Materials Science Forum Vols. 505-507 (2006) pp 619-624 online at http://www.scientific.net © (2006) Trans Tech Publications, Switzerland Online available since 2006/Jan/15
Process Reengineering of Collaborative Mold Design and Manufacturing – A System Engineering Evaluation Approach Amy J.C. Trappey 1,a, Tung-Hung Lu 2,b 1
Department of Industrial Engineering and Engineering Management, National Tsing Hua University. Hsinchu, Taiwan 300, R.O.C Fax: 886-3-5722204 Tel: 886-3-5717654
2
Industrial Technology Research Institute, CAST. Bldg. 52, 195 Sec.4, Chung Hsing Rd., Chutung, Hsinchu, Taiwan 310, R.O.C. Fax: 886-3-5826464 Tel: 886-3-5913408 a
[email protected], b
[email protected]
Keywords: Injection molds; process analysis; collaborative management.
Abstract. The mold design/manufacturing plays a crucial role in the development of high-volume mold-injected, pressed, and/or formed products. A mold fabrication consists of a set of sub-processes and usually takes several months to complete its design and production. Due to the shortening of product lifecycle, the sequence of process execution has to be reengineered to improve its efficiency. This research focuses on the as-is and the to-be process analyses of the mold design and manufacturing. The current practice of mold industry is discussed using the as-is process model. Then, the new collaborative and integrated mold design and manufacturing practice is described in the to-be process model. The as-is model and the to-be model also consists of three key views and their relationship. Finally, the comparison of the as-is and the to-be models is conducted using a systematic approach. We evaluate their processes in simulated quantitative measures such as cycle time and cost. Introduction Products made by injection-molding can be easily seen everywhere in our daily life. No matter how a product is designed originally, its mold design always plays a crucial role in the end-product design processes. The processes of mold design, machining and final assembly involve not only a great deal of design knowledge but also many manufacturing technologies and facilities. Therefore, most end-product manufacturers are implementing the collaborative strategy and outsource their mold production to their suppliers. The collaborative strategy can be described as a company leveraging suppliers’ capability to meet its needs in mold fabrication by releasing design and/or production orders to their suppliers [1-3]. Enterprises use the collaborative strategy to enhance their global competitiveness, which has been proven to be a successful approach. Many companies in Taiwan have benefited from the OEM business model in the last two decades. The manufacturing cost in Taiwan has steadily increased considerably. Thus, many OEM production orders have been transferred to low labor cost countries such as Mainland China and Vietnam. In order to increase competitiveness, many companies in Taiwan have changed from OEM manufacturing orientation to ODM design/manufacturing strategy. Many previous research mainly focus on mold associated parts design collaboration [4], activity optimization [5], supply chain management [6], knowledge management and information system design [7-11]. This paper presents an innovative collaborative design service model for mold design/manufacturing (i.e., ODM) industry, namely, to form a virtual enterprise for integrated design and manufacturing processes.
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Modeling as-is mold fabrication processes The mold fabrication is a collection of activities organized into a set of processes. They include reverse engineering process, CAD design process, CAM (NC codes generation and verification) process, heat and surface treatment process, mold assembly process, mold testing process, and final refinement. These processes usually occur sequentially at different fabrication stages that involve different suppliers. Due to shorter product lifecycle, the sequence of process execution has to be reengineered to be more efficient. The goal of the process reengineering is to minimize the fabrication cycle time. Therefore, the challenge is how to model the whole processes and identify a way to make the process execute in a more efficient manner. Figure 1 shows the as-is model of current mold fabrication process. The model is constructed by the Petri Net process modeling methodology which uses INCOME4 Process Designer tool [12]. By using this tool the complex process modeling can be easily managed. If a process is composed of multiple sub processes, then it can be further drilled-down such as the “Fabricate Molds” process illustrated in Figure 1.
