BS EN ISO 25178-2:2022

What is ISO 251782 - Terms, definitions and surface texture parameters about?

ISO 25178 is a series on geometrical product specifications (GPS). Geometrical product specification is the international symbol language used to express tolerances in technical drawings.

ISO 251782 specifies parameters for the determination of surface texture by areal methods. Geometrical product specification defines the nominal geometry of the components that make up the product, and the tolerances that quantify the allowable deviations from this nominal geometry.

Who is ISO 251782 - Terms, definitions and surface texture parameters for?

ISO 251782 on the terms, definitions and surface texture parameters is useful for:

• Research and development facilities
• Scientific laboratories
• Design engineers

Why should you use ISO 251782 - Terms, definitions and surface texture parameters?

Geometrical product specification is the system used to define the geometrical requirements of workpieces in engineering specifications, and the requirements for their verification. ISO 251782 is a geometrical product specification (GPS) standard and is to be regarded as a general GPS standard. It influences the chain-link B of the chains of standards on areal surface texture. The ISO/GPS matrix model given in ISO 14638 gives an overview of the ISO/GPS system of which ISO 251782 is a part. The fundamental rules of ISO/GPS given in ISO 8015 apply to this document and the default decision rules given in ISO 14253‑1 apply to the specifications made in accordance with this document unless otherwise indicated.

For more detailed information on the relation of ISO 251782 to other standards and the GPS matrix model, see ISO 251782. An overview of standards on profiles and areal surface texture is given in ISO 251782. ISO 251782 develops the terminology, concepts, and parameters for areal surface texture. Throughout ISO 251782, parameters are written as abbreviations with lower-case suffixes (as in Sq or Vmp) when used in a sentence and are written as symbols with subscripts (as in S q or V mp) when used in formulae, to avoid misinterpretations of compound letters as an indication of multiplication between quantities in formulae. The parameters in lower case are used in product documentation, drawings, and datasheets. Using ISO 251782 you can specify parameters for the determination of surface texture by areal methods.

What’s changed since the last update?

BS EN ISO 251782:2022 supersedes BS EN ISO 25178‑2:2012. BS EN ISO 251782:2022 includes some technical changes with respect to BS EN ISO 25178‑2:2012. These include:

• The reference height for the areal material ratio is now defined by default from the highest point instead of from the reference surface (3.2.8)
• Former Clause 5 has been moved to Annex B
• Former Clause 6 is now Clause 5 on Feature parameters
• Designations AreaS and PerS in Table 2 replace former designations
• Attributes defined in Table 4 have been renamed for consistency