How to select the helix angle of end mill?


The basic edge shapes of end mills (helix groove shapes) are straight and helix. The helix angle can be divided into 30 degrees, 45 degrees, 50 degrees, and so on. Compared with a straight edge, helix edge end milling cutter has the advantages of light cutting, smooth cutting, high efficiency and wide application range, so it has been widely used in milling. Now let’s talk about how to distinguish between them.

Small helix end mill and large helix end mill

First of all, we need to know the relationship between helix angle and other factors of opposite milling cutter.

  • Helix angle and cutting resistance:

The tangential cutting resistance decreases with the increase of helix angle, while the axial cutting resistance increases with the increase of helix angle.

  • Helix angle and anterior angle:

With the increase of helix angle, the actual rake angle of end mill increases and the edge becomes sharper.

  • Helix angle and machined surface accuracy:

Generally, the perpendicularity and flatness tolerance of the machined surface increase with the increase of the helix angle, but when the helix angle is greater than 40°, it will decrease with the increase of the helix angle.

  • Helix angle and tool life:

On the other hand, when the helix angle is very small, the slight tool wear will obviously reduce the cutting performance of the tool, cause vibration and make the tool unable to continue to use. When the helix angle is too large, the tool rigidity becomes worse and the tool life is reduced.

  • Helix angle and material to be cut:

When processing soft materials with low hardness, large helix angle is used to increase the front angle and improve the sharpness of the edge; when processing hard materials with high hardness, small helix angle is used to reduce the front angle and improve the rigidity of the edge.

So how do we choose the helix angle?

For the stainless steel materials with low thermal conductivity and great influence on the heat transfer of the cutting edge, it is helpful to extend the tool life by using a large helix angle end mill.

In addition, the characteristics of finish machined surface are changed due to helix angle. For example, when smooth finishing is required, large helix angle end mills are sometimes used. However, when using the end mill with large helix angle, the cutting resistance will increase and the force of the right helix angle cutter will also increase. Therefore, corresponding measures must be taken, such as using the tool holder with high clamping rigidity. Although the rigidity of the tool can be ensured, the end mill with small helix angle is sometimes used when the rigidity of workpiece such as thin plate processing is low.

In short, the larger the helix angle of end mill, the longer the contact length between workpiece and cutting edge. In this way, the load on the cutting edge per unit length can be reduced and the tool life can be prolonged. But at the same time, the cutting resistance will increase, so it is necessary to consider using the tool holder with high clamping rigidity.

The helix angle is one of the main parameters of the helix edge end mill. The change of helix angle has a great influence on the cutting performance of the cutter. With the development of CNC machining technology and flexible manufacturing technology, it is very convenient for us to change the size of the helix angle in tool manufacturing process. If we further study the influence of helix angle on the cutting performance of helix edge end mill, when manufacturing and selecting the helix edge end mill, combining with the performance of machine tool and fixture, and considering the performance of the material to be processed, machining accuracy, machining efficiency, tool material and tool life, the size of helix angle will undoubtedly promote high efficiency and high-efficiency Finish milling plays an important role. UKO will not give up the exploration and research of CNC cutting tools and constantly bring new technologies and products to customers.

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