Karhevuutta

Karhevuutta is a Finnish noun referring to the quality of being rough or coarse, especially in tactile terms. It describes surface texture or the perceived harshness of a touch or feel. In everyday Finnish, it can describe both physical roughness (a rough surface) and figurative roughness (a coarse or harsh demeanor), but in technical usage it predominantly means material or surface roughness.

In materials science and engineering, karhevuutta influences friction, wear, adhesion, and visual or haptic perception. Surfaces with high karhevuutta feel rough and can grip better but wear faster; smoother surfaces reduce friction and wear but may feel less grippy or less premium. Measurement uses profilometry: Ra, Rz, Rq, and other parameters quantify average roughness and peak-to-valley heights. Methods include contact profilometry and non-contact optical profilometry; standards such as ISO 4287 and ISO 25178 are commonly referenced.

Factors affecting karhevuutta include manufacturing processes (machining, grinding, casting, plating), material properties (hardness, grain structure), finishing (polishing, coating, texturing), and environmental conditions (humidity, temperature). In product design, controlling karhevuutta balances function, ergonomics, and aesthetics; textile applications relate roughness to feel and warmth.

See also: surface finish, roughness, haptics, tactile perception.