Hammer Mill; Usage, Construction, Working Principles, and Types

A Hammer Mill machine is widely used in the Pharmaceuticals and Food industries to cutting Materials into small fragments or small pieces (Also called Size Reduction). The main component of a hammer mill is a row of hammers that are hinged on a central shaft and contained in a strong metal container. Size reduction is achieved by Impact.

Usage of Hammer Machine

Hammer mill is used in the Pharmaceuticals, Food beverage, and Cosmetic industries to Reduce material particle size.

Working Principle:

The principle of the Hammer mill is based on the Impact between a rapidly moving hammer mounted on the rotor and powder material.


Hammer Mill construction
  • Hammers are made up of stainless steel (316L for material contact parts and 304 for non-contact parts).
  • A Hammer mill is essentially a steel drum or milling chamber containing a verticle or horizontally rotating shaft.
  • Hammer contains 4 to 5 small size hammer
  • The lower part of the hammer mill consists of a screen through which material can pass after desirable size reduction.
  • Finally, after desirable size reduction material passes through the duct screen to collect in a container.


  • Feed the material into the hammer mill through the hopper and press the start button.
  • The Hammar assembly starts to rotate (with 8000 to 15000 RPM speed), and particle size reduces into small particles due to dynamic impact.
  • After the reduction of particles falling within the container through the screen.

Types of Hammer mill Machines

Hammer mills are of two types, Horizontal shaft (Moves horizontally)and verticle shaft (Moves Vertically) types. They differ only by moving conditions, although the remaining things are the same.

Types of Hammer

Hammers are of two types, Stirrup and Bar shaped. Bar shape hammers are used extensively in tablet granulation.

Read Also: Colloidal mill; Working and Principle


  • It produced rapid action in grinding
  • Hammer also useful for hard particles
  • East and Fast to use
  • Required less space and is easy to dismantle, and clean.


  • Produced more sound.
  • Be careful to use heat-sensitive materials because the hammer produced more heat.
  • Can’t be used to grind fiber materials.


Principle of hammer machine


the pressure/ stress is applied between which components in the mill

Stress is need to apply in the hammer to crush the powder and it is usually applied between the hammer and feed

which types of hammer-shaped is used in granulation

Bar shape is used in tablets granulation processing

Hammers are made of which material?

Hammer is made of stainless steel

Particle size in hammer depends on?

Particle size in the hammer mill depends on the feed rate.

What are the factors that affect the particle size of materials?

Factors including no. of hammer, rotor speed, and size of the screen are used.

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