Kuivapainoon

Kuivapainoon is the Finnish term for the dry pressing process, a powder forming method in which dry, free-flowing powders are compacted in a mold to form a solid green body. The method relies on high uniaxial pressure and uses little or no liquid binder, which yields a relatively high green density and can reduce or eliminate debinding steps before sintering.

Process: The powder is loaded into a die and compressed with a piston to form a green compact. This uniaxial pressing typically produces parts with simple geometries; in some cases, additional methods such as cold isostatic pressing are used to improve density uniformity. After pressing, the green body is ejected from the die and subjected to sintering to achieve final density and strength. Binderless pressing minimizes post-processing, while some formulations may include a small amount of binder or lubricants to improve flow or handling.

Materials and applications: Dry pressing is used for ceramic powders (for example alumina and silicon carbide), ferrites and other magnetic ceramics, refractory materials, and certain metal or carbide powders. It is common in the manufacture of components that require relatively simple shapes and high green density, such as discs, sleeves, and substrates. The technique is often chosen for high-volume production where forming equipment costs are a consideration.

Advantages and limitations: Advantages include a simple setup, high green density, and reduced processing steps. Limitations include limited ability to form complex geometries, sensitivity to powder flow properties, and potential density variations if pressing is uneven. Kuivapainoon forms part of the broader fields of powder metallurgy and ceramic forming.