ISO 25178-6:2010

Overview

ISO 25178-6:2010 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 6 establishes a classification system for methods used primarily to measure surface texture. Rather than prescribing measurement procedures or numerical tolerances, this part of ISO 25178 defines how measurement methods are grouped, describes relationships among method classes, and provides concise descriptions of specific techniques. The standard supports consistent terminology and helps users select appropriate measurement approaches for areal surface texture evaluation.

Key Topics

• Three method classes: The standard defines and differentiates the three principal classes of surface texture measurement methods:
  • Line-profiling methods (produce z(x) profiles)
  • Areal-topography methods (produce z(x,y) surface maps)
  • Area-integrating methods (produce numerical results based on integrated area properties)
• Definitions and terms: Clear terms for measurement coordinate systems, surface profile/ordinate, and method-specific terminology (e.g., contact stylus scanning, phase-shifting interferometric microscopy, coherence scanning interferometry, confocal microscopy, AFM, SEM stereoscopy).
• Illustrated relationships: Diagrams and narrative showing how methods relate and overlap (for example, some areal methods can also produce line profiles).
• Brief method descriptions: Concise descriptions of common techniques such as contact stylus scanning, phase‑shifting interferometry (PSI), coherence scanning interferometry (CSI), confocal chromatic microscopy, structured light/triangulation, digital holography, scanning probe methods (AFM/STM), and optical scatter techniques.
• Supporting material: Informative annexes on metrological limitations (Annex A) and the relation to the GPS matrix model (Annex B), plus normative references (e.g., ISO 4287, ISO 25178‑2, VIM).

Applications

• Selecting measurement technology: Helps engineers and metrologists decide whether to use profile, areal, or area-integrating approaches based on application needs.
• Standards alignment: Guides instrument manufacturers and calibration labs in determining which other ISO 25178 parts or instrument-specific standards apply.
• Quality control and R&D: Useful for quality engineers, surface metrology laboratories, and researchers who need to understand capabilities and limitations of different measurement classes.
• Procurement and specification: Assists procurement specialists and product designers in writing clear specifications for surface texture measurement methods.

Related Standards

• ISO 25178 series (notably ISO 25178‑2 for terms/parameters and instrument-specific parts such as ISO 25178‑601/602/603)
• ISO 4287 (profile method terminology)
• ISO/IEC Guide 99 (VIM - metrology vocabulary)

Keywords: ISO 25178-6, surface texture, areal measurement, classification, line-profiling, areal-topography, area-integrating, surface metrology, interferometry, confocal microscopy, AFM, coherence scanning interferometry.