Overview
ISO 25178-600:2019 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 600 - defines the metrological characteristics for areal topography measuring methods. It specifies the terminology and measurement-related characteristics for instruments that produce areal surface topography maps (height fields). Because surface profiles can be extracted from areal maps, many terms and concepts are also applicable to profilometry. This part centralizes common metrological aspects across the ISO 25178 areal series.
Key Topics
This standard covers the essential metrological properties and definitions needed to evaluate, specify or compare areal topography measuring systems:
- Coordinate system & measurement loop: instrument coordinate axes (x, y, z), z-scan axis, and the closed measurement chain linking probe and workpiece.
- Measurement area & measuring volume: definitions of measured area and the instrument’s spatial ranges.
- Response function & amplification coefficients: relationship between true and measured quantities, slope (scaling) and linearity deviation.
- Linearity & flatness deviation: local and global departures from ideal responses and plane references.
- X–Y mapping deviation and sampling interval: spatial mapping errors, pixel/ sampling spacing and sampling zones.
- Noise & repeatability: instrument noise vs. measurement noise (environmental influences), surface topography repeatability as a performance metric.
- Digitisation (Dz) and Instrument Transfer Function (ITF): vertical resolution and frequency-dependent height response of instruments.
- Informative annexes: maximum measurable local slope (Annex A) and relation to the GPS matrix model (Annex B).
Applications
ISO 25178-600 is practical for anyone specifying, testing, calibrating or using areal surface measurement systems:
- Metrology labs & calibration services: define metrological characteristics and assess measurement uncertainty and repeatability.
- Instrument manufacturers: document performance (ITF, linearity, noise), validate designs and produce compliant datasheets.
- Quality engineers & R&D: select appropriate measurement methods for functional surface requirements in precision manufacturing.
- Sectors: aerospace, automotive, medical devices, optics, semiconductors and precision engineering where surface texture affects function, wear or optical performance.
- Standards developers & researchers: harmonize terminology and link areal methods to profilometry and GPS matrix requirements.
Related Standards
Keywords: ISO 25178-600, areal topography, surface texture, metrological characteristics, instrument transfer function, measurement noise, sampling interval, x-y mapping deviation, surface texture standard.
Open preview (PDF)Geometrical product specifications (GPS) — Surface texture: Areal — Part 600: Metrological characteristics for areal topography measuring methods