Spiral growth manufacturing is a new innovative powder based rapid manufacturing
technique. The innovation exists in the methodology in which powder layers are deposited.
Unlike other pre-placed powder systems, the deposited layers move relative to the location at
which they are processed. This is made possible by a rotating build drum into which powder is
deposited, in spiralled layers, from a stationary hopper. With this configuration powder can be
continuously deposited and levelled and simultaneously processed, eliminating delays in the
build cycle. Stainless steel and cobalt-chrome powder is selectively melted using a 100W flash
lamp pumped Nd:YAG laser. This paper reports on factors affecting build rate and on build
strategies for creating a number of axis-symmetric thin and thick walled cylinders. Experimental
results suggest that build rate for thin walled structures bonded to a substrate will ultimately be
governed by tangential movements of the powder particles when frictional forces are not
sufficient to accelerate the particles along a curved path, provided that enough laser power is
available for melting. Even melt pool balling, which is evident when melting one layer at high
speeds, diminishes in multiple layer builds due to re-melting and infilling.Mechanical Engineerin
