Figure 1.2 Different Types of Face Milling 1.3 WORKING PRINCIPLE OF MILLING MACHINE Working of a milling machine is based on the fact that milling cutter is fed against workpiece. This is achieved by developing relative motion with precise control between workpiece and rotating milling cutter. Feed motion is generally given to the workpiece The Working Principle of Hammer Mills (Step-by-step Guide) A hammer mill is an essential machine in the pharmaceutical and food processing industries. You can use it to crush, pulverize, shred, grind and reduce material to suitable sizes. Even though there are many types of hammer mills, the working principle is still the same.