The Working Principle of Hammer Mills (Step-by-step Guide .In case you're new to hammer mills in pharmaceutical and food processing industries, here are three crucial steps that will help you understand how this equipment works. . Moreover, collision between particles to particles play an instrumental role in this size reduction process.size reduction how a hammer mill works,Hammer mill by Saraswathi.B - PharmainfoOpenings in perforated screens or grate bars; Number, size and type of hammers; Grinding plate setting; Rotor speed. Hammer mills. Based upon the speed and the cutters used in hammer mill produces very fine ultra sized particles. This are mainly operated at 2500 rpm or 1000 to 2500 rpm for the reduction of the large.