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Modularization has played a significant role in product design and system configuration for both manufacturers and customers. Modularization enables mass customization, collaborative product design, concurrent engineering, and short product development cycle from the view point of manufacturers, while it enables high reusability, easy system configuration, and quick installation of parts from the viewpoint of customers. One of the key enablers of modularization is standardized interfaces that connect parts. The standardization has facilitated computational product design by enabling the automation of product design processes. As technology evolves, challenges from the variants of standardized interfaces, such as different versions of an interface, have emerged. A version mismatch causes incompatibility. In order to increase compatibility, interfaces are designed to support backward compatibility. This paper proposes an artificial intelligence planning–based mathematical framework for computational system configuration to support backward compatibility. The case study shows the significance of the design with the consideration of backward compatibility by demonstrating the capability of the proposed framework that automatically discovers a better design solution that cannot be identified when backward compatibility is not considered. Finally, experiments are conducted to prove the optimality of the solutions from the mathematical framework and to showcase the advantages of the framework. The proposed mathematical framework is expected to serve as a benchmarking tool, in terms of solution quality and time, for heuristic methods to be developed in the future. [ABSTRACT FROM AUTHOR]

Assembly sequence planning is one of the most important processes in mass production. However, this process is currently impeded by the lack of feedback for the next process how to plan an excellent assembly line. In this paper, we introduce the priority graph model, develop the subassembly recognition method, and design the selection algorithm with feedback weights for assembly line design in topological sequencing. We show that the method can quickly plan a satisfactory sequence compared to heuristic algorithms. Due to the different weights from assembly line designers, satisfactory assembly sequences with different adaptability can be planned. This work has implications for co-design of assembly sequence planning and assembly line design. [ABSTRACT FROM AUTHOR]

Model-based definition (MBD) technology has gained popularity in recent years. It provides an opportunity for a deeper integrated digital design and manufacturing of mechanical products. Automated manufacturability analysis (AMA) could solve increasing production costs and the manufacturing cycle caused by design defects and is the crucial support of concurrent engineering. This paper studies a systematic method for automated manufacturability analysis, which converts the design model to a structuralized feature model (SFM) with machining feature recognition. Furthermore, the machining feature-associated graph (MFAG) is proposed to describe SFM, and the meta-model expression of the knowledge rule is detailed. Finally, AMA knowledge modeling and reasoning methods are introduced. The method proposed in this paper addresses the automated manufacturability analysis of machining parts and provides a reference for MBD application in concurrent engineering. [ABSTRACT FROM AUTHOR]

Smart manufacturing, tailored by the 4th industrial revolution and forces like innovation, competition, and changing demands, lies behind the concurrent evolution (also known as co-evolution) of products, processes and production systems. Manufacturing companies need to adapt to ever-changing environments by simultaneously reforming and regenerating their product, process, and system models as well as goals and strategies to stay competitive. However, the ever-increasing complexity and ever-shortening lifecycles of product, process and system domains challenge manufacturing organization's conventional approaches to analysing and formalizing models and processes as well as management, maintenance and simulation of product and system life cycles. The digital twin-based virtual factory (VF) concept, as an integrated simulation model of a factory including its subsystems, is promising for supporting manufacturing organizations in adapting to dynamic and complex environments. In this paper, we present the demonstration and evaluation of previously introduced digital twin-based VF concept to support modelling, simulation and evaluation of complex manufacturing systems while employing multi-user collaborative virtual reality (VR) learning/training scenarios. The concept is demonstrated and evaluated using two different wind turbine manufacturing cases, including a wind blade manufacturing plant and a nacelle assembly line. Thirteen industry experts who have diverse backgrounds and expertise were interviewed after their participation in a demonstration. We present the experts' discussions and arguments to evaluate the DT-based VF concept based on four dimensions, namely, dynamic, open, cognitive, and holistic systems. The semi-structured conversational interview results show that the DT-based VF stands out by having the potential to support concurrent engineering by virtual collaboration. Moreover, DT-based VF is promising for decreasing physical builds and saving time by virtual prototyping (VP). [ABSTRACT FROM AUTHOR]

Within product development processes, computational models are used with increasing frequency. However, the use of those methods is often restricted to the area of focus, where product design, manufacturing process, and process chain simulations are regarded independently. In the use case of multi-material lightweight structures, the desired products have to meet several requirements regarding structural performance, weight, costs, and environment. Hence, manufacturing-related effects on the product as well as on costs and environment have to be considered in very early phases of the product development process in order to provide a computational concept that supports concurrent engineering. In this contribution, we present an integrated computational concept that includes product engineering and production engineering. In a multi-scale framework, it combines detailed finite element analyses of products and their related production process with process chain and factory simulations. Including surrogate models based on machine learning, a fast evaluation of production impacts and requirements can be realized. The proposed integrated computational product and production engineering concept is demonstrated in a use case study on the manufacturing of a multi-material structure. Within this study, a sheet metal forming process in combination with an injection molding process of short fiber reinforced plastics is investigated. Different sets of process parameters are evaluated virtually in terms of resulting structural properties, cycle times, and environmental impacts. [ABSTRACT FROM AUTHOR]

