Abstract: Formative assessment is an important element for supporting any learning process, with the provision of feedback being one of its most effective strategies. However, despite the extensive body of research on feedback and its importance to learning, its effectiveness and usefulness, and thus its expected effect, are not always guaranteed. This, in part, can be attributed to issues concerning how students make sense of and act upon feedback and the gap between how students receive and perceive feedback and how teachers structure and provide it. After the introduction of a newly developed feedback intervention aimed at improving the learning experience and, consequently, performance outcomes, it is now time to determine the next steps. This requires insight into and understanding of the usefulness and effectiveness of the recently introduced educational intervention, and this insight should be based on empirical evidence. This paper reports on the first part of an empirical study organized as a two-part project aimed at determining to what extent the new feedback intervention has had a positive impact on the learning experience and outcomes. The study also aims to determine the effect sizes and their relationships, along with the impact of the feedback characteristics on the goals in relation to the complex task of creating robust and best practice-compliant CAD models.

Keywords: CAD model alterability | design intent | dormant deficiency | Feedback effects | skill and competency development

Abstract: Educational 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.

Keywords: competency development | formative feedback | knowledge discovery | MCAD model analysis and assessment | radial visualization | visual analysis

Abstract: Background: Simulation has been recognized as a shift in healthcare education that can improve skills and patient safety and outcomes. High-fidelity simulation of critical medical situations can be a source of stress among participants that can interfere with students' abilities leading to unexpected emotional responses. The aim of this study is to determine if two simulation methods, high-fidelity (HF) and procedural simulation (PS), may be associated with stress responses at a self-perceived and biological level (salivary cortisol variations), and to compare stress levels of the two different simulation method. We also wanted to find independent variables associated with cortisol total hormonal output. Methods: A quasi-experimental before-after study was used including the administration of questionnaires, and biomarkers evaluation by salivary cortisol samples before and after simulation. A total of 148 students were eligible and agreed to participate in the study. We used paired T-test for mean comparison regarding State-trait anxiety for both HF and PT simulations. For NASA-TLX we performed a T-test mean comparison between groups. We used paired T-test mean comparison for cortisol analysis. Multivariable linear regression has been used to assess variables associated with AUCg values and perceived stress. Results: values of STAI-Y scores were relatively higher at the end of the HF and PS sessions. NASA-TLX was significantly higher at baseline for the HF simulations, with respect to the PS simulation. Cortisol fold increase was significantly different in the two groups. Linear regression showed that cortisol AUCg was related to the STAI-Y score in both groups. Conclusion: Participating students developed a stress response both after in the HF and PS training, testified by psychological and biological outputs. According to our results, stress levels were increased for simply being in a simulation scenario than to the intrinsic complexity of the task required. More studies are needed to confirm this trend and to clarify the role of simulated stress response in a long-term learning scenario.

Keywords: Anxiety | Cortisol | High-fidelity | Medical training | Simulation | Stress

Abstract: Fully constrained features and sound associativity are prerequisites for robustness and alterability of parametric feature-based CAD models. However, errors in associativity are very difficult to detect with traditional static analysis approaches, due to effects that remain hidden until parameter changes and model re-creation take place. Currently, studies on associativity-related CAD model deficiency have not advanced to the point of being a part of model analysis. In this paper, the novel concept of dormant deficiency, together with a three-level classification, a graph-based knowledge network, a human readable visualization of cause and effect relationships, and a software tool are presented in a newly developed approach to dynamic CAD model analysis. Within this approach, dormant deficiencies are triggered to facilitate a methodic knowledge-driven method of detecting errors in associativity. This is achieved through systematic analysis of deficiency generating effects and their related symptoms, followed by systematic backtracking to their root causes. A selection of representative examples used for testing and evaluation of the approach is included within the empirical results from practice.

Keywords: Design intent | Dynamic CAD model properties | Feature dependency | Formative feedback | Parametric feature-based CAD model alteration | Robust CAD models

Abstract: Within the field of industrial engineering, the use of systems for computer-aided design in mechanical engineering (MCAD) has been consolidated over the years. However, the potential benefits and advantages that these MCAD systems are capable of bringing to the product development process are still limited by, among other factors, the prevalent application of low-quality modeling strategies. This situation is reflected in the numerous MCAD models being created which can hardly be altered without causing unexpected and undesired side effects and errors, even though model alterability and reusability are essential requirements within the traditional design process. To improve this situation, MCAD curricula and education at institutions of higher education need to be restructured to further the development of skills and competency. This includes the development of MCAD modeling behavior in students, which is the outcome of understanding how to translate and correctly apply domain core concepts within strategic MCAD modeling. The aim of this paper is two-fold. Firstly, it attempts to provide an overview of efforts to restructure the MCAD course at the institution represented by the authors. Secondly, it tries to outline the individual stages of the development and implementation of the proposed innovative systematic approach to MCAD education, and to report on and summarize results achieved and experiences noted. A study of work previously published by the authors will facilitate a better understanding of this educational project, and such work is referenced below, but cannot be repeated, due to space limitations.

Keywords: Learning experience design | Learning from errors | MCAD skills and competency development | Reflection on performance and outcome

Abstract: Automation of CAD model grading is obviously capable of considerably reducing the time required for analyzing and assessing CAD models created by students, though the type and complexity of CAD model that can be analyzed, and the quality of the feedback that is generated, are still quite limited. Recent trends to allow students to use the same software tools as teachers use for grading CAD models suffer, from the methodological and conceptual approach, because grading provides feedback that is based on a finalized result, and thus always contains one assessment criterion that is related to the completeness of the solution. Being structured in this manner, it cannot be a direct part of the process and learning experience during the performance itself, that is the design, creation, and alteration of a CAD model. This paper reports on efforts and results from the first step of a two-step project to improve this situation as follows. Firstly, a learning-experience-oriented approach is presented, aimed at improving skill and expertise development in regard to robust and alterable parametric feature-based solid model creation. Secondly, a novel concept and a key metric for CAD model assessment and core behavior evaluation are introduced. Thirdly, a newly developed software tool is presented. This tool is dedicated to supporting students in putting into practice this learning-experience-oriented approach.

