How To Select the Edge Shape of the End Mill?


In the selection of end mill, there are many matters needing attention, such as the hardness of the end mill, the number of edges, diameter, edge length and so on. Today we will introduce an easily overlooked factor, end mill edge profile.

Positive rake


The sharp cutting edge design is adopted in the front corner. As shown in the figure below, the angle between A and B is small, and the angle α is positive. So the blade will be sharper.

This design can reduce the cutting resistance and obtain good surface roughness even under vulgar conditions. However, this kind of edge shape is not suitable for materials with high hardness, and is more suitable for soft materials which are prone to crack and weld.

Applicable materials: resin, copper, stainless steel, ordinary steel, Quenched and tempered steel, etc.

Negative rake


The negative rake is suitable for machining at low speed. As shown in the figure below, the angle between A and B is large, and the angle α is negative. So the blade will be thicker.

This design can increase the cutting resistance and reduce the surface roughness. Good surface roughness can be obtained by machining at high speed. The negative rake edge tool with high strength is suitable for machining high hardness steel which is easy to cause chipping.

Trial materials: high hardness steel, cast iron, etc.

In addition to the common parameters, there are many variables to be considered in the selection of end mills. In the previous article, we introduced the difference between the left and the right end mill, and What’s the difference between flat, ball nose and corner radius. Friends in need can check in.

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