The cutting performance of indexable insert drill that has non-axisymmetrical geometry for drilling of difficult-to-cut materials is investigated. A twisted drill is also used to compare the cutting performance. The cutting characteristics are evaluated by tool flank temperature at peripheral corner edge θα, thrust force Ft, chip geometry and surface roughness Ra. The temperature of cutting tool is measured using a two-color pyrometer with an optical fiber. As work materials, the carbon steel, stainless steel, titanium alloy and nickel-base alloy are used. The θα and Ft of indexable insert drill are lower than that of solid drill in cutting of titanium alloy and nickel-base alloy. In the case of titanium alloy, the Ft of indexable insert drill is only 40% in the case of solid drill. On the other hand, this tendency reversed for stainless steel, and θα and Ft of indexable insert drill become higher than that of solid drill. The chip geometry by indexable insert drill is divided into parts in fragments so that there is chip breaker on the rake face of insert while the chip geometry by solid drill is continuous and long. The difference of surface roughness by the indexable insert drill and solid drill is negligible in the cutting of difficult-to-cut materials.
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