Michele Germani

Aesthetic and functional analysis for product model validation in reverse engineering applications

Abstract Reverse engineering techniques are broadly used in the development process of products with meaningful aesthetic properties. Many stylists prefer to evaluate the product shape on the basis of a full-scale hand made physical mock-up. Such model has then to be converted into a 3D CAD model, to begin the product engineering and production processes. A critical aspect of the RE process is that the physical mock-up, made by the stylist, usually does not take into account the engineering production constraints. The surface reconstruction activity must then be followed by a modelling phase, where the engineering designer modifies the reconstructed model shape in order to make it suitable for production. At the end of this process, no matter how accurate and precise the surface reconstruction phase has been, the product model will be different from the original mock-up, and then it needs to be submitted to the stylist for the validation of its shape. For the stylist, getting used to working with physical models, the shape validation on a virtual model is not a trivial task. The objective of this research is to develop a software tool to support the identification of aesthetic and functional regions of the product model shape, that have been modified with respect to the original mock-up. The proposed approach is based on the decomposition of a 3D surface analysis problem into a simpler 2D curves analysis problem. This approach simulates the traditional method used by stylists to evaluate the quality of shapes. The implementation of the developed algorithms has been performed using a commercial software package (I-deas FreeForm by EDS/Unigraphics) and it has been successfully applied on real test cases.

CAD-integrated LCA tool: comparison with dedicated LCA software and guidelines for the improvement

CAD-integrated LCA tools are developed in order to support SLCA (Simplified Life Cycle Assessment) method and they could be used as eco-design tools in the design phase. Nevertheless they are still a long way from being accurate and properly usable. The present work aims at demonstrating this assumption in concrete terms by focusing the attention on the mechanical field. A comparison analysis between CAD-integrated LCA tools and dedicated LCA tools has been proposed in order to determine the main causes of error and to propose guidelines for improvement. An approach based on these guidelines is presented and preliminarily evaluated.

A QFD-based method to support SMEs in benchmarking co-design tools

Efficient collaborative product design is crucial for extended enterprises willing to develop complex products pursuing a short time to market. However, successful collaborative product design depends on the ability to effectively manage and share engineering knowledge and data throughout the entire product development process. Co-design software platforms aim to facilitate cooperation in distributed teams. In the context of Small and Medium Enterprises (SMEs) the advanced co-design software implementation to support the supply chain is not a trivial task. SMEs have peculiar characteristics such as flexibility, ICT skills and financial resources, which are difficult to be integrated within a structured design network. This paper presents a method to define and evaluate a co-design platform dedicated to SMEs in the mechanical product field. System architecture is defined by applying suitable metrics based on collaborative process characteristics in order to assess functionality performance of the available tools. Benchmarking is based on different levels of collaboration recognized in the typical product development process in SMEs. Correlation between process metrics, software functionalities and specific collaboration requirements is managed by adopting Quality Function Deployment (QFD) techniques. A practical case study allows the robustness of the proposed method to be verified and the main advantages and future developments to be discussed.

A method for performance evaluation of RE/RP systems in dentistry

Purpose – The purpose of this paper is to investigate a method for comparing the scanning and reproducing accuracy of highly shaped objects like plaster casts used in dentistry.Design/methodology/approach – Theoretical considerations on errors introduced by the scanning systems and subsequent point clouds data elaboration have led to a method to estimate the accuracy of the whole process. Suitable indices have been chosen and computed at each stage. As a final result, the overall chain, scanning and reproducing systems can be assessed. In order to validate the proposed method casts have been scanned by means of commercial systems and then reproduced by using different rapid prototyping technologies, materials and parameters. Error indices have been computed and reported.Findings – Since it is not possible to define reliable and meaningful reference models for non‐standard shapes, an absolute accuracy value for the scanning process cannot be stated. Anyway the proposed method, thanks to relative performanc...

Self-configuring components approach to product variant development

The use of modularity in the design of a new product or the adoption of a product platform, as the base to define new solutions within a product family, offers the company a chance to meet diverse customer needs at low cost because of economies of scale in all phases of the products life cycle. At present, the concept of modularity in product design is becoming widely used in many industries such as automobiles and consumer electronics. However, if modularity and mass customization have attracted the interest of industries and researchers, the greatest efforts have been focused on the theoretical aspect whereas the related design support technologies have been only partially implemented. In this context, our intent is to develop highly reusable models, which are able to reconfigure themselves on the basis of new functional requirements. The proposed approach is based on the definition of what we call self-configuring components and multiple-level functions. To describe the approach, a practical example related to the design of modules for woodworking machines is reported.

Design for sustainability of product-service systems

Recently, numerous manufacturing companies are moving from product to services to create new business opportunities and to increase the product value. At the same time, sustainability is a crucial aspect for industry. In this context, the research challenge is defining a structured methodology to support the design for sustainability of product-service systems (PSS). While product sustainability has been investigated during the last decades and can be assessed by several tools, sustainability of PSS is almost unexplored. This paper defines an integrated lifecycle and proposes a methodology to identify a set of sustainability indicators to compare different use scenarios and find out the best ones. It adopts a holistic approach to assess sustainability on the basis of the three main impacts: environmental, economical and social. The methodology is illustrated by means of an industrial case study proposing a new model called ‘Hot water as a service’ evolving traditional water heaters.

