The GPS (Geometrical Product Specifications and Verification) concept is intended to cover industry needs with respect to the improvement of product quality and reduction of design and production costs.

One of the main driving forces is the observation that businesses that outsource need a common technical language for communicating with sub-contractors. Furthermore, quality procedures impose a discipline on personnel that reduces erroneous interpretations of specifications and minimises the risks associated with the client-supplier relationship.

All this has led to a rationalisation of standards for dimensional and surface texture metrology, providing them with a rigorous mathematical foundation, reducing duplication, identifying gaps and eliminating contradictory standards, and creating unambiguous languages for specifications.

The Technical Committee TC 213 in charge of GPS standards has defined, within the context of the ISO 14638 standard, a matrix in which every GPS standard must be registered, by ticking one or more boxes. This matrix has 6 columns, describing the different phases from specification to verification, called the GPS chain links.

• Column 1: product documentation indications
• Column 2: definition of tolerances
• Column 3: definition of characteristics of actual (real) feature
• Column 4: assessment of the workpiece deviations - comparison with specified limits
• Column 5: measurement equipment requirements
• Column 6: calibration requirements - measurement standards

A chain link matrix should be added in the future to include 3D surface textures.

 GPS standards to know

The table below summarises the GPS standards that apply to the measurement of surface texture and form deviations.

For more information:  www.iso.ch

 Back to Surface metrology guide

Other relevant pages:

  Metrology guide
  Mountains® platform
  Standard packages