Approach Angle

Approach Angle

In machining, the approach (or entry) angle is when the cutting edge is engaged with the material in the feed’s direction. The effects described below are valid for both milling and turning.

Effects Of the Approach Angle on Other Machining Terms

Chip Load (Chip thickness):

  • CL – Chip Load / Chip thickness
  • Fz – Feed per tooth in milling or Feed per revolution in turning.
  • As the approach angle decreases the chip thickness for the same feed decreases.
  • This phenomenon is called Axial Chip Thinning.
  • As the approach angle gets smaller, the chip thickness is reduced according to the formula: CL= F X SIN(KAPR°)

Machining Power Consumption

The approach angle on most cutting tools is 90°. However, there are many tools with 45° and high feed cutters with approach angles as low as 12°. As the angle decreases, chip thickness is reduced by SIN(KAPR). Since the chip thickness is one of the components of the formula of the specific cutting force, it indirectly also influences the required machining power. As the approach angle decreases, the machining power rises.