Keywords: CAD model alterability and associativity | Dormant deficiency | Formative feedback | Reflection on performance and outcome | Skill and competency development

Abstract: This article reports the results of a research aimed to evaluate the ability of a haptic interface to improve the user experience (UX) with virtual museum systems. In particular, two user studies have been carried out to (1) compare the experience aroused during the manipulation of a 3D printed replica of an artifact with a pen-like stylus with that aroused during the interaction (visual and tactile) with a 3D rendering application using a haptic interface and PC monitor, and (2) compare the users' perceived usability and UX among a traditional mouse-based desktop interface, haptic interface, and haptic gamified interface based on the SUS scale and the AttrakDiff2 questionnaire. A total of 65 people were involved. The considered haptic application is based on the haptic device Omega 6 produced by Force Dimension, and it is a permanent attraction of the Museo Archeologico Nazionale delle Marche. Results suggest that the proposed haptic interface is suitable for people who commonly use mouse-based computer interaction, but without previous experience with haptic systems, and provide some insights useful to better understand the role of haptic feedback and gamification in enhancing UX with virtual museums, and to guide the development of other similar applications in the future.

Keywords: haptic interface | user experience | Virtual museum | virtual reality

Abstract: Advancing formative assessment in MCAD education is an important but difficult problem. Success in this endeavor requires feature-based MCAD model assessment to consider the quality of a model from various viewpoints. That includes the absolute criteria that are associated with technical domain knowledge and also criteria related to model deficiencies. For the latter, this entails assessing the results of wrong or inappropriately applied system commands, and of partial or entire modeling strategies. Here, an approach that combines the perceptual abilities, creativity, and domain knowledge of the human user with the computational power of current desktop computing has great potential to contribute to solving the problem. The aim of the current paper is two-fold. Firstly, it presents a novel approach to analyzing feature-based characteristics of MCAD models, an approach that is aimed at advancing formative assessment in the educational context. This approach is based on visual analytics and efforts to combine visualization, human factors, and data analytics. Secondly, it reports on the technical architecture and concrete implementation of a newly developed visualization environment for a software tool to enable and put into practice this novel MCAD model assessment approach. The development of this new visualization environment is based on an advanced visualization pipeline that employs radial visualization, while supporting dedicated user interaction techniques to facilitate analytical processes.

Keywords: Advanced visualization pipeline | Formative feedback | Radial visualization | Strategic knowledge built-up | Visual analysis of multivariate data

Abstract: Today's product development processes rely on Mechanical Computer-Aided Design (MCAD) systems that implement a geometric-centered perspective in design. The development of long discussed feature-based MCAD has not yet led to systems that truly support semantic and functional representation of features, which hampers also the use of these models for functional reasoning. This paper investigates the present feature-based MCAD limitations. It illustrates, through simple examples, how to use ontological analysis and feature re-classification to introduce software extensions in existing MCAD that achieve a newer level of semantic representation of features, and enhance the cognitive understanding of the final model. The proposal also shows how to automatically validate these features from the functional viewpoint.

Keywords: Design rational | Feature | Functional feature | MCAD | Ontological analysis | Semantic representation

Abstract: New tools are needed to support CAD course reform efforts. These reforms aim to increase the development of strategic knowledge and modeling skills within CAD competency, and their implementation requires better structured and more frequent assessment and feedback. In particular, formative assessment and formative feedback are essential. Unfortunately, within CAD education, dedicated techniques and tools are not yet available to support the implementation of formative assessment, and, in particular, to assist learning goal and outcome-oriented assessment of CAD models produced by students. The aim of the current paper is two-fold. Firstly, it strives to present a novel approach for parametric feature-based solid model assessment in the educational context. This is based on deficiency analysis in relation to learning outcomes. Secondly, it reports on the implementation and application of a newly developed software tool module to enable and put into practice this novel CAD model assessment approach. The new module will be combined with a module for surface CAD model assessment to form an integrated semi-automatic software tool that is aimed at supporting assessment of both parametric feature-based solid models and surface models.

Keywords: Competency development | Formative feedback | Geometric CAD model usability | Reflection on performance and outcome | Strategic knowledge build-up

Abstract: To address some of the shortcomings of the traditional approach to CAD education in relation to the increasingly complex and highly competitive global labor markets, while also taking advantage of recent developments in educational research and cognitive science related to how students learn, a novel approach to improving CAD education has been developed and implemented. The approach integrates negative knowledge and learning from errors as crucial elements in combination with traditional teaching methods (positive knowledge) and formative assessment/feedback. To examine different facets of teaching/learning-related phenomena aimed at providing grounds for improving learning outcomes achieved within a recently restructured MCAD course, empirical research was conducted. In this paper, the results of that empirical research are presented and discussed in regard to learning experience and self-evaluated competency development. The results and insight gained herein are based on student feedback from a set of over 700 questionnaires collected and analyzed using a multi-method approach.

Keywords: Competency development | Curriculum design | Integrated teaching method | Learning experience | Negative expertise | Strategic knowledge build-up

Abstract: The development of new and valuable products, from conceptual design to production, is to date supported by advanced methodologies based on ICT tools allowing many controls and checks before proceeding to heavy spending investment decisions. The increasing use ICT allow highlighting product design process and solutions able to improve people’s quality of life. Key product development principles based on human-centered approaches and eco-sustainability concepts prove to be themain factors affecting both the products’ users as well as the product manufacturing staff. This paper outlines product’s development approaches state of the art, foreseeing at the same time possible research trajectories to define manufacturing industry future scenario based on more sustainable economical, environmental and social design choices.

