What Is a Bead Mill?

Bead Mills That Offer Nanotechnology

Bead mills are grinding and dispersing machines designed to grind and/or disperse particles down to the micro and nano scales. Beads (grinding media) inside the grinding chamber are agitated by rotating the shaft and the particles are ground and/or dispersed by the collision and shear force of the beads. The outlet of the grinding chamber has a filtering structure to separate beads from particles, retaining beads inside the chamber and enabling continuous production of fine particles.

Principles of Bead Mill Technology

Dry Bead Mills

Dry bead mills employ a system to produce fine particles in air or inert gas atmosphere. With beads of relatively large diameter inside, large and coarse particles can be ground easily.

There are two types of dry bead mill operations: continuous or batch operations. Ashizawa Finetech dry bead mills adopt continuous (pass) operation capable of mass-producing fine particles.

Dry Bead Mills
Pass operation

Wet Bead Mills

Wet bead mills employ a system to produce fine particles in liquid. As the minute beads inside are agitated at high speed, the machines are capable of producing particles down to the nano size.

There are three types of wet bead mill operations: circulation, pass, and batch operations. Ashizawa Finetech applies operation types according to the purpose of the products.

Wet Bead Mills
Re-Circulation System

Comparison Between Dry and Wet Bead Mills


Dry processing is optimal for micro-size particles and wet processing is suitable for nano-size particles.
As beads with a relatively large diameter are employed in dry bead mills, large and coarse particles can be readily ground by vigorous agitation. As wet bead mills employ minute beads, finer particles can be produced with strong shear and friction force caused by agitating beads at high speed.

  • Beads Used


    Beads (grinding media)

    e.g. Photo of zirconia beads in 0.3 mm diameter

    • Size : 0.03 to 2 mm diameter
    • Material : Ceramic, glass, steel
  • Comparison List of Object Sizes


    1 nm (nanometer) = one thousandth of a micrometer = one billionth of a meter