Rakevinkel

Rakevinkel, or rake angle, is a geometric parameter of cutting tools that describes the orientation of the rake face relative to the surface of the workpiece during material removal. It is defined as the angle between the rake face and a plane parallel to the workpiece surface. The rake angle affects how chips are formed and flow away from the cutting edge and is usually specified for each tool geometry.

The sign of the rake angle can be positive, neutral (zero), or negative. Positive rake angles generally reduce cutting forces and improve chip control and surface finish, but they weaken the cutting edge and can wear faster under heavy loads. Negative rake angles strengthen the edge and can extend tool life in tough materials or interrupted cuts, at the expense of higher forces and temperatures. Zero rake provides a compromise between edge strength and chip flow.

Selection of the rake angle depends on the workpiece material, tool material and coating, coolant or lubrication, and the machining operation (for example turning, milling, or drilling). Carbide and ceramic tools typically employ positive rake angles to enhance performance, while high-speed steel tools may use smaller positives or near-zero rake. Indexable inserts have fixed rake angles defined by their insert geometry.

Rake angles can be straight or curved along the edge, and some tools employ variable rake angles to optimize chip formation across the cutting zone. The rake angle is distinct from the clearance (relief) angle, which measures the gap between the tool flank and the workpiece to avoid rubbing.

Rakevinkel is the term used in several Scandinavian languages; in English the equivalent concept is rake angle.