litistymisprosessi

Litistymisprosessi is a term used in Finnish-speaking contexts to describe a class of material forming operations in which a workpiece is subjected to compressive forces to reduce thickness, increase density, or shape a cross-section. The process relies on plastic deformation of the material under controlled pressure, often with the aid of heat or lubrication to manage flow and reduce wear on tooling.

The core principle is the application of compressive stress through dies, punches, rolls, or platens, driving material to flow and fill the intended geometry. Temperature, pressure level, dwell time, and lubrication are key parameters that influence density, grain structure, surface finish, and the presence of defects. In many variants, the material is preform-pressed and then finished to the final dimensions in subsequent steps such as sintering, annealing, or bonding.

Variants include uniaxial pressing, which applies force in one direction; hot pressing, where elevated temperatures promote diffusion and densification; cold pressing, performed below recrystallization temperatures; and isostatic pressing, which distributes pressure uniformly from all directions for complex shapes. Rolling and calendering are related flattening methods used to produce sheets, films, or laminates and can be considered forms of litistymisprosessi in broader practice.

Materials commonly treated include metals and alloys, ceramics, polymers, and composite systems. Applications span powder metallurgy with green-body forming, ceramic shaping, and polymer film or sheet production. Advantages are improved density, uniform cross-sections, and better surface finish, while challenges include residual stresses, cracking risk, tool wear, and the need for precise control of temperature and pressure.