Lapping according to DIN EN ISO 8589 is a machining process with a geometrically undefined cutting edge. It is used primarily on hard surfaces such as steel or ceramics, on workpieces with narrow dimensional tolerances and on workpieces with good surface properties, such as certain degrees of roughness. With lapping, in contrast to other machining processes, the tool is loose in the form of a grain that is not held in the tool. The lapping grain, together with the lapping agent, usually a liquid or paste, forms the lapping mixture. The lapping mixture is applied and guided between the workpiece and the lapping wheel so that orderless cutting paths are created and the grain can move and roll freely. These relative movements are used for machining in several directions. To avoid scoring in the workpiece, the lapping grain must be very homogeneous. In addition to the cutting process, the surface of the workpiece is hardened during lapping due to the deformation of the lapping grain tips caused by the rolling of the lapping grain. Lapping mixtures with primarily Al2O3, SiC or diamond grains are currently used in industry.