CIRP Encyclopedia of Production Engineering

2019 Edition
| Editors: Sami Chatti, Luc Laperrière, Gunther Reinhart, Tullio Tolio

Form Error

  • Albert A. WeckenmannEmail author
Reference work entry



The form error deviation of the real (manufactured) feature (i.e., line, axis, surface, center plane) from the geometrically ideal nominal feature is to be measured and evaluated by analogy to the definition of the form tolerance in ISO 1101. It is the minimum distance of the quasi-parallel boundaries of a zone, in which the entire surface of a real feature, its line element, its axis, or its center plane remains. The boundaries of the zone are formed:
  • For standard features
    • In 2D case by two geometrically ideal 2D features (lines), which are in a common plane

    • In 3D case by two – geometrically ideal – nominal features

The nominal 3D features or the nominal 2D lines must show everywhere the same distance to each other (Euclidian distance evaluated for the entire feature mathematically by Chebyshev criterion).
  • For profiles (free-form lines or sculptured surfaces):
    • For “profile any line” or “profile any...

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Copyright information

© CIRP 2019

Authors and Affiliations

  1. 1.Quality Management and Manufacturing MetrologyUniversity Erlangen-NurembergErlangenGermany

Section editors and affiliations

  • M. Alkan Donmez
    • 1
  1. 1.National Institute of Standards and Technology (NIST), 100 Bureau Drive - Stop 8220GaithersburgUSA