End Mills Information
End mills are widely used, multiple-flute cutters typically used for machining metals or plastics. They are typically mounted vertically and have two or more helical flutes. End mills are usually configured to cut with their ends and on their sides.
End 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:
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Square end - Square end tip geometry for end mills have a square or straight end that features no radius, chamfer, or other finish.
Ball nose - Ball nose end mills tips have a “ball nose” whose radius is one half of the cutter diameter. This type of end mills tip is useful for machining female semicircle grooves of radii.
Radius tip - Radius-tipped end mills ends are straight flutes with ground radius on the very tip.
Chamfer 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 an end 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 end mill takes over and produces closer tolerances and higher-quality surface finish.
Other considerations for end mills include cutter size and construction criteria.
Size considerations for end 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 cutting ends are typically limited to single end and double end.
Single end mills feature cutting flutes or edges on one end of the tool; this is the most common end mill configuration.
Double end mills incorporate cutting geometry on both ends, so that the tool can be flipped or reversed when one end wears.
Materials & Coatings
The material of the end 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 end mills include micrograin carbide, which is used most-often in surface finishing applications, and ceramic.
Coatings for end mill machines 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 end mills may also be available depending on the manufacturer.
There are several standards which are used in the proper design and function of end mills. A selection of these standards are listed below.
ASME B94.19 -This Standard covers high speed steel milling cutters and end mills of one piece construction as listed in Tables 1 through 62. It also includes general definitions, sizes, and tolerances.
BS ISO - 1641-1 - End Mills And Slot Drills - Part 1: Milling Cutters With Cylindrical Shanks
ISO 1641-3 - This part of ISO 1641 specifies the general dimensions and designation of several milling cutters with 7/24 taper shanks.
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