Additive manufacturing is typically a flexible alternative to conventional manufacturing processes. However, manufacturing costs increase due to the effort required to experimentally determine optimum process parameters for customized products or small batches. Therefore, simulation models are needed in order to reduce the amount of effort necessary for experimental testing. For this purpose, a novel technological simulation method for directed energy deposition additive manufacturing is presented here. The Dexel-based simulation allows modeling of additive manufacturing of varying geometric shapes by considering multi-axis machine tool kinematics and local process conditions. The simulation approach can be combined with the simulation of subtractive processes, which enables integrated digital process chains.

Dünnwandige Strukturbauteile neigen aufgrund der Schwingungsanfälligkeit häufig zu Ratterschwingungen. Durch eine Modalanalyse können Stabilitätskarten berechnet und Ratterschwingungen vermieden werden, was sehr aufwendig ist. Das ZeTeM Bremen und das Institut für Fertigungstechnik und Werkzeugmaschinen IFW Hannover erforschen mit der Airbus GmbH einen softwarebasierten Ansatz zur Simulation von Nachgiebigkeitsfrequenzgängen. Durch eine Kopplung von NC- und FE-Simulation erfolgt eine simulative Abschätzung des Bauteilschwingungsverhaltens. Thin-walled structural components often tend to chatter vibrations due to their compliancy. Modal analyses can be used to calculate stability maps and avoid chatter vibrations, but this is time-consuming. ZeTeM Bremen and IFW Hannover together with Airbus GmbH are researching a software-based approach to simulate the frequency response function (FRF). Coupling NC and FE simulation allows for a simulative approximation of the component dynamics.

Engine manufacturers generate about 50% of their total turnover with maintenance. Damaged parts can either be replaced by spare parts or can be regenerated by e.g. local welding processes. One major step of the manufacturing part of the process chain for regeneration after the material deposition is the removal of excess weld material by cutting, which is called recontouring. Recontouring is often the last process step, which defines the final surface integrity and thus the performance of the repaired parts. Thereby, each component has a batch size of one by reason of individuality. In industrial praxis, the recontouring is done mainly with high manual effort. This results in uncertain and unreproducible repair processes for each component. Hence, a major challenge for recontouring processes is the reduction of the required manual effort by an automated method. In the subproject C1 “simulation-based process design of recontouring technologies”, machining investigations and technological simulations were applied in combination with suitable models for a process adaption in order to reach the required workpiece properties. A special focus was the transition from the undamaged area to the deposited material. Furthermore, a method for effective process planning was developed for the generation of 5-axis milling tool paths. This increases the effectiveness of the process planning by adapting them to the individual shape of the component. The present paper gives an overview of the main results of the investigation of methods for the individual process planning of recontouring technologies based on process simulations. This includes the development of an algorithm for the automatic planning of the recontouring process. A Dexel-based simulation method was developed and experimentally validated which allows the prognosis of the geometrical shape of the material deposition. Based on that, the influence of the resulting material allowance on the recontouring was studied. The aim was the generation of a part quality that satisfies the requirements of the functional review. The evaluation of the part quality was conducted by a Dexel-based technological process simulation of the recontouring process. This allowed the prediction of the workpiece surface as well as the research of the influence of the process parameters on the main residual stresses.