How To Choose An End Mill?

Milling cutters are one of the most commonly used tools in CNC machining, and there are many types of them. End mills are one of the most commonly used. It can be considered from four dimensions, grade and quality of cemented carbide material, tool geometry design, precision manufacturing process and coating type.

The hardness of the end mill depends on the proportion and grade of carbides in its material. For example, when the carbide content is the same, if the carbide particles are smaller and the number is greater, the hardness will be better. The precision manufacturing process can keep the end mill consistent, which means that the machined parts can also achieve better consistency. A good coating can improve end mill life and cutting performance. The geometrical shape has a great influence on the end mill. The geometry of the current mainstream end mills is not only a fusion of art and engineering, but also the result of long-term, trial-and-error.

End mill geometries involving a combination of variable helix and indexed flute geometries, core geometries, OD relief eccentric and facet relief designs, with wiper flats and pad grinding or end grinding end face design, etc.

End mill geometries are becoming more and more "weird" as tool makers try to increase material removal rates while reducing "chatter" when cutting.

Regenerative chatter occurs when the harmonics between the tool and workpiece are at different frequencies, causing the two objects to collide, which is detrimental to surface finish and dimensional accuracy, as well as tool and machine life.

High helical tools (over 35 degrees) have long been popular due to their strength, rapid feed and high chip removal rates. But its disadvantage is that it is more prone to vibration. To address this, some tool manufacturers have optimized around variable helix and pitch. The result is the use of more complex geometries, resulting in increasingly exotic end mill styles.