What type of rake angle indicates the cutting edge slopes down and away from the workpiece centerline?

A positive rake angle indicates that the cutting edge slopes down and away from the workpiece centerline. This geometry is beneficial for many cutting processes, as it allows for a more efficient cutting action and often results in reduced cutting forces and improved chip formation. With a positive rake angle, the cutting tool engages the material in a way that helps to shearing the material more easily, which can lead to better surface finishes and greater tool life.

In contrast, other rake angles serve different functions. A neutral rake angle has the cutting edge aligned in a way that neither enhances nor obstructs cutting performance significantly, while a negative rake angle, which slopes upward and toward the workpiece centerline, can lead to increased cutting forces and is typically used for harder materials. Direct rake angle does not denote a specific angle type but simply refers to the angle of the cutting edge actually presented to the workpiece. Thus, the defining characteristics of a positive rake angle make it the correct answer in this context.