Fabrication and application of micro thin film thermocouples for transient temperature measurement in nanosecond pulsed laser micromachining of nickel

In order to investigate the complicated transient thermal phenomena in laser micromachining, it is essential to accurately measure time-resolved temperatures of workpiece resulted from the transient laser–material interaction. While numerous analytic and numerical models have been developed, little experimental results are available for a solid understanding of transient thermal phenomena in nanosecond pulsed laser micromachining. In this paper, micro thin film thermocouples (TFTCs) with a high spatial and temporal resolution were fabricated on electroplated nickel substrates and used to measure transient surface temperatures in nanosecond pulsed laser micromachining by ablation. Transient temperatures were successfully measured, and the effect of laser energy fluences on peak temperatures was experimentally investigated. This study demonstrates that the micro TFTCs can be useful in measuring the transient temperatures micrometers away from the laser–material interaction region on the workpiece during laser micromachining, and the measured data could be utilized to validate and improve existing analytical and numerical models.