Choosing Indexable End Mills For High Speed Machining Or 5 Axis

There are numerous carbide tooling manufacturers that produce high end indexable end mills for a wide range of industries. Some of the newest cutters have been developed as a result of high speed machining and 5 axis machines.

Newer grades of tool steels perform extremely well in tool and die or mold making applications, but they can make life very difficult for the cutting tools used. Take D-2 for example: this steel is very hard and abrasion resistant, but also very hard on cutters, including carbide.

As a result, many shops have chosen to use indexable end mills for both roughing and finishing operations. Quality tool holders are precision made and the repeatability of the cutter index procedure is very good.

One obvious benefit of indexable end mills is the numerous cutting edges available upon indexing. Some inserts have 4 edges that can be used with each insert. This can be a real money maker and time saver in your shop.
Carbide inserts

Newer coatings on a micro substrate of carbide enable the edges to hold up much longer than uncoated.

Sandvik has the Shell-end mill Coro-Mill 390 that is in the same class as a solid carbide end mill. This cutter has true 90 degree shoulders and is capable of producing a near mirror finish. Noise and vibration are held to a minimum as well.

Another popular cutter is the Iscar HM90 E90A-D1.50-3-W1.25-C Carbide indexable helical end mill. This comes with a 1.5” diameter and is a real workhorse. Because the cutters are tangentially located, the heat buildup is minimized and plunge cutting a possible.

If you intend to use indexable carbide inserts for high speed machining, make sure the indexable end mills and toolholders are balanced and graded for the demands of the higher speeds. A small deviation becomes a real problem at 40K rpm!

5 axis machining is a great application for indexable end mills. The fast stock removal rates and fine finishes available fit well with the overall approach of 5 sided machining. Machinists, tool and die makers, and mold makers love these cutters because of their reliability and ease of use.

Obviously, once your needs are for a cutter less than 1” diameter, it is probably not wise to use an indexable end mill. Not only that, you probably will not be able to find one!