Abstract:
In direct laser deposition, (DLD) metallic powder injected into a laser generated melt
pool on the substrate surface, melts and after movement of the laser solidifies. By
overlapping and offsetting these clads, construction of a three-dimensional, fully dense
near net shape part is possible. The cost of powder wasted in commercial DLD machines
has been a concern to the industries. The deposition efficiency of these machines has
been limited to 5 – 40%. More than 60% of the powder is wasted and is being disposed
off which makes the system economically and environmentally expensive. Although
efforts to recycle the powder have been practiced but this has not been adopted in many
sectors, including the aerospace industry, because of the fear that the re-use of powder
may lead to a drop in part quality.
The objective of this study is to investigate whether the deposition
efficiency of DLD process can be enhanced. In previous studies, powder delivery nozzle
diameter, table speed and powder carrying gas delivery rate were found to be the most
influential parameters. All pointed towards the speed of powder particles and the powder
stream diameter. In this study, it is aimed to achieve the powder flow by vibrating the
powder delivery nozzle using sonic frequencies. The nozzles with different diameters,
with different vibrating frequencies will be used to find the best flow.