Abstract: In recent years, long distance learning has become more and more popular. Web based technologies, that allow the sharing of information in real time, as well as the development of Learning Management Systems, provide the required technological support to implement long distance courses. However, long distance learning is characterized by a completely different relationship between teacher and student, in respect to the traditional teaching approach. It is then important to understand if this difference can affect the students learning outcomes. In this paper the comparison is presented between the summative assessment of two separated groups of students, attending an engineering drawing course, that is part of the curriculum for the bachelor degree in mechanical engineering. One group attended the course in a traditional form, while the second group attended the course in remote. The aim of the study is to verify if significant differences exist between the two groups of students, in terms of learning outcome. The identification of such differences is the premise to develop appropriated teaching strategies, aimed to overcome possible deficiencies related to the teaching approach.

Keywords: Engineering drawing | Learning outcomes | Online teaching

Abstract: Recent efforts to reform CAD education are aimed, among other things, at increasing the development of strategic knowledge and modeling skills within CAD competency. This requires better structured and more frequent assessment and feedback than can be achieved with current, mostly summative-based, techniques. Here, formative assessment and formative feedback appear to offer a viable solution. Unfortunately, within CAD education, dedicated techniques and tools are not yet available to support the implementation of formative assessment, and, in particular, to assist learning goal and outcome oriented assessment of CAD models produced by students. Moreover, those frameworks and tools for CAD model analysis and evaluation that are available and deployed within commercial and industrial settings cannot be directly used in educational settings, due to differences in assessment criteria and evaluation goal settings. The aim of the current paper is, firstly, to present a novel approach for surface model assessment in the educational context, which is based on deficiency analysis in relation to learning outcomes, and, secondly, to report on the implementation and application of a newly developed software tool to enable and put into practice this novel surface model assessment approach.

Keywords: Competency development | Formative feedback | Geometric CAD model usability | Reflection on performance and outcome | Strategic knowledge built-up

Abstract: With the rising importance of CAD models for product development and the recent strong promotion of hybrid geometric modeling from within the industry, the focus of teaching methods in current CAD education, as practiced in most institutions of higher education, needs to be reconsidered. From a pedagogical point of view, this situation represents a challenge, as it requires new, innovative teaching methodologies which advance the development of competency going beyond basic domain knowledge and skills limited to operating a CAD system. In this paper, a new and innovative direction for CAD education is offered, which is based on the integration of traditional teaching methods with an educational approach using negative knowledge. Central aspects of framework development and concept translation are presented together with promising results obtained through a multi-method oriented empirical study of this newly developed and now fully implemented approach.

Keywords: CAD model usability | certainty in goal-oriented action | learning from errors | Negative expertise | reflection on performance and outcome | strategic efficiency

Abstract: Due to the full integration of CAD systems into modern product development and engineering, the competency to create usable geometric models has become an essential requirement for current CAD users. To avoid serious repercussions for future engineering labor, the focus of CAD education needs to be raised from the teaching of knowledge that is merely aimed at operating a system, to the development of basic strategic knowledge. From a pedagogical point of view, this situation represents a challenging task that requires new, innovative teaching methodologies. These new methodologies must facilitate the development of know-how and cognitive ability to organize domain knowledge within a holistic mental model allowing for accurate perception of the significance of circumstances and the possible consequences of actions. In this paper a new direction for CAD education is presented, based on the integration of traditional teaching methods with an educational approach based on negative knowledge. Analysis of first empirical results of this newly developed and implemented approach showed promising results. Improvements were observed in a better understanding of issues related to the usability of CAD models and an increased capability to recognize critical modeling situations and thus prevent the mistakes typically made by novices. Also, successful autonomous attempts could be observed of recovery from situations caused either by an accumulation of small mistakes or by severe modeling errors, which usually require remedial intervention by academic supervisors.

Keywords: Learning from errors | Negative expertise | Normative geometric knowledge | Strategic knowledge

Abstract: With a steadily increasing use of CAD systems within digital prototypes in product design and development, the capacity to create viable geometric models that can be used in various computer-aided engineering processes is becoming an indispensable necessity. However, with the current trend of commercial CAD systems increasingly to promote hybrid geometric modeling environments, this requirement poses a new challenge for education, as it requires a teaching strategy that goes beyond the sum of subject learning in surface modeling and solid modeling. In this paper, a novel teaching approach is introduced, which integrates negative knowledge as one crucial element in combination with traditional teaching methods to support competency development that reaches beyond the acquisition of basic modeling skills and domain knowledge.

Keywords: curriculum design | hybrid geometric modeling | learning from errors | Negative expertise | shape engineering | transversal abilities

Abstract: When we approach shape representation, we need to choose which modeling constructs to adopt, e.g., low-level geometric elements like edges and (sur)faces, or more general elements like protrusions, bumps and holes, among others. The latter can be described as spatial configurations of the former satisfying unity and, possibly, identity criteria. However, once these are brought into the picture, we need to understand what they are, how they relate to their shape, as well as how complex shapes result from the combination of simpler ones. We address in the paper these issues and sketch an initial approach based on patterns.

Keywords: CAD systems | Feature | Shape modeling

Abstract: Design intent representation is a well-known issue in the MCAD domain, and is related to the readability, alterability, and usability of CAD models. The recent widespread introduction of functionality and commands in modern CAD systems, aimed at facilitating explicit modeling, introduces not only a new modeling paradigm supplementary to the feature-based approach, but also a new perspective on how the design intent can be captured and represented. Taking into account the traditional method of communicating design intent with functional dimensioning in mechanical drawings, in this paper a novel approach is presented, aimed at translating this traditional design intent representation from 2D into 3D. Objectives are directed towards the specification and implementation of dimensioning correspondence mapping and the identification as well as examination of shortcomings in current systems. This should help direct future improvements aimed at supporting 3D dimensioning within 3D explicit modeling systems.

