US Patent 7607869 Cutting insert having main and secondary chip formers

As seen in a side view of a cutting insert, the cutting insert is provided with cutting edges that slope in opposite directions. A rake surface extends at the upper surface inwardly from the cutting edges. An inward portion of the rake surface forms a main chip former. A first end of the rake surface adjacent a raised cutting corner and distal a lower cutting corner is provided with a secondary chip former that extends from adjacent the raised cutting corner to the main chip former.