Product Code: ICAL08_801

A Gas-free Powder Delivery System for 100% Deposition Efficiency in Direct Laser Deposition
Authors:
Wei Wang, The University of Manchester; Manchester Great Britain
Andrew Pinkerton, The University of Manchester; Manchester Great Britain
Lin Li, The University of Manchester; Manchester Great Britain
Presented at ICALEO 2008

Metal powder delivery systems have been used widely in direct laser deposition (DLD) processes. Most current commercial DLD systems use a gas to carry the metallic powders to the point of delivery through a feed tube and then a nozzle. The major drawback of this method is that wastage of the expensive powder is very high. Although powder recycling has been practiced, in most cases the reported deposition efficiency remains below 30%. To overcome or mitigate this process deficiency, a gas-free powder delivery system has been developed. The system uses sonic/ultrasonic vibration to deliver a stream of powder through a feed nozzle to the laser generated melt pool, with a powder stream diameter smaller than the laser beam diameter on the target surface. Experimental tests are carried out with a 1.5 kW diode laser to build multiple layer parts. The test results show that up to 100% deposition efficiency can be achieved by using the developed DLD system. The deposition qualities in term of surface roughness, microstructure and porosity with different experimental parameters (laser power, traverse speed etc) are studied and compared with the results produced by current DLD methods.