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Int J Adv Manuf Technol (2002) 19:812820 2002 Springer-Verlag London Limited

Development of a Remote Collaborative Forging EngineeringSystem

J. P. Tsai 1 , Y.-C. Kao 2 and R S Lee 31 Centre for Virtual Design, Far East College, Taiwan; 2 Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Taiwan; and 3 Department of Mechanical Engineering, National Cheng Kung University, Taiwan

The ever-growing demand for high-quality products with lower cost and shorter time-to-market is a challenge in todays globalmarket. This paper presents a methodology for merging the newtechnologies of networking and multimedia, with a conventional forging system to form a remote collaborative forging engineer-ing system. The activities of conventional forging engineeringdesign and manufacturing processes planning were analysed and a structural model is proposed for forging enterprises toinvestigate and improve their engineering activities. The syn-ergy of networking and multimedia technologies is adopted incommunicating and coordinating the activities of the engineersof a multinational enterprise dispersed in different locations,using computer supported cooperative work. For the next generation forging engineering environments, the concept of aremote collaborative forging engineering system provides anew approach and strategy to enhance their competitive advan-tages; and it also provides a fast, economical and experience-

sharing method for the enterprises. An industrial example isused to illustrate the proposed system.

Keywords: Computer supported cooperative work (CSCW);Concurrent engineering; Forging engineering; System model-ling; Videoconferencing

1. Introduction

In order to cope with the strong competition in todays globalmarket, enterprises should equip themselves with the abilityfor efcient and effective communication [1] in order to trans-fer the right information to the right people at the right timeand at the right place. In the last two decades, manufacturingglobalisation has been growing rapidly and its importance isincreasing. This can be attributed to the rapid growth of worldtrade and the substantial increase in the number of multinationalenterprises engaged in multilocation operations [2]. Much effort

Correspondence and offprint requests to : R.-S. Lee, Department of Mechanical Engineering, National Cheng Kung University, Tainan,701 Taiwan. E-mail: mersl mail.ncku.edu.tw

has been focused on computer supported cooperative work (CSCW) since the 1980s [36]. A CSCW environment containscommunication tools such as application software sharing, elec-tronic whiteboard, text chat board, le transfer, and videoconf-erencing. Most of the work focused on creating an environmentfor co-authoring documentation and information-exchange, suchas collaborative word-processing or collaborative CAD andCAE, but rarely focused on collaborative product and processdevelopment. The application of multimedia tools in the manu-facturing industry [7,8] has been paid signicant attention sincethe advent of the Internet. Most of the manufacturingcompanies have begun to integrate multimedia and networkingtechnologies for shortening the cycle time of new productprocurement, research and development, and sale and service,etc. Furthermore, the current trend of quick response inmanufacturing has forced companies to adopt new manufactur-ing strategies in organising and performing their productdevelopment processes, considering subtasking and outsourcingdistributed in multilocations.

Product and process development is a very complicatedengineering process including intensive interactions amongdevelopment tasks, and requires iterative discussion to com-municate and coordinate the redesign processes such as designfor manufacturing and assembly. The concept of concurrentengineering and integrated product and process developmenthas been current for several years. The essence of concurrentproduct and process development is an integrated and collabor-ative process, where people in different disciplines cooperateto design products and specify relevant processes throughcoordination, communication, and negotiation [9,10]. Chenet al. [11,12] used object-oriented modelling and feature-basedtechniques to propose a collaborative framework of team datamanagement for concurrent product and process development.Lee et al. [13,14] integrated knowledge, geometry, and data todevelop a concurrent mould design system. Since new productand process development involve simultaneously a wide varietyof design and manufacturing expertise, and adopting new multi-media and network techniques, concurrent engineering wouldbe a feasible solution to integrate worldwide dispersed expert-ise.

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Remote Collaborative Forging Engineering System 813

This paper proposes a collaborative forging engineering sys-tem by combining IDEF0 (the integrated de nition for functionmodelling) structural analysis modelling, the concurrent engin-eering concept, and CSCW methodology to speed up andimprove product and process development. There are four stepsin the proposed system:

1. Analysis of conventional forging engineering processes.

2. Process modelling of a remote collaborative forging engin-eering system.3. Framework development of the remote collaborative forging

engineering system.4. Construction of the remote collaborative forging engineering

system framework.

