Selective Laser Melting of thin wall parts using pulse shaping

Pulse shaping is a technique used to temporally distribute energy within a single laser pulse. This provides the user 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 produce thin wall Inconel 625 (R) parts using pulse shapes that delivered a variety of different energy distributions. Parts built with and without pulse shape control were measured for width, top and side surface roughness. The efficacy of pulse shaping control is discussed including potential benefits for use within the Selective Laser Melting process. Pulse shaping was shown to reduce spatter ejection during processing, improve the top surface roughness of parts and minimise melt pool width. (C) 2009 Elsevier B.V. All rights reserved.