Workflow Methodology for Collaborative Design and Manufacturing Carlos Vila, Antonio Estruch, Héctor R. Siller, José V. Abellán, and Fernando Romero Department of Industrial Systems Engineering and Design, School of Experimental Sciences and Technology, Universitat Jaume I, Av. de Vicent Sos Baynat s/n. 12071 Castellón, Spain
[email protected]
Abstract. During product development processes, collaboration has become a common practice between different departments and companies that are involved in their activities. Product Lifecycle Management (PLM) tools can facilitate collaboration among distributed teams within the context of an extended enterprise, but the efficient use of them is still hard to achieve. In this work, we propose a workflow based approach in order to implement product development collaboration, focusing the discussion on a case study of the integration of design and manufacturing activities, using workflow functionality offered by PLM software. Keywords: Workflow Management, Collaborative Engineering, Extended Enterprise, Product Lifecycle Management.
1 Introduction In the age of the extended enterprise, the quick expansion of the Internet provides the infrastructure by which information can be simultaneously available to all those involved in product lifecycle activities from product design to product recycling. Collaboration has become the mainstay of product and processes development but it must not end just with engineering design activities, it should continue with other activities such manufacturing process planning, manufacturing, production and those that concern the product lifecycle [1, 2]. It is obvious that collaboration is needed in all the activities of the product lifecycle (Fig. 1.) and if there is any problem within two activities of the chain it will affect all the others. In this scenario we would like to pay attention to the problems between product design and manufacturing. Today, computer aided tools enable collaboration among marketing department, product designers and manufacturing engineers to avoid manufacturing problems and decrease lead times in product development. Typically, these tools integrate the product development data within a Web shared database [3]. Nevertheless, real practice is far away from total collaboration [4]. In the framework of the extended enterprise, where companies collaborate and compete, designers need to know the exact capacities of the processes used by the Y. Luo (Ed.): CDVE 2007, LNCS 4674, pp. 42–49, 2007. © Springer-Verlag Berlin Heidelberg 2007
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Fig. 1. Collaboration across Product Lifecycle
enterprises responsible for product manufacturing in order to make an efficient process planning which is the bridge activity between design and manufacturing [5]. Although collaborative engineering (CE) depends on the use of modern web based collaboration, the real situation of many CE implementations reminds us that, by simply adopting the required technology, it does not ensure the success. Therefore, it is needed not only a web-based tool for collaboration (Product Lifecycle Management, PLM, or Computer Support for Collaborative Work, CSCW) but also a workflow based methodology that enables the integration and coordination of products life cycle processes and the information exchange between all the people involved [6,7]. Literature reports some research efforts in the direction of collaborative manufacturing and distributed networks [8-10] with applications based on the Information and Communication Technologies (ICT) through the Internet. With this aim, the research presented in this paper is part of a project conceived for collaborative design and manufacturing within a manufacturing cluster, where workflow models support and coordinate the information sharing and the management of the product development activities. We present a particular case study, in which we propose a framework for the coordination of the design, process planning and manufacturing activities, through a workflow model and its implementation in a commercial product lifecycle management tool (PLM).
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2 Workflow Modeling Technologies and Tools The advantages of the collaborative design and manufacturing derive from an enterprise’s ability to use efficiently the entire network of employees, supplier, vendors, buyers, and customers. The flows of information that lie at the core of the coordination and collaboration among network members, not only link disparate information sources, they also provide an opportunity to build knowledge-based tools [7]. Therefore, it is necessary to define all the activities and the global knowledge of the cooperative design and manufacturing processes and implement them with a workflow in order to encourage the collaboration. The term "workflow" is defined as the automation of a business process in the course of which documents, information or tasks move from one participant to another in order to perform some action, in accordance with a set of procedural rules [11]. A workflow model is considered as a model of a process in the real world. Components of a process may include all necessary actions or steps, and the resources and information required to perform them. The main problem with workflow technology is the diversity of available standards. From Software Information Systems point of view, there are several emerging industry standards and technologies. The Business Process Execution Language for Web Services (BPEL) [12] is emerging as a de-facto standard for implementing business processes on top of Web services technology. Numerous workflow platforms support the execution of BPEL processes. However, BPEL modeling tools do not have the necessary level of abstraction required to make them usable during analysis and design phases of high complexity processes like collaborative product development process. On the other hand, the Business Process Modeling Notation (BPMN) [13] has attracted the attention of business analyst and system architects as a language for defining business process blueprints for subsequent implantation. The BPMN is a graph-oriented language in which control and action nodes can be connected almost arbitrarily. Also supported by numerous modeling tools, none of these can directly execute BPMN models, but only few support the translation of BPMN to BPEL in order to execute the model. XML Process Definition Language (XPDL) [14] is a process design format that represents the “drawing” of the process definition that enables to save and exchange the process diagram. Last XPDL 2.0 contains extensions in order to be able to represent all aspects of BPMN. Workflow technology has found its way into mainstream application development tools and application integration middleware. We can now use workflow technology in e-commerce to coordinate the interaction with customers and inter-enterprise processes or in packaged applications as a means of customization. The skills and level of abstraction, required by the users of software products involved in the product design and manufacturing, force software suppliers to hide all the above considerations and provide embedded workflow engines and specific modeling tools with graph-oriented workflow designers, with specialized activity nodes that can be used for customization of process workflow models. Common PLM tools does not use any of the mentioned emerging standards and use instead proprietary workflow modeling methodologies and execution technologies
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that have been adopted and accepted by their users and do not fit easily with new standards without important changes. Perhaps, when those new standards, allow the accomplishment of the increasing required levels of interoperability with external systems like ERP (Enterprise Resource Planning), software vendors will be forced to adopt and support all of them. In this research a PLM software, with an embedded workflow engine and modeling user interface, is used in a case study to support a collaborative environment for the design and manufacturing in an extended enterprise context, in which a main organization interacts with several suppliers for product development.
