Comparison of cutting performance of end mills with different helix angles

The comparison of cutting performance of end mills with different helix angles mainly lies in tool life, cutting resistance, machining accuracy, applicable materials, etc. The following is a specific analysis:

Tool life

Large helix Angle: The larger the helix Angle of the end mill, the longer the contact length between the workpiece and the cutting edge, and the smaller the load applied to the unit length of the cutting edge, which is conducive to extending the tool life. For instance, for difficult-to-cut materials such as stainless steel with low thermal conductivity and significant heat impact on the cutting edge tip, as well as hard materials with high hardness, as the hardness increases, the cutting resistance also increases. Using end mills with large helix angles is beneficial to tool life. However, when the helix Angle is too large, the rigidity of the cutting tool deteriorates and its service life will be reduced.

Small helix Angle: When the helix Angle is very small, even slight tool wear will significantly reduce the cutting performance of the tool, cause vibration, and make the tool unusable.

Cutting resistance

Large helix Angle: The cutting resistance will increase. The tangential cutting resistance decreases as the helix Angle increases, but the axial cutting resistance increases as the helix Angle increases. At the same time, the force that the right helix Angle tool exerts outward will also increase. Therefore, corresponding measures must be taken, such as using a tool holder with high clamping rigidity.

Small helix Angle: The cutting resistance is relatively small, but the sharpness of the cutting edge may not be as good as that of large helix Angle tools.

Machining accuracy

Large helix Angle: Generally, the perpendicularity and flatness tolerance values of the machined surface increase with the increase of the helix Angle, but when the helix Angle is greater than 40°, it shows a decreasing trend as the helix Angle increases.

Small helix Angle: When processing some workpieces with high precision requirements, it may be easier to control the processing accuracy, but other factors also need to be comprehensively considered.

Applicable materials

Large helix Angle:

Soft materials: When processing soft materials with low hardness, using a large helix Angle can increase the rake Angle and improve the sharpness of the cutting edge.

Difficult-to-machine materials: For difficult-to-machine materials such as stainless steel with low thermal conductivity and significant heat impact on the cutting edge tip, using a large helical Angle end mill for cutting can help extend the tool life. For instance, the 60° helical Angle type end mill suitable for high-speed cutting of difficult-to-cut materials such as SUS304 stainless steel has a unique blade shape that can suppress the influence of cutting heat on the cutting tip.

Small helix Angle: When processing hard materials with high hardness, using a small helix Angle can reduce the rake Angle and enhance the rigidity of the cutting edge.

Chip removal performance

Large helix Angle: As the helix Angle increases, the chip removal situation will deteriorate. When milling grooves with a high helix Angle, a small amount and rapid cutting method must be adopted.

Small helix Angle: Chip removal is relatively smooth, but the cutting discharge capacity may not be as good as that of large helix Angle tools. However, by choosing the appropriate cutting conditions, the weakness of chip removal can be overcome.

Tool rigidity

Large helix Angle: The rigidity of the tool is relatively poor. When using a tool with a large helix Angle for processing, it is required that the tool holder has good rigidity; otherwise, the tool is prone to fall off the tool holder.

Small helix Angle: The tool rigidity is relatively good. In cases where the rigidity of the workpiece is relatively low, such as in thin plate processing, small helix Angle end mills are sometimes used. They adopt a multi-edge design, providing good tool rigidity and minimizing the tool allowance during side cutting. The tool tip has undergone sharp corner protection treatment, which can effectively prevent chipping at the tool tip.