1. Field of the Invention
The invention pertains to the field of indexable cutting inserts. More particularly, the invention pertains to an indexable, double sided, nonagon cutting insert.
2. Description of Related Art
Modern high-performance cutting tools use replaceable and typically indexable inserts owing to the high cutting speeds and feeds supported by the superior insert materials. Common materials for inserts include tungsten carbide, polycrystalline diamond and cubic boron nitride.
Indexable inserts use a symmetrical polygonal shape, such that when the first cutting edge is blunt they can be rotated or flipped over, presenting a fresh cutting edge which is accurately located at the same geometrical position. Geometrical repeatability saves time in manufacturing by allowing periodical cutting edge renewal without the need for tool grinding, setup changes, or entering of new values into a CNC program.
Common shapes of indexable inserts include square, triangular and rhombus (diamond) providing four, three and two cutting edges, respectively, on each side of the insert. A double-sided or invertible square insert, for example, can be flipped over to provide eight cutting edges.
The number of cutting edges is directly related to the cost per edge of the cutting insert. The more cutting edges that are available, the more the cutting insert has value. Thus, it is desirable to provide a cutting insert with multiple cutting edges.