Optimized Nanosecond Pulsed Laser Micromachining of Y‐TZP Ceramics

TLDR

Laser processing is being explored as an alternative to mechanically machining hard ytrrium‑stabilized tetragonal zirconia polycrystals, but the wide range of variables such as wavelength, focus, pulse width, power, and repetition rate makes finding optimal conditions challenging. This study investigates the parameters of a 60‑ns Nd:YAG laser for micromachining Y‑TZP ceramics. The authors used a 60‑ns Nd:YAG laser, systematically varying wavelength, focus, pulse width, power, and repetition rate to determine optimal micromachining parameters for Y‑TZP. At room temperature, Y‑TZP absorbs 1064 and 532 nm light only above a machining threshold with a 1.6 µm penetration depth, and under these conditions the authors achieved a maximum material removal rate of ~2 mm³/min, noting that pulse overlap and the combination of scan speed and repetition rate critically affect processing efficiency.

Abstract

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 mm 3 /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.