This paper deals with an integrated design approach for additive manufacturing (AM), as a design for additive manufacturing (DfAM) approach. This DfAM approach focuses on two important activities of manufacturability analysis, as well as material and process selection in the concept of concurrent engineering and integrated design approach (CE/ID). It could be considered as a guideline for the researchers in the early phase of the product development process. For this purpose, a novel process and resource selection problem for AM is formalized as an additive manufacturing process and resource selection problem (AMPRSP). This problem is defined to investigate simultaneously the manufacturability, and process and resource selection issues for AM. A multi-criteria evaluation system (MCES) is proposed to solve this problem by evaluating the manufacturability of the product, and selecting the AM resources. Firstly, the AM process, machine, and material are explored and selected regarding technical and economic evaluation criteria. Then, the most appropriate alternative for fabrication with AM is selected by considering the sub-criteria including build time, accuracy performance, and cost. To solve this multi-criteria problem, an analytic hierarchy process (AHP) method is employed. Overall, this evaluation system is a step-by-step methodology that includes screening, comparative assessment, and a ranking process to select the most suitable alternative for AMPRSP. Finally, the proposed approach is illustrated by an industrial case study. [ABSTRACT FROM AUTHOR]

This paper presents a cyber design for manufacturing (DFM) framework for concurrent material and process selections. An internet-of-things (IoT) interface is developed wherein design, material, and process databases are accessed in a cloud-based environment. Digital designs are processed to extract dimensional features and functional requirements. A Node-RED IoT simulator is developed to provide seamless interconnectivity to translate design specifications with material and process databases via web sockets. The output from the cloud system is incorporated within a decision-making algorithm. The analytical hierarchy process (AHP) is implemented where alternatives are hierarchically compared to generate weights based on combinatorial order ranking of the designer preferences. A material-process index (MPI) is developed that integrates the material and process generated weights with material-process compatibility for selecting the optimal material and process combination. The proposed methodology is applied to an electrical power distribution interchangeable fuse cutout system to validate the approach. Material and processes are selected on a standalone basis without considering their compatibilities. Further, the MPI function is implemented that integrates functional preferences for material, process, and their compatibilities to contrast against standalone material and process selections. The material-process combination with the highest MPI was chosen as the optimal solution for a product design. The cyber DFM methodology developed in this research can be extended to different application domains based on flexible user chosen criteria. [ABSTRACT FROM AUTHOR]

As competition shifts away between competitors to supply chains, simultaneous sharing of technical expertise on product design is key to manufacturing success. Thus, purpose of this study is to examine the mediating effect of concurrent engineering of product design (CEPD) on the relationship between advanced manufacturing technology (AMT) and supply chain performance (SCP). The paper is a cross-sectional study, and data was collected among top managers of manufacturing companies. Cluster and systematic random sampling techniques were used to select the respondents. Structural equation modeling (Amos graphic) was used for analysis. The study found a positive relationship between advanced manufacturing technology and supply chain performance, advanced manufacturing technology and concurrent engineering of product design, and concurrent engineering of product design and supply chain performance. It also concluded that concurrent engineering of product design is a full mediator between advanced manufacturing technology and supply chain performance. [ABSTRACT FROM AUTHOR]

In computer-aided manufacturing process planning, the determination of fixtures is often completed after a process plan is generated. This strategy does not consider the manufacturing dependency between the process planning and the fixture design, which in fact needs to be thoroughly assessed before any conclusion regarding the optimality of a plan or the quality of a proposed fixture can be made. In this paper, a concurrent approach is presented in which the fixture design and machine planning are combined in an automated search process that starts with simply a CAD model. First, a rule-based algorithm is used to define all feasible manufacturing operations for the given CAD model. Then, a hierarchical search technique is developed to discern which operations are best in terms of manufacturing time, cost, and fixture quality. The fixture quality is a quantitative measure derived based on a collection of fixture design guidelines from manufacturing experiences and engineering handbooks and is intended to give a consistent and complete assessment of a fixture design. Cases studies and discussion are provided to showcase distinct characteristics of our algorithm. A real implementation of one suggested plan is also presented in order to validate the effectiveness and practicality of our approach. [ABSTRACT FROM AUTHOR]

Tolerance design is always a challenging task for engineers, since it need to satisfy multidisciplinary functions. Engineering design is done in two stages: assembly design and detail design. In the first stage, an assembly is designed considering certain system level functions and in secondary detail design stage; decomposition of the assembly is done and process tolerancing is employed for the parts. At the secondary detail design stage, designer adopts geometrical dimensioning and tolerancing (GD&T) concepts for process tolerancing. Hence, assembly and detail design are done in different phases with dissimilar perspectives. As a result, geometric tolerance design often lands in conflict, redesign, and in the case of concurrent engineering, costly reiterations are performed. This conflict occurs because of two vital reasons: (1) a gap exists between these two design stages and no common relation between them; (2) GD&T is adopted in the secondary stage, which is not available in primary stage. This paper offers a framework for a design engineer to bridge the gap and to establish the relation between these stages. A nonlinear combinatorial optimization problem is framed based on assembly function requirement (AFR), and tolerance values are optimized with appropriate constraints. Nontraditional Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and differential evolution (DE) algorithms are used to solve the problem. For the allocated position tolerances, appropriate sensitive factors are indicated to facilitate design improvement. Finally, a case study is used to illustrate the complete framework. [ABSTRACT FROM AUTHOR]

Two key decisions in designing cellular manufacturing systems are cell formation and layout design problems. In the cell formation problem, machine groups and part families are determined while in the facility layout problem the location of each machine in each cell (intra-cell layout) and the location of each cell (inter-cell layout) are decided. Owing to the fact that there are interactions between two problems, cell formation and layout design problem must be tackled concurrently to design a productive manufacturing system. In this research, two problems are investigated concurrently. Some important and realistic factors such as inter-cell layout, intra-cell layout, operations sequence, part demands, batch size, number of cells, cell size, and variable process routings are incorporated in the problem. The problem is formulated as a mathematical model. Three different methods are described to solve the problem: multi-objective scatter search (MOSS), non-dominated genetic algorithm (NSGA-II), and the ε-constraint method. The methods are employed to solve nine problems generated and adopted from the literature. Sensitivity analysis is accomplished on the parameters of the problem to investigate the effects of them on objective function values. The results show that the proposed MOSS algorithm performs better than NSGA-II and produces better solutions in comparison to multi-stage approaches. [ABSTRACT FROM AUTHOR]

