88,022 research outputs found
Virtual prototyping in the design process of optimized mould gating system for high pressure die casting
No full textPurpose – High Pressure Die Casting is a widely used industrial process to manufacture complex-shaped products in light alloys. Virtual prototyping techniques, especially numeric based simulations of the casting process, allow the die filling process to be evaluated and help faster optimization of the gating system, which is the most critical element of the mould. This paper presents a four step approach to design optimal moulds taking advantage of the simulation tools.
Design/methodology/approach - No formalized method to design an optimal gating system is available yet and the majority of the studies aim to optimize existing geometries or to choose from alternative solutions. Rather than optimizing the geometries of predefined designs by running attempt trials, the proposed approach defines a procedure to position cavities, gating systems and, finally, to determine the whole mould geometry.
Findings - The approach is demonstrated through three different industrial applications. The design of a 6-cavity mould for gas cooking burners is reported at first. Then, two test cases, a cup and a radiator, are reported for showing different arrangements of the gating system. The reached quality of the mould design has been assessed using metallographic analyses of the casts.
Originality/value – The design of a mould is strictly correlated to its product and mainly based on a trial-and-error approach. Numerical simulations offer a powerful and not expensive way to study the effectiveness of different die designs and filling processes. The paper proposes a structured approach for the definition of the gating system. It ultimately leads to improvements in both product quality and process productivity, including more effective control of the die filling and die thermal performance
Product Model Definition Support for Knowledge Aided Engineering Applications Development
No full textA Step-based framework to combine creativity, project management, and technical development in industrial innovation
No full textInnovative Technologies to Support Positioning of Corrective Appliances in Orthodontic Treatments
No full textTime Compression Technologies (TCT) are strongly widening their application fields, particularly in not traditional sectors, such as archaeology, jewellery, architecture and so on. The biomedical domain, especially orthodontics, is one of the most interesting. The design and positioning processes of corrective dental appliances consist of phases which can strongly benefit from Reverse Engineering (RE) and Rapid Prototyping (RP) techniques in terms of quality and time reduction. In these last years new systems have been developed to support the operator work but, unfortunately these technologies are still not largely used in orthodontic laboratories. In this context, the present paper, facing the problem of critical activities identification in corrective treatments orthodontic practice, proposes a low cost and easy to use technical solution in order to support orthodontists for a rapid and accurate positioning of vestibular and lingual brackets. In particular a new CAD (Computer Aided Design) software system to support the dental appliances design process has been implemented
Automatic tolerance inspection through Reverse Engineering: a segmentation technique for plastic injection moulded parts
No full textThis work studies segmentations procedures to recognise features in a Reverse Engineering (RE) application that is oriented to computer-aided tolerance inspection of injection moulding die set-up, necessary to manufacture electromechanical components. It will discuss all steps of the procedures, from the initial acquisition to the final measure data management, but specific original developments will be focused on the RE post-processing method, that should solve the problem related to the automation of the surface recognition and then of the inspection process.
As it will be explained in the first two Chapters, automation of the inspection process pertains, eminently, to feature recognition after the segmentation process. This work presents a voxel-based approach with the aim of reducing the computation efforts related to tessellation and curvature analysis, with or without filtering. In fact, a voxel structure approximates the shape through parallelepipeds that include small sub-set of points. In this sense, it represents a filter, since the number of voxels is less than the total number of points, but also a local approximation of the surface, if proper fitting models are applied.
Through sensitivity analysis and industrial applications, limits and perspectives of the proposed algorithms are discussed and validated in terms of accuracy and save of time. Validation case-studies are taken from real applications made in ABB Sace S.p.A., that promoted this research. Plastic injection moulding of electromechanical components has a time-consuming die set-up. It is due to the necessity of providing dies with many cavities, which during the cooling phase may present different stamping conditions, thus defects that include lengths outside their dimensional tolerance, and geometrical errors.
To increase the industrial efficiency, the automation of the inspection is not only due to the automatic recognition of features but also to a computer-aided inspection protocol (path planning and inspection data management). For this reason, also these steps will be faced, as the natural framework of the thesis research activity.
