Fliessfähigkeit

Fliessfähigkeit, often translated as "flowability" or "runnability," is a property that describes the ease with which a material, particularly powders or granular substances, can flow or be moved. It is a crucial characteristic in various industrial processes, including material handling, processing, and manufacturing.

The flowability of a material is influenced by several factors. These include particle size distribution, particle shape, surface roughness, moisture content, and the presence of binding agents. For instance, materials with a narrow particle size distribution and spherical particles tend to exhibit better flowability than those with a wide distribution or irregular shapes. Moisture can often lead to clumping and reduce flowability, while some binding agents, used in specific applications, are designed to enhance it.

In practical terms, poor flowability can cause significant problems. It can lead to bridging and ratholing in hoppers and silos, blockages in conveying systems, and inconsistent filling of molds or dies. This can result in production delays, increased waste, and defects in finished products.

Conversely, good flowability is desirable for efficient and reliable processing. It ensures smooth transfer of materials, uniform packing, and consistent product quality. Various methods and additives are employed to improve the flowability of powders, such as using flow aids, controlling particle morphology, or modifying surface properties. Measuring flowability is often done through standardized tests like angle of repose, flow through an orifice, or shear cell testing.