Yongsheng Ma

Associative feature modeling for concurrent engineering integration

In typical product development processes, like plastic injection mould design, design information flow is not well supported by the current available IT systems. At different stages of a product life cycle, from documentation of requirement specifications, to conceptual design, detailed structure design and production, engineering knowledge is striped off except the bare minimum geometrical and control data, such as computer-aided design (CAD) solid models and cutting tool paths. Associative relations among engineering features are normally ignored; hence data consistency and design changes are difficult to be managed. In this paper, interfacing knowledge oriented tools and CAD application is identified as a technical gap for intelligent product development, and the concept of associative feature is introduced. For high-level reasoning and the execution of decisions, to define associative features in the form of self-contained and well-defined design objects is essential. As a case study, cooling channels in the design of plastic injection moulds with a CAD tool are modeled as an illustrating associative feature type. Potential integration among different applications based on such associative features is also explored.

Collaborative process planning and manufacturing in product lifecycle management

Companies are moving towards quickly providing better customer-centric products and services improve market share and market size with continuously growing revenue. As such, the effective collaboration among customers, developers, suppliers, and manufacturers throughout the entire product lifecycle is becoming much more important for the most advanced competitiveness. To address this need, a framework for product lifecycle collaboration is proposed in this study. The details of these collaboration models throughout the entire product lifecycle are depicted. As one of the key elements in product lifecycle collaboration, technology to support collaborative product manufacturing is proposed, developed and implemented in this study. It is hoped that the developed technology for collaborative product manufacturing will lay a frontier basis for further research and development in product lifecycle management.

Paradigm shift: unified and associative feature-based concurrent and collaborative engineering

With widely used concurrent and collaborative engineering technologies, the validity and consistency of product information become important. In order to establish the state of the art, this paper reviews emerging concurrent and collaborative engineering approaches and emphasizes on the integration of different application systems across product life cycle management (PLM) stages. It is revealed that checking product information validity is difficult for the current computer-aided systems because engineering intent is at best partially represented in product models. It is also not easy to maintain the consistency among related product models because information associations are not established. The purpose of this review is to identify and analyze research issues with respect to information integration and sharing for future concurrent and collaborative engineering. A new paradigm of research from the angle of feature unification and association for product modeling and manufacturing is subsequently proposed.

Towards unified modelling of product life-cycles

This paper presents the potential of modelling a products life-cycle using the Unified Modelling Language (UML). The potential benefits and limitations are discussed. An example of a vacuum cleaner is cited in support of this approach. Model consistency across the various life cycle stages of the product is of major concern and an algorithm for constraint management is proposed and prospective research directions highlighted.

Feature-based CAD-CAE integration model for injection-moulded product design

One prominent characteristic of product design for injection-moulded parts is that design and analysis (e.g. flow simulation) go hand in hand to ensure that the design is manufacturable by the injection-moulding process. Despite the wide use of CAD and CAE systems, the two processes are still not integrated. There is no generic, unified model that allows both design and analysis information to be specified. In this paper, a feature-based CAD-CAE integration model is proposed to tackle the problem. The model comprises a hierarchy of CAD-CAE features such as part, wall, hole, rib, boss and treatment. The features are defined by their attributes and behaviours. With this model, information relating to both design and analysis can be specified and modified. The specified information from the design process is used to activate relevant CAE analysis routines, thus supporting integration from the CAD to the CAE process. If any of the specified design constraints is not satisfied from the CAE results, the initial model can be modified and the CAE analysis executed again. Hence, the model also supports integration from the CAE to the CAD process. A design case illustrates the bidirectional integration process.

A survey of manufacturing oriented topology optimization methods

Presents a survey of manufacturing oriented topology optimization methods.Investigates the length scale control and geometric feature based design for machining oriented topology optimization.Investigates the part ejection and rib thickness control for injection molding/casting oriented topology optimization.Proposes the future research direction for additive manufacturing oriented topology optimization. Topology optimization is developing rapidly in all kinds of directions; and increasingly more extensions are oriented towards manufacturability of the optimized designs. Therefore, this survey of manufacturing oriented topology optimization methods is intended to provide useful insight classification and expert comments for the community.First, the traditional manufacturing methods of machining and injection molding/casting are reviewed, because the majority of engineering parts are manufactured through these methods and complex design requirements are associated. Next, the challenges and opportunities related to the emerging additive manufacturing (AM) are highlighted. SIMP (Solid Isotropic Material with Penalization) and level set are the concerned topology optimization methods because the majority of manufacturing oriented extensions have been made based on these two methods.

Market segmentation for product family positioning based on fuzzy clustering

To compete in the marketplace, manufacturers have been seeking for expansion of their product lines by providing product families. One difficulty for product family positioning is that diverse customer needs can no longer be satisfied by a mass marketing approach. Realizing the importance of customer purchase behaviours for product family positioning, this paper proposes a fuzzy clustering-based market segmentation approach. With a focus on engineering characteristics, the fuzzy clustering-based market segmentation helps plan the right products to target segments effectively and efficiently. An application of the proposed methodology in a consumer electronics company producing vibration motors is reported. The evaluation of the proposed methodology is also discussed.

Unified Feature Modeling Scheme for the Integration of CAD and CAx

AbstractIn concurrent engineering, it is difficult to organize product information in an interconnected and consistent way due to complicated interrelations and proprietary data formats. This paper proposes an information representation scheme which accentuates feature association and feature unification. Feature association establishes persistent relations among different features constituents while feature unification provides a generic format for different application features. A unified feature defines common attributes and methods of all the supported application features. Feature relations are identified in application, feature and feature constituent levels for controlling the consistency among different application feature models.

Change propagation algorithm in a unified feature modeling scheme

Product lifecycle stages are inter-related and mutually constraining. Due to the sequential nature of the product development processes, some constraints or conflicts may emerge in a later stage and require modifications to the decisions made in earlier stages. The iterations between stages are hence unavoidable and must be managed carefully to maintain the consistency, integrity and validity of product information models. Due to the inter- or intra-stage relations, a chain of changes is very likely to occur as the consequence of an initial change. Modeling and maintaining these relations are important in collaborative engineering to evolve the state of the whole product model in a consistent manner. This paper introduces a new method of modeling associative engineering relations in a unified feature modeling scheme and elaborates a change propagation algorithm for the information consistency control among multiple applications of product lifecycle stages. The algorithm is established on a JTMS-based dependency network. Two case studies are used to illustrate the proposed dependency network and change propagation algorithm.

Associations in a Unified Feature Modeling Scheme

Features allow one to associate human knowledge and product geometry. The authors proposed, in earlier publications, a unified feature modeling scheme with the aim to maintain the integrity and consistency of a product model. Different application feature models within and across different product life-cycle stages are integrated, and especially, nongeometric relations (besides geometric ones) are handled. In this paper, as an improvement to the previous work, two types of associations are introduced: sharing and dependency. In the context of conceptual and detail design stages, these associations are described and the implementation is discussed in detail.