Overview
EN ISO 25178-604:2025 - "Geometrical product specifications (GPS) - Surface texture: Areal - Part 604" specifies the design and metrological characteristics of coherence scanning interferometry (CSI) instruments for areal surface topography measurement. Adopted by CEN in 2025, this updated part of the ISO 25178 series replaces the 2013 edition and aligns CSI instrument requirements with GPS principles. Because areal data can be reduced to profiles, the standard is also applicable to profiling measurements.
Key topics and requirements
- Instrument requirements (Clause 4): Summarizes normative features and the information flow needed for reliable areal topography acquisition.
- Metrological characteristics (Clause 5): Defines the measurement performance parameters that CSI systems should meet (referenced to ISO 25178-600 for metrological definitions).
- Design features (Clause 6): Clarifies instrument types, scanning mechanisms and typical optical arrangements used in CSI and white‑light interferometry.
- Principles and error sources (Annex A & B): Annex A outlines CSI principles (fringe localization, interference phase evaluation, scan mechanics); Annex B describes common influence quantities and measurement uncertainty contributors.
- GPS alignment (Annex C): Relates CSI instrument characteristics to the ISO GPS matrix model and broader GPS rules.
Technical terms explained in the standard include CSI scan, CSI signal (correlogram) and alternative names (white light interferometry, vertical scanning interferometry, coherence probe microscopy), helping ensure consistent terminology across metrology and manufacturing contexts.
Applications and who uses it
This standard serves professionals involved in high‑precision surface measurement and instrument design:
- Metrology laboratories validating CSI systems and calibrating areal measurement devices
- Instrument manufacturers developing or certifying non‑contact interferometers (white‑light/CSI)
- Quality and process engineers in aerospace, automotive, optics, semiconductors, medical implants and precision machining who rely on areal texture data
- R&D teams and academics studying surface topography, tribology and coatings
- Standards bodies and conformity assessors implementing GPS rules
Practical uses include characterizing surface roughness, waviness and form on components where non‑contact, high‑resolution areal mapping is required.
Related standards and keywords
- Normative reference: ISO 25178-600 (metrological characteristics for areal topography)
- Part of the ISO 25178 series and the GPS framework (ISO 14638, ISO 8015)
- SEO keywords: EN ISO 25178-604:2025, coherence scanning interferometry, CSI, areal surface texture, surface topography measurement, white light interferometry, metrological characteristics, GPS, profiling measurements
For implementation, consult the full EN ISO 25178-604:2025 text and associated ISO 25178 parts for measurement procedures and parameter definitions.
