What is Arbor Milling?

Arbor milling is a high-speed metalworking and machining process that uses a rotating multi-toothed cutting blade to cut or shape the surface of a stock material. As the blade of an arbor mill turns, it cuts small pieces of the stock material and ejects the debris from the cut, leaving a smoothed edge that requires very little finishing. The process differs from drilling in that the arbor milling machine's blades turn on a rotational axis that is parallel to the cut surface.

This cutting process is used for a variety of applications in the metalworking and manufacturing industries. It has the ability to quickly remove the debris while leaving a clean cut that requires little — if any — finishing, so the arbor milling machine has become industry-standard equipment. With the different arbor milling blade types, including carbide, tool steel, diamond and ceramic, the types of materials that can be milled and the resulting surface finishes are widely varied. As a highly versatile tool that can easily be adapted to a number of uses, the arbor milling machine sees use in the automotive industry, aeronautics fields and other manufacturing sectors.

The cutting blade of the arbor milling machine is positioned at the end of a rotating axle, and the stock material is pushed into the blade's rotation. If the stock material is pushed in the same direction as the blade's rotation, it will be pulled along by the blade, and this is called climb milling. If the stock material is pushed into the blade going against the rotation, it is known as conventional milling.

The arbor milling machine can be set up to function at any angle but the most common setup in industry usage is the horizontal milling machine. With the various configuration options and arbor mill blades available, the arbor milling process can be used for a variety of cutting purposes, including flat cuts, shaping and forming contours on the stock material's surface. The arbor mill is designed for shaping the surface of stock materials, so the process is often used to create joints and channels in metalworking projects.

The process of arbor milling is appropriate for most materials with a hardness of C25 on the Rockwell scale of hardness. Common industrial metals used with the arbor milling process are brass, aluminum, cast iron and steel. With the use of specialized arbor mill equipment, such as carbide or diamond-tipped blades, harder stock materials can be milled using this process as well.