Finite element modelling of substrate thermal distortion in direct laser additive manufacture of an aero-engine component

The shape complexity of aerospace components is continuously increasing, which encourages researchers to further refine their manufacturing processes. Among such processes, blown powder direct laser deposition process is becoming an economical and energy efficient alternative to the conventional machining process. However, depending on their magnitudes, the distortion and residual stress generated during direct laser deposition process can affect the performance and geometric tolerances of manufactured components. This article reports an investigation carried out using the finite element analysis method to predict the distortion generated in an aero-engine component produced by the direct laser deposition process. The computation of the temperature induced during the direct laser deposition process and the corresponding distortion on the component was accomplished through a three-dimensional thermo-structural finite element analysis model. The model was validated against measured distortion values of the real component produced by direct laser deposition process using a Trumpf DMD505 CO2 laser. Various direct laser deposition fill patterns (orientation strategies/tool movement) were investigated in order to identify the best parameters that will result in minimum distortion.