This paper presents a cost modelling system for lean product and process development to support proactive decision making and mistake elimination at the design stage. The foundations of the system are based upon three lean product and process development enablers, namely: Set-based concurrent engineering, knowledge-based engineering, and mistake proofing (Poka-yoke). The development commenced with an industrial field study of eleven leading European industries from the aerospace, automotive, telecommunication, medical and domestic appliance sectors. Based on the requirements of industrial collaborators, the developed system comprises six modules: value identification, manufacturing process/machines selection, material selection, geometric features specification, geometric features and manufacturability assessment, and manufacturing time and cost estimation. The work involved the development of a feature-based cost estimation method for the resistance spot welding process. The developed system was finally validated using an industrial case study. The developed system has the capability to provide estimates related to product cost and associated values concurrently, facilitate decision making, eliminate mistakes during the design stage, and incorporate 'customer voice' during a critical decision making stage. [ABSTRACT FROM AUTHOR]

This paper describes the development of an intelligent system based on concurrent engineering for generating design alternatives at the conceptual design stage. The proposed system encompasses a design analysis module, a design evaluation module, a knowledge acquisition and storing module, a user interface and databases. It is also integrated with a spreadsheet application for storing data and numerical analysis and works in combination with a material selection software Cambridge engineering selector (CES) to facilitate the material selection process. The tangible advantage of implementing this system is that it enables the designer to explore and experiment with alternative ideas in the early design stage, and it results in design solutions that are functionally sound- and cost-effective. It also has the capability for design alternatives evaluation, material selection and modelling the product detailed design on the computer-aided design system. Therefore, an efficient product development process is generated. Three case studies are demonstrated and discussed to validate the proposed system. [ABSTRACT FROM AUTHOR]

Thoughtful consideration of products maintenance features early in design stage can reduce or eliminate maintenance costs, reduce downtime, and improve safety. As such, the effective collaboration of product designers and maintenance technicians throughout the product design process is becoming much more important for the most advanced competitiveness. To address this need, a visualization system that enables maintainability-related technicians cooperated with product designers in a networked manufacturing environment is proposed in this study. This paper presents a systematic approach to implementation of a Web-based visualization system by using virtual reality technology. The system aims at providing a simulated environment and concurrent engineering processes to facilitate communication, coordination, control, and integration of product maintainability validation and improvement activities. The result of this research will help increase product maintainability, reduce development cycle time and cost, and hence increase product marketability. [ABSTRACT FROM AUTHOR]

The manufacturability evaluation is an important component of virtual manufacturing and concurrent engineering, and hot spot of this research is focused on manufacturability evaluation based on feature at present. In this paper, using the object-oriented modeling methodology, according to the manufacturing features of the gears used in automobile, the gears are classified into cylindrical gears and bevel gears to carry on the feature modeling separately; the manufacturing resources are classified into the basic information of the manufacturing equipments and the feature processing capability information to establish information models, and the association relationship of features, machine tools, and process equipment is established simultaneously. All of the models established in the article provide the information support for manufacturability evaluation and lay a good foundation for virtual manufacturing. [ABSTRACT FROM AUTHOR]

The pump industry is the one which is yet to exhibit agile characteristics by evolving new models quickly in accordance with the dynamic demands of the customers. The researchers have not yet explored the potential of infusing agile characteristics in the pump industry. In order to initiate exploration in this direction, the research reported in this paper was carried out. To begin with, the empirical equations used for designing the pump components namely impeller and casing were referred. Subsequently, a software to compute the parameters using these empirical equations was developed. By inputting these parameters in a Pro/E software package, four new solid models of impeller and casing were designed. These newly designed models were subjected to analysis using GAMBIT and FLUENT software packages. Subsequently, rapid prototyping technology was adopted to develop the prototype of one of those models of impeller. In order to obtain the industry view of this research, four practicing experts were approached with a questionnaire to gather their reactions. The results of their reactions indicated that this research could be practically applied to achieve agile product development through the interfacing of computer-aided design (CAD) and rapid prototyping technologies. [ABSTRACT FROM AUTHOR]

Efficient and effective forging process selection for a given set of product characteristics and requirements is a multicriterion problem strongly influenced by interdependent factors like product complexity, design requirements, product quality, resource availability, and cost. These factors are formalized based on the information provided regarding the role and experiences of experts in product–process design; however, design representation is considered as a network of product and process parameters and expert’s knowledge as a set of constraints applied on the parametric network. This paper proposes an integrated product–process approach to evaluate its consistency and is useful in selecting suitable forging process and product design parameters. Computer support tool has been developed to present and to integrate the product parameters, the process characteristics, and the expert’s knowledge related to forging domain to select an appropriate forging process evaluated through a constraint propagation algorithm. This approach is validated through a case study presented at the end. [ABSTRACT FROM AUTHOR]

