Face mills are primarily used for milling a face on the surface of a plate or bar. They are predominantly used to cut with the ends of the cutter rather than their sides. The term "face" refers to the creation of a flat face on the work piece. Face mills often have a larger diameter than the width of the workpiece being faced, so that the surface can be processed in one pass.
Face mills may be of solid construction, or with holders and inserts. They can be used with a number of end or tip geometry options, including square end, ball nose, radius tip, and chamfer tip. Square end tip geometry for face mills have a square or straight end that features no radius, chamfer, or other finish. Ball nose face mills tips have a “ball nose” whose radius is one half of the cutter diameter. This type of face mills tip is useful for machining female semicircle grooves of radii.
Other ends and tips for face mills include radius or chamfer-tipped. Radius-tipped face mills ends are straight flutes with ground radius on the very tip. Chamfer tip ends feature an angled section of the side or the end. These tips produce an angled cut of chamfered edge on a workpiece.
When selecting a face mill, consideration must be made to the desired finish type. There are typically two finish options: roughing / hogging and finishing. Roughing and hogging mills are designed so that the machine geometry, flutes, and materials can be used for rapid and heavy material removal. They are typically used to machine workpieces close to the desired finishing dimensions, where a finishing face mill takes over and produces closer tolerances and higher-quality surface finish.
Other considerations for face mills include cutter size and construction criteria. Size considerations for face mills relate to the cutting diameter, shank or arbor diameter, flute or cutting edge length, overall tool length, and radius dimension and angle when applicable. Construction options for face mills include the number of flutes of cutting edges. This number can vary with the cutter diameter, milling material, and other factors. Two-flute face mills are often used with ductile materials that produce long chips. Face mills using higher-number of flutes can be used to minimize chip load and vibration.
The material of the face mill is important for understanding the level of cutting the machine can handle. Materials like carbide, cobalt, and diamond are hard and can be used in high-speed applications, whereas materials like steel are used for general metal machining. Other material options for face mills include micrograin carbide, which is used most-often in surface finishing applications, and ceramic.
Coatings for face mills are important considerations as well, as they can provide additional production against corrosion and abrasion, increase the tool’s hardness, provide lubrication and smoothness assistance, and improve the overall lifetime of the tool. Other considerations and options for face mills may also be available depending on the manufacturer.