Tolerantiebands

Tolerantiebands, in Dutch often used to refer to tolerance bands, are the allowable ranges of variation around a nominal value for a physical quantity, such as a dimension, electrical parameter, or performance criterion. They define the limits within which a part or measurement must lie to be considered acceptable, enabling interchangeability and reliable function in assemblies.

Tolerance bands can be bilateral or unilateral. A bilateral tolerance allows variation above and below the nominal value within a defined width, while a unilateral tolerance restricts variation to only one side. Tolerances are typically specified as a nominal value plus upper and lower limits, for example 20.00 mm with a tolerance of +0.10/ -0.00 mm, producing a tolerance band from 20.00 to 20.10 mm. Standards often express tolerances as tolerance classes or grades (for example ISO IT grades) and can apply to holes and shafts with defined fit systems such as hole basis or shaft basis.

Applications of tolerantiebands span manufacturing, engineering, and quality control. In mechanical engineering, they govern fits between mating parts (such as shafts and holes) to ensure proper assembly and function. In electronics and other fields, dimensional and electrical tolerances guide design, testing, and production. Quality systems use tolerance bands to classify parts as in-spec or out-of-spec, and to assess process capability and measurement uncertainty.

Etymology and related concepts include tolerance zone, upper and lower deviation, tolerance class, and fit types. Overall, tolerantiebands provide a practical framework for managing variation in design, production, and inspection.