Overview
EN ISO 12180-2:2011 - "Geometrical product specifications (GPS) - Cylindricity - Part 2: Specification operators" defines the complete specification operator for cylindricity of complete integral features (features of type cylinder). Published by CEN and identical to ISO 12180-2:2011, this GPS standard specifies how to unambiguously describe the measurement and extraction operations used to assess cylindricity, including probing system characteristics and filtering considerations that affect the transmitted measurement band.
Key topics and technical requirements
- Scope: Applies only to complete integral cylindrical features (cylindricity specifications for whole cylinder features).
- Complete specification operator: A full ordered set of unambiguous specification operations (as per ISO 17450-2) that define the transmission band for the cylindricity surface and associated stylus geometry.
- Probing system:
- Contacting probing with a stylus tip is part of the operator.
- The theoretically exact stylus tip geometry is a sphere; the standard discusses probe-tip radius effects.
- Probing force is specified as 0 N to exclude elastic deformation from the operator.
- Filtering and extraction:
- Extraction always involves a filtering process; additional mean-line (Gaussian, spline, wavelet) or non-linear (morphological) filters may be applied.
- The standard notes the importance of explicitly stating filter parameters (e.g., undulations per revolution - UPR) because defaults were not agreed at publication - unspecified operators lead to ambiguous specifications.
- Annexes address harmonic content, sampling strategies, aliasing, and the Nyquist criterion for adequate digitization.
- Compliance and decision rules: Use ISO 14253-1 for proving conformance or non-conformance.
Practical applications and users
EN ISO 12180-2:2011 is used where robust, repeatable cylindricity assessment is required:
- Quality and metrology engineers defining inspection specifications for shafts, bores and other cylindrical parts.
- CMM and form-measuring instrument vendors implementing GPS operators in measurement software.
- Manufacturing engineers specifying acceptance criteria in drawings and contracts.
- Calibration labs and inspection houses that must interpret or prove conformance to cylindricity tolerances.
Practical benefits include removing ambiguity in measurement method, ensuring comparable results across suppliers, and guiding sampling/filtering strategies to avoid aliasing or misinterpretation of harmonic content.
Related standards
Using EN ISO 12180-2:2011 helps create clear, enforceable cylindricity specifications that align with the ISO GPS framework and reduce measurement ambiguity in production and inspection workflows.
