What is positive rake angle?

Positive rake angle is one of the design parameters that is important for cutting tools. It refers to the angle between the face of the tool and the workpiece when the tool is cutting. A positive rake angle means that the front face of the tool is angled away from the workpiece, creating a sharp cutting edge that bites into the material being cut. This allows cutting forces to be directed up and away from the workpiece, reducing the amount of cutting force required and increasing cutting efficiency.

The advantages of using a positive rake angle include maintaining a sharp cutting edge, reducing friction between the tool and the workpiece, and for increasing the chip flow by creating a thinner, easier to remove chip. Positive rake angle is commonly used in high-speed machining operations where the goal is to remove material quickly and efficiently. It can also be used on materials that are soft or ductile, or when depth of cut and feed rates are low.

However, the disadvantage of using a positive rake angle is that it can also result in a weaker cutting edge due to reduction of strength by the axial bending moment. Therefore, the material and design of cutting tools must be carefully chosen to ensure that they can withstand the forces generated during the cutting process.