Abstract Nowadays additive manufacturing is affected by a rapid expansion of possible applications. It is defined as a set of technologies that allow the production of components from 3D digital models in a short time by adding material layer by layer. It shows enormous potential to support wind musical instruments manufacturing because the design of complex shapes could produce unexplored and unconventional sounds, together with external customization capabilities. The change in the production process, material and shape could affect the resulting sound. This work aims to compare the music performances of 3D-printed trombone mouthpieces using both Fused Deposition Modelling and Stereolithography techniques, compared to the commercial brass one. The quantitative comparison is made applying a Design of Experiment methodology, to detect the main additive manufacturing parameters that affect the sound quality. Digital audio processing techniques, such as spectral analysis, cross-correlation and psychoacoustic analysis in terms of loudness, roughness and fluctuation strength have been applied to evaluate sounds. The methodology herein applied could be used as a standard for future studies on additively manufactured musical instruments.
This work aims to present the application of mechanical modeling software in three dimensions in the medical field, analyzing the procedures used by the engineer to support the orthopedic surgeon in preoperative planning.The first step of the procedure involves CT examinations in patients selected for surgery: DICOM images are managed in post-processing to obtain multiplanar reconstructions of the bone lesion to be treated.The files are then optimized, made shareable and imported into CREO's work platform; this is part of a family of CAD software products for mechanical design, developed by PTC, and is the fundamental application dedicated to parametric modeling.The result will be a faithful representation of the anatomical part both before and after surgical procedure, screening all the intermediate phases.The doctor will assess different lines of action according to the results, than he will communicate them to the engineer who, consequently, will correct and regenerate the model.The method finds its power in the dialogue between engineer and doctor: in complex cases closer collaboration is needed while, for the evaluation of less demanding injuries, the exam could be assigned as a remote project which, once completed, is returned to the medical facility of competence.
Fused Deposition Modeling (FDM) 3D printing technology has widespread in a variety of scientific fields, since rapid prototyping and low-cost investments well meet flexibility of application.Mechanical engineering is taking an essential role in Orthopaedics and Traumatology.As a patient-specific approach and minimally invasive surgeries are progressively needed in today's medical routines, highly-customized 3D printed devices and surgical instruments represent a milestone in medical equipment.Virtual preoperatory planning and computer aided surgical simulations (CASS) enhance 3D visualization of human anatomy, giving doctors full understanding of traumas and deformities.Custom cutting guides (CCGs) represent the cutting edge of patient-dedicated surgical routines, allowing for a sensible reduction of operative time and risk of human error.While maxillofacial surgery (MFS) has already adopted customized 3D printed tools, pediatric orthopaedics (PO) and general long bones surgery strive to put these devices into common practice.Limitations to a large-scale implementation rely on collaboration with the industrial world, as engineering and designing skills are inevitably demanded.Here displayed is the prototype for a femoral cutting guide designed for a pediatric application of the IOR -Rizzoli Orthopaedic Institute of Bologna.The device was printed in a High-Temperature PLA, supporting common steam heat sterilization and maintaining designed geometry.
The aim of this work is to complete the QFD analysis carried out in a previous work that aimed to identify the main features that contribute to the success of a modern urban transport means: the hoverboard. Starting from this analysis, through the TRIZ methodology, resolutive principles have been identified for the realization of innovative solutions of the said urban transport means. In practice this analysis aims to manage the next phase of conceptual design realized with the QFD methodology and tries to guide the design process in its next phase. In this work was used the hill model, a characteristic model of the TRIZ methodology, and the technical innovative problems encountered were reformulated in terms of technical contradictions. Subsequently, general principles of inventive solutions were obtained using one of the tools of TRIZ: the matrix of contradiction. Finally, starting from these general principles of solution, innovative constructive solutions have been developed to be applied to the design of an innovative hoverboard.
Lightweight bioinspired structures are extremely interesting in industrial applications for their known advantages, especially when Additive Manufacturing technologies are used. Lattices are composed of axial elements called ligaments: several unit cells are repeated in three directions to form bodies. However, their inherent structure complexity leads to several problems when lattices need to be designed or numerically simulated. The computational power needed to capture the overall component is extremely high. For this reason, some alternative methodologies called homogenization methods were developed in the literature. However, following these approaches, the designers do not have a local visual overview of the lattice behavior, especially at the ligament level. For this reason, an alternative mono-dimensional (1D) modeling approach, called lattice-to-1D is proposed in this work. This method approximates the ligament element with its beam axis, uses the real material characteristics, and gives the cross-sectional information directly to the solver. Several linear elastic simulations, involving both stretching and bending dominated unit cells, are performed to compare this approach with other alternatives in the literature. The results show a comparable agreement of the 1D simulations compared with homogenization methods for real tridimensional (3D) objects, with a dramatic decrease of computational power needed for a 3D analysis of the whole body.