Fig. 1. The as-is mold fabrication process In Figure 1, there are two organizations, i.e., the original brand company (OBC) and supplier, involved in the processes. The respective responsibilities of these two organizations are listed in Table 1. It shows that once the product mold design project is initiated formally, the project manager (PM) is ready for outsourcing of CAD modeling construction, mold design, manufacturing and associate parts/components purchasing from vendors. As a result of mass outsourcing, a PM has to deal with many suppliers. This situation makes it more difficult for the PM to integrate all outsourced activities and to monitor the project schedules accurately. In “fabricating molds” activity, there exists another drilled down critical process, which is shown in the lower right of Figure 1(a). This activity is dispatched to a machining service company (supplier). The supplier has to fabricate and test the mold to satisfy the specifications set by the product design team. The most critical part of this diagram is in the “Test Mold” activity. The supplier needs to transport molds from its factory back to OBC’s mold division for testing. The testing is conducted by the mold testing team. Time needed for traveling back and forth between the mold manufacturer and the OBC is far from being economical. After these molds are transported to the OBC site, they will be placed in a waiting line until the testing machine is available. A lot of time is wasted from this limitation. If molds fail the test, they will be transported back to the supplier to be repaired and modified. After fixing the problems on the mold, the mold will
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be shipped back to OBC again. These processes can go iteratively for several rounds and create huge inefficiency. At last, when the OBC receives the final molds, the OBC can proceed the pilot runs and, subsequently, mass production using the injection molding machine with the proper molds. Table 1. The list of responsibilities of OBC and supplier. Organization
Responsibility
Involved roles
OBC
z z z z z z z
Sales Project manager Product design team Mold testing team
Supplier
z z z z z
Project initiation Product design Selecting suppliers for outsourcing Outsourcing result verification Mold testing Mold refinement Validate design with manufacturing ability Reply the quotation Reply the actual fabricate completion schedule Fabricate parts following the design specification Deliver the mold Refine the mold after testing
R&D manager R&D engineering team
The as-is process for mold design and manufacturing has some critical problems and shortages, such as the inefficiency in outsourcing management, lack of unsystematic approach in engineering change management, mold testing and refinement rerouting, and passive communication between OBC and supplier. In the following section, we propose a new to-be process model that is developed to eliminate these problems for mold design and manufacturing industry. Modeling the collaborative processes The as-is process model needs to make some changes for collaboration. First of all, in order to increase the abilities in real time event handling and quick response to the engineering change, the project management needs the supports of a platform, called “collaborative mold integrated design and manufacturing (CMIDM)” platform. This platform provides a set of functions to assist the project manager to manage and handle events occurring through out the entire project lifecycle. Table 2 illustrates the major functions of CMIDM. The main concept of CMIDM platform focuses on the improvement of communication and management between OBC and their suppliers. The CMIDM also provides a finished project back tracking mechanism for adopting successful project know-how. Thus, the project manager can quickly learn from successful experiences from other projects. The well defined document management and engineering change process will reduce mistakes caused by incorrectness or out of date information flow. The real time task monitoring mechanism makes progress of every task transparent to all project members. In addition, the integration of real time message service such as interactive text chatting, VOIP service, desktop sharing, and 3D CAD view-markup service will improve the overall communication in engineering manner. The whole process chain integrated by CMIDM platform decrease, the engineering changes and cut down the process cycle time. Secondly, the mold testing processes in as-is model needs to change. The mold modifications after the testing always happen in several times thus will spend several transportations between OBM and mold fabrication shop. Besides, the mold testing needs to wait until the production injection/press machine is available. This is one reason that mold fabrication processes takes such a long time. Based on these reasons, we propose OBC also establishes a Mold Testing Service Center (MTSC). The MTSC provides all required testing resources for mold manufacturer to verify and modify new molds. The MTSC solves the non-value added rerouting and time wastes while waiting for the availability of machines on the production line for mere testing. The testing status will feed back to CMIDM platform and project manager can monitor the testing status. Figure 2 shows the to-be process which is incorporated into the CMIDM platform.
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Table 2. The function list CMIDM platform.
By Applying CMIDM with the early involvement, the collaborative platform releases the mold specifications to suppliers, collocates all mold production technologies, and saves time and cost with mold testing service center. From the strategic point of view, CMIDM service provides a possibility for the OBC project manager to manage more than one project at a time and the CMIDM project manager can concentrate on handling the progress of mold fabrication in a systematic way. Process modeling comparison Figure 3 shows activities in time-scheduling point of view between as-is and to-be process models. Comparing the as-is model with the to-be model, the main disadvantage of as-is model is time-consuming. On the other hand, the to-be model takes the advantage of the CMIDM platform and MTSC owns the critical path for the mold industry. Saving most of unnecessary processes could turn the mold industry into a much more profitable one. In summary, there are significant improve in to-be model such as: z Purchase components In the to-be model, the IDM service is fully collaborative with supplier. Therefore, suppliers can understand the component demands concurrently.
