What affects the cutting edge strength of a tool?

The cutting edge strength of a tool is significantly influenced by the rake and relief angles. The rake angle is the angle formed between the cutting edge and a line perpendicular to the surface of the workpiece. A favorable rake angle helps reduce cutting forces and improves chip flow, which can enhance the overall strength and performance of the cutting edge during machining. When the rake angle is appropriate, it can help minimize the stress on the cutting edge material, thereby increasing its strength and lifespan.

The relief angle, on the other hand, is the angle that prevents the cutting edge from rubbing against the workpiece as it advances through the material. Proper relief angles reduce friction and heat buildup at the cutting edge, which are critical factors in maintaining the integrity of the tool. An inadequate relief angle could lead to increased wear or premature failure of the cutting edge due to excessive load and heat.

While the other options, such as the length of the tool, material of the workpiece, and depth of cut, can impact performance, they do not directly relate to the cutting edge strength in the same way that rake and relief angles do. For example, while a longer tool may introduce additional deflection and potential for chatter, or the workpiece material could determine the difficulty of cutting,