The proper selection of cutting insert geometry is the up-most important factors during effective cutting. So pay attention, we are going to share you the most straightforward insight about cutting insert geometry, tool signatures based on a mold of the single-point cutting tool in this article, in order to help you comprehend their internal relations.

Main and auxiliary cutting edge

To remove metal chips from workpieces, the cutting edges need to cut along two surfaces. For this purpose, cutting tool is provided with two cutting edges, The main cutting edge, and an auxiliary cutting edge. The main cutting edge cuts the main portion of chips, while auxiliary cutting edge cuts the second surface and removes material.

Take a look at the smooth corner on the main joint point of the main cutting edge and auxiliary cutting edge. This corner is known as the nose of tool.

Nose

The radius of nose greatly affects the surface finishing and strength of tool.

Rake angle and relief angle

Material removal is easier when there is an angle between the cutting edge and surface, which is known as the rake angle of the tool, more specifically, as the back rake angle. It can be observed in the tool’s lateral side view.

To avoid the rubbing between cutting tool and workpiece, a relief angle(clearance angle) is provided as shown.

Increasing rake angle toward processed workpiece’s surface(positive direction) not only improves sharpness and strength of cutting edge but also decreases cutting power and cutting heat.

Relief angle is mainly designed for reducing wear between the tool and the part, simultaneously lower condition of cutting edge’s heat dissipation.

## Side rake angle and side relief angle

Similar relief angle and rake angle are given in the auxiliary cutting edges. Its cross-sectional shape is shown here. There are side rake angle and side relief angle.

## End cutting edge angle and side cutting edge angle

Then look at the tool’s top view. You can witness the cutting edges form angles as shown. They are called end cutting edge angle and side cutting edge angle.

The seven parameters together completely define the geometry of the cutting tool. We hope you have a conceptual overview of it. Thank you!