Features of a milling cutter

Milling cutters come in a variety of forms and sizes. There are further options for coatings, rake angle, and the number of cutting surfaces.

Milling cutter shapes:

Several typical milling cutter forms are utilized in the industry today.

Flutes/teeth:

The flutes of a milling bit are the deep helical grooves that run up the cutter, whereas the tooth is the sharp blade along the edge of the flute. The tooth slices the material, and the spinning of the cutter pulls chips of this material up the flute. Most cutters have one tooth per flute, however, others have two teeth per flute. The terms flute and teeth are frequently used interchangeably. Milling cutters can have one to several teeth, with the most frequent being two, three, and four. In general, the more teeth a cutter has, the faster it can remove material. As a result, a four-tooth cutter may remove material twice as quickly as a two-tooth cutter.

Helix angle:

Milling cutter flutes are almost invariably helical. If the flutes were straight, the entire tooth would contact the material at the same time, generating vibration and decreasing accuracy and surface quality. When the flutes are set at an angle, the tooth enters the material gradually, decreasing vibration. Finishing cutters typically have a higher rake angle (tighter helix) to provide a superior finish.

Center cutting:

Some milling cutters can drill directly through the material (plunge), whereas others cannot. This is because the teeth of some cutters do not extend to the center of the end face. These cutters, on the other hand, can cut downwards at an angle of 45 degrees or so.

Roughing or Finishing:

There are various types of cutters available for removing large amounts of material with a bad surface finish (roughing) or removing a lesser quantity of material with a good surface quality (finishing). Serrated teeth on a roughing cutter may be used to break material chips into smaller bits. These teeth leave a rough surface in their wake. A finishing cutter may have a large number of teeth (four or more) for gently removing material. However, because of the huge number of flutes, there is little room for efficient swarf removal, making them less suitable for removing large amounts of material.

Coatings:

The correct tool coatings can have a significant impact on the cutting process by boosting cutting speed, tool life, and surface polish. Polycrystalline diamond (PCD) is a very strong coating that is used on cutters that must survive abrasive wear. A PCD-coated tool can outlast an uncoated tool by up to 100 times. The coating, however, cannot be applied at temperatures above 600 degrees Celsius or on ferrous metals. TiAlN coating is sometimes applied to aluminum machining tools. Aluminium is a somewhat sticky metal that can solder itself to tool teeth, making them appear blunt. However, it does not adhere to TiAlN, allowing the tool to be used in aluminum for much longer.

Shank:

The correct tool coatings can have a significant impact on the cutting process by boosting cutting speed, tool life, and surface polish. Polycrystalline diamond (PCD) is a very strong coating that is used on cutters that must survive abrasive wear. A PCD-coated tool can outlast an uncoated tool by up to 100 times. The coating, however, cannot be applied at temperatures above 600 degrees Celsius or on ferrous metals. TiAlN coating is sometimes applied to aluminum machining tools. Aluminium is a somewhat sticky metal that can solder itself to tool teeth, making them appear blunt. However, it does not adhere to TiAlN, allowing the tool to be used in aluminum for much longer.