4 research outputs found
Influence of laser beam profile on the selective laser melting process of AlSi10Mg
No full textArt. 022059, 11 S.Selective laser melting (SLM) offers great potential to manufacture customized and complex metallic parts. Major drawbacks that limit its industrial application are the high cost of the process that is related to low process speeds and issues with reproducibility. One important process parameter that has the potential to increase the reproducibility and speed of the process is the laser beam intensity profile. Since its influence has not been sufficiently investigated, the goal of this study is to analyze the effect of the beam profile on the SLM process of AlSi10Mg. Single tracks and density cubes are manufactured with different process parameters and two beam profiles (standard Gaussian and Donut beam profiles) and analyzed with respect to appearance, the size of melt tracks, porosity, and the types of defect. The results reveal several advantages of the Donut beam profile such as fewer defects and a significantly broader process window that promises a more robust process.32Nr.
Influence of Process Parameters on the Quality of Aluminium Alloy EN AW 7075 Using Selective Laser Melting (SLM)
No full textAbstractSelective laser melting (SLM) is an additive manufacturing process, forming the desired geometry by selective layer fusion of powder material. Unlike conventional manufacturing processes, highly complex parts can be manufactured with high accuracy and little post processing. Currently, different steel, aluminium, titanium and nickel-based alloys have been successfully processed; however, high strength aluminium alloy EN AW 7075 has not been processed with satisfying quality. The main focus of the investigation is to develop the SLM process for the wide used aluminium alloy EN AW 7075. Before process development, the gas-atomized powder material was characterized in terms of statistical distribution: size and shape. A wide range of process parameters were selected to optimize the process in terms of optimum volume density. The investigations resulted in a relative density of over 99%. However, all laser-melted parts exhibit hot cracks which typically appear in aluminium alloy EN AW 7075 during the welding process. Furthermore the influence of processing parameters on the chemical composition of the selected alloy was determined
Measurement of actual powder layer height and packing density in a single layer in selective laser melting
No full textS.176-183For a detailed numerical analysis of laser-material interactions and melt pool dynamics in selective laser melting (SLM), it is important to consider correct powder layer height and packing density in a single layer. Thus far, most experts assume that the powder layer height, which is equal to the leveling height of the build platform divided by the packing density of the powder bed, reaches a steady state after several layers. However, this assumption neglects the fact that a certain amount of powder is deposited (e.g., by spatter), and therefore, does not contribute to the molten powder layer height and that the packing density in a single layer is smaller than in ""bulk."" To determine the actual powder layer height and packing density in a single layer, experiments are conducted using two different materials (SS 17-4 PH and Ti6Al4V) and layer heights (30 and 50 mm). The results reveal that the powder layer height is between 4 and 5.5 times the leveling height of the build platform and is, therefore, significantly larger than that assumed thus far. This is an important finding to consider when one investigates the details of the laser-material interaction and melting process in SLM, e.g., by numerical simulations. The measured packing density varied between 44% and 56%.2
Influence of Process Parameters on the Quality of Aluminium Alloy EN AW 7075 Using Selective Laser Melting (SLM)
No full textS.918-926Selective laser melting (SLM) is an additive manufacturing process, forming the desired geometry by selective layer fusion of powder material. Unlike conventional manufacturing processes, highly complex parts can be manufactured with high accuracy and little post processing. Currently, different steel, aluminium, titanium and nickel-based alloys have been successfully processed; however, high strength aluminium alloy EN AW 7075 has not been processed with satisfying quality. The main focus of the investigation is to develop the SLM process for the wide used aluminium alloy EN AW 7075. Before process development, the gas-atomized powder material was characterized in terms of statistical distribution: size and shape. A wide range of process parameters were selected to optimize the process in terms of optimum volume density. The investigations resulted in a relative density of over 99%. However, all laser-melted parts exhibit hot cracks which typically appear in aluminium alloy EN AW 7075 during the welding process. Furthermore the influence of processing parameters on the chemical composition of the selected alloy was determined.8
