Cut point

The cut point in screening and filtration processes refers to the particle size at which the proportions of oversize and undersize particles in the throughput are equal. Simply put, it’s the characteristic particle size at which a screen or filter separates a particle stream into two fractions—larger particles are retained, while smaller ones pass through (often defined as the 50% passing size).

A “sharp” cut point means the separation is very precise, with particles clearly above or below this threshold reliably separated and minimal mixing between fractions. The actual cut point depends on factors like the screen opening size, particle shape, mesh type, and operational parameters (e.g., vibration intensity, feed rate).

In practice, screening machines and filters are selected specifically based on the desired cut point to separate particular size ranges—such as 5 mm in gravel or ore processing, or 100 µm in powder classification. Although architectural fabrics are rarely used for particle size separation, when they serve to keep out leaves or insects, an effective opening size can be considered analogously. However, the term “cut point” remains primarily relevant in industrial contexts.