Vibro Sifter Mesh Size Guide: Mesh to Micron Chart

By Sterial Machinery engineering team · Published 2026-10-22

Choosing the right screen is the most important decision when setting up a vibro sifter. Sterial Machinery's screens are available from 4 mesh to 300 mesh. Here is how to pick one.

What "Mesh" Means

Mesh number is the number of openings per linear inch of screen. A 40 mesh screen has 40 openings across one inch. Higher mesh numbers mean smaller openings. Because wire diameter also takes up space, the actual opening is smaller than 1 inch divided by the mesh number – which is why standard charts list the nominal opening in microns (µm).

Mesh to Micron Chart

Nominal openings for common US standard (ASTM E11) test sieve numbers. Industrial woven screens with different wire diameters may differ slightly – confirm the opening with your screen specification.

How to Choose the Right Mesh

1. Start from the specification. If your product must pass 425 µm, start with a 40 mesh screen.
2. Decide the job. For scalping lumps from an otherwise good powder, choose a screen coarser than the largest acceptable particle so good material passes quickly.
3. Consider the material. Sticky, moist or fibrous materials may need a slightly coarser screen or more screen area.
4. For grading, pick two screens. Top screen = maximum size, bottom screen = minimum size. Use a double deck.
5. Trial if possible. A short trial with your material confirms output at a given mesh.

Common Mistakes

• Choosing a mesh finer than needed – output drops sharply and blinding increases.
• Ignoring wire diameter – two "40 mesh" screens can have different openings.
• Using a damaged screen – a small tear lets oversize through. Inspect before each batch.
• Overfeeding – a deep bed stops fines reaching the mesh.

Related: powder sieving machine · how a vibro sifter works.