Feature recognition is the key to the computer-aided design (CAD) and computer-aided manufacturing (CAM) integration to build a computer-integrated manufacturing system. There are two approaches to CAD feature recognition: platform-dependent and platform-independent. In the platform-independent approach, the part’s geometrical data are extracted from a neutral file such as DXF, IGES, or STEP. In contrast, the platform-dependent approach extracts the information of the design features directly from a design-by-feature solid model through the object-oriented model of a part. This paper explains a platform-dependent approach which is implemented to translate design features into manufacturing information. This approach begins with simplification using the suppression of fillets, and clustering non-intersecting design features is done. Then, the rule-based method is employed in order to recognize machining features. Finally, the needed manufacturing information such as tool accessing direction, dimensions, material removal regions, and geometrical and topological data is recognized. The application of the proposed system would be exhibited in generating machine path code for rapid prototyping and CNC machines and providing a database for computer-aided process planning. The proposed system was implemented on Autodesk Inventor and successfully tested for many complex 3D models. [ABSTRACT FROM AUTHOR]

Particle swarm optimizers are routinely utilized in engineering design problems, but much work remains to take advantage of their full potential in the combined areas of sensitivity analysis and tolerance synthesis. In this paper, a novel Pareto-based multiobjective formulation is proposed to enhance the operations of a particle swarm optimizer and systematically distribute tolerances among various components of a mechanical assembly. The enhanced algorithm relies on nonlinear sensitivity analysis and the statistical root sum squares model to simultaneously optimize product performance criteria, the manufacturing cost, and the stack-up tolerance. It is shown that the proposed algorithm can accomplish its optimization task by successfully shifting nominal values of design parameters instead of the expensive tightening of component tolerances. Several numerical experiments for optimal design of a stepped bar assembly were conducted, which highlight the advantages of the proposed methodology. [ABSTRACT FROM AUTHOR]

This paper is the first of two which present a methodology for determining the dimensional specifications of all the component parts and sub-assemblies of a product according to their dimensional requirements. To achieve this goal, two major steps are followed, each of which is described in a paper. In the first paper, all relationships necessary for finding the values of dimensions and tolerances are represented in a matrix form, known as a Dimensional Requirements/Dimensions (DR/D) matrix. In the second paper, the values of individual dimensions and tolerances are determined by applying a comprehensive solution strategy to satisfy all the relationships represented in the DR/D matrix. The methodology is interactive and suitable for use in a concurrent engineering (CE) environment. The graphical tool presented in this paper will assist a CE team in visualizing the overall D&T problem and foreseeing the ramifications of decisions regarding the selection of dimensions and tolerances. This will assist the CE team to systematically determine all the controllable variables, such as dimensions, tolerances, and manufacturing processes. [ABSTRACT FROM AUTHOR]

Dimensioning and tolerancing (D&T) is a multidisciplinary problem which requires the fulfillment of a large number of dimensional requirements. However, almost all of the currently available D&T tools are only intended for use by the designer. In addition, they typically provide solutions for the requirements one at time. This paper presents a methodology for determining the dimensional specifications of the component parts and sub-assemblies of a product by satisfying all of its requirements. The comprehensive solution strategy presented here includes: a strategy for separating D&T problems into groups, the determination of an optimum solution order for coupled functional equations, a generic tolerance allocation strategy, and strategies for solving different types of D&T problems. A number of commonly used cost minimization strategies, such as the use of standard parts, preferred sizes, preferred fits, and preferred tolerances, have also been incorporated into the proposed methodology. The methodology is interactive and intended for use in a concurrent engineering environment by members of a product development team. [ABSTRACT FROM AUTHOR]

The research results presented in this paper are related to the specification of a method and models that tackle the problem of manufacturing processes selection and the integration, as soon as possible, of their constraints in the product modelling (i.e. information synthesis). This method is based on a skin and skeleton design/manufacturing interface model that ensures connection between design and manufacturing information. The use of these features is justified by their capacity to make a product representation which allows integration of both design and manufacture data and therefore assists the product breakdown definition (including the 3D forms) by least commitment. This method first analyses the product data issued from functional analysis and component selection (form, roughness, tolerance interval, etc.). Then, it deals with manufacturing information (manufacturing processes constraints). The approach is formalised with IDEF and UML models and has been consolidated with software developments based on C++ and open CASCADE technologies. [ABSTRACT FROM AUTHOR]

The globalization and competition in the automobile industry makes it necessary to reduce the time spent on product development. Therefore, computer aided product development has become one of the most important techniques in the automobile industry. According to the concurrent engineering concept, an integrated CAD/CAE/CAM system for automobile stamping die development is established. The system is based on 3D surface construction CAD software STRIM, CAD/CAE software CATIA, stamping formability analysis software DYNAFORM, CAM software CADCEUS, a stamping design knowledge-based system, and a product database. This paper uses the development of trunk lid outer panels as an example to showcase the power of the system, in which the different development stages can be performed simultaneously. The system can greatly reduce the development time and cost, improve the product quality, and push products into the market in a relatively short time. [ABSTRACT FROM AUTHOR]

This paper describes the development of a Web-based integrated system for collaborative product development evolving from marketing analysis to prototype generation. The proposed system encompasses a marketing information system (MIS), a human resources management (HRM) system, a supply-chain management (SCM) system, a communication media, an integrated product design studio, a user interface and databases. It enables project planners, marketing analysts, designers, suppliers, and manufacturing planners to work at the early stages to reduce any unnecessary wasted time, resources, and costs, thus increasing the total product quality, maximising the organisation resources used, and reducing the total product cost and product lead time to better face global competition. The tangible advantage of implementing this system is that it provides an integrated environment for total product development from concept to realisation. Therefore, an efficient product development process is generated. One case study is demonstrated and discussed to validate the proposed system. [ABSTRACT FROM AUTHOR]

