Semi-automatic Design for Disassembly Strategy Planning: An Augmented Reality Approach

Abstract The mounting attention to environmental issues requires adopting better disassembly procedures at the product's End of Life. Planning and reckoning different disassembly strategies in the early stage of the design process can improve the development of sustainable products with an easy dismissing and recycling oriented approach. Nowadays many Computer Aided Process Planning software packages provide optimized assembly or disassembly sequences, but they are mainly based on a time and cost compression approach, neglecting the human factor. The environment we developed is based upon the integration of a CAD, an Augmented Reality tool, a Leap Motion Controller device, see-through glasses and an algorithm for disassembly strategies evaluation: this approach guarantees a more effective interaction with the 3D real and virtual assembly than an approach relying only on a CAD based disassembly sequence planning. In such a way, the operator may not test in a more natural and intuitive way automatic disassembly sequences, but he/she can also propose different strategies to improve the ergonomics. The methodology has been tested in a real case study to evaluate the strength points and criticalities of this approach

Augmented Reality to Support On-Field Post-Impact Maintenance Operations on Thin Structures

This paper proposes an augmented reality (AR) strategy in which a Lamb waves based impact detection methodology dynamically interacts with a head portable visualization device allowing the inspector to see the estimated impact position (with its uncertainty) and impact energy directly on the plate-like structure. The impact detection methodology uses a network of piezosensors bonded on the structure to be monitored and a signal processing algorithm (the Warped Frequency Transform) able to compensate for dispersion the acquired waveforms. The compensated waveforms yield to a robust estimation of Lamb waves difference in distance of propagation (DDOP), used to feed hyperbolic algorithms for impact location determination, and allow an estimation of the uncertainty of the impact positioning as well as of the impact energy. The outputs of the impact methodology are passed to a visualization technology that yielding their representation in Augmented Reality (AR) is meant to support the inspector during the on-field inspection/diagnosis as well as the maintenance operations. The inspector, in fact, can see interactively in real time the impact data directly on the surface of the structure. To validate the proposed approach, tests on an aluminum plate are presented. Results confirm the feasibility of the method and its exploitability in maintenance practice

3D-printing of porous structures for reproduction of a femoral bone

Background: 3D-printing has shown potential in several medical advances because of its ability to create patient-specific surgical models and instruments. In fact, this technology makes it possible to acquire and study physical models that accurately reproduce patient-specific anatomy. The challenge is to apply 3D-printing to reproduce the porous structure of a bone tissue, consisting of compact bone, spongy bone and bone marrow. Methods: An interesting approach is presented here for reproducing the structure of a bone tissue of a femur by 3D-printing porous structure. Through the process of CT segmentation, the distribution of bone density was analysed. In 3D-printing, the bone density was compared with the density of infill. Results: The zone of compact bone, the zone of spongy bone and the zone of bone marrow can be recognized in the 3D printed model by a porous density additive manufacturing method. Conclusions: The application of 3D-printing to reproduce a porous structure, such as that of a bone, makes it possible to obtain physical anatomical models that likely represent the internal structure of a bone tissue. This process is low cost and easily reproduced

Production readiness assessment of low cost, multi-material, polymeric 3D printed moulds

Fused Deposition Modelling (FDM) technology allows to choose a large variety of materials and it is widely used by companies and individuals nowadays. The cost effectiveness of rapid prototyping is achievable via FDM, that makes this technology useful for research and innovation. The application of 3D printing to aid production is the most common approach. Moreover, the use of 3D printing in prototypes result in a waste of material since no reuse is considered. In the following manuscript, this technology is applied to mould fabrication by achieving a low surface roughness at a modest cost compared to conventional manufacturing methods. Moreover, the possibility to use a combination of thermoplastic materials is analysed by examination of the CAD model optimized for Additive Manufacturing (AM) from scratch and was verified using metrology tools. Several moulds were finally built and applied to the specific case study of carbon fibre laminated components. This manuscript aims to analyse the manufacturing process by comparing the mould surface geometry before and after the smoothing process. The achieved tolerance between the produced moulds is ±0.05 mm that ensures the repeatability of the process from an industrial point of view; whilst the deviation between CAD and mould is ±0.2 mm. To combine an accurate FDM process together with chemical smoothing proved to be a powerful strategy to produce high quality components that can be inserted in the production process by means of traditional manufacturing techniques. This will aid to reduce the cost of standard manufacturing for low production batches and prototypes of carbon fibre composites

A New Car Concept Developed with Stylistic Design Engineering (SDE)