The proposed system can facilitate the rationalisation andsynchronisation of the design and manufacture of forging tools,and thus can improve ef ciency and quality, resulting in areduction of the product development cost in a competitiveforging engineering environment.

2. Analysis of Conventional ForgingEngineering Processes

Conventionally, product design is an iterative process. Forinstance, the result of engineering analysis may demand achange in the design stage that, in turn, affects related manufac-turing and assembly stages. Therefore, proper communicationand coordination, in advance, is indispensable to avoid awaste of time and costs that might arise from redesign. Thecharacteristics of the conventional forging engineering processinvolve many iterative activities for design change, as shownin Fig. 1. A new methodology or strategy is explored tointegrate the available experts to discuss collaboratively and

provide in-time opinions and contribute their experiences toshorten the cycle time of process development. This paperproposes a framework for a remote collaborative forging engin-eering system to improve product development cycles.

3. Process Modelling of a RemoteCollaborative Forging Engineering System

The analysis and re-engineering of a forging engineering systemis presented in this section. An integrated de nition for func-tional modelling structural analysis methodology was employedrst to analyse the conventional forging engineering processes,

and then the CSCW concept was associated with this modelto form a remote collaborative forging engineering system.

3.1 Process Modelling with the IDEF0 FunctionalModelling Methodology

IDEF0, one of the IDEF family of methods, is used to analysethe forging engineering process. It is a structural analysis andmodelling technique specially designed for the modelling of decisions, actions, and activities of organisations or complex

Fig. 1. Conventional forging engineering system process.

and interrelated systems [15]. IDEF0 is also known as afunctional modelling method for analysing and communicatingthe functional perspectives of a system, because it provideseffective assistance in organising system analysis and promot-ing communication between the analyst and the customer.

The result of IDEF0 functional modelling is a hierarchical,functional decomposition of process functions, each of whichconsists of ve basic elements:

1. Functional block.2. Input.3. Output.4. Control.5. Mechanism.

Functional blocks represent the activities or tasks of thesystem or process being investigated. Inputs to a function arematerials transformed by the function. Outputs of a functionare the results transformed from the inputs by the function.Controls to a function are the constraints, criteria, or conditionsgoverning the performance of the function. Mechanisms arethe means used to perform or the resources used to supportthe function. One of the special characteristics of IDEF0modelling is its hierarchical decomposition process. The higheractivities represent more general and abstract concepts, whichcan be decomposed into lower-level activities representing morespeci c and detailed concepts.

The model developed for a remote collaborative forgingengineering system, as shown in Fig. 2, is the synergy of theIDEF0 structural analysis model and the CSCW methodology.The purpose of remote collaborative forging engineering system

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814 J. P. Tsai et al.

Fig. 2. IDEF0 diagram of system analysis for remote collaborative forging engineering system (A0 layer).

analysis is to realise the characteristics of product and processdevelopment of forging engineering, including the activitiesand tasks, constraints, supporting resources, and informationow. These activities are:

1. Requirement analysis.2. Preliminary design.3. Process and die design.4. Forgeability evaluation and process simulation.5. Machinability evaluation of die electrode.6. Die electrode machining.7. EDM and forging die manufacture.

3.2 Topics Included in the Remote CollaborativeForging Engineering System

To describe the contents of the required cooperative work in

a remote collaborative forging engineering system, Fig. 3illustrates the engineering processes, communication methods,and the subjects of coordination in a collaborative session of the system. The communication and coordination of a virtualteam may be empowered by means of CSCW tools throughvarious network services. The demand for a broader bandwidthis increasingly necessary for digital audio and video datatransmission owing to the signi cant data networking load.The exploitation of new technologies along with the enhance-ment of the network backbone has improved transmissionquality by adopting QoS (quality of service) of network. Amore detailed description and explanation of CSCW tools andnetwork services are given in Section 4. There are varioustopics in different sessions of the remote collaborative forgingengineering system, as shown in Fig. 3. Process modellingrequires the construction of a proper framework so as tofacilitate discussion panels in collaborative sessions on thesetopics.