3 A Case Study: Design and Manufacturing in a Collaborative Environment Usually, the collaboration in product development can be found among marketing, conceptual design, detailed design and prototyping. This collaboration can be inside or outside the organization but it always imply sharing knowledge and data. In the field of manufacturing, internal resources and external suppliers are required to perform specialized operations, which increase the complexity of the collaborative environment. The context of our case study involves several geographically distributed companies, members of an extended enterprise dedicated to the design and manufacture of a discrete product that requires metalworking operations. One of these companies is the owner of the product to manufacture, that works in close collaboration with other enterprises dedicated to different tasks of the design process like for example detail design and engineering analysis. The definitive manufacturing contract is assigned to one of the rest members of the supply chain that compete each other for it. In order to integrate this distributed environment, is proposed a methodology for collaborative product development, focused on product design and process planning activities. As mentioned above, process planning is a critical activity in the transition from design to manufacturing, especially when exists outside participants. In order to facilitate the interaction between them, three levels of manufacturing process plan activities can be establish: meta-planning, macro-planning and micro-planning [5]. Meta-planning is performed to determine the manufacturing process and the machines that fit the shape, size, quality and cost requirements of the parts that have been designed. In macro-planning the equipment is selected, the minimum number of assemblies needed to manufacture the part is determined and the sequence of operations is established. Micro-planning is concerned with determining the tools to be used, the stages they have to follow during the manufacturing process, and the parameters associated to shop floor operations so that productivity, quality of the parts and manufacturing costs can be optimized. The methodology proposed here is divided in three mainstays: description of the collaborative environment, definition of the product lifecycle phases, and design of the workflow required to enable the collaboration.
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3.1 Description of Collaborative Environment
PROJECT TIME
Concurrent Design and Collaboration Collaborative Manufacturing and Competition
PLM Tool
GEOGRAPHICALLY DISTRIBUTED ENVIRONMENT
PLM tools are used for product data management during its lifecycle and for organizing, controlling and accessing related information. PLM predecessor, known as PDM (Product Data Management), are limited to store CAD/CAM files, text files and other document formats [15]. PLM add functionalities to manage the complete product lifecycle and organize activities performed by all involved participants through workflow enactment (definition and execution). The collaborative environment proposed here make use of a PLM tool (Windchill by PTC), a CAD/CAM application (Pro-Engineer Wildfire 3.0) and Internet tools. With the aid of these resources, the extended enterprise members interact as shown in Fig. 2.
Fig. 2. Proposed environment for Collaborative Product Development
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3.2 Definition of the Lifecycle Phases and the Workflow The workflow automates the running of tasks that allow the product development to move on from one stage to another during its lifecycle. The modeled workflow is a global composition of several workflows linked each other in order to be launched consecutively (Fig. 3). The definition of product lifecycle phases is essential for correct workflow definition and design. This case study involves the following phases of product development: conceptual design, detail design, proposal for manufacturing, quotation, planning and manufacturing. Each of these stages is delimited by approval “gates” that determine the transition from one stage to another, as the tasks set out in the workflow are completed.
Fig. 3. Workflow Deployment across Collaborative Product Development
3.3 Workflow Execution The activities carried out by workflows are explained as follows. The main enterprise coordinates all product development activities and manages workflow enactments.
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Also performs market analysis and ‘conceptual design’ stage activities like realization of virtual mock ups that meet aesthetical and functional requirements. Interacting within the PLM tool, enterprises dedicated to detailed design work in technical specifications like material selection, geometrical dimensioning and tolerancing (GD&T), etc. Once the product model is finished, it is ready for product analysis and rapid prototyping as the conclusion of the detail design stage. Meta-planning is the trigger activity of the ‘proposal for manufacturing’ stage, performed by the purchasing department of the main enterprise, for technological process selection and for sending quotation requests to the right sub-contractors. Once quotation requests are received, macro-planning activities need to be done by supplier’s technical department in order to make cost estimation in the quotation stage. After the main enterprise receives quotations and selects the best supplier, the technical department of the supplier is authorized to begin micro-planning activities, in the planning stage. During this, a machine operator provides shop floor information to the micro-process planner, in order to incorporate the real machine capabilities in the final process plan, and to correct any inconsistence in the machining parameters calculations. Finally, the product development ends with the manufacturing stage, and all generated files were stored in the PLM database for further use.
4 Conclusions The research work presented here has been developed with the aim of helping companies in the implementation of web-based collaborative environments. The effort for studying a PLM deployment in an extended enterprise, has forced us to make a detailed analysis of the problem of distributed design and manufacturing, especially when external enterprises are involved and compete each other. As a result of this analysis, we have enumerated all the required participants and activities that must be incorporated in a workflow model that must be implemented to help collaborative product development. The workflow approach exposed here can be taken into account as a guide for the systematic execution of collaborative product development tasks and it allows the controlled interaction between different members of the extended enterprise. Furthermore, the use of a friendly workflow designer tool can help to the straightforward definition of the suitable collaborative scenario. The success of implementing the developed workflow depends not only on the acquisition of the PLM software but also in the overcoming of the cultural barriers of the cooperative work among product designers, process planners, manufacturers and external participants, all of them geographically dispersed. The next steps of this pilot project are to establish metrics for evaluating the organizational impacts in short and medium terms, and to prepare a survey that helps to determine the readiness of different supply chain environments for the implementation of this approach.
Acknowledgements The research team would like to acknowledge the main support of the Caja CastellóBancaixa Foundation and Universitat Jaume I. Particular thanks go to the Programme Alßan: European Union Programme of High Level Scholarships for Latin America (scholarship # E04D030982MX).
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