TS EN ISO 12780-2

TS EN ISO 12780-2 is the standard that defines the specification operators used for straightness within the Geometrical Product Specifications (GPS) framework. It focuses on integral features only and, more specifically, on complete straightness profiles for line-type features. In general technical terms, straightness describes how far a real line element departs from an ideal straight line, so a well-defined specification operator is essential for consistent interpretation in design and measurement.

Role of the straightness specification operator

The scope of this part is limited to the complete specification operator for straightness. In GPS language, a specification operator is the rule set that tells users how a geometrical characteristic is to be interpreted when it appears on a technical drawing or product specification. For straightness, the aim is not merely to name a tolerance concept, but to define the geometric logic used to assess form deviation of a line-type feature.

Technical context in practice

Straightness may be assessed on an axis, an edge, a generatrix, or another line element, which makes the relationship between the measured feature and the interpretation rule important. Standards in this area help designers, metrologists, and quality engineers use the same terminology with the same meaning. In surface and form metrology, the way the departure from ideal geometry is defined has a direct effect on comparability of results. This part sits in that chain as the structure that organizes the straightness specification itself.