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Fig. 3. Remote collaborative forging engineering system.

4. Framework Development of theRemote Collaborative Forging EngineeringSystem

4.1 Generic Remote Collaborative EngineeringSystem Framework

In order to depict the system s function and the requirementsfor software, hardware, network service, and infrastructure,this paper constructs a three-layered framework for a remotecollaborative forging engineering system, as shown in Fig. 4.The upper layer is the application layer, the intermediate layeris the control layer, and the lower layer is the physical layer.The main function of the application layer is knowledge shar-ing; and its activities focus on collaborative discussion andevaluation among the virtual team. The virtual team comprisesmembers such as:

1. Product design engineer.2. Product manager.3. Manufacturing engineer.4. Technician.5. Material specialist.

6. Quality control specialist.7. Industrial designer.8. Vendor s or supplier s representatives.

Discussion and evaluation issues include surface error analy-sis at the design or manufacturing stage, selection of materialand devices, appearance and shape of the product, and theselection of a manufacturing process.

Key functions of the control layer are videoconferencing andapplication sharing. Videoconferencing provides a communi-cation and coordination channel for local and remote engineers.However, application sharing provides an engineering appli-cation software (such as CAD/CAE/CAM) sharing function sothat engineers can view identical engineering-simulation scenesfrom individual computer monitors. To achieve this goal, thispaper adopts the methodology of CSCW. CSCW tools includeapplication sharing, videoconferencing, electronic whiteboard,text chat board, and le transfer. Videoconferencing is usedfor dynamic and in-time video and audio transmission for aone-on-one direct conversation to clear up long-standing ques-tions [16], while the demand for QoS is very high becausedelays in video or audio transfer may cause misleading infor-mation or impatience. However, an electronic whiteboard isused to share and discuss static data such as texts, images,

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Fig. 4. Generic remote collaborative forging engineering system framework.

and sketches. The lower layer, or physical layer, is devisedfor hardware device communication through network servicesunderlying its infrastructure. Hardware devices comprise com-puters, monitors, cameras, microphones, CODEC cards forvideo and audio data compression/decompression, network cards, and multi-point control units (MCUs) for group video-conferencing.

4.2 Construction of the Remote CollaborativeForging Engineering System Framework

A collaborative forging engineering system framework isconstructed by considering distributed forging engineeringactivities. This framework, as shown in Fig. 5, consists of ve modules:

1. CAD module.2. CAM module.3. CAE module.4. CSCW tools and network services module.5. Database and knowledge base module.

These modules are explained in the following subsections.

4.2.1 CAD Module

The CAD module is the kernel of the entire system andincludes three subactivities:

1. Requirement analysis.2. Preliminary design.3. Process and die design.

This module communicates with customers and exchangesexperiences for engineering activities. Traditionally, advancedusers apply CAD software for engineering drafting and/ordrawing based on their experiences in the designing functionand the geometry, but the technology know-how cannot beaccumulated by so doing. The CAD module offers not onlydie design technology but also provides effective integrationand support for database sharing.

4.2.2 CAM Module

This module includes two subactivities:

1. Die electrode machining.

2. EDM and forging die manufacture.

These subactivities are the main tasks in the die makingprocesses. In general, manufacturing staff must propose reason-able manufacturing processes, methods, and sequences basedon manufacturing practices that are normally provided byexperienced personnel. Only the database or knowledge basecontains the die making rules or experiences, and the rationalmanufacturing processes can be scheduled through the inter-active operation with the CAM module. Numerical control(NC) codes can then be processed more rapidly and correctly.The CAM module considers the current work load as thenecessary item to deal with and also offers suggestions onimpractical designs.

