Most roller mills will use a saw tooth or Dawson configuration. To get a particle size of 800 microns, it is necessary to have rollers with 10 to 12 grooves per inch. Most manufacturers will also recommend a differential drive of 10-25 percent with rolls turned so that the sharp edge of each roll meets the grain. Roll speed ranges from 350 to 600 RPM depending upon surface speed. This low speed will create less dust and wear.
Roller mills can process grain with half the energy of a hammer mill and give equal particle size.
Feed Mixing Mixing efficiency refers to how well a batch of feed is mixed. Various types of mixers will require different amounts of time to thoroughly mix feed. Vertical mixers are used most often on the farm. Portable grinder mixers are normally a single screw vertical mixer and will require about 15 minutes after the last ingredient has been added to adequately mix a batch of feed. Horizontal mixers require 5 to 10 minutes after the last ingredient has been added for proper mixing.