| 摘要 |
<p>A double negative cutting insert (1) has opposite top and bottom sides between which transverse flank surfaces (9) extend, adjacent to which cutting edges (12, 16) are formed. More precisely, there are at least four useful major cutting edges (12), which separately extends from an active operating corner (10) towards a nearby first inactive corner (11). The individual major cutting edge (12) co-operates with a minor cutting edge (16) with the purpose of face machining the surface, that is left after material removal. The cutting insert has an octagonal basic shape, the top and bottom sides thereof having an identical shape with four spaced-apart supporting projections (18), which are placed near the four inactive corners (11) and have plane abutment surfaces (19) located in a common plane. An individual land (20) adjacent to the major cutting edges (12) has a concavely arched shape in order to provide a positive cutting geometry during operation. Thanks to the octagonal basic shape, the active corners of the cutting inserts may be made strong. <IMAGE></p> |
