datumgräns

A datumgräns, often translated as datum line or baseline, is a fundamental concept in metrology and engineering used as a reference for measurements. It establishes a defined starting point or an imaginary line from which other dimensions, positions, or geometric features are measured. The purpose of a datumgräns is to ensure consistency and accuracy in manufacturing and inspection processes, allowing for the reproducible measurement of parts and assemblies.

In practice, a datumgräns can be represented by a physical feature of a part, such as a machined surface, a hole, or an edge. Alternatively, it can be an abstract reference plane or axis defined within a coordinate system. The selection of appropriate datumgräns is crucial for establishing a functional measurement system. They are often designated with letters or symbols in technical drawings to clearly indicate their reference status.

The concept of datumgräns is closely related to datum features and datum targets, which collectively form a datum reference frame. This frame provides a complete and unambiguous basis for controlling the form, orientation, location, and profile of a part's features. Without well-defined datumgräns, it would be difficult to ascertain whether a manufactured part meets its design specifications, leading to potential assembly issues and functional failures.