Owing to intricate interdependency and information feedback among tasks, the concurrent design process probably cannot converge to the correct solution when there are wrong integration and improper interaction between activities. Therefore research on concurrent design process optimization is necessary. In the paper, a novel methodology is proposed to analyze and optimize the concurrent engineering process scientifically. Based on design structure matrix and graph theory, coupled task recognition and design task level plotting are performed for the concurrent design process of aluminum profile extrusion product development. Three factors are used to describe the coupling property of activity, namely sensitivity, complexity and affection factors, which provide the basis to analyze development process quantitatively. And an optimism algorithm is presented to define the initial iteration order of coupled task set. Finally a rational and efficient concurrent design process model is constructed, which can make aluminum profile product development faster, with lower costs and higher quality. The methodology proposed is also applicable to other concurrent engineering fields. [ABSTRACT FROM AUTHOR]

Although many conceptual design methods have been proposed, there is still ample room for improvement. First, most conceptual design methods do not relate concepts generation by a combination of basic features to the feasibility of the concepts. Second, those methods may have ignored customer preferences in modeling concept selection. To overcome these shortcomings, a quality-engineering-based conceptual design approach is proposed in this paper by integrating the use of quality function deployment (QFD), morphological matrix analysis (MMA), multi-attribute decision-making techniques (MADM), and possibilistic optimization models (POMs). A possibility distribution function (PDF) is applied to account for the uncertainties of technology development cost in the early design stages, and a mathematical framework is established by incorporating the customer-perceived relative importance into a possibilistic optimization model for design concept selection, which plays a central role in the proposed methodology. Contrary to deterministic optimization models (DOMs), the proposed possibilistic optimization can produce results that are more informative and more reliable to the designers. [ABSTRACT FROM AUTHOR]

A new approach to converting a design feature model (DFM) to a machining feature model (MFM) step-by-step during a design process has been proposed. In the approach, the MFM is incrementally set up and updated through performing a local machining feature recognition on certain areas of a design part’s B-rep when its design features are updated. The areas to be recognized as machining features are determined through geometric reasoning according to the statuses of the DFM and the dynamically generated MFM of the part. To facilitate the above geometric reasoning, a dynamic link list (DLL) has been developed to record the changed topological elements during the design process and the relationships between the DFM and the MFM. Based on the automatic and effective conversion process from design models to machining feature models, the proposed approach can support the establishment of a concurrent product development environment to link product design and manufacturing processes seamlessly. [ABSTRACT FROM AUTHOR]

A product assembly or disassembly is completed by means of proper tools. The selection of feasible tools is an important process in planning a complete assembly or disassembly sequence. A key tooling consideration in assembly or disassembly planning is to reason the available space for a tool application during the assembly or disassembly of a product. Currently, assembly tool reasoning about space mainly depends on simulation-based or user-interactive approaches because of its computational complexity. These approaches are inappropriate in dealing with various what-if scenarios regarding assembly or disassembly planning in a rapid product development. They also depend on users’ expertise or experience in assembly or disassembly. This paper presents a novel approach to the geometric feasibility analysis for fast assembly tool reasoning. Techniques described in this paper are advantageous not only in the aid of generating a complete assembly or disassembly plan but also in the efficient support of such systems as computer-aided assembly planning (CAAP), design for manufacturing (DFM), design for assembly (DFA), design for disassembly (DFD), and computer-aided tool selection (CATS). [ABSTRACT FROM AUTHOR]

The planning and control of product development is based on the pre-estimation of product design time (PDT). In order to optimize the product development process (PDP), it is necessary for managers and designers to evaluate design time/effort at the early stage of product development. However, in systemic analytical methods for PDT this is somewhat lacking. This paper explores an intelligent method to evaluate the PDT regarding this problem. At the early development stage, designers lack sufficient product information and have difficulty in determining PDT via subjective evaluation. Thus, a fuzzy measurable house of quality (FM-HOQ) model is proposed to provide measurable engineering information. Quality function deployment (QFD) is combined with a mapping pattern of “function→principle→structure” to extract product characteristics from customer demands. Then, a fuzzy neural network (FNN) model is built to fuse data and realize the estimation of PDT, which makes use of fuzzy comprehensive evaluation to simplify structure. In a word, the whole estimation method consists of four steps: time factors identification, product characteristics extraction by QFD and function mapping pattern, FNN learning, and PDT estimation. Finally, to illustrate the procedure of the estimation method, the case of injection mold design is studied. The results of experiments show that the intelligent estimation method is feasible and effective. This paper is developed to provide designers with PDT information to help them in optimizing PDP. [ABSTRACT FROM AUTHOR]

Here, an attempt is made to present a state-of-the-art review of papers on facility layout problems. This paper aims to deal with the current and future trends of research on facility layout problems based on previous research including formulations, solution methodologies and development of various software packages. New developments of various techniques provide a perspective of the future research in facility layout problems. A trend toward multi-objective approaches, developing facility layout software using meta-heuristics such as simulated annealing (SA), genetic algorithm (GA) and concurrent engineering to facility layout is observed. [ABSTRACT FROM AUTHOR]

