Geometrical Product Specifications (GPS)—
Surface imperfections—
Terms, definitions and parameters
1 Scope
This standard defines terms relating to surface imperfections in order to establish a common vocabulary to be used in technical documents, technical drawings, scientific publications, etc. to specify to what extent surface imperfections are allowed and to aid in the specification of methods of measuring surface imperfections.
The surface imperfections defined in this standard are not related to surface roughness or surface waviness.
It does not specify the desirability or undesirability of surface imperfections, which depend on the application or function of the surface.
For specific applications and manufacturing processes, additional terms and definitions may be necessary. Such terms and definitions will be specified in relevant standards.
Some types of specific surface imperfections are defined in other standards as well.
2 General terms and definitions
2.1
reference surface
surface, having the form of a geometrical surface, from which the parameters of surface imperfections are assessed
Notes:
1 The reference surface passes through the highest peak of the real surface excluding the imperfections, and is equidistant from the mean surface determined by the least squares method.
2 The reference surface is determined over a specified surface area, or over a limited part of the surface area related to the size (dimensions) of a single imperfection, the size of the area being sufficient to assess the imperfection while suppressing the influence of form deviation on the assessment.
3 The reference surface has a geometric surface and coincides in practice with the surface of the area adjacent to the imperfection.
2.2
surface imperfection evaluation area (A)
portion of the real surface or the whole real surface of a workpiece on which surface imperfections are specified and inspected
Foreword I
ISO Foreword II
1 Scope
2 General terms and definitions
3 Characteristics and parameters of surface imperfections
4 Specific types of surface imperfections
Annex A (Informative) Relation to the GPS matrix model
Index in English
