What is a Hammer Mill?

A hammer mill is a high speed recycling machine designed to reduce the size of scrap material. It is a steel drum which contains hammers mounted to a rotating shaft. With the rotor spun at high speed, the hammers impact material fed into the machine, shredding and crushing it through repeated blows.

What are hammer mills used for?

There are a huge range of applications for hammer mills across numerous different industries. Hammer mills are fundamentally designed to reduced bulk material into smaller pieces. Due to this, hammer mills may be used for crushing large rocks in the mining industry, milling grain in the agricultural sector, and even during fruit juice production.

However, one of their primary uses is within recycling and waste management. Hammer mills are a key component of a recycling plant, used for shredding soft materials (like paper or garden) as well as heavy-duty applications, such as processing scrap car engines as part of the ELV recycling process, and recycling WEEE.

How does a hammer mill work?

Prior to going through a hammer mill, certain materials will need to be processed with a single or double shaft shredder in order to reduce the size and volume of the initial mass. This then means that the hammer mill can further separate and densify the material.

Hammer mills differ in terms of capacity - how much scrap material can enter into the fedding mechanism. The velocity of the mill is one factor that affects the amount of material that can be processed by a hammer mill, as is the number of hammers and the characteristics of the materials being crushed. Knowing these factors is crucial to ensuring that a hammer mill functions optimally.

ALthough there are different types of hammer mills, the basis process is the same. The material (e.g. scrap metal) is fed into the grinding chamber through a chute. It is then repeatedly struck by hammers; these are attached to a high speed, rotating shaft inside the mill chamber. These repeated hammer blows cause the material to be crushed. With hammer mills like the Forrec Z15/1000, the rotation speed of the hammer mill can be easily controlled and adjusted.

Following this process, perforated screens or grates covering the opening of the mill keep coarse material for further grinding while allowing finished materials to pass through.

The size of the finished material (i.e. the output fraction) depends on a variety of factors, such as screen size, shaft speed and hammer configuration. Depending on the configuration of the hammer mill, then, a diverse array of products can be processed, leading to improved recovery rates of valuable metal waste.

What is a Hammer Mill?