An approach to assessing virtual environments for synchronous and remote collaborative design

This paper considers applying novel Virtual Environments (VEs) in collaborative product design, focusing on reviewing activities. Companies are usually anchored to commercial ICT tools, which are mature and reliable. However, two main problems emerge: the difficulty in selecting the most suitable tools for specific purposes and the complexity in evaluating the impact that using technology has on design collaboration. The present work aims to face both aspects by proposing a structured benchmarking method based on expert judgements and defining a set of benchmarking weights based on experimental tests. The method considers both human-human interaction and teamwork-related aspects. A subsequent evaluation protocol considering both process efficiency and human-human interaction allows a closed-loop verification process. Pilot projects evaluate different technologies, and the benchmarking weights are verified and adjusted for more reliable system assessment. This paper focuses on synchronous and remote design review activities: three different tools have been compared according to expert judgements. The two best performing tools have been implemented as pilot projects within real industrial chains. Design collaboration has been assessed by considering both process performance and human-human interaction quality, as well as benchmarking results validated by indicating some corrective actions. The final benchmarking weights can thus be further adopted for an agile system benchmark in synchronous and remote design. The main findings suggest defining both an innovative process to verify the expert benchmark reliability and a trusty benchmarking method to evaluate tools for synchronous and remote design without experimental testing. Furthermore, the proposed method has a general validity and can be properly set for different collaborative dimensions.

CAD tools for designing shoe lasts for people with diabetes

In the context of a research program aiming at defining a framework to acquire patient data and support the whole shoe design and manufacturing process, this paper presents new CAD tools to design and validate lasts for shoes designed specifically for people with diabetes. Shoe last customising systems have already been proposed in the literature. However, tools for designing shoes for people with diabetes do not currently have the capacity to modify the last in order to reduce the risk of foot ulceration, whilst at the same time preserving the style of the shoe. The main contributions of the work are given by a method to identify the required design features to guarantee the footwear preventive function, the determination of a systematic protocol for orienting and measuring the virtual models of the feet and the lasts, and the definition of geometrical operators to modify the last shape according to its original aesthetic and the required footwear parameters. Such variables are computed by a knowledge based system on the basis of the patients pathology. The paper presents the implementation of two CAD tools and describes the procedures and the geometrical algorithms to handle the last geometry. Finally a case study is reported to show the advantages provided by the proposed approach in terms of achieved quality of the design process and expected footwear performance.

A structured agile design approach to support customisation in wellness product development

The global market is evermore volatile and turbulent; it requires rapid responses to the emerging customers needs, also to unpredictable ones. Companies are forced towards a continuous research and innovation in terms of flexible technologies and processes in order to provide a high level of market adaptability. In this context, agile approaches, intended as a set of strategies to face the market variability, have to be investigated. They have to interest all processes related to the product development phase. This paper is focused on how to implement an efficient agile strategy in product design. The proposed approach is based on product modularity and on the integration of computer-aided design (CAD)-based tools to support feasibility analysis on virtual prototypes. It allows the concurrent management of possible changes in both product and process platforms by adopting virtual prototypes for performing simulations. The implemented platforms and the connected virtual prototype are structured according to modularity principles. The virtual prototype is defined as a collection of geometrical, functional, structural, manufacturing, environmental information, contained in the modules of the product and process platforms. An industrial example, belonging to the wellness production field (such as bathtubs and shower stalls), is described to validate the agile approach. It has been applied to solve a particularly meaningful problem: how to improve the bathtubs production process by reducing manufacturing and assembly costs while improving product customisability, eco-sustainability and quality. Once analysed, the context and the design constraints, in terms of cost, of environmental performance and, mainly, of aesthetic product features customisation, a new manufacturing process has been introduced based on the injection moulding technology instead of traditional thermoforming sheets.

An Approach to Support the Implementation of Product Configuration Tools

Companies applying mass customization paradigm regard the design process as a configuration task where the solution is achieved through the extraction of a new instance from a modular product structure. In this context product configuration management tools are evermore important. Although tools have been already proposed, they fail in real industrial contexts. Main causes are recognizable in high efforts in systems implementation and lack of flexibility in products updating. This research aims to develop an approach to overcome drawbacks and simplify the implementation and the use of product configuration systems also in redesign activities. The paper initially reviews existing systems in terms of design knowledge representation methods and product structure formalization techniques. Then, an approach based on Configuration Virtual Prototypes which store and manage different levels of knowledge, is presented. In particular, a framework is outlined in order to represent design data and its formalization in configuration tools. Three different domains are managed and connected via Configuration Virtual Prototypes: Product Specifications, Geometrical Data and Product Knowledge. Specifically, geometrical data aspects are analyzed in detail providing approaches for eliciting knowledge introduced by parametric template CAD models. The approach will be exemplified through a real application example where an original tool has been developed on the based of the described method. Benefits of the system will be shown and briefly discussed, in particular in terms of reachable flexibility in solutions.Copyright