MICROCUTTING OF NiTiCu ALLOY WITH PULSED FIBER LASER

Laser microcutting of thin sheets made of innovative and hard to machine materials, such as shape memory alloys (SMAs), is a very interesting topic. Innovative laser sources, such as pulsed fiber lasers, are becoming promising tools to be used in precise and fast operations in industrial applications. The positive features of this type of laser sources are high beam quality, strong focusability, high pulse energy and consequently high productivity. On the contrary the most important drawback is the pulse width in nanosecond regime, which means thermal effects in the workpiece. The investigated material is a nickel-titanium-copper (Ni40Ti50Cu10) alloy, a ternary SIVA derived from NiTi binary alloy. In this work the effect of laser process parameters, such as number of laser passes, type of shielding gas, gas pressure and process speed on the cutting edge quality features, such as the amount of spatter and the kerf width, was studied. Finally functional characterization, i.e. differential scanning calorimetry (DSC) and mechanical measurements (nanoindentations), of the laser cutting edge was performed.