Roundness tolerance

The roundness of an object depends mathematically on the curvature of its surface. If it is a two- or three-dimensional object with a single convex curvature, it is a circle or a sphere, respectively. Roundness tolerances play a major role in the manufacture and operation of equipment. The roundness of an object is therefore an expression of its shape. According to common standards for form and position tolerances, roundness tolerances are form tolerances. The rule here is that the circumferential line to be toleranced must lie orthogonal to the center axis between two concentric circles in all cutting planes. Roundness tolerances are decisive for inspection and measurement processes around the dimensional accuracy and concentricity of workpieces. Methods of cross-section measurement, tactile and visual procedures, for example, are suitable for checking them. Round components are usually manufactured using primary forming, machining, joining or printing processes.