STL format is widely used as a de facto industry standard in the rapid prototyping industry due to its simplicity and robustness. However, on account of its shortcomings and inadequacy in applications, many interface alternatives have been brought forward. In this paper, a new scheme is proposed to enhance the approximation accuracy and to extend functions of STL by means of introducing additional feature and attribute codes into STL format. The geometry feature code describes a tetrahedron based on the STL triangular facet, which provides better approximation to the object surface covering. The attribute code attaches attributes of object surfaces such as colours and markers to STL triangular facets. Moreover, the enhanced STL also shares the structure of binary STL format by filling feature and attribute codes into its blanks, and therefore is compatible with STL. Compared with STL, the enhanced STL provides not only higher accuracy with the same file size and compatible format, but also colour and marker functions for rapid prototyping. [ABSTRACT FROM AUTHOR]

So far, there has been an extraordinary development of computer-aided tools intended to generate, present or communicate 3D models. But there has not been a comparable progress in the development of 3D-CAD systems intended to assist designers in representing and manipulating both geometric and non-geometric design information based on solid models, thus facilitating concurrent engineering (CE). Design objects continue to be produced by traditional means using the computer as little more than a drafting tool. In addition, the state-of-the-art 3D-CAD systems are incapable of encoding engineering uncertainties since only precise single-valued assignments are allowed for their modeling operations. Recently, set-based CE (SBCE) has been attracting public attention as an emerging CE paradigm. Such a set-based design (SBD) approach presents many possibilities in handling the uncertainties that are intrinsic at the early phases of design. This paper addresses a novel concept – set-based parametric design (SBPD) – which combines the SBD practice with the parametric modeling technique widely used in most 3D-CAD systems. A preference set-based design (PSD) model and a design information solid (DIS) model are proposed to incorporate the SBPD concept into the current 3D-CAD systems. Finally, a prototype system is implemented to illustrate the potential to achieve a SBPD practice. [ABSTRACT FROM AUTHOR]

This work is motivated from set-based concurrent engineering (SBCE) paradigm. In contrast to the traditional design practice, SBCE considers a broader range of design possibilities (i.e., design space) from the outset, explicitly communicates and reasons about sets of design alternatives, and gradually narrows the sets to eliminate inferior alternatives until a final solution remains. Thus, the key to success of SBCE is the proper implementation of the space representation method to define the possible design region, the space mapping method to obtain the performance space achievable by the initial design space, and the space narrowing method to eliminate infeasible subspaces from the initial design space. This paper proposes a novel space-based design methodology for preliminary engineering design. The main characteristic features of our approach are to incorporate the designer’s preference structure with degrees of desirability in specifying both design space and performance space, and to find a ranged set of design solutions that satisfy changing sets of performance requirements through set-to-set space mapping from design space to performance space and space narrowing to eliminate infeasible design subspaces. Central to the proposed design methodology is the integration of meta-modeling techniques, modified fuzzy arithmetic, design of experiment (DoE), robust design techniques, and uncertainty analysis. A preliminary parametric design example of a vehicle side impact beam is demonstrated to show the effectiveness of the proposed methodology and its availability in the large-scale multi-objective design synthesis problem. [ABSTRACT FROM AUTHOR]

In the traditional process of designing a manufacturing system, a sequential approach treats each of the design steps individually, without considering the requirements of concurrent design activities. The lack of systematic and concurrent consideration of the interactive impact of design decisions leads to repeated and excessive changes in the design and process. To resolve this problem, this research develops a production engineering-oriented virtual factory – a planning cell-based manufacturing systems design approach. The manufacturing systems design process based on a planning cell is reengineered according to the concept of concurrent engineering. The process modeling of a production engineering-oriented virtual factory is proposed at generic and particular levels. An illustrative example of an engine assembly plant demonstrates the effectiveness of the new approach. [ABSTRACT FROM AUTHOR]

Concurrent or collaborative engineering (CE) has inspired research in the area of design decomposition, which facilitates the concurrency of product lifecycle functions from the earlier stage of the product development process and reduces the complexity of a design problem. The decomposition-based design, on the other hand, necessitates various integration efforts for recombining the decomposed design problems. This is the second of a two-part paper proposing a multi-agent system (MAS) framework for integrated product design in a computer network-oriented CE environment. Part II discusses the applications of the proposed MAS framework to concurrent engineering design. The proposed framework realises the systematic and timely design integrations between multi-functional/cross-functional team members in a dynamic design environment, by enabling model integration, solution integration and tool integration. The proposed design agents make the problem-specific engineering models or heterogeneous design tools interoperable and network-accessible, and also provide the interaction spaces for communicating, integrating or coordinating the individual design solutions. Throughout the paper, the proposed system is illustrated with a successful implementation of a continuously variable transmission (CVT) design problem over the Internet . [ABSTRACT FROM AUTHOR]

In today’s global market, more and more manufacturing companies have realised that the ability to quickly develop a customised product in an economic and efficient way is critical for them to survive in the keen competitive international market, particularly for one-of-a-kind production (OKP) companies. A new generation of OKP systems needs to be developed to maintain competitiveness in the global marketplace and to improve the ability to rapidly combine the strengths of manufacturing partners to meet market needs. In this paper, the main objectives of rapid OKP development in the global manufacturing environment are discussed. The background of recent approaches for rapid development of OKP products is reviewed. After systematically reviewing the existing OKP systems and recent developments of new technology and systems, the authors discuss current issues and requirements for developing a new generation of OKP systems for rapidly producing OKP products. At the end of this paper, a reference system structure is proposed for rapid development of OKP products in the global manufacturing environment . [ABSTRACT FROM AUTHOR]