Keywords: 2D/3D dimensioning mapping | 3D driving dimensions | explicit modeling

Abstract: Purpose-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. The purpose of this paper is to present 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 six-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.

Keywords: Gating system | High pressure die casting | Numerical simulation | Paper type Research paper | Shape optimization

Abstract: ABSTRACT: In this paper a framework based on the concept of functional dimensioning features is presented. It is aimed at supporting a methodological approach to explicit modeling with a focus on issues related to its use in MCAD education and practice. The proposed framework is based on the assumptions that shape, dimensions, and required manufacturing precision of a mechanical component are designed to fulfill specific functionalities. Principle formation and development regarding geometric entities and associated functional meaning are approached with an orientation on the concepts and definitions introduced by the GPS system of standards. Application of the GPS standards requires that dimensions and tolerances of the functional elements are specified within the nominal representation of a part or component. The traditional method of representing such information is a 2D technical drawing. However, explicit modeling provides new perspectives and opportunities for approaching 3D modeling, since it allows the addition of geometrical constraints and driving dimensions directly on the 3D model. In this context, the concept of functional dimensioning features is introduced, aimed at providing an integrative correspondence between concepts as specified by the GPS standards and the operative framework as provided by explicit modeling.

Keywords: CAD education | design intent | functional dimensioning | GPS standards

Abstract: Traditional computer-aided design (CAD) education in mechanical engineering still remains a major challenge today both in industrial settings and in academia. As in many other CAD-related engineering disciplines, there are several shortcomings to be surmounted in the dissemination and development of procedural knowledge and skills in the form of know-how related to the operation of CAD systems. Unfortunately, current educational philosophy does not offer a pedagogy providing sufficient strategic knowledge and understanding to enable students to use CAD systems as intended - that is as knowledge-intensive design and communication tools to properly develop and convey design intent. However, apart from knowing what to do, there is another important aspect to strategic knowledge which is frequently over-looked and ignored in research today, and that is knowing how to avoid serious mistakes. This is a central quality of professional expertise, which is commonly referred to in the literature as negative knowledge. Research presented and discussed in this paper is aimed at providing a framework for negative knowledge and domain knowledge related model evaluation concepts that allow for direct translation of this approach into practice, with the goal of improving learning behavior, skill acquisition and competency building for CAD education in mechanical engineering. © 2013 CAD Solutions, LLC.

Keywords: CAD education | Design intent | Feature-based design | Negative expertise

Abstract: 3D optical scanning systems are used more and more for quality control purposes. The effective utilization of such systems needs an efficient virtual planning of the product acquisition viewpoints. Literature shows how 3D CAD product models can be used as reference in order to manage the verification process and as a basis for the computation of the optimal viewpoints. However, in the mechanical field, a variety of inspection tasks is experienced by engineers involved in the quality control process: GD&T verification, production phases control such as sheet metal cutting, evaluation of aesthetic appearance of parts, global shape deformation measurement and specific point deviations assessment. This leads to the necessity of flexible view planning approaches which adapt to the specificity of the required inspection task. The present work targets the development of a comprehensive view planning approach in which several algorithmic options are triggered by the product features to be inspected. Algorithms have been implemented in a prototypal software system which has been experimented as an off-line application to provide inputs to a multi-axis degree of freedom robot arm mounting an optical 3D scanner. Two test cases from die casting and automotive fields are presented. They show the computation of acquisition poses in a suitable sequence and efficiency in the obtained results. © 2012 Springer-Verlag.

Keywords: 3D scanning | GD&T | Inspection | Quality control | View planning

Abstract: Since the assessment of the novelty, feasibility and value of new product ideas is highly subjective and uncertain, it is hard for companies to come up with a final product which successfully embodies customer needs, as well as company requirements. The major goal of this study is to propose a design and managerial step-based framework, moving from idea generation until the early steps of concept embodiment. Russian Theory of Inventive Problem Solving, together with multicriteria-based selection methods are employed. A case study from the household appliances industry is presented, discussing how to guide technical solutions implementation in new product ideas. Copyright © 2011 Inderscience Enterprises Ltd.

Keywords: Decision-making | Engineering conflicts | Idea generation | Product development | Product innovation | Project management

Abstract: Since the assessment of the novelty, feasibility and value of new product ideas is highly subjective and uncertain, it is hard for companies to successfully apply their innovation strategies and coming up with a final product which is able to concurrently and successfully embody both customers' needs as well as company requirements. Without forcing the innovation process in a more rigid and constrained structure, the implementation of selected formal approaches in specific innovation process stages may reduce and guide this uncertainty especially in design, managerial and decision-making activities. In this paper both a design and managerial step-based framework is proposed to help firms achieve greater success in their efforts to develop new products. Already existing and well assessed methods and techniques, together with more recent and under development ones, are employed in authors' framework, which moves from idea generation until the early steps of concept implementation. The main paper aim is then to persuade companies avoiding the classical and wasteful trial-and-error approach and make them more predictable and responsive to continuous change and uncertainty. A case study is discussed in order to demonstrate the framework effectiveness, specifically focusing on its last step, when the technical implementation of the new concept has to be performed. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Concept implementation | Decision-making | Engineering conflicts | New product development process | Project management

Abstract: In recent years the importance of eco-design in the design process of a product has drastically increased. Eco-design is a design methodology aimed at reducing the environmental impact of a product throughout its complete life cycle. Within this context, life cycle assessment (LCA) is considered a powerful method of facilitating judgment on the environmental qualities of a design solution. However, before a complete LCA can be applied, the life cycle inventory (LCI) needs to be compiled. This is often a task too expensive and time consuming to complete in practice, since the data required is huge in amount and difficult to obtain. In this paper a novel approach is presented to supporting computer-aided compilation of life cycle inventories for simplified LCA. At the center of this approach is a software tool with an architecture that is capable of interfacing parameters of a LCA database with a PLM (Product Life cycle Management) database. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Eco-design | Life cycle assessment | Life cycle inventory | Product life cycle management

Abstract: 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 © by ASME.

