Machinability and Material Removal Mechanism of Face Centred Cubic (FCC) Conductive Ceramic TiBCN in EDM Processing

Fcc-TiBCN powder synthesized by boronizing of Ti was pressured into monolithic block by hot pressing (HP) method. Then the block material was machined by wire-cut EDM. The machinability and the material removal mechanisms were discussed of Fcc-TiBCN block in wire-cut EDM. Results show that the machinability of Fcc-TiBCN is satisfying. The discharge current has little relationship on surface roughness in the range of factory-adjusted optimum settings. The discharge duration and pulse interval time play an important role on the quality of machined surface and EDM machining efficiency. In order to obtain excellent quality of the machined surface, the number of power tube turned on can not exceed 6, and the pulse interval time must be as long as possible. The mini roughness of machined surface is 0.4μm～0.6μm as the number of power tube turned on is 5, the pulse interval time and discharge duration is set in the range of 20～22μs and 65～75μm, respectively. There are three material removal mechanisms of TiBCN conductive ceramic in the EDM machining process: spalling, melting and evaporation. Spalling is the main mechanism resulted by thermal stress superposing.