Producing metal parts from Fused Filament Fabrication (FFF) 3D printing coupled with a metal/polymer hybrid filament, considering the advantages of high-performance and low cost, has generated considerable research interest recently. This paper addresses the studied relationship between variable printing/sintering directions and the properties of the sintered metal parts. It was shown that the printing directions played a significant role in determining the properties of final products, such as shrinkage, tensile stress, and porosity. The shrinkage in the layer direction because of anisotropic behavior is more minor than in the other dimensions. The microstructural analysis indicated that the printing directions had influenced the form and position of porosity on the produced metal parts. Most porosities occurred on the surfaces printed parallel to the printing bed. Furthermore, the sintering orientations had no possible benefits for dimension shrinkage, weight shrinkage, density, and porosity position of produced metal parts. However, the sintering direction “upright” resulted in parting lines inside the sintered tensile samples and made them fragile. The best printing-sintering combination was “on-edge-flat”.
Ultrasonic treatment (UST), more precisely, cavitation and acoustic streaming, of liquid light metal alloys is a very promising technology for achieving grain and structure refinement, and therefore, better mechanical properties. The possibility of predicting these process phenomena is an important requirement for understanding, implementing, and scaling this technology in the foundry industry. Using an established (casting) computational fluid dynamics (CFD)-simulation tool, we studied the ability of this software to calculate the onset and expansion of cavitation and acoustic streaming for the aluminum alloy A356, partly depending on different radiator geometries. A key aspect was a holistic approach toward pressure distribution, cavitation, and acoustic streaming prediction, and the possibility of two- and (more importantly) three-dimensional result outputs. Our feasibility analysis showed that the simulation tool is able to predict the mentioned effects and that the results obtained are in good agreement with the results and descriptions of previous investigations. Finally, capabilities and limitations as well as future challenges for further developments are discussed.
Energy consumption, greenhouse gas emissions, environmental impact levels, and the availability of materials as well as their sustainable usage are all topics of high current interest. The energy intensive processes of casting production such as heat treatment are particularly affected by the pursuit of sustainability. It has been estimated that up to 20% of the total energy demand in a non-ferrous foundry is required to provide the heat energy necessary during heat treatment processes. This paper addresses the application-oriented development of a sustainable configuration of the heat treatment process at the example of the aluminium-casting alloy A356 (AlSi7Mg0.3). Based on calculations of the physically necessary operating modes and under investigation of previous parameter recommendations, experimental studies were carried out to investigate the effects of various heat treatment parameters on the ultimate mechanical properties of the alloy. Since the achievable mechanical properties of the finished casting are decisive, the static and dynamic casting properties resulting from the heat treatment with optimized process parameters were compared with those of conventional process control. Significant optimization potential is shown for reducing the treatment time and thus lowering the energy consumption.
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