What is a negative rake angle in machining?

A negative rake angle refers to the configuration of a cutting tool where the angle slopes down towards the cutting edge. This design means that the cutting edge is oriented in such a way that it can provide greater stability and durability during the machining process. Tools with a negative rake angle are often used for machining hard materials or for operations that require a strong cutting edge, as they can withstand higher cutting forces and reduce the wear on the tool.

In contrast, a positive rake angle, where the tool slopes away from the cutting edge, tends to facilitate easier cutting and can provide a smoother finish, yet it may not be as effective for tougher materials. The terminology and concept of rake angles are critical in determining the behavior of cutting tools in various machining applications, influencing factors such as machining efficiency and tool life.