Polycrystalline cubic boron nitride (PCBN) is a difficult-to-machine ceramic material due to its ultra-high hardness and good chemical and thermal stability. In this paper, we report a novel CO2
laser cutting method based on crack separation mechanism for electrically insulating PCBN blanks with aluminum nitride as the binder phase. During the localized laser heating of the blank surface in an oxygen-rich environment, the binder phase undergoes chemical transitions resulting in a build-up of tensile stresses due to shrinkage and thermal gradients. These tensile stresses in the surface layers lead to crack formation and subsequent separation of PCBN wafers along the laser path. The material removal mechanism was investigated in both CO2
laser alone and hybrid CO2
laser/waterjet cutting systems. In comparison to CO2
laser alone, hybrid CO2
laser/waterjet system required more energy but produced better cut quality in terms of kerf, cut straightness, taper and surface roughness. Published in the Transactions of NAMRI/SME
, Vol. 36, 2008, pp. 517-524.