Types of Chip Formation in Machining of Several Metals at Various Cutting Speeds

Orthogonal cutting of eight kinds of the work materials including cast irons, steels and copper alloy was experimentally photographed at the cutting speeds ranging from 10 mm/min to 200 m/min, in order to organize systematic knowledge on the formation, separation and the final shape of the chip. The results of these tests were as follows:The chip formation phenomenon exhibits characteristic variation of its type at various cutting speeds, inherently to the cut metal. Various steels and the brass show similar tendency of chip formation whereas cast irons behave differently. When the cutting speed is increased, the chip formation mechanism changes from crack type to shear type, and from shear type to flow type. The shape of the chip meantime changes from the powder or fragmental chip to the spiral chip, and from the spiral chip to the helical or tangled chip. At low speed, the chip is mostly separated from the workpiece at the point of the tool tip, while, at high speed, it is separated at the place far from the tool tip.