Optimized Nanosecond Pulsed Laser Micromachining of Y-TZP Ceramics

Owing to the inherent difficulty of mechanically machining hard, ytrria-stabilized tetragonal zirconia polycrstal (Y-TZP) ceramics, laser processing has recently been investigated as an alternative. However, owing to the vast range of variables such as wavelength, focus position, pulse width, power, and repetition rate, finding the optimum processing conditions can be difficult. In this report, we examine the parameters for a nanosecond pulsed (60 ns) Nd:YAG laser. It was found that at room temperature, the absorption of Y-TZP at 1064 and 532 nm is very low; however, it becomes highly absorbing above a "machining threshold" with a penetration depth of 1.6 μm above the threshold. In this condition, we have found the combination of processing variables that provides the optimum material removal rate (up to ∼2 mm³/min). Additionally, it was found that the pulse overlap has a significant influence on the efficiency of the processing and therefore the combination of scan speed and repetition rate must be carefully considered.