During the past two decades, concurrent or collaborative engineering (CE) has presented new possibilities for successful product development. In addition, the advances in computer networks and information technology have brought engineering design context into a new era. As a promising approach to accommodate the radical pace of changes in the context of engineering design, agent technologies have been attracting public attention and are being used in an increasingly wide variety of applications. However, little attention has been paid to multi-agent system (MAS) frameworks for CE environments that enable systematic and timely design integrations in both hierarchical and heterarchical design topology. This is the first of a two-part paper proposing a MAS framework for integrated product design in a computer network-oriented CE environment. Part I first proposes a hybrid agent network architecture to develop lightweight, dynamic and large-scale distributed systems, and then proposes a hybrid agent architecture based on our finite state automata (FSA) formalism that can exhibit both hybrid behaviours and hybrid interactions. Finally, some ideas for building an integrated product design environment are presented using the proposed agent and network architecture. Part II discusses the applications of the proposed MAS framework to concurrent engineering design. [ABSTRACT FROM AUTHOR]

A multidisciplinary robust optimization design framework, concurrent subsystem robust design optimization, is proposed to obtain robust optimum solution in the large-scaled and coupled system. In this framework, response surfaces in the form of artificial neural networks provide information pertaining to system performance characteristics, and individual subsystems engage in performing robust optimization design in parallel while communicating with the system level. This optimization approach incorporates uncertainty analysis and generates a global robust optimum solution in an iterative fashion. Two applications are considered, and the results demonstrate that the approach yields a reasonable robust optimum solution, and it is a potential and efficient multidisciplinary robust optimization approach . [ABSTRACT FROM AUTHOR]

In a concurrent design environment, a robust optimum method is presented to directly determine the process tolerances from multiple correlated critical tolerances in an assembly. With given distributions of multiple critical assembly dimensions, the Taguchi quadric quality loss function is first derived. The quality loss is then expressed as the function of pertinent process tolerances. A nonlinear optimal model is established to minimize the summation of manufacturing costs and product quality loss. An example illustrates the proposed model and the solution method . [ABSTRACT FROM AUTHOR]

As product complexity and marketing competition increase, a collaborative product development environment is necessary for production engineers developing high quality products in short lead-times. To support product designers from different fields, disciplines, and locations, wishing to exchange and share data/information, the neutral form product information models, independent of application platforms, are the underlying requirement of the collaborative development environment. In this paper, a complete solution for neutral product information modelling is proposed. A series of issues referring to the representation of product information models are discussed in detail. The system function modelling, product information modelling, and description of product information model are seriatim discussed. Based on STEP standard and IDEF definition methods, taking rolling bearing as an example, an application case of complete product information modelling is stated. Within VC++ environment, the implementation of product information models is described. Lastly, several general rules for product information modelling are stated. The studies provide a set of complete solutions for product information modelling with neutral forms independent of application platforms. It provides a feasible scheme for product information exchange and sharing within collaborative product development and concurrent engineering environments . [ABSTRACT FROM AUTHOR]

In this paper, a novel method for reconstructing and fabricating a missing ear is presented based on rapid prototyping (RP) and the FreeForm modelling system. Using the method, the image of the normal ear is extracted, mirrored, and positioned onto the image of the deformed side of the face precisely, and the undersurface of the ear prosthesis can match the remnant tissue of deformed side perfectly without making a wax ear. In the clinic, six ear prostheses have been produced and applied successfully. The results suggest that high accuracy has been achieved in shape, size, and protrusion of the ear prostheses, which indicates that the application of RP techniques in conjunction with the FreeForm modelling system is a suitable approach for fabricating ear prosthesis. [ABSTRACT FROM AUTHOR]

Computer Internet communication technology offers tremendous potential for building computer communication and software platforms for rapid development of OKP products to meet global competition. In the past few years, a variety of Internet-based systems have been developed for the purpose of Rapid Product Development (RPD). Among these systems, Internet-based “Design for X (DFX)” systems have been recognized as efficient tools for implementing concurrent engineering and playing a key role in RPD. Internet-based DFX or IDFX systems can be applied by manufacturing companies to rapidly produce high-quality products with low costs and thus higher profits. However, the implementation of IDFX systems is not an easy task. The reason is that many new techniques are involved in the application of the IDFX and the PD processes are normally sophisticated and vary with product development environments. In this paper, as illustrated by case studies, two typical applications of IDFX, i.e. Internet-based design for manufacture (IDFM) and Internet-based design for cost (IDFC) systems, are proposed for rapid and economical tool/ mould making. The structure and the key models of the systems are discussed. [ABSTRACT FROM AUTHOR]

Slicing is a fundamental process planning task and an important procedure in rapid prototyping. However, most research currently focuses on the slicing of homogeneous objects and few approaches for slicing of heterogeneous objects have been reported in the literature. In this article, we present an approach for adaptive slicing of functionally graded material objects. Unlike homogeneous objects, functionally graded material objects contain both geometry and material information. The layer thickness is computed by considering not only geometry but also material variation along the build direction. The continuous material distribution in each layer is discretised into step-wise gradings by subdividing the slice into sub-regions, which can be regarded as homogeneous material regions. An algorithm that summarised the slicing procedure is described and an example is also presented. [ABSTRACT FROM AUTHOR]

Dimensional requirements greatly influence the performance of a product, yet there is no systematic process for determining them. Often as a result, some dimensional requirements are overlooked at the design stage, which forces costly changes at a latter stage of product realisation (such as manufacture and assembly). A methodology is presented here which will assist extracting the dimensional requirements for a product from the customers’ needs. It is suitable for use in a Concurrent Engineering (CE) environment and incorporates some of the existing methodologies used in CE viz. quality function deployment, tree diagrams (The New Seven Tools) and Pugh’s concept selection method. It provides a systematic way of determining the dimensional requirements of a product and establishes clear links between customer needs and the dimensional requirements. These links will help the CE team to understand the product requirements and how they are to be satisfied through the dimensional aspects of a design. [ABSTRACT FROM AUTHOR]