4.2.3 CAE Module

The evaluation of the activities in the CAE module is one of the major tasks in this work. The main characteristic of CAEis that it takes advantage of the computation capability of acomputer to analyse the designed processes before the diecavity is made, for example, the simulation of forging processessuch as die lling, stress strain and temperature distribution.Although computer simulation cannot replace shop oor testingtotally, a signi cant lead time reduction of die trial and relatedcost can be obtained. This module consists of two subactivities:

1. Forgeability evaluation and process simulation.

2. Machinability evaluation of die electrode and die electrodemachining.

The nite element analysis system DEFORM (DesignEnvironment for FORMing) [17] was adopted in the forge-ability evaluation through process simulation; VERICUT [18]was adopted to verify the die electrode machining path.

4.2.4 CSCW Tools and Network Services Module

The CSCW tools and network services module is includedhere to support an effective and robust information sharing

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Fig. 5. Remote collaborative forging engineering system framework.

environment for distributed work. This module provides thenecessary tools and techniques for system coordination, com-munication and resource sharing through appropriate net-working services. The proposed system can be borderless andwork effectively through this module.

4.2.5 Database and Knowledge Base Module

This module provides the channel for establishing parametricdesign data, constructing impractical rules and related searchengines. For example, commercial CAD/CAM/CAE softwarecan already offer rational databases or knowledge bases directlyor indirectly for supporting engineering activities such as manu-facturing process planning, machine tool and die material selec-tion. This module is very important for process automationand system integration.

5. Implementation and Discussion

5.1 System Conguration and Example

The system con guration, as shown in Fig. 6, illustrates theimplemented remote collaborative forging engineering systembetween the Metal Forming Laboratory (MFL) at the NationalCheng Kung University (NCKU), and the Precision MetrologyLaboratory (PML) at the National Taiwan University (NTU)in Taiwan. In order to reduce the load for both computer andnetwork, and for the sake of convenient communications andscanning of the details of the sample part, one computer was

dedicated to ISDN videoconferencing, while the other wasused for application sharing and electronic whiteboards. Thereason for using ISDN for videoconferencing is its popularityand economy, since, at present, only a few network servicescan provide a QoS of constant bandwidth. To study thefeasibility of adopting the Internet for application sharing, thispaper performs network analysis and evaluation of the Internetbetween NCKU and NTU, which is described in Section 5.2.

The devices and software used for ISDN videoconferencing[19] include a PC, a high-resolution camera, a high-perform-ance microphone, a PC-based CODEC card, an ISDN network card, and professional videoconference software developed byVisual Basic under an NT operation system environment. Theapplication software sharing for a collaborative session onCAD/CAE/CAM engineering analysis and simulation adopteda remote control software pcANYWHERE [20] developedby SYMENTEC . An industrial example for turbine bladeforgings and forging die electrode machining, as shown in Fig.7, is used to illustrate the product development processes in

applying the methodology of the remote collaborative forgingengineering system. The collaborative discussion session onthe simulation of the die lling condition and the material owcondition for the forged part is shown in Figs 7( a ) and 7( b).The collaborative discussion session on the undercut problemof the die electrode is shown in Fig. 7( c); and cutting para-meters are then adjusted to generate a new cutting tool path,as shown in Figs 7( d ) and 7( e). A new die electrode machiningpart is then machined showing the improved cutting condition,as shown in Fig. 7( f ).

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Fig. 6. System con guration.

5.2 Network Performance Analysis and Evaluation

The ISDN network service was provided by Chunghwa Tele-com Company in Taiwan, and the Internet network serviceprovider was TANet (Taiwan Academic Network). The mediumof ISDN videoconferencing adopted in this paper has two lineswith ISDN/BRI (basic rate interface) so that a constant band-width 256 Kbps (kilobits per second) is provided betweenNCKU and NTU. However, the performance of the Internetmust be analysed and evaluated because of its unpredictablecharacteristics. Processes to analyse and evaluate the perform-ance of the Internet are discussed as follows.

The effects of queuing and dynamic routing are observedfrom MFL. The RTT (round trip time) for the connectionwas tested on a weekly basis. The presence of a congestedlink resulted in an unpredictable deferral of the packet trans-mission at the computer node. Since all Internet packets have

a limited lifetime, when the deferral becomes too long, thedata packet is eliminated and considered as lost. Generally,networking quality is related to RTT, packet loss and stan-dard deviation.

