Practice Essentials 🛠️

🔍 Acceptance test: performed at new-machine delivery to confirm that performance meets the contract and the manufacturer’s MPE declaration. Do it after installation, leveling, and stabilization, following the Chapter 6 procedures throughout.
🔧 Reverification test: performed periodically (typically yearly) to confirm the machine still meets its original specification. A simplified test set may be used, but the methods and artifacts must match the acceptance test, otherwise data are not comparable.
📊 Interim check (Annex A): a low-cost, high-frequency drift monitor between reverifications. Annex A.2 gives methods for interim testing with uni-directional artifacts and comparison with specifications.
📋 Product documentation and data sheets (Chapter 9): manufacturers should state the MPE values of E₀, E₁₅₀, and R₀, together with their test conditions, in the product documentation and data sheets — the most important source of information for procurement comparison.
🧭 Traceability: calibrated length artifacts should be traceable to national or international standards and recalibrated periodically; artifact uncertainty should be significantly smaller than the machine’s MPE.

✅ Treat the acceptance test as a three-party activity: supplier, user, and an independent metrology body each send representatives; agree on procedures and artifacts in advance; record environmental data on site; and sign the report jointly. Results obtained this way carry legal and quality-system weight and avoid later disputes.

6. Frequently Asked Questions ❓

❓ Q: How do E₀/E₁₅₀ relate to the B89.4.1 volumetric performance test?
A: They share the goal of assessing overall spatial indication consistency but differ in approach. B89.4.1 decomposes errors for diagnostics; the E₀/E₁₅₀ route gives directly decidable numbers. In practice, use this report for acceptance decisions and B89.4.1 for problem diagnosis.

❓ Q: Why test multiple orientations and multiple lengths?
A: Machine errors vary with position and direction; measuring a single length in one orientation exposes only the “best-case” performance. A combination of orientations and lengths approximates the worst case of real measurement duty, ensuring that the stated specification is conservative and reliable for the user.

❓ Q: Does the data-rejection rule (7.1.2) allow throwing out bad data freely?
A: No. Rejection must be based on predefined, documented criteria (e.g., gross-error tests); each rejection must be justified and supplemented by repeated measurements, and the final report should show results before and after rejection. If the rejection rate is high, the test conditions or the machine state are suspect — stabilize and retest.

❓ Q: Can an interim check replace a full reverification?
A: It supports, not replaces. The interim check (Annex A) monitors trends and detects degradation early, typically using one or a few calibrated lengths at fixed orientations for fast measurement. When interim results approach the specification limit or show a sudden change, schedule a full reverification to confirm the state.

ASME B89.4.10360.2-2008.pdf