Kennametal has developed a ceramic grade that can be used for machining gray cast iron in high-speed grooving applications, to produce valve and automotive brake discs components, brake drums, wheel hubs and parts for pumps. These ceramic tool inserts also can be used for side turning and groove-and-turn applications.
The A4 groove and turn inserts are made of Kyon 3500 — a silicon nitride Si3N4 ceramic grade developed by Kennametal Inc. (www.kennametal.com). The inserts also are available in carbide grades. Kennametal says the A4 inserts can be used for plunge grooving, and for groove-and-turn applications on gray cast iron, and it plans to develop supplemental Kyon grades for aerospace and other applications
The inserts have an extra-long clamping surface, a top guide rail that resists side deflection and a 120° V-prism on the bottom to seat them securely in toolholders. "This fixturing results in high rigidity and improved system performance," says Helmut Gremer, product manager for grooving, for Kennametal Europe. A4 double-ended inserts are available in rectangular and full-radiused styles with cutting widths from 0.125 in. to 0.250 in. (3 mm to 8 mm .) The A4 system includes a full line of toolholders in addition to inserts, and can be used for turning, facing, grooving, face-grooving and cut-off. The system cuts I.D. and O.D. applications with no turret indexes.
The company's existing A4 toolholders can be used with the Kyon 3500 inserts to provide higher feed rates and improved performance, and that can result in reduced machining time and increase savings when compared with current tool insert systems. The company says users can replace carbides for grooving and turning gray cast iron with these ceramic tools for high-speed grooving.
In addition, Kennametal says the toughness of Kyon 3500 and its advanced insert design can increase feed rates 20 to 40 percent more than with competitive products.