Thermal experiments in direct metal laser sintering

This paper discusses recent work undertaken to quantify energy absorptance and material conductivity during the laser processing of a powder bed. A carbon dioxide laser was used in experiments, directly sintering single lines and layers on the surface of a stainless steel powder bed. Thermocouples positioned under the bed’s surface measured temperature changes with time. Using adapted equations, experimental quantities were combined to calculate the proportion of incident laser energy absorbed and held by the bed. Response to different situations was tested, such as use of an inert atmosphere and change of scanning conditions. When scanning layers at various values of scan spacing, it was discovered that this change in scan spacing led to a change in energy absorptance.