In manufacturing, milling machines are very important. Aside from the fact that this machine is used for machining solid materials, a milling machine is also used for planing, die-sinking, keyway cutting, and routing, among others. The milling machine provides convenience to the operator because the workpiece is moved toward the cutter. In this manner, machining is more effective.
Some of the most important components of the milling machine are the mill tools. These tools are actually the cutting tools which are attached to the milling machine for the cutting process. There are many types of mill cutting tools depending on the shape and the size. Moreover, milling cutters are categorized according to coatings and rake angle. The cutting process is achieved by the movement of the cutter within the machine.
In order to achieve effective cutting, the features of the milling cutter must be critically considered. The milling cutter features include shape, flutes, center cutting, helix angle, shank, roughing, and coatings.
Shape. The shape of the cutter determines the type of cutting operation it can perform. There are many standard shapes used in various industries.
Flutes. These are deep helical grooves running up the cutter. Along the edge of the flutes, sharp blades are located. These blades are referred to as the teeth and are the components that cut through the material.
Center Cutting. This is the orientation of the cutting tool which determines whether the cutting tool can plunge through a material or not.
Helix Angle. The helix angle sets the gradual entry of the tooth on the material. Moreover, the helix angle reduces vibration of the cutting tool.
Shank. This is the cylindrical part of the cutting tool that is attached to the milling machine and is responsible for holding the tool in place.
Roughing. A cutter configuration which is composed of serrated teeth effective for breaking the material into smaller pieces.
Coatings. Coatings are responsible for improving the surface finish, increasing the speed, and increasing the tool life.
While each of these features dictate the performance of the cutting tool, the type of cutting done is determined by the various types of cutting tools as well. The different types of milling cutters are slot drill, ball nose cutter, slab mill, face mill, and fly cutter to name a few.
Slot Drill. The slot drill is capable of drilling straight down into the material. This consists of two flutes, with which one tooth is found at the center of the end face.
Ball Nose Cutter. This cutter is similar to the slot drill, however, the end of the cutters are hemispherical. This cutter is most commonly used in machining three dimensional contoured shapes.
Slab Mill. Slab mills are typically used for the quick machining of large broad surfaces.
Face Mill. This type of cutter uses multiple disposable carbide or ceramic tips mounted on its cutter body.
Fly Cutter. This consists of a single body from which one or two tool bits are inserted. The individual cutters of this cutter are replaceable as with the face mills.
Fig.1. Types of Mill Cutters
Fig.2. Face Cutter