Keywords: Design automation | Modularity | Product configuration

Abstract: Geometric modeling has evolved as a tool for the development of computer graphics, computer aided design, and computer aided manufacturing. Geometric modeling has recently been further developed and extended towards new application domains, such as biomechanics, micro-electro-mechanical systems, embedded applications, and nanotechnology. The content-sensitive geometric modeling has become an important approach in the design of microelectro- mechanical systems. The geometric models with content-sensitive modeling can be used for visual evaluation and as the basis and input for device performance and manufacturability analyses. The hexagon-based geometric model has been used to classify the defects and to connect boron nitride nanotubes with boron nitride sheet perpendicularly. Content-sensitive geometric modeling tools can help designers in the early stages of product development process. The geometric robustness of a part or assembly can give an in-depth vision of the importance of parts.

Abstract: Mechanical product quality is strongly influenced by the respect of Geometrical Tolerances (GT). On the other hand, competitiveness forces companies to improve their productivity making the tolerance verification process faster and faster and more flexible. Component control by 3D full field optical digitizing systems and specific CAD-based (Computer Aided Design) inspection software tools are important steps forward for the achievement of the above-mentioned goals. However, the adoption of these solutions in industry is minimal. This may be due both to technological factors, i.e. poor systems usability, and organizing factors, i.e. clear separation between design department and quality control department. In this context, our research aims at developing a new easy to use CAD-based tool for simulating, driving and optimizing the GT inspection process. Once a component has been digitized, the developed software system automatically realizes the tolerances virtual control. Hence, the designer can prescribe tolerances, pilot the measurement system and verify the component conformity. The implemented tool is based on Full of Information (FoI) CAD models, which contain tolerance data, linked to a knowledge database, where measurement strategies and verification rules are stored. A computation engine calculates the measurement paths and performs the tolerances verification. The prototypal system has been tested on different real cases. Experimental results showed high performances in terms of timesaving and robustness. © 2008 Elsevier Inc. All rights reserved.

Keywords: 3D shape measurement | Augmented CAD models | Quality control automation | Reverse engineering

Abstract: International competition intensification and product development process shortening have heightened the pressure to innovate, representing this issue nowadays a hallmark of all mature companies. Product innovation process is not always successful, due to its high level of uncertainty which makes difficult the best technical solutions selection, notably during the early stages of the product development process. Even if the decision making phase appears to be critical, formal and effective methodologies and tools are not often systematically applied in industry, and furthermore they lack both of rigor and of the capacity to really support human decision-making phases. In this paper a design paradigm is discussed in order to support the early phases of the product innovation process. Once evaluated the high potentials of TRIZ theory in supporting the idea generation phase, this work is focused on testing and improving the u-sDSP decision making approach in order to enable an agile implementation of this formal technique in the industrial context. The authors' proposed methodology is then applied to an industrial case study from the domestic appliances industry.

Keywords: Decision-based engineering design | Product innovation | Project screening

Abstract: The application of life cycle assessment (LCA) is usually aimed at products where most parameters relating to architecture, processes and materials are defined and known. However, application of conventional LCA for products or services that are incomplete in their specification is quite difficult or even impossible, if too many significant parameters are unknown. In our previous work targeting the development of eco-design tools, an approach integrating LCA methodology with the concept of product modularity has been introduced. In this paper, further improvements of this novel approach, being based on fuzzy logic and its application, are presented. In this context, fuzzy logic is being used to increase user friendliness of the interface while avoiding any circumstances of compromising the precision of quantitative results computed. A set of fuzzy attributes, membership functions and an inference algorithm are used to evaluate the modification of design parameters of modular products regarding their influence on environmental impact indicators. Copyright © 2009 Inderscience Enterprises Ltd.

Keywords: AFF | Alternative function fulfilment | Fuzzy logic | LCA | Life cycle assessment | Modular product architecture | Sustainable manufacturing

Abstract: 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.

Keywords: Aesthetic product development | Agile design | Customisation | Injection moulding

Abstract: Virtual Reality (VR) systems provide new modes of human computer interaction that can support several industrial design applications improving time savings, reducing prototyping costs, and supporting the identification of design errors before production. Enhancing the interaction between humans and virtual prototypes by involving multiple sensorial modalities, VR can be adopted to perform ergonomic analysis. The main problems deal with the evaluation both of functional and cognitive sample users behavior as VR interfaces influence the perception of the ergonomic human factors. We state that ergonomic analysis performed in virtual environment can be successful only if supported with a structured protocol for the study both of functional and cognitive aspects and with the proper VR technologies combination that answers to the specific analysis tasks. An ergonomic analysis protocol is presented. It allows the assessment of the consumers/ response in term of behavioral and cognitive human factors, comprehending both operational and emotional agents. The protocol is also used to identify the best combination of visualization and haptic interfaces to perform the analysis. An experimental example, belonging to house appliances field is adopted to investigate the application of the protocol in the virtual set up. Copyright © 2008 by ASME.

Abstract: While incremental innovation is for most companies a well assessed process, radical product innovation is often handled with difficulty, mainly due to myriad obstacles in the idea-to cash process which limits company's ability to innovate. As a typical approach, engineers firstly try to find innovative solutions only inside their technological product space, basically thinking accordingly to their commonly assessed know-how. In this paper an industrial case is analyzed, showing how TRIZ methodology offers to technicians a systematic way to solve problematic contradictions and find effective ideas. © 2008 International Federation for Information Processing.

Keywords: Concept design | Idea generation | Radical innovation | TRIZ

Abstract: In 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.

