Project Details
Projekt
Modelling of sinter forging under consideration of uncertainty propagation
Applicants
Dr.-Ing. Lennart Hinz; Dr.-Ing. Johanna Uhe
Subject Area
Primary Shaping and Reshaping Technology, Additive Manufacturing
Measurement Systems
Measurement Systems
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 558606079
The powder pressing, sintering and sinter forging process chain enables the powder metallurgical production of complex components with outstanding microstructural properties and high material utilization and precision. Like all industrial processes, powder pressing, sintering and forging are subject to stochastic fluctuations in the process parameters, resulting in components that are subject to uncertainties. In interlinked processes, these uncertainties are propagated and can be amplified, attenuated or eliminated by mutual interactions. In particular, the stochastic nature of the powdery base material leads to diverse interactions and fluctuations in the subsequent process steps. For example, density gradients formed in the semi-finished product during powder pressing can lead to distortions in the sintered or sinter-forged components. Numerical approaches and corresponding material models that take compressible material behaviour into account are already available for designing and optimizing the powder metallurgy process route. However, the focus here is generally on an isolated process description without consideration of the interactions. The uncertainty of process parameters and their effects have not yet been taken into account. The aim of the project is therefore the cross-process modeling of the sinter forging process chain, taking into account the uncertainties that occur as well as their interaction and propagation. For this purpose, the process chain is implemented experimentally and equipped with metrological sensors. One of the focal points of the project is in-situ component monitoring for the continuous reconstruction of geometry and surface temperature in the sintering process in order to collect data for modeling uncertainty propagation and to predict core temperature and density distribution during the sintering process using soft sensors. As the powder pressing and sintering processes are difficult to measure, the uncertainty quantification is carried out using fast-calculating metamodels, which are trained using FE simulations. For a final analysis of the epistemic and aleatory uncertainty development, the developed models of the sub-processes are linked and the development of uncertainty along the process chain is quantified. Finally, validation is carried out using the experimental process chain. The developed models form the basis for an inverse multi-criteria optimization of the process chain, taking into account the propagation and interaction of uncertainty. In this way, the overall robustness can be increased by adjusting the process parameters or the energy input can be minimized by adjusting the sintering and heating times and temperatures.
DFG Programme
Priority Programmes
