ISO 25178-1:2016

Overview

ISO 25178-1:2016 - Geometrical product specifications (GPS) - Surface texture: Areal - Part 1: Indication of surface texture specifies the rules for indicating areal (3D) surface texture requirements in technical product documentation. It standardizes the use of graphical symbols and the composition of complete indications (parameters, tolerances, filters, manufacturing process, surface lay, machining allowance and annotation planes) so that areal surface texture requirements are clear and unambiguous on drawings, specifications, contracts and reports.

Key topics and requirements

• Graphical symbols: Defines the basic, expanded and complete graphical symbols for areal surface texture (including symbols that show material removal required or not permitted and an “A” marker to indicate areal texture).
• Composition of the complete symbol: Mandatory positions (positions a–f) for information such as:
  • parameter designation and numerical limit (within oblique slashes),
  • type of scale-limited surface and nesting indices (S‑L, S‑F),
  • transmission band and filter designations,
  • manufacturing method or treatment,
  • surface lay/direction,
  • machining allowance and annotation plane(s).
• Tolerancing rules: Guidance on indicating upper/lower limits (U/L), bilateral tolerances and default assumptions; how parameter values relate to the allowed extremes.
• Parameter definition and non-defaults: Requirements to include supplemental information (filters, nesting indices, specification operators) so measurement and verification are unambiguous.
• Proportions and placement: Annexes provide symbol proportions, dimensions and recommended placement on drawings and digital product definition data.
• Digital product data: Notes on integration with digital documentation practices (referencing ISO 16792 and related parts of the ISO 25178 series).
• Supporting annexes: Examples of annotations, filter symbols, nesting indices, association symbols and relation to the GPS matrix.

Practical applications and users

ISO 25178-1:2016 is intended for anyone who specifies, communicates, measures or verifies areal surface texture in product development and quality control:

• Design engineers and CAD drafters creating technical drawings and 3D models
• Manufacturing engineers and process planners specifying surface treatments and machining allowances
• Metrologists and inspection teams performing areal surface measurements and reporting results
• Supplier and procurement teams ensuring contractually required surface functionality
• Software and measurement-system developers implementing areal surface parameter handling

Using ISO 25178-1 helps ensure consistent communication of areal surface requirements, reduces ambiguity in inspections, and improves interoperability between design, manufacturing and quality systems.

Related standards

• ISO 25178-2: Terms, definitions and surface texture parameters
• ISO 25178-3: Specification operators
• ISO 1302: Indication of surface texture in technical product documentation
• ISO 1101: Geometrical tolerancing fundamentals
• ISO 16792: Digital product definition data practices
• ISO 14406: Extraction

Keywords: ISO 25178-1:2016, areal surface texture, GPS, graphical symbols, surface texture parameters, technical product documentation, nesting indices, filters, surface lay.