Keywords: Change propagation | Modular structure | Product architecture

Abstract: In the context of styling products development, it is well known that sketches are the most immediate and used means for the 'external representation' of the industrial designers' intentions; the designer, however, also needs physical full-scale models, in order to evaluate the aesthetic solution. Reverse engineering techniques support the transformation of the physical mock-ups in digital ones, in order to perform the engineering developments. The observation of the design phases highlights the need to study new methodologies and computer-based tools, in order to simplify the reverse engineering process and to improve the quality of the final result. The conversion from real to virtual can be time consuming and strongly critical, in terms of product aesthetic and functional contents preservation. The process can be affected by several misunderstandings in the communication of the design values from the designer to the product engineers. In this paper, we propose a method for the formalization and recognition of the aesthetic properties within the different modes of design representation. The proposed method is based on the examination of the design principles used by the designer during the creative process (aesthetic intentions) and on techniques for the representation of creative ideas. In particular, we analyse the free-hand sketches and drawings to retrieve both the implicit (lines/curves) and explicit information (textual notes). Such information is used to develop a set of rules to support the identification of the styling lines on the points cloud data. The method has been experimented using a commercial computer-aided design system to manage the heterogeneous data (points cloud data, sketches and notes). The preliminary validation process shows good results in terms of time-saving. This is mainly due to two factors: the remarkable simplification of the surface reconstruction phase and the continuous monitoring of the aesthetic coherence.

Keywords: Character lines | Cognitive perspective | Design intent | Hand-made sketches | Reverse engineering

Abstract: As experience in EcoDesign increases, academic and industry thinking is moving towards the more advanced stages of EcoDesign; moving away from product improvement and product redesign into the more holistic approaches of Alternative Function Fulfilment (AFF) and system innovation. This paper investigates how modularity concept, applied to product design, allow much degrees of freedom for the designer, more possibility to reduce environmental impact related to product life-cycle and increase the interaction between LCA and the earlier stages of the (Eco)design process. A method, based on the product modularity concept, to increase LCA usability for the designers is proposed in this paper.

Keywords: Alternative Function Fulfilment | Ecodesign | LCA | Modularity

Abstract: Identifying theories and methods to link geometrical tolerances specification and inspection processes is a widely spread research topic. The growing use of virtual product models which not only represent the geometry information, but also collect attributes, notes, parameters, rules and procedures, can facilitate the digital simulation of many real processes. In the present work we are interested in using such technologies for the purpose of simulating the inspection process of manufactured products. In particular, we propose an approach for virtual inspection of geometrical tolerances based on a feature-based 3D CAD model coupled with a 3D points cloud data model. The 3D CAD model stores the tolerances specifications defined by the designer as well as the specification of the inspection methods. The points cloud model is a complete representation of the manufactured product and it is defined by the digital acquisition of the real product. The acquisition phase is performed with non-contact techniques to ensure high performances in terms of speed. The information stored in the CAD model is used to select and drive the different inspection procedures to be performed on the acquired data. © 2007 Springer.

Keywords: Automated inspection | Feature-based model | Geometrical tolerances | Reverse engineering

Abstract: The paradigm of Mass Customisation (MC) is today fundamental for the European fashion industry. Footwear industry is still labour intensive and companies need solution to reduce costs and remain competitive in the global market. In particular, specialized companies that produce customized medical shoes prescribed for people with feet malformations deal with small batches or unique pairs. This work presents some approaches and low-cost solutions related to foot measurement and CAD data elaboration for facilitating the diffusion of "made-to-measure" products. An integrated process made of hardware devices and customized software is explored and described aiming to increase production efficiency and reduce costs.

Keywords: 3D design tools | 3D foot measurement | Mass customization | Personalised shoes

Abstract: Injection molding is a diffuse technology used to manufacture a large number of products. The molded component production chain involves many specialized "actors" employed in different companies, generally small and medium-sized enterprises. The coordination of the distributed product development team and the "vertical" and "horizontal" collaboration have to be supported by suitable methods and tools in order to minimize process iterations due to misunderstandings and errors. This paper describes the preliminary study of a methodology to implement the inter-company collaboration in the mold design context. The methodology will be based on a set of procedures, rules and tools that support the management of all mold design processes. © 2006 ISAM.

Keywords: Agile design | Collaborative design | Feature sharing

Abstract: The use of recycled materials reduces the need for primary materials and it also minimizes the amount of waste in the production process. Therefore, by using recycled materials, the total material flow necessary for the production of a product can be reduced. Moreover, the total consumption of resources for the production of recycled material is, usually, remarkably inferior that in the production of the same amount of primary material. The purpose of this study is to validate this concept in the injection-moulding field using the Life Cycle Assessment (LCA) methodology. LCA quantifies and evaluates the environmental impacts of a product from the extraction of raw materials, through manufacture and use, to final disposal. Today, most people involved in the industrial engineering community (consultants, manufacturers, researchers and institutional actors) assert that Life Cycle Assessment (LCA) is one of the most successful tool to assess environmental considerations in the product design process. The main goal of this research work is to support the design decision-making process and quantify the resources saving of the use of a post consumer material instead of a primary one in the development process of the injection moulded products. The material object of this study is the Polyethylene Terephthalate (PET). In particular the test case is about the life cycle assessment of a PET clotheshorse, developed in collaboration with a SME Italian company. Traditionally the clotheshorses are made of Polypropylene (PP) or other metallic material, the purpose of this is to compare the traditional solution with the use of recycled PET for the clotheshorse production. The result of this study validates the assumption that the use of recycled material is a more environmental friendly practise and the use of the LCA methodology permitted to quantifies this environmental advantage.

Keywords: Eco-design | Injection moulding | LCA | Recycled PET

Abstract: The sustainable development of our societies is one of the priorities of the European Commission. Through its new Integrated Product Policy (IPP), the European Commission is developing a series of measures that influence the supply and demand of environmentally sound products. Some IPP tools are based on product and process self-declarations, while others require the performance of a Life-Cycle Assessment (LCA). Life-Cycle Inventory (LCI) data availability is the fundamental premise in order to be able to perform an LCA. In this paper we report the work we have done to investigate the diffusion of required LCA data along the supplier chain with the aim of identifying strategies to increase the awareness of Small and Medium Enterprises (SMEs) in respect to LCA, to suggest methodologies to facilitate the collection of sound LCI data and to test available low-cost software tools to support LCA, with particular reference to the production phase. © 2005 IEEE.