5.3 Discussion

The methodology of IDEF0 and the CSCW concept have beenused to analyse the information ow of a remote collaborativeforging engineering system in this paper, as shown in Fig. 2,

so that the requirements (devices, members, constraints andknowledge) can be understood clearly for supporting the planfor implementing the proposed system process and constructingthe framework, as shown in Figs 3 and 4.

The framework of a remote collaborative forging engineeringsystem proposed in this paper, as shown in Fig. 5, provides anew concept and viewpoint to accelerate product and processdevelopment and possesses scalability, exibility, and integrityfor other cooperative engineering activities. It supports a practi-cal and economical method to share hardware, software andknowledge for engineers in dispersed geographical locations.

The evaluation of samples or prototypes requires a video-conferencing system with a high resolution and a stable trans-mission quality for video and audio so that ISDN is adoptedfor the networking to provide a constant 256 Kbps bandwidth.Since the Internet is the most economic choice for academicsand enterprises for CSCW work and sharing global resources,it is used to bridge the CSCW work, providing an environmentto evaluate collaboratively computer-aided engineering activi-ties. The system con guration and framework proposed in thispaper, as shown in Figs 5 and 6, therefore employ a hybridnetworking system including ISDN and the Internet. Owing tothe unreliable characteristics of the Internet, its performancehas been analysed and evaluated before the practical application[21]. Therefore, adoption of a better QoS that is supported bythe Internet service provider and net-provider will improvethe results.

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Fig. 7. Snapshots to illustrate the application of the remote collaborative forging engineering system. ( a ) Discussion on the simulation of the dielling condition for the forged part. ( b) Discussion on the simulation of the material ow condition (e.g. velocity, direction, etc.) for the forgedpart. ( c) Discussion on the undercut problem for the machined part (die electrode). ( d ) Discussion on the resetting of the cutting parameters soas to generate a new cutting path. ( e) Discussion on the simulation of the new cutting path. ( f ) Discussion on the improving condition for thenew machined part (die electrode).

6. Conclusions and Future Work

6.1 Conclusions

This paper presents a systematic approach towards the develop-ment of a remote collaborative forging engineering system for

a concurrent product and process development environment.Synergy of IDEF0 structural analysis methodology, multimediaand network techniques, CSCW methodology, the concurrentengineering concept, and forging engineering activities havebeen employed to develop a rational, extensive, practical, andreal-time collaborative system for accelerating product and

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process development. An economic, practical, and ef cientmethod has been proposed for constructing an environmentconducive to remote collaborative forging engineering andresource sharing through the hybrid networking of the Internetand ISDN. Furthermore, network performance analysis andevaluation for the Internet has also been explored to providea quanti ed reference basis before the execution of remotecontrol algorithms between geographically dispersed locations.

The proposed approach, methodology, and system framework are generic for other applications. The results of this researchwill facilitate rationalisation and synchronisation of new pro-duct and process development, and thus improve the ef ciencyand quality of product development whilst reducing the cost.

6.2 Future work

Future work will focus on the following aspects:

1. Issues of collaborative design, analysis, and practical fabri-cation along with remote control and monitoring will beextended on the proposed remote collaborative forgingengineering system.

2. Engineering activities will be analysed in more detail toidentify the most necessary process for remote collaborativework. Thus, the priority for implementing concurrent productand process development can be ascertained using the mosteconomic and effective strategy.

3. System infrastructure will be enhanced, and advanced net-work performance will be evaluated.

Acknowledgements

The authors would like to thank the National Science Councilfor support under grants NSC 89 2218-E-006 061 for theNational Cheng Kung University and NSC 89 2212-E-269

008 for the Far East College. Thanks are also extended L. W.Chen for his collaborative testing and to Professor Y. M. Chen,Enterprise Engineering and Integration Laboratory, Institute of Manufacturing Engineering at National Cheng Kung University,for his valuable suggestions; Professor K. C. Fan and hisgraduate student C. L. Chang, Precision Metrology Laboratory,Department of Mechanical Engineering at National TaiwanUniversity, for their collaborative testing.

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