How much metal are you removing and how fast are you removing it? A common question among mold shops today, which leads to the next topic: high-feed metal removal. High-feed cutters give you the advantage of machining efficiently and affordably.

You can actually achieve a metal removal rate two to three times faster than a conventional mill. Many new CNC machines that are produced today are stronger and more powerful giving machinists the capability of using the high-feed technology.

High-feed milling normally uses several features in the carbide insert to achieve high efficiency. In the past many mold shops would use a round insert in milling applications. Recently, many companies manufacture inserts that can achieve higher feedrates compared to the traditional round insert. The insert’s characteristics are essential to successfully and safely achieve high-feed milling.

High-feed inserts usually have a strong geometry. Trigon shapes are commonly seen in high-feed mills. These inserts often display a large nose radius, a thicker insert size and an advantageous lesser approach angle (>45 degrees). The combination of these traits enables the machinist to apply a higher feedrate (with a smaller depth-of-cut)—in some instances as much as 0.118 inches per tooth on the milling cutter.

Several cutters on the market offer an even stronger double-side negative insert. These stronger double-sided inserts strengthen the inserts’ capabilities. Negative milling inserts with a positive geometries are now a popular way of milling.

Common traits of a negative insert are that the inserts are normally thicker in size and have a positive geometry. Double-sided inserts are very beneficial. The first and most obvious reason is that you get double the usable corners on the insert (which is the trendy green thing to do); and, in addition to more usable cutting edges, inserts are now stronger. If used correctly a machinist can actually increase tool life with certain negative milling cutters. In certain designs of high-feed milling cutters, the negative styles have been known to actually reduce cutting force when compared to their single-sided relative.