Several broad categories of end- and face-milling tools exist, such as center-cutting versus non-center-cutting (whether the mill can take plunging cuts); and categorization by number of flutes; by helix angle; by material; and by coating material. Each category may be further divided by specific application and special geometry.
A very popular helix angle, especially for general cutting of metal materials, is 30°. For finishing end mills, it is common to see more tight spiral, with helix angles 45° or 60°. Straight flute end mills (helix angle 0°) are used in special applications, like milling plastics or composites of epoxy and glass. Straight flute end mills were also used historically for metal cutting before invention of helical flute end mill by Carl A. Bergstrom of Weldon Tool Company in 1918.
There exist end mills with variable flute helix or pseudo-random helix angle, and discontinuous flute geometries, to help break material into smaller pieces while cutting (improving chip evacuation and reducing risk of jamming) and reduce tool engagement on big cuts. Some modern designs also include small features like the corner chamfer and chipbreaker. While more expensive, due to more complex design and manufacturing process, such end mills can last longer due to less wear and improve productivity in high speed machining (HSM) applications.
It is becoming increasingly common for traditional solid end mills to be replaced by more cost-effective inserted cutting tools (which, though more expensive initially, reduce tool-change times and allow for the easy replacement of worn or broken cutting edges rather than the entire tool).
End mills are sold in both imperial and metric shank and cutting diameters. In the USA, metric is readily available, but it is only used in some machine shops and not others; in Canada, due to the country’s proximity to the US, much the same is true. In Asia and Europe, metric diameters are standard.
Post time: Aug-04-2022
