Metal Additive Manufacturing Conference - MAMC 2021

Laser Metal Deposition (LMD) is an established repair process for components such as thin-walled turbine blades. Repair of thin-walled structures encounters several challenges due to the limited heat transfer. If the narrow process window is not met, mechanical properties and geometric accuracy deteriorate. Because of the rising temperature during the LMD process, its parameters usually need to be adjusted with increasing build height. Currently, the development of repair processes for thin-walled structures is usually based on iteratively adjusting the process parameters. For a predictive process development, the fundamental influence of LMD process parameters on part deviation and the resulting mechanical properties must be understood. In this paper, the influence of build strategy and process parameters such as laser power and feed rate on geometric accuracy and resulting residual stresses is investigated. To approximate the heat transfer within thin-walled structures, material is deposited onto the edges of IN718 sheets. In situ thermography is used to study the temperature curve. Furthermore, geometric accuracy and residual stresses are measured post mortem.