Roller Grinder - IFA - Iowa Farm Automation- micron grinder mill ,A roller-grinder is a specific type of mill used to grind a wide range of products, while an HD roller-grinder is a specific type of mill used to grind a high capacity of a wide range of products.Grinder. Mill. Bean to Bar. Selmi GroupGrinder Mill for cocoa mass creation Third component of the Selmi Bean to Bar range, this machine has the specific task of grinding the cocoa nibs in particles of size between 200 and 250 microns.