This paper advances previous reported work on the mapping and modelling of single
tracks and layers produced in powder beds of tool steel and stainless steel powders by a CO2
laser. For single tracks it reports on predicted and simulated track masses. It validates the
simulations, including the use of absorption close to 1.0 when cylindrical tracks are formed. It
also reports on melt pool temperature calculations and estimated melt pool dimensions which are
used, in conjunction with bed physical properties, to explain why the single tracks form as either
continuous with a crescent shape cross-section, continuous with an elliptical section,
discontinuously irregularly broken, discontinuously balled or only partially melted as scan
speeds and laser powers change. It then extends its scope, experimentally, to consider effects of
scan spacing on single layer formation.Mechanical Engineerin