Support structures are required in direct metal laser melting (DMLM) additive manufacturing (AM) technologies to support parts during the production of metal components. Support structures are required for most downward-facing surfaces (generally those at less than 30 degrees from the build platform) because the powder bed alone is not sufficient to hold the liquid phase in place that is created when the laser is scanning the powder. Supports are typically formed as either scaffolding or sometimes as hollow or cellular structures, and all need to be removed after printing. As such, they represent a considerable waste of material, energy and time employed for their construction and removal. In order to build complex geometries with overhanging and undercut surfaces, DMLM has to solidify these expensive materials into sacrificial support structures in order to control curling, deformation and shrinkage of the part caused by thermal stress, overheating, or by being dragged over by the machine's powder re-coating system. This paper aims to explore the current state of the art and near future developments, in particular automated placement softwares used in the design, structure and placement of support structures in the nascent precious metal DMLM process.

Author: Frank Cooper