datumsachse

A datumsachse, often translated as datum axis, is a fundamental concept in mechanical engineering and metrology. It represents a theoretically perfect line used as a reference for establishing the location and orientation of other features on a part. Unlike a physical feature, a datum axis is an abstract geometric construct. It is typically derived from a cylindrical or conical feature on the part, such as a bore, pin, or shaft.

The primary purpose of a datum axis is to provide a stable and repeatable reference for measurements and manufacturing processes. When a feature is designated as a datum, it means it is intended to be a primary reference point. The datum axis is then defined by the center of this cylindrical or conical feature. This allows for precise alignment and control during machining operations and subsequent inspection.

In geometric dimensioning and tolerancing (GD&T), datum axes play a crucial role in defining the tolerance zones for other features. By establishing a datum axis, designers and engineers can specify how much deviation is acceptable for other parts of the object relative to this primary reference line. This ensures that mating parts will fit together correctly and that the overall functionality of the assembly is maintained. The concept is essential for achieving interchangeability of parts in mass production.