29 Mar BSI – New international guidance on surface texture published.

The  British Standards Institution (BSI) has recently published the anticipated BS EN ISO 21920 series of international standards on surface properties in technical product documentation.

Discount available for CMF Members.

The process of casting usually ends with the machining, grinding, or sanding of the cast component to achieve the desired dimensional accuracies, shape, and surface finish. This is because surface texture plays an important role in determining how a finished cast product will interact with its environment.

It is an aspect of component development that has been measured and verified for over 80 years across every field of engineering, to improve the performance of manufactured products.

The handful of international standards that are related to profile specifications, measurements, or analysis, were developed with the aim of guiding designers and manufacturers to comply with the agreed best practices with regards to profiling surface texture.

However, many of these industry specifications were last revised in the late 1990s and have since been regularly adopted without any changes.

Given the advancement that has occurred in the technology governing engineering techniques over the years and the publication of more recent standards in the field of geometrical product specifications (GPS), it became apparent that a refresh to the standardization for surface texture was necessary.

The result is the newly published international BS EN ISO 21920 suite of updated surface texture standards, developed by the global committee ISO/TC 213.

This new standard series will support the work of manufacturers, mechanical engineers, design engineers, and engineering designers who operate in the aerospace, defence, automotive, rail, nuclear, and medical devices sectors.

It will also be useful to any engineering or manufacturing organizations that produce engineering drawings (using 2D manual drawings or 3D CAD-generated models) in their product design and development processes.

What’s new in surface texture standardization and what does this new standard series cover?

Comprising the new standard series, BS EN ISO 21920-1 has been developed alongside BS EN ISO 21920-2 and the new BS EN ISO 21920-3:

  • BS EN ISO 21920-1:2022 Geometrical product specifications (GPS) — Surface texture: Profile — Part 1: Indication of surface texture provides a modern approach to the indication of surface texture requirements on mechanical engineering drawings (and CAD models).
  • BS EN ISO 21920-2:2022 Geometrical product specifications (GPS) — Surface texture: Profile — Part 2: Terms, definitions and surface texture parameters provides updated terms and definitions and parameters for surface texture requirements used on engineering drawings and CAD models. It replaces several standards – BS EN ISO 4287:1998, BS EN ISO 12085:1997, BS EN ISO 13565-2:1998 and ISO 13565-3:2000 – which have been the main surface texture standards for industry for many years.
  • BS EN ISO 21920-3:2022 Geometrical product specifications (GPS) — Surface texture: Profile — Part 3: Specification operators provides specifications on the complete specification operator for surface texture by profile methods.

One of the main changes introduced in the new BS EN ISO 2190 series is that surface texture profile parameters are now defined on the evaluation length.

Other key changes introduced under the new best practice guidance include:

  • The maximum tolerance acceptance rule will now be the default tolerance acceptance rule
  • The inclusion of definitions of new parameters, in particular parameters based on the watershed transformation

All these standards are available to purchase individually, or as a collection in the Surface Texture Specifications Solution Pack, from the BSI Shop online.

What’s the industry impact of these new standards?

Combined, the new guidelines within these standards will be used by manufacturing and production engineers, as well as the metrologists and quality control teams, who measure and verify that the specifications for the surface texture of components have been met.

It is important for the manufacturing industry to adopt this new standard series, as it will help provide quality assurance with regards to component surface texture throughout the supply chain.

Importantly, this new standard series will replace the long-standing industry front-runner, BS EN ISO 1302, as the definitive specification for texture indication.

As a result, manufacturers will likely need to update their analysis software, and designers to adapt their specifications to adhere to this new industry guidance.

This standard series is available to purchase online from the BSI Shop.

CMF Members can take advantage of a discount on the PDF versions.

Angela Mason
Angela Mason