Did you know that there are two major endmill designs available on the market today? The first is the “Conventional” design, which is most common. It features primary “relief” with a secondary clearance that is flat or concave. The clearance angle is measured over the high points at the angle transitions. It is easy to regrind and can be used for both axial and radial clearances.
The other design is “Eccentric.” Eccentric relief endmill design on the other hand, combines the primary and secondary relief into one constant drop. The continuous drop provides the strongest cutting edge. However, the eccentric grind is primarily used for radial clearance. So, on many endmills with the ER grind, you will still see the Primary/Secondary on the face.
Now that we understand the technical differences between the two styles of endmill designs, the next question is which design is likely to work well for your next application. The chart below shows when each type of design is likely to work best with your application:
The eccentric relief works very well in most materials, but there is still a valuable reason to use the primary/secondary grind. The primary/secondary grind is capable of machining softer materials, light depths of cut, thin walled parts, etc. For this reason, you’ll always see a combination of the two styles offered, to cover most situations.
Heat is the enemy of carbide.
Excessive temperature breaks down the Colbalt Binder, which holds the Tungsten
Carbide in place. WIDIA-Hanita has developed a coating that gets you more time
out of your tools.
WIDIA-Hanita Victory solid carbide end
mills use a combination of pre-coat process, coating, and post coat treatment.
The pre-coat process removes any grinding damage. You can’t see it with the
naked eye, but it’s there and can affect the cutting-edge integrity and chip
flow characteristics. This process smooths all surfaces in preparation for
coating. The Victory coating is an Advanced AlTiN treatment with aluminum
content which oxidizes with high temperatures and lends itself to high surface
speed capability and better tool life. After coating, the post-coat process
creates a smooth and hard surface. This also improves the compressive strength
of the coating, preventing it from flaking or wearing too soon. The cutting
edge is very consistent for strength and enhanced chip flow.
Innovative edge preparation provides consistent tool life by eliminating most microchipping caused by grinding. The post-coat finish reduces the chip build-up and improves chip flow. Combined, Victory grades increase tool life and provide higher MRR, shorter cycle times, and fewer tool changes.