Keywords: Environmental product declaration | Life-cycle assessment data | Small and medium enterprise

Abstract: Time 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.

Keywords: CAD | Computer Aided Dental Appliances Positioning | Lingual Orthodontic Treatment | Time Compression Technologies

Abstract: 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 product's 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.

Keywords: Feature-based Model | Functional Analysis | Product Configuration

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. © 2003 Elsevier Ltd. All rights reserved.

Keywords: Physical mock-up | Product engineering | Style | Virtual mock-up

Abstract: Styling design, as every creature of the modern world, is born from various and multiple parents: taste's, evolution, marketing requirements, technical design constraints, costs and qualitative standards of the project. Furthermore, the multiplying of material and technological resources, extends the creative potential of designers, yet requires the acquisition of new knowledge: this leads to the need, from the very preliminary stages, of concurrent engineering approaches to manage the product development process and the different product views depending on the specialists involved. Time Compression Techniques (Rapid Prototyping, Reverse Engineering, conceptual modelling, process simulation) are suitable tools in implementing Concurrent Engineering principles, especially if based on Internet applications. However, today, the research effort has to be oriented towards the definition of an effective and well-structured model of the design process to successfully integrate such technologies. In this context the goal of the present work is the study of a styling product development methodology to minimize the process iterations maintaining an aesthetically coherent product model representation. We focus on the product model definition (using functional-aesthetic features) and on the 3D digitizing phase, that is the most critical aspect for the shape preservation. A practical example, developed in the office furniture domain, is reported.

Abstract: The definition of methodologies to support the development of product families is a challenging problem which has received much attention, as can be seen in the literature referenced. In this context, the configuration of solution phase is a basic task. When a company studies a new product variant it is important to evaluate, early in the process, different alternatives. The product cost can be among one of the most meaningful criteria used to determine an optimal solution. Therefore, it is advantageous to be able to estimate the cost in the design phase, where the larger part of it is committed. This work shows how a cost estimation method can be used effectively within a framework, to manage the configuration of a product variant. In more detail we describe a low-cost prototypal software system which allows the configuration of the solution and the determination of production costs related. Additionally a practical example is shown, which documents results of collaborative efforts with an industrial partner, who is a manufacturer of woodworking machines for the wood panels polishing (calibrating/sanding). To optimise results while at same time complying to the company's needs, the cost estimation tool implemented has been used in the machining operations domain.

Keywords: Cost estimation | Feature-based cad model | Modularity | Product configuration

Abstract: Concurrent Engineering methodology and process analysis and modeling showed the importance of tools that allow the designers to evaluate, from the beginning, different aspects of product definition. 3D CAD systems, simulation tools and virtual prototyping technologies can support the designer during her/his decision-making activity but, in order to provide an effective support, they must be tailored to the needs of the design process of each specific product. During last years, different types of tools appeared on the market to support this tailoring activity and to promote the development of product-dependent applications. In this paper, we have focused the attention on software tools named KAE (Knowledge Aided Engineering) development shells. Applications implemented by using this type of tools can support experts during the decision making process to evaluate alternative solutions. They provide a kernel for the integration of different technologies, and represent a basic step for the development of the product design. In this paper we present a brief overview of the architecture of a typical KAE application and we provide a survey of the most significant systems that we have developed, within different application domain, taking advantage of the KAE technology. © 2003 by Springer Science+Business Media New York.

Keywords: Feature technology | Knowledge aided engineering

Abstract: The efforts made by a company to focus on the manufacturing process to minimize production costs are not any more sufficient to launch competitive products on the market. In recent years, the industry has focused on the integration and optimization of the phases of the product development process and on the introduction of innovations in the attempt to tackle and solve the above mentioned issues. The paper presents the results of a research project whose aim is to study a methodology for the evaluation of the impact and costs related to the adoption of new and innovative technologies for knowledge and innovation management within currently implemented companies' product development processes (As-Is process).

Keywords: Knowledge management | Product development process | Product innovation | Technical creativity

Abstract: The evolution of computer aided design (CAD) systems and related technologies has promoted the development of software for the automatic configuration of mechanical systems. This occurred with the introduction of knowledge aided engineering (KAE) systems that enable computers to support the designer during the decision-making process. This paper presents a knowledge-based application that allows the designer to automatically compute and evaluate mass properties of racing cars. The system is constituted by two main components: the computing core, which determines the car model, and the graphic user interface, because of which the system may be used also by nonprogrammers. The computing core creates the model of the car based on a tree structure, which contains all car subsystems (e.g., suspension and chassis). Different part-subpart relationships define the tree model and link an object (e.g., suspension) to its components (e.g., wishbones and wheel). The definition of independent parameters (including design variables) and relationships definition allows the model to configure itself by evaluating all properties related to dimension, position, mass, etc. The graphic user interface allows the end user to interact with the car model by editing independent design parameters. It visualizes the main outputs of the model, which consist in numeric data (mass, center of mass of both the car and its subsystems) and graphic elements (car and subsystems 3D representation).

Abstract: A method for a conservative reconstruction of damaged or incomplete geometrical models into flawless and consistent Brep based solid models are introduced. Practical experiments employing the approach of space point tolerance driven face sewing within a prototype testbed implemented showed already promising results for a limited range of investigated models containing structural errors and data exchange inflicted errors.