The work structure concerns with six chapters. In Chapter 1, an introduction to the whole procedure is presented, focusing on reasons and utilities of the application of RE techniques in industrial engineering. Chapter 2 analyses acquisition issues and methods that are related to our application, describing: (a) selected hardware; (b) adopted strategy related to the cloud of point acquisition. In Chapter 3, the proposed RE post-processing is described together with a state of art about data segmentation and surface reconstruction. Chapter 4 discusses the proposed algorithms through sensitivity studies concerning thresholds and parameters utilised in segmentation phase and surface reconstruction. Chapter 5 explains briefly the inspection workflow, PDM requirements and solution, together with a preliminary assessing of measures and their reliability. These three chapters (3, 4 and 5) report final sections, called “Discussion”, in which specific considerations are given. Finally, Chapter 6 gives examples of the proposed segmentation technique in the framework of the industrial applications, through specific case studies
Development of a Multilayer Change Propagation Tool for Modular Products
No full textIn this work we focus our research on the product design related aspects; currently we deal with modularity, product architecture and change propagation issues along the design process. In order to apply abstract concepts to design practise different approaches and tools have been proposed; anyway presently concrete software solutions and applications examples are still lacking. Companies modify their products for a number of reasons and rarely start from new ideas when designing. Due to the lack of suitable tools and methodologies designers are not aware of modifications impacts and propagations when trying to change or update a product. In this paper we present our research efforts in developing a methodology and the related software tool to support change management during the product redesign. It is conceived as guiding tool based on a product multilevel representation: from functional contents to implementation design; currently the designer can obtain a complete presentation of the product parts characteristics and their relations. In this way the resulting graphical model becomes a company tacit knowledge repository about the product. Operational functionalities are provided to support the designer during his activities. This work has been carried out and tested on the redesign process of a washing machine in collaboration with an Italian company, leader in house working appliances
A product model architecture to support the configuration of solution phase in gas turbine plants design
No full textGli impianti turbogas per la produzione industriale di energia stanno assumendo un ruolo importante negli ultimi tempi. Il processo di progettazione dell’impianto è dato da un insieme di attività decisionali complesse ed iterative che coinvolgono tecnici con competenze diverse. La soluzione raggiunta sotto forma di layout di impianto e geometrie delle sezioni deve essere verificata dal punto di vista strutturale, acustico, fluidodinamico e dipende anche dalle esigenze di ingegnerizzazione. Se sono necessarie modifiche le analisi precedenti devono essere ripetute.
Risulta quindi evidente che dalle primissime fasi di definizione dell’impianto il team di sviluppo dovrebbe essere supportato da strumenti collaborativi e coordinati in modo da sviluppare contemporaneamente il prodotto, ognuno dal suo punto di vista tecnico.
In questo contesto questo articolo si pone due obiettivi principali: 1) lo studio e lo sviluppo di uno strumento di progettazione per la configurazione automatica di un impianto turbogas, 2) lo studio di un sistema di progettazione capace di creare selettivamente l’informazione indispensabile alle diverse attività di analisi e di rigenerare la configurazione dell’impianto in base ai risultati delle analisi stesse
Graphical Representation of Parametric Feature-Based MCAD Model Characteristics
No full textEducational reforms and recent trends have pushed CAD education further into the mainstream of higher education. This has resulted in a rapidly increasing number of students enrolling in introductory level CAD courses, producing a flood of digital assignment submissions that need to be evaluated in a timely manner. This overwhelming situation has led to accelerated work on software tools for autonomous analysis and grading. However, the type and complexity of CAD model that can be analyzed, and the quality of the feedback that is generated, are still quite limited. In response to this predicament, and also efforts to reform an actual mechanical engineering CAD (MCAD) course, a new approach, framework, and software tool have been developed, based on visual representation and analysis of metrics. These novel instruments are aimed at supporting a more diverse and inclusive analysis and assessment of MCAD models, with a focus on the overall outcome a student produces, which includes model structure, history of model creation, and modeling strategy. The first part of this paper presents the novel approach and instruments for enhanced feature-based MCAD model analysis in the educational context. The second part of this paper reports on their development and implementation, and on the empirical results obtained during testing and evaluation
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