Rapid prototyping processes produce parts layer by layer directly from 3D CAD models. An important technique is required to slice the geometric model of a part into layers and to generate a motion code of the cross-sectional contour. Several slicing methods are available, such as slicing from sterolithgraphy (STL) files, tolerate-error slicing, adaptive slicing, direct slicing, and, adaptive and direct slicing. This paper proposes direct slicing from 3D CAD models and generating a G-code contour of each layer using PowerSOLUTION software (Delcam International, Birmingham, UK). PowerSOLUTION includes two main modules: PowerSHAPE is used to build 3D CAD models and PowerMILL is used to produce G-Code tool paths. It provides macro language, picture files and cutting paths for secondary development work. The authors used macro commands to write an interface generating direct slicing from 3D CAD models and G-code contours for all layers. Most well-known controllers in the market accept the G-Code. Therefore, it is easier to apply this scheme in a CNC-machining center to produce rapid prototyping such as laminated object manufacturing (LOM) for complex geometries. The interface was successfully applied the interface to the UV resin spray rapid prototyping (UVRS-RP) machine that was developed to produce RP. [ABSTRACT FROM AUTHOR]

Adaptive slicing varies layer thickness by taking the geometry change of the CAD model in the build direction into account to improve surface finish. Direct slicing generates exact slice contours from the original CAD model and avoids an intermediate representation, known as an “STL file”. At present, most direct slicing approaches are restricted to some CSG solids or some CAD systems. In this paper, an approach toward adaptive direct slicing with non-uniform cusp heights independent of CAD systems for rapid prototyping is presented. First the geometry model is imported into the adaptive direct slicing system from CAD systems using the standard STEP format. Using OpenGL graphics libraries, the solid model is then displayed and the user is prompted to specify the allowable cusp height for each highlighted surface. Lastly, the CAD model is sliced adaptively with different cusp heights (tolerance requirements) for different surfaces. With non-uniform cusp heights, adaptive slicing has a higher efficiency. Implementation details and results are also presented. [ABSTRACT FROM AUTHOR]

Investment casting (IC) offers an economical method for mass producing complex, shaped metal parts. However, high tooling cost and lead times associated with the fabrication of metal moulds for producing IC wax (sacrificial) patterns result in cost justification problems for customised single casting, small- and medium-quantity production. Rapid prototyping (RP) techniques can reduce the costs associated with single-part or small-quantity production as they can be applied to the fabrication of sacrificial IC patterns containing complex and intricate designs with significant cost and lead-time savings. In this project, a benchmark model is designed to assess the fused deposition modelling (FDM) process for creating sacrificial IC patterns. In addition, an indirect approach toward producing wax patterns via silicone rubber moulding is investigated. Cost and lead time comparisons between the two IC pattern production methods were carried out and presented. The dimensional accuracies of metal castings generated from the RP-produced patterns are also presented. [ABSTRACT FROM AUTHOR]

A new method for optimal concurrent process tolerance is proposed. Information related to process planning is used during the structure design stage of a product. The functional tolerances of the assembly of a product are considered process tolerances. A nonlinear optimal concurrent process tolerance model has been established to minimize the total manufacturing cost with different weight factors for the operations of the product. The constraints include concurrent process tolerance chains, the standard coefficient of process tolerance, and the economical maximum tolerance of the machine tools. In order to obtain optimal process tolerances, a new approach based on grey difference degree is presented in this paper. This approach takes the sequence consisting of the optimal value of every objective as the standard sequence, and that consisting of the actual values as the objective sequence. Thus, grey difference degree is calculated and used as the objective of the function. Finally, a practical example is introduced to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Teamwork is one of the important features of concurrent engineering (CE). Some qualitative and conceptual models of cross-functional teams in CE and their organisation patterns have been proposed in the literature. A quantitative approach to solving the team organisation problem is needed in practice, but little work has been done on this. In this paper, a mathematical model based on integer programming is proposed to formulate the team organisation problem. In the mathematical model, the following requirements for team organisation are considered: 1. The similarities between the current task and the completed tasks. 2. The technical abilities, creation abilities, management abilities, work achievements, and cooperation abilities of the developers. 3. The numbers, workloads, and utilisation rates of the developers. The team organisation problem is decomposed into a series of independent subproblems. A tabu search algorithm is proposed to solve the subproblems. And an example derived from a research institute of the Ministry of Information Industry of China is presented to illustrate the team organisation approach proposed in this paper. The computed result shows that the approach is feasible and the algorithm effective. By solving the subproblems one by one, we can obtain the solution to the whole team organisation problem. [ABSTRACT FROM AUTHOR]

In order to build the complex built-in labyrinth design of an emitter which is a key element in water-saving devices, rapid prototyping and manufacturing (RP&M) is used to design the emitters and to manufacture corresponding rapid tooling (RT). Detailed CAD design of the emitter, CAD process design, and the generation of RT process modelling of the emitter have been carried out using parameterised design. Prototypes have been built using RP techniques to perform the rapid verification and modification of the emitter design; rapid tooling (RT) for the emitter has been fabricated using a metal spraying process to carry out trial-production. Finally, with the fabrication ofa precision mould as the basis, emitter mould design and manufacturing have been completed. As a result, the integration of design/verification/manufacturing of a mould and its products is realised. [ABSTRACT FROM AUTHOR]