Selective Laser Melting of Inconel 625 using Pulse Shaping

Pulse shaping is a technique used to temporally distribute energy within a single laser pulse. This allows the user to have an added degree of control over the heat delivered to the laser material interaction zone. Pulses that induce a gradual heating or a prolonged cooling effect can be generated with peak power/pulse energy combinations specifically tailored to control melt pool properties and eventual part formation. This investigation used a pulsed 550W Nd:YAG laser to melt 0.1mm layers of Inconel 625 from a powder bed. Initially a set of optimization experiments were completed to develop laser parameters that enabled the production of thin wall parts with low top and side surface roughness. Thin wall parts were then built using pulse shape control employing a variety of pulse energy distributions. Parts built with and without pulse shape control were measured for width, top and side surface roughness. The effectiveness of pulse shaping control is discussed including potential benefits for use within Selective Laser Melting (SLM).