Combined wire and powder feeding laser direct metal deposition for rapid prototyping

Most direct laser deposition (DLD) processes utilise metallic powders to obtain near net shape objects. On the other hand wire feeding has been used in many laser-cladding applications. Each feeding method has its own advantages and disadvantages. Wire feeding laser deposition typically has higher deposition rate and higher material usage rate than the powder feeding deposition process whilst powder feeding gives better geometry control. In this study a new approach is investigated by combining wire and powder feeding to achieve higher build rate and higher material usage efficiency whilst maintaining the geometry accuracy. Single layer clad build by the three methods are compared and analysed in terms of cost, catchment efficiency, surface roughness and microstructure. A 1.5 KW diode laser is used to deposit 316L steel. The results showed that by combining both wire and powder, higher catchment efficiency is achieved, that surface roughness is increased but remains constant for all the worked out parameters, that microstructure remains the same for all the three deposition methods. A comparison between the three methods is described and its characteristics presented.