Iskanje po katalogu digitalne knjižnice

Opis: This article has presented a technical concept for producing precisely desired Additive Manufactured (AM) metallic products using Artificial Intelligence (AI). Due to the stochastic nature of the metallic AM process, which causes a greater variance in product properties compared to traditional manufacturing processes, significant inaccuracies in metallurgical properties, as well as geometry, occur. The physics behind these phenomena are related to the melting process, bonding, cooling rate, shrinkage, support condition, part orientation. However, by controlling these phenomena, a wide range of product features can be achieved using the fabricating parameters. A variety of fabricating parameters are involved in the metal AM process, but an appropriate combination of these parameters for a given material is required to obtain an accurate and desired product. Zero defect product can be achieved by controlling these parameters by implementing Knowledge-Based System (KBS). A suitable combination of manufacturing parameters can be determined using mathematical tools with AI, considering the manufacturing time and cost. The knowledge required to integrate AM manufacturing characteristics and constraints into the design and fabricating process is beyond the capabilities of any single engineer. Concurrent Engineering enables the integration of design and manufacturing to enable trades based not only on product performance, but also on other criteria that are not easily evaluated, such as production capability and support. A decision support system or KBS that can guide manufacturing issues during the preliminary design process would be an invaluable tool for system designers. The main objective of this paper is to clearly describe the metal AM manufacturing process problem and show how to develop a KBS for manufacturing process determination.
Ključne besede: metallurgical properties, geometry, additive manufacturing, artificial intelligence, knowledge-based system
Objavljeno v DKUM: 25.09.2024; Ogledov: 0; Prenosov: 3
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Opis: The selective laser melting (SLM) process for manufacturing metals continues to be challenging in terms of achieving the maximum metallurgical properties that the process can provide. There are a variety of manufacturing parameters in the process that have individual characteristics, and when combined with other variables, the characteristics can be varied. However, in this study, the two most important manufacturing parameters, namely build direction and laser power, were considered to investigate their effects on density and tensile properties. Previously, the best scanning speed, hatch spacing, and layer thickness were determined, which directly affect the volumetric energy density in the SLM process. In this study, three different orientations and three different laser powers were selected, namely the X, Y, and Z directions and 55 W, 75 W, and 95 W laser power, respectively. Significant differences in product density were observed for the samples fabricated in the different orientations and with the different laser powers. The specimens fabricated in the Z direction always exhibit higher strength and ductility, which are significantly different from the specimens fabricated in the X and Y directions, while the laser power was 75 W and 95 W, respectively
Ključne besede: cobalt-chromium alloy, orientation, density, tensile strength, ductility, selective laser melting
Objavljeno v DKUM: 25.09.2024; Ogledov: 0; Prenosov: 2
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Opis: When manufacturing complicated products where both material and design play a role, especially thin and curved components, it is difcult to maintain accurate dimensions in Selective Laser Melting. Considering these difculties, this article presents the dimensional errors in the fabrication of Ti-6Al-4V discs and their thermomechanics during manufacturing. Various combinations of laser processing parameters were used to fabricate the 2.00 mm thick discs with a diameter of 5.70 mm. It was found that the thickness shortened and the round shape changed to an oval shape for most of the discs. The thickness decreased along the build-up direction from the bottom to the top and formed a taper that increased with increasing energy density (ED). The horizontal diameter of the discs changed slightly, while the vertical diameters changed remarkably with increasing ED. On the other hand, reducing the laser power resulted in a reduction of the roundness error, while it caused a reduction of the thickness. The hatch spacing signifcantly afected the volume of the melt pool and caused a change in the vertical diameter. The central part of the curved surface of the discs became concave and the concavity increased due to the increasing ED.
Ključne besede: dimension, Ti-6Al-4V, lase power, scanning speed, hatch spacing, selective laser melting
Objavljeno v DKUM: 29.03.2024; Ogledov: 219; Prenosov: 9
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Opis: Osnovni namen diplomske naloge je ugotoviti, katere napake se pojavijo, ko že imamo stabilen proces brizganja plastike. V diplomski nalogi so opisane osnove brizganja plastike. Narejena je analiza napak, ki so se pojavile med delovanjem, in podane so smernice za reševanje napak. Na podlagi analize podatkov je izdelana podatkovna baza za tehnologe, s katero bodo hitro in učinkovito reševali napake pri brizganju plastike. S tem se zmanjša srednji čas popravila napak, kar pomeni, da se zmanjša izmet in je manj zastoja v proizvodnji. Z analizo napak, ki so se pojavile, so bile določene tudi kritične točke v proizvodnji.
Ključne besede: Plastika, brizganje plastike, napake, proizvodnja
Objavljeno v DKUM: 28.02.2024; Ogledov: 371; Prenosov: 42
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Opis: Accuracy and precision are essential in extrusion-based material handling such as three-dimensional (3D) bioprinting. However, the elasticity of components, backlash, variability of nozzle and cartridge shapes, etc. can lead to unpredictable printing results, which is further complicated by the wide range of rheologically diverse materials and complex sample designs. To address this issue, we present an algorithmic approach to compensate for the discrepancies between piston motion and material extrusion in syringe-based extrusion systems. This approach relies on cyclical, iterative optimization through rapid piston movements, which are adjusted based on extrusion analysis. In this work we establish a general theoretical framework for extrusion and link the rheological properties of prepared hydrogels with shear rates in a typical bioprinting process. The determined properties are compared with the success of the developed algorithm to modify machine instructions for precise material deposition of short, interrupted lines, as well as multi-layered scaffold structures. Overall, our approach provides a means of improving the accuracy and precision of complex extrusion-based bioprinting systems, without prior knowledge of set-up or material properties, making it highly versatile and suitable for a wide range of applications, particularly when the combined set-up and material properties are too complex for solely predictive approaches.
Ključne besede: 3D bioprinting, syringe extrusion, optimization, algorithm
Objavljeno v DKUM: 21.04.2023; Ogledov: 684; Prenosov: 93
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