Abstract: Current research trends are extending from partially integrated product and process modeling to life cycle modeling, in order to provide a framework and methodologies based on a holistic approach for the support of sustainable product development. Within given scope we are interested to investigate, if feature technology, introduced in the late seventies and developed over the paste twenty years provides the potential, if further enhanced, to be used as a means to provide basic integration for geometry related processes and models over different product life cycle stages. In a first approach, feature neighborhoods are developed and introduced as an extension, to foster evaluation of disassembly / reassembly on grounds of feature-based product descriptions. An attempt to support product maintenance and material recycling within life cycle modeling while investigating structural dimension and limits of improved feature models as a means of geometrybased model integration.

Abstract: An approach to the problem of controlling feature semantics in feature-based modeling is proposed by using self validation features, an entity concept developed to implement feature specification replenished with self validation capabilities. Together with this approach the traditional feature definition is extended in order to include the set of rules that allows for feature instances to control the consistency of their shape in respect to functionality associated. In order to realize a tight integration between feature semantics and shape representation an interfacing mechanism, based on an entity monitor, has been studied.

Abstract: Within our approach we apply feature-based models and techniques, realized within typed attributed entity (TAE) structures. In particular, we are interested in the handling of additional fabrication relevant form structures and the automatic determination of fabrication parameters. To verify developed methodologies and to demonstrate the applicability of our taken approach, several selected parts, taken from precision machinery engineering and aerospace engineering were modeled and processed.

Abstract: Due to life cycles of artifacts, which become shorter, rapid prototyping development and tight feedback among product requirements, design, and manufacturing are gaining increasing importance. Classical rapid prototyping technologies such as computer-numerically-controlled (CNC) machinery, which remain still time consuming and expensive, are getting superseded by a growing propensity to apply new solid freeform fabrication (SFF) technologies, which became commercially available since 1987. Although, being on the market for only less than a decade, remarkable progress in various directions such as accuracy, used materials, through-put, and equipment costs, has been achieved in SFF technologies. However, there are still several technological as well as methodological problems left. Within given scope, we would like to tackle some, taken from the methodological field, which seems still weakly developed compared to existing technology. Within our approach we apply feature-based models and techniques, realized within typed attributed entity (TAE) structures. In particular, we are interested in the handling of additional fabrication relevant form structures and the automatic determination of fabrication parameters. To verify developed methodologies and to demonstrate the applicability of our taken approach, several selected parts, taken from precision machinery engineering and aerospace engineering were modeled and processed. An implemented prototype environment and a stereolithography apparatus (SLA) were used for integrated knowledge handling, computation and SFF fabrication.

Abstract: Requirements of intelligent CAD systems are aimed to enable them to support the designer throughout his/her entire activity, starting from conceptual design and ending with, according to given specifications, an almost complete design object description. Cunent approaches featuring geometrical constraint-based systems with parametric or variational models, allow the designer to consider the realized design object description as an archetype of a family, based on a unique morphological model with unambiguous sets of parameterized rules. However, functionality for both design and reasoning, are limited to the low geometric level, leaving most of related information from the design intend and related technology unconsidered. Our objective of given study is, to extend the present functionality of existing approaches by integrating different types of knowledge and incorporate dedicated semantics in form features and feature-based methodologies. As a basic representation, typed attributed entity structures (TAE) are used. Computation is performed over domain structured alphabets of attributed symbols using a conditional attributed rewriting system. An application example in form of a wing rib, taken from aerospace engineering, is used, to verify and demonstrate the modeling and consistent handling of knowledge formations within our developed framework. Current limits of our new approach are discussed and a comparison related to the functionality of existing systems is undertaken, to direct the focus on further enhancements and extensions of our approach.

Abstract: The realization of sculptured shapes using CAD systems is still today a very complex and time consuming operation. For these reasons, design by physical modeling is still in use and remains in force in many industries (automotive, ski boots, sport articles). For the manufacturing of complex free-form surfaces, in situations in which it is more desirable to proceed from a physical model to a numerical definition rather than use mathematics to derive the physical part, copy milling techniques are widely used. This paper gives a brief overview about copy milling techniques for 3 axis copy milling machines, and proposes a feature based method to support an automatic tool path generation for the super-finishing phase. The proposed method is divided in two parts: super-finishing features recognition and tool path generation. Using copy milling techniques, the model of the object to be milled is obtained by digitizing. Therefore a global mathematical surface description of the model does not exist. In such a situation a model interpretation phase is required to recognize the super-finishing features and thus proceed to the tool path generation. A two step algorithm for super-finishing feature recognition on a digitized model is proposed: features are recognized on the basis of the digitized point density and the normal vectors of the triangles generated by the surface reconstruction (based on Delaunay triangulation method). The tool path is then generated using a method based on the calculation of the Voronoi diagram on the area identified as super-finishing feature. The super-finishing feature recognition and tool path generation modules have been integrated as part of a more general CAM system for copy milling called HICAM. The architecture of such a system will be presented together with examples of solutions obtained by means of the use of the implemented prototype modules.

Abstract: According to the general design theory a design process is an evolutionary process which step by step transfers the model of the design object from the design specification to the design solution. In our framework, design object specification and iterating evaluation are performed over different contexts using feature-based design, and feature recognition/transmutation. These activities are integrated to achieve consistency between given design requirements and design objects. Features are used to relate elements of different domains, in order to represent design objects with shape and meaning within a context. The basic concept of topology and attributed entities is used to define a homogeneous architecture of the modeling space of our reference kernel. It is reflected in the uniform use and structure of an attributed feature graph, an attributed boundary representation, and a knowledge representation in form of conditional attributed rules. For design by feature and feature recognition we propose to use a conditional attributed rewrite system as a generative as well as a recognition device to represent knowledge of control and operationalization in a uniform way. Morphisms realize a bi-directional mapping between the entire modeling space of the reference kernel and an alphabet of attributed symbols, which together with rewrite rules define our rule-based design object specification. Knowledge representation for reflective functionality and strategies of design and recognition are specified with a conditional attributed rewrite system on a meta level. Central components of a prototype implementation, according to our proposed reference model kernel, will be introduced and discussed together with first results of modeled and evaluated objects.