Surface Metrology Guide


Surface metrology makes it possible to control numerous functions on mechanical components and manufactured objects. Reducing wear of a moving part and increasing its lifespan, ensuring sealing between shafts and seals, decreasing fuel consumption and reducing carbon dioxyde emissions, optimizing efficiency of solar cells, obtaining luxurious aspects on brushed metal surfaces, reducing heating in electronic components, making autocleaning surfaces, etc. All these functions can be obtained by programming and controlling specific surface texture. This guide, freely proposed by Digital Surf, contains numerous resources for self-training and for adoption of good practices. The company Digital Surf has been strongly involved in surface texture analysis for more than twenty years, via François Blateyron, who has been an active member of standardization committees in France and at ISO/TC 213 (now as the new convener of WG16 on surface texture). This activity has allowed Digital Surf to contribute to the development of standards by bringing its experience in metrology algorithms and has made it possible to develop advanced features in MountainsMap® based upon early drafts of the standards and therefore offer ready-to-use tools as soon as the standard is published.


Areal parameters

Introduction to Surface Texture

History of surface texture metrology until the latest ISO 25178 standard on areal surface texture.

Structure of ISO 25178

Introduction to ISO 25178, the standard on areal surface texture that describes parameters, instruments, etc.

Revision of ISO 25178

The recent revision of ISO 25178-2 in December 2021 fixes several errors and introduces new parameters.

Areal Field Parameters

Areal field parameters from ISO 25178-2, with amplitude parameters (Sa, Sq, etc.) and spatial and hybrid parameters (Sdr, Sal, etc.).

Areal Functional Parameters

Areal functional parameters on bearing ratio, Sk parameters, functional indices and volume parameters, largely used in the automotive industry.

Areal Feature Parameters

Areal feature parameters calculated by segmentation, that allows the characterization of specific structures.

This video introduces the reasons why surface texture is specified and verified on engineered products, and gives the basic concepts you should know before using surface texture analysis. Duration: 10 min 58
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Profile parameters

Profile Parameters

Panorama of parameters defined in various standards for the evaluation of roughness and waviness profiles.

Parameters from ISO 21920

Introduction to the new standard that will modernize profilometry and that should replace all previous profile standards.

Parameters from ISO 4287

Introduction to the classical roughness parameters, in particular Ra, Rz or RSm, and their waviness and primary equivalent.

R&W Parameters from ISO 12085

This standard is used in the automotive industry to caracterize profile motifs, close to functional requirements.

Rk parameters from ISO 13565

This standard specializes on functional stratified surfaces made by a multipass manufacturing process.

And also:

This video explains the modifications introduced to surface texture parameters in the new ISO 21920 standard, compared to former standards ISO 4287, ISO 4288, ISO 1302, ISO 13565, etc. Duration: 13 min 27
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Operations and Analyses

Leveling and Form Removal

Methods of leveling and form removal required to create the primary profile or the SF surface.

Filtration Techniques

Explore filtration operators and several filters defined in ISO 16610 as well as other innovative applications.

Fractal analysis

A powerful multi-scale geometrical analysis to explore profile and surface behaviors and their relation to function.

Freeform surface analysis

Learn about the next revolution on surface analysis, suitable for additive manufactured surfaces.

And also:

This video introduces the bases of filtration in surface texture and explains how filters act on the spectral content of profiles and surfaces. Duration: 19 min 57
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Documentation

Indication of surface texture on technical drawings?

How to write surface texture specifications on a technical drawing, according to ISO 1302.

Metrology Courses in Video

Series of on-line video courses about surface texture metrology. The videos are free to use. They are available in English or in French with English sub-titles.

Metrology Standards

This section provides a list of important ISO and national standards in the field of surface texture.

Selected Bibliography

Comprehensive bibliography of scientific papers and metrology books that are useful for surface texture analysis.

And also:

This video introduces the graphical language used to indicate surface texture specifications on technical drawings, according to ISO 1302. Changes introduced by the new ISO 21920-1 are also discussed.
Duration: 15 min 04
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