angle of entry

Determined by the position of the milling cutter’s centerline relative to the edge of the workpiece. Depending on the cutter diameter and the radial width of cut, the angle of entry can be negative or positive. A negative angle of entry occurs when the cutter’s centerline is located on the workpiece. Such an angle is recommended because the insert contacts the workpiece by its strong front rake, not by its weak cutting edge. To produce a negative angle of entry, the radial width of cut should exceed the cutter radius. A positive angle of entry occurs when the cutter’s centerline is not located on the workpiece. It happens when the radial width of cut is less than the cutter radius. A positive angle of entry should be avoided because the insert contacts the workpiece by its weakest part—the cutting edge.