Double-pulse Machining As a Technique for the Enhancement of Material Removal Rates in Laser Machining of Metals

Several nanosecond 0.53-μm laser pulses separated by several tens of nanoseconds have been shown to significantly enhance (three to ten times) material removal rates while minimizing redeposition and heat-affected zones. Economic, high-quality, high-aspect ratio holes (>10:1) in metals are produced as a result. A phenomenological model whereby the second laser pulse interacts with the ejecta produced by the first laser pulse and in close proximity to the material surface is consistent with the observations. Incident laser wavelengths of 1.05 and 0.35 μm also benefit from this pulse format.