A bottom-up approach to experimentally investigate the deposition of austenitic stainless steel in laser direct metal deposition system

Abstract

Direct metal deposition (DMD) is a method of metallic part fabrication under the classification of additive manufacturing process. In DMD, parts are manufactured by melting powder particles reaching the deposition zone, layer by layer with a laser beam. This potential process promises manufacturing flexibility of complex shapes deposition with a range of challenging materials. The work presents the establishment of laser, powder and deposition parameters in a newly developed metal-based direct laser deposition system. The experiments are performed using a 1.2-kW diode laser of 976-nm wavelength coupled with coaxial fed powder delivery nozzle. Geometrical characteristics and mechanical properties of the deposited single-wall, multi-layer wall are determined and discussed. The study also discusses some of the challenges met during the deposition and their potential resolutions. Issues with uniformity of layer width, layer height and mechanical properties such as surface finish and micro-hardness are addressed. The specific aim of this experimental work is to effectively control the process parameters towards building a sound thin wall clad deposition and to further use those parameters for the development of a functional 3D component. A 3D functional component is deposited using 300 W laser power, 4 mm/s scanning speed, 1.05 g/min powder feed rate and 50% overlap ratio which shows a good geometrical resemblance with the original part. The study thus can provide intuitive guidance for deposition to metal additive manufacturing enthusiasts.