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z Conceptual stage In the as-is model, the conceptual stage is completed by the OBC itself. However, in the to-be model, the IDM service will use design-in strategy for early involvement in the product definition activity. z Reverse engineering and distribute CAD In this activity, time consuming can be calculated easily. The total completion time of the to-be model is shorter than the as-is model. The main reason is that IDM service has more opportunities than as-is model to reuse mold components. Reverse engineering and distributed CAD can be done much more efficiently in to-be model. z Confirmation of mold design Collaborative platform provides web environment for design collaboration. It reduces the transportation time between all parties. z Transport molds for testing and refinement The CMIDM service provides a professional mold testing center. Therefore, IDM also reduces the transportation time in mold testing and refinement. z Save transportation and waiting time for testing Because of the testing and modification is executed in MTSC in to-be model, the mold transportation activity is not necessary to be executed. The existence of professional mold testing center avoids transportation and waiting time in mold testing activities.
Fig. 2. Collaborative mold design and manufacture process model.
Fig. 3. Comparison of time consumption between as-is and to-be models
Conclusion This paper presents an improved methodology in mold design and manufacturing process, by introducing CMIDM platform to improve the overall management abilities, consolidate the engineering communication, and ensure information integrity. The new idea of setting up “mold testing service center” solves inefficiency problems of mold testing, and cuts down the overall process cycle time. There are two major contributions in the research. First, in communication aspect, by taking advantages of the CMIDM platform, it provides real time message/CAD model collaboration and online job dispatching to make the engineering communication effectively. Second, in management aspect, it enhances the control of project scheduling and progress reporting, and
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further incidences to customers immediately. These will benefit the management of projects more effectively and profitably. Acknowledgments This research is partially supported by the Industrial Technology Research Institute (ITRI) and the National Science Council (NSC), Taiwan, ROC. References [1] Lee, R.S., Chen, Y.M. and Hsin, Y.C.; Kuo, M.D. (1998) ‘A framework of a concurrent process planning system for mold manufacturing’, Computer Integrated Manufacturing Systems Vol. 11, No.3, pp. 171-190. [2] Chung, J. and Lee, K. (2002) ‘A framework of collaborative design environment for injection molding’, Computers in Industry Vol. 47, No. 3, pp. 319-337. [3] Lee, R.S., Chen, Y.M., and Lee, C.Z. (1997) ‘Development of a concurrent mold design system: a knowledge-based approach’, Computer Integrated Manufacturing Systems Vol.10, No. 4, pp. 287-307. [4] Chin K.S. and Wong, T. N. (1996) ‘Knowledge-based Evaluation for the Conceptual Design Development of Injection Molding Parts’, Engineering Applications of Artificial Intelligence Vol.9, No. 4, pp. 359-376 [5] Hameri, A.P. (1997) ‘Project management in a long-term and global one-of-a-kind project’, International Journal of Project Management Vol. 15, No 3, pp. 151-157. [6] Fu, Y. and Piplani, R. (2004) ‘Supply-side collaboration and its value in supply chains’, European Journal of Operational Research Vol. 152, No. 1, pp. 281-288. [7] Ma, Y.S. and Tong, T. (2003) ‘Associative feature modeling for concurrent engineering integration’, Computers in Industry Vol. 51, No. 1, pp. 51-71. [8] Jia, H.Z., Ong, S.K., Fuh, J.Y.H., Zhang, Y.F., and Nee, A.Y.C. (2004) ‘An adaptive and upgradeable agent-based system for coordinated product development and manufacture’, Robotics and Computer-Integrated Manufacturing Vol. 20, No. 2, pp. 79-90. [9] Chen, Y.M. and Liu, J.J. (1999) ‘Cost-effective design for injection molding’, Robotics and Computer-Integrated Manufacturing Vol. 15, No. 1, pp. 1-21. [10] Jacobsen, K., Eastman, C., and Tay, S.J. (1997) ‘Information management in creative engineering design and capabilities of database transactions’, Automation in Construction Vol. 7, No. 1, pp. 55-69. [11] Twidale, M.B., Nichols, D. M., and Paice, C.D. (1997) ‘Browsing is a collaborative process’, Information Processing & Management Vol. 33, No. 6, pp. 761-783. [12] Promatis. (2003), ‘INCOME suite: Modeling, simulation and visualization of business processes’, http://www.promatis.com/cbusiness/products/income/index.htm.
