Asymmetric substrate thermal conditioning in DED-LB/M: effects on geometry and properties

The laser- and metal-powder-based directed energy deposition process (DED-LB/M) introduces a significant amount of heat into the substrate or workpiece. Complex thermal mechanisms, resulting from rapid melting, solidification, and cooling, are leading to complex thermal mechanisms in the deposited structures and the substrate workpiece. The cooling behavior of the built structure and the substrate workpiece depends on the specific geometry. Different geometries can lead to different cooling rates and mechanical as well as geometric properties. By controlling the heat balance and cooling behavior, the properties of the built structures can be influenced. The cooling behavior can be influenced by controlling the substrate workpiece temperature. While heating the substrate slows down the cooling process, cooling the substrate accelerates the cooling rate. In this study, the influence of an external, asymmetric substrate temperature control on the DED-LB/M process was investigated. For this study, an asymmetric temperature control platform was developed, enabling localized control of the substrate temperature within a single workpiece. Therefore, the cooling behavior of the deposited structure could be influenced locally. The influence of asymmetric substrate temperature control was investigated based on the geometric and mechanical properties of the deposited structures.