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SOFT TISSUE DIAGNOSIS IN MAXILLOFACIAL SURGERY: A PRELIMINARY STUDY ON THREE-DIMENSIONAL FACE GEOMETRICAL FEATURES BASED ANALYSIS
Full text linkSustainable production of AlSi10Mg parts by laser powder bed fusion process
Full text linkLaser powder bed fusion (L-PBF) is an additive manufacturing technology that allows producing complex and lightweight parts without the use of specific tooling during the building process. However, despite continuous developments, some problems limit its use in series production. To introduce these systems in mass production, it is necessary to solve the problems and exceed the limits related to the requirements of industrialization: higher productivity, less material consumption, less over-production, and less waste, greater stability of the process, and higher quality of the final components. In this study, good practices to reduce resource consumption are presented. The production rate of the L-PBF technique was increased to produce AlSi10Mg alloy components. All the samples were manufactured with 90-μm-layer thickness increasing productivity by approximately 65%. A design of experiments (DOE) method was used to analyze the effect of process parameters on the densification percentage. The produced samples were observed with a non-destructive process, the X-ray computed tomography system, to detect the presence of defects and pores. It has been found that a combination of parameters can induce porosities with a morphology such that after stress relieving the density increases rather than decreases as has been widely discussed in the literature. The mechanical properties are comparable with the literature values for conventional technologies. Good values of as-built surface roughness were also achieved despite the layer thickness
Computer Aided Morphological Analysis for maxillo-facial diagnostic: a preliminary study
Full text linkThis article compares most of the three-dimensional (3D) morphometric methods currently proposed by the technical literature to evaluate their morphological informative value, while applying them to a case study of five patients affected by the malocclusion pathology. The compared methods are: conventional cephalometric analysis (CCA), generalised Procrustes superimposition (GPS) with principal-components analysis (PCA), thin-plate spline analysis (TPS), multisectional spline (MS) and clearance vector mapping (CVM). The results show that MS provides more reliable and useful diagnostic informatio
Dynamic depreciation for parts produced using laser-based powder bed fusion of polymers
No full textLaser-based powder bed fusion of polymers (PBF-LB/P) is one of the most widely used additive manufacturing technologies for producing complex and customized components. One of the key aspects of this process is the recycling of the powder, which is central to the technology’s overall efficiency. During reuse cycles, the powder undergoes inevitable chemical, physical and mechanical changes that directly affect the quality of the final artifacts. This directly impacts process sustainability and production costs. The Sum-of-the-Year’s Digits (SOYD) depreciation model, which has been proposed in the literature for metal powders, assumes an initial moderate decline in value, followed by a slower decline upon reuse. However, polymer powders can degrade more quickly than metal powders, reaching a point of no return sooner. Therefore, the SOYD model has been modified by introducing a nonlinear function to better reflect the non-constant loss of value of the powder. Initially, the loss of value accelerates, then stabilizes, and accelerates again towards the end of the powder’s useful life. The proposed depreciation model was used in a case study with two scenarios, which considered the varying residual economic values of recycled polyamide 12 (PA12) powder. The analysis shows that the method used to calculate powder reuse, whether in processing cycles or hours, can significantly impact on the overall material cost and, consequently, the final product cost
Esercitazioni 3D al computer e scenari simulati di medicina d'emergenza e delle catastrofi: il ruolo del fotorealismo
No full textA MORPHOLOGICAL METHODOLOGY FOR THREE-DIMENSIONAL HUMAN FACE SOFT-TISSUE LANDMARKS EXTRACTION: A PRELIMINARY STUDY
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