1,721,050 research outputs found
Additive manufacturing as a potential and functional alternative in foot orthotics production
No full textFoot orthotics are devices designed and manufactured for helping people in physical disabilities. They work properly when they are personalized: fitting with the plantar foot. Although CNC machining allows a digital design and flexible manufacturing of customized devices, it remains only a potential alternative in comparison with current thermoforming procedures able to guarantee a feasible personalized approach. The consistency of Fused Deposition Modeling, as a direct digital manufacturing
technique, was investigated with the final attempt to propose it as a feasible alternative. The technological opportunities were investigated through a characterization of material and process parameters verified with geometrical and functional tests, finally validated by an economic point of view. Different additive strategies have been performed in order to better understand correlations between process parameters and product specifications
A Review of Prostatitis
No full textA recent Review on prostatitis provided a comprehensive summary but presented computed tomography (CT) as the sole advanced imaging technique for suspected prostatic abscess. In our view, magnetic resonance imaging (MRI) offers distinct advantages over CT in this clinical context. Transrectal ultrasonography (TRUS) is the first-line study for diagnosis of prostatic abscess, with sensitivity approaching 80%, and provides the added benefit of enabling image-guided drainage. Its limitations include operator dependency, patient discomfort, and inability to reliably assess extraprostatic spread of infection. For patients unable to undergo TRUS, CT is widely used because it is an easily accessible and cost-effective alternative. Computed tomography effectively visualizes larger abscesses and gas-forming infections but is less sensitive for small or multiloculated abscesses. For patients who are hemodynamically unstable, CT is useful because it can be rapidly obtained and iswidely available.However, the rationale for CT use does not apply to subacute or chronic presentations of prostatitis, for which MRI can have improved diagnostic accuracy. Magnetic resonance imaging provides superior soft tissue contrast, allowing earlier and more accurate identification of abscesses, which appear T1-hypointense and T2-hyperintense with restricted diffusion and peripheral enhancement. Diffusion-weighted imaging further enhances abscess detection and characterization, with very low diffusion coefficient values reflecting pus content. Magnetic resonance imaging also is helpful in defining extraprostatic extension of infection to seminal vesicles, periprostatic tissues, or pelvic sidewalls. In addition, MRI does not use ionizing radiation, an important consideration in younger or middle-aged men who require follow-up imaging because CT radiation increases oncologic risk andmay impair spermatogenesis, potentially affecting fertility. With an external phased-array coil, high-quality images can be obtained without an endorectal probe, improving tolerability in symptomatic patients
Direct digital manufacturing of shoe heels through Fused Deposition Modeling
Full text linkAdditive manufacturing process chains for direct part production in the footwear sector are being investigated almost exclusively for athlete shoe soles and orthotics. This paper focuses on the direct digital manufacturing of high heels for woman shoes, which could provide solutions for personalized production and complex design for high added-value shoes. The study aims at testing the introduction of additively manufactured components into conventional shoe production lines. Sample heels of two common designs have been fabricated by the Fused Deposition Modeling technique, assembled with conventional mounting machines, and tested for wearability according to standard procedures. The experimentation has shown that fully process compatible and functional heels can be produced for a basic design under some restrictions, and has allowed to identify critical issues to be dealt with for future applications on more critical heel shapes. These results will help to develop methods for a robust heel design exploiting the flexibility and creative freedom allowed by additive processes
A tool for computer-aided orientation selection in additive manufacturin processes
No full textThe paper presents a method for the optimal selection of build orientation for parts fabricated by additive processes. It is based on widely accepted selection criteria such as build speed, process cost and surface quality, which are evalutated through empirical models and balanced according to the need of each different application. Compared to existing methods, it tries to improve the treatment of surface quality for complex shaped parts. For this purpose, it takes into accunt additional criteria such as the integrity of fine form details and the distribution of estimated defects over specific regions of interest on part surface. A two-step selection procedure combines a generation of near-optimal orientations with a visual evaluation of canddate solutions. The method has been implemented in an interactive software tool and tested on some example cases
Edge quality in Fused Deposition Modeling: I. Definition and analysis
Full text linkPurpose – To discuss the problem of the geometric accuracy of edges in parts manufactured by the FDM
process, as a preliminary step for an experimental investigation.
Design/methodology/approach – Three geometric variables (inclination, included and incidence angle) were
defined for an edge. The influence of each variable on the geometric errors was explained with reference to
specific causes related to physical phenomena and process constraints.
Findings – Occurrence conditions for all causes were determined and visualized in a process map, which was
also developed into a software procedure for the diagnosis of quality issues on digital models of the parts.
Research limitations/implications – The process map was developed by only empirical considerations and
does not allow to predict the amount of geometric errors. In the second part of the paper, experimental tests
will help to extend and validate the prediction criteria.
Practical implications – As demonstrated by an example, the results allow to predict the occurrence of
visible defects on the edges of a part before manufacturing it with a given build orientation.
Originality/value – In literature, the geometric accuracy of additively manufactured parts is only related to
surface features. The paper shows that the quality of edges depends on additional variables and causes to be
carefully controlled by process choice
A methodological approach to radical technological changes and improvements in electron beam technology
No full textVirtual reality for assembly simulation and ergonomic analysis in automotive chain of production
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