5th CIRP conference on High Performance Cutting edition:5th location:Zurich date:4-7 june 2012
This paper presents an initial study on the feasible machining of zirconia ceramics in the hard state by means of poly crystalline diamond (PCD) inserts. Experiments were conducted on a Mori Seiki turn-mill centre; a fully sintered yttria stabilized tetragonal zirconia poly crystalline ceramic (Y-TZP) was used as work piece material. PCD tools with small rake angle (0˚) and large nose radius (0.8 mm) were chosen for the experiments. The study on the influence of process parameters, such as depth of cut, feed and cutting speed (>300 m/min), on surface quality and tool wear was approached by means of a mixed full factorial experimental design. The machined samples along with process chips were also observed by scanning electron microscope (SEM) to achieve a deep understanding of the occurring material removal mechanisms (MRM) and to analyse the integrity of the resulted surface. The PCD inserts after usage were also inspected. The findings show that surface roughness below 0.6 m are easy achievable, although the repeatability of the results is quite poor; the machining mode is mainly based on a combined ductile-brittle material removal; adhesion of the work piece is regarded as the most significant wool wear mechanism.