SIST EN ISO 25178-605:2025 PDF

Overview

EN ISO 25178-605:2025 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 605 - specifies the design and metrological characteristics of non-contact point autofocus probe (PAP) instruments for areal surface topography measurement. Published February 2025 and endorsed by CEN, this second edition replaces the 2014 version and aligns PAP instrument requirements with the ISO GPS framework. Because areal data can produce profiles, the document’s methods are also applicable to profiling measurements.

Key topics and requirements

• Instrument scope and definitions: Precise terms such as point autofocus probe (PAP), probing system, working distance, spot size, focus range, vertical range, and autofocus repeatability are defined to standardize language for PAP instruments.
• Instrument requirements (Clause 4): Summarizes normative features and the information flow needed for PAP areal measurement systems.
• Metrological characteristics (Clause 5): Describes the metrological parameters relevant to PAP measurements (repeatability, measurable reflection ratio, speckle noise, temperature drift, etc.).
• Design features (Clause 6): Clarifies instrument types and essential design elements such as autofocus mechanism, objective, autofocus sensor, and z-position sensor.
• Informative annexes:
  • Annex A: Principles of PAP instruments for areal surface topography.
  • Annex B: Sources of measurement error and influence quantities.
  • Annex C: Relationship to the ISO GPS matrix model.
• Normative links: References ISO 25178-600:2019 for metrological characteristics and aligns with ISO GPS principles (ISO 14638, ISO 8015, ISO 14253-1).

Practical applications and users

EN ISO 25178-605:2025 is intended for professionals and organizations involved in surface texture measurement and instrument development, including:

• Metrology laboratories and calibration facilities
• Surface metrology instrument manufacturers (PAP system designers)
• Quality control and inspection teams in precision manufacturing
• R&D teams in optics, tooling, automotive, aerospace and other industries where surface topography affects function
• Standards bodies and conformity assessors implementing GPS-compliant measurement workflows

Practical benefits include standardized terminology, guidance on key metrological parameters, and clear expectations for PAP instrument performance - aiding consistent areal and profile measurement results across laboratories and suppliers.

Related standards

• ISO 25178-600:2019 - Metrological characteristics for areal topography measuring methods (normative reference).
• ISO 14638, ISO 8015 and ISO 14253-1 - GPS framework and decision rules referenced for consistency with the ISO GPS matrix model.

Keywords: EN ISO 25178-605:2025, point autofocus probe, PAP instruments, areal surface topography, surface texture, GPS, metrological characteristics, non-contact measurement.