This video from Sandvik Coromant shows ceramic milling in action. The ceramic insert grade seen here, CC6060, is typically used for milling Inconel 718 engine casings (the workpiece seen here is Inconel 718) as well as for milling components for oil drilling equipment. In both cases, the value of milling with ceramic rather than carbide is a higher metal removal rate.
Sandvik lists these basic tips for using ceramic milling cutters:
1. Ceramic milling inserts typically run at 20 to 30 times the speed of carbide inserts, but at lower feed rates (about 0.040 inch per tooth). Due to the intermittent cutting, ceramic milling is a cooler operation than ceramic turning. For this reason, cutting speed of 2,300 to 3,300 sfm is feasible in milling, versus the 650 to 1,000 sfm typical for turning.
2. Ceramics have a tendency toward notching, which is why round inserts are primarily used. The round shape ensures a low entry angle.
3. Ceramics can handle high temperature, but not fluctuating temperature. For this reason, coolant should never be used with ceramic cutters.
4. Ceramics have a negative effect on surface integrity and topography, and are therefore not used when machining close to the finished component shape.
5. The maximum flank wear when using a ceramic insert in heat resistant superalloy material is 0.04 inch.
