Industrial Applications of Laser Additive Manufacture

Two laser additive manufacture approaches will be discussed in this presentation. The first is Laser Metal Deposition (LMD) which uses metal powder or wire as a filler material which is fed, through a nozzle, to a melt pool created by a high power laser beam. Precise track welds can be created using CNC control. Applications range from the cladding of surfaces to a layer wise build-up of unsupported 3D geometry. This paper introduces the methods to fabricate a net shape thin wall (<1mm thick) aero engine combustion casing using 3+2 axis CNC manipulation of a powder nozzle and substrate. Substrate manipulation during LMD is necessary for the manufacture of geometries which exhibit overhanging features. In support of this work, mathematical algorithms to slice an STL file and generate a 5 axis tool path, coupled with developments in in-line ultrasonic inspection for quality control are also reported. The effect of geometry, laser power, scan speed, powder feed, layer thickness and nozzle standoff on wall thickness, magnitude of the distortion and surface roughness was investigated.  In particular, results successfully demonstrated a final part geometry with a consistent wall thickness and surface finish.

The second is Selective Laser Melting (SLM), which is well established for the manufacture of titanium and steel alloys. The development of aluminium alloys however has only been represented by casting alloys with moderate strength (e.g. AlSi10Mg). During this work, the laser beam spot sizes were observed to have significant effect on the resultant mechanical properties. The objective of the work presented is to demonstrate further the capabilities of SLM for achieving high strength results for aluminium alloys.