In this work, a structured design method, the Stylistic Design Engineering (SDE), is applied for the construction of a new minivan car, in particular a new city car, which we will call FIAT 600 Omega. The SDE, or Stylistic Design Engineering, is a structured engineering method for carrying out automotive design projects. The SDE method consists of six different phases: (1) Analysis of stylistic trends; (2) Sketches; (3) 2D Computer Aided Design (CAD) drawings; (4) 3D CAD models; (5) Rendering; (6) Solid stylistic model (also called style maquette). This project deals with the external redesign of the Fiat 600 multiple, a small minivan which was very successful in the 1950s and 1960s. SDE is a methodology consisting of various technologies and design methodologies that will be further explained in detail, such as the Pininfarina method, the Quality Function Deployment (QFD) method, Benchmarking (BM), and Top Flop Analysis (TPA). The work was organized according to the different phases. Initially, the Fiat style was studied, in particular the style of the FIAT 600 MULTI PURPOUSE VEHICLE (MPV). This step is essential to better understand the characteristics of the brand and also the main characteristics carried out over the decades. Then we moved on to the freehand sketching phase, based on what we learned in the previous phase of the study. When a satisfactory shape was found for the new car, by analyzing and discarding the different proposals of the various types of style, we proceeded to the evaluation of the proportions and dimensions through two-dimensional drawings and finally we obtained the three-dimensional shape of the new car thanks to 3D CAD software and rendering software. Many advantages in the industrial world SDE takes together with its development. In fact, until the early 2000s, car design and styling was considered quite a craft activity, not a technical or scientific one, mostly based on the great capability of famous car designers and masters, just like Giugiaro, Zagato, Bertone, Pininfarina, Stephenson, Bangle, etc. Then, thanks to the industrial activity of Eng. Lorenzo Ramacciotti, former CEO of Pininfarina Spa and Mechanical Engineer, and also thanks to the academic studies developed at ALMA MATER STUDIORUM University of Bologna, SDE became the object of attention, because it is able to systematize the car design process and reduce costs. With SDE, a good design research or an industrial product development team can complete a car design project, also without the presence of a mentor. Car Design Process finally becomes with SDE a scientific method; Car Design becomes with SDE an industrial method. Industrial needs are nice products made in a short time; SDE is structured to attend these issues. Industrial challenges follow innovation, in shape and functionality; SDE is able to recognize innovation. Industrial benefits can be reached with SDE, ensuring beautiful aesthetic projects are realized systematically and with low costs

Virtual Surgical Planning, 3D-Printing and Customized Bone Allograft for Acute Correction of Severe Genu Varum in Children

Complex deformities of lower limbs are frequent in children with genetic or metabolic skeletal disorders. Early correction is frequently required, but it is technically difficult and burdened by complications and recurrence. Herein, we described the case of a 7-year-old girl affected by severe bilateral genu varum due to spondyloepiphyseal dysplasia. The patient was treated by patient-specific osteotomies and customized structural wedge allograft using Virtual Surgical Planning (VSP) and 3D-printed patient-specific instrumentation (PSI). The entire process was performed through an in-hospital 3D-printing Point-of-Care (POC). VSP and 3D-printing applied to pediatric orthopedic surgery may allow personalization of corrective osteotomies and customization of structural allografts by using low-cost in-hospital POC. However, optimal and definitive alignment is rarely achieved in such severe deformities in growing skeleton through a single operation

Studio e realizzazione di un sistema di realta' virtuale per la progettazione ingegneristica

Dottorato di ricerca in disegno e metodi dell'ingegneria industriale. 12. ciclo. A.a. 1998-99. Coordinatore e tutore Franco PersianiConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

REAL-TIME GEOMETRIC SIMILARITY RETRIEVAL THROUGH FAST STRING MATCHING

This paper presents a CAD interface for intrinsic and real-time component standardization. A GT-like mechanical parts’ coding scheme has been also implemented and an intelligent integration with cost assessment through PDM and CNC code fast programming has been included. Basically two applets have been developed: the first is used to create a database of parts machined in the past by the company, and to encode new components when a 2D drawing is provided. The other can be used as a CAD add-on tool to be used for parts standardization. In both cases the components’ features are encoded in a string using a scheme based on the Group Technology (GT) approach; the matching is performed in real time thanks to an algorithms which compare correspondent fields of the strings. The paper briefly presents the encoding rules, the software applet developed, and the matching algorithm. The direct implementation and company’s PDM integration have been done in order to obtain an “on the road” test in order to evaluate designing times and efficiency in cost estimation and CNC code fast programming of a real mechanical component. After the 3 months usage, tests demonstrate a component diversity reduction by 20% on components already in production and over 30% in new parts developed exploiting the CAD interface