The milling cutter is a rotary cutting tool, often with multiple cutting points. As opposed to drilling and other simple machining processes, where the tool is advanced along its rotation axis, the cutter in milling is usually moved perpendicular to its axis so that cutting occurs on the circumference of the cutter. As the milling cutter enters the workpiece, the cutting edges (flutes or teeth) of the tool repeatedly cut into and exit from the material, shaving off chips (swarf) from the workpiece with each pass.
The milling process removes material by performing many separate, small cuts. This is accomplished by using a cutter with many teeth, spinning the cutter at high speed. A sufficient stock material is useful for finishing parts to precise sizes and shapes and flat surface,and to maintain the tolerances specified and the surface roughness parameters.
- End mills are those tools which have cutting teeth at one end, as well as on the sides. The words end mill are generally used to refer to flat bottomed cutters.
- Roughing end mills quickly remove large amounts of material. This kind of end mill utilizes a wavy tooth form cut on the periphery. These wavy teeth form many successive cutting edges producing many small chips, resulting in a relatively rough surface finish. During cutting, multiple teeth are in contact with the workpiece reducing chatter and vibration. Rapid stock removal with heavy milling cuts is sometimes called hogging. Roughing end mills are also sometimes known as ripping cutters.
- Ball nose cutters are similar to slot drills, but the end of the cutters are hemispherical. They are used to add a radius between perpendicular faces to reduce stress concentrations.
- Milling cutters come in several shapes and many sizes: cylindrical cutters, eyptical cutters and drills to performe milling operations.