Performance of single Si3N4 and mixed Si3N4+PCBN wiper cutting tools applied to high speed face milling of cast iron

In this work two face milling cutter systems were used in high speed cutting of gray cast iron under cutting condition encountered in the shop floor. The first system, called ‘A’, has 24 Si₃N₄ ceramic inserts all with square wiper edges. The second system, called ‘B’, is a mixed tool material system, having 24 wiper inserts, 20 of them are Si₃N₄ intercalated by four PCBN inserts. Cutting speed (v_c), depth of cut (doc) and feed rate per tooth (f_z) were kept constant. Surface roughness (R_a and R_t) and waviness (W_t), tool life (based on flank wear, VB_Bmax) and burr formation (length of the burr, h) were the parameters considered to compare the two systems. System ‘B’ presented better performance according to all parameters, although only end of life criterion based on R_t parameter has been reached.