• Industrial Engineering and Management Systems
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• 제7권2호
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• pp.160-170
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• 2008

This paper proposes a mathematical model for converting conveyor assembly line to cellular manufacturing in complex production environments. Complex production environments refer to the situations with multi-products, variant demand, different batch sizes and the worker abilities varying with work stations and products respectively. The model proposed in this paper aims to determine (1) how many cells should be formatted; (2) how many workers should be assigned in each cell; (3) and how many workers should be rested in shortened conveyor line when a conveyor assembly line should be converted, in order to optimize system performances which are defined as the total throughput time and total labor power. We refer the model to a new production system. Such model can be used as an evaluation tool in the cases of (i) when a company wants to change its production system (usually a belt conveyor line) to a new one (including cell manufacturing); (ii) when a company wants to evaluate the performance of its converted system. Simulation experiments based on the data collected from the previous documents are used to estimate the marginal impact that each factor change has had on the estimated performance improvement resulting from the conversion.

• 한국CDE학회논문집
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• 제19권2호
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• pp.148-156
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• 2014

Generally, over 95% of manufacturing cost is determined in the design and manufacturing preparation step, especially a great part of productivity is determined in the manufacturing preparation step. In order to improve the manufacturing competitiveness, we have to verify the problems that can be occurred in the production step and remove the unnecessary factors in the manufacturing preparation step. Thus, manufacturing industries are adopting digital manufacturing system based on modeling & simulation. In this paper, we introduce e-FEED system (electronic based Front End Engineering and Design) that is the integrated design and analysis system for optimized manufacturing line development based on simulation automation and explain the work process (Design, Analysis and Optimization) about manufacturing line development using e-FEED system. Also, the effect is described through the real implementation cases.

• 동력기계공학회지
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• 제4권4호
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• pp.92-98
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• 2000

Modern manufacturing systems should cope with the frequent changes in a product model and disturbances in manufacturing process. The control system of such systems must cover a constant adaptation and high flexibility. Holonic Flexible Manufacturing Cell(HFMC) is introduced to handle these issues more successfully. It is based on the concept of autonomous co-operating agent, called 'Holon', which is a building block of a manufacturing system for transforming, transporting, storing and/or validating information and physical objects. In this paper the basic structure of the HFMC is represented by using Unified Modeling Language and Open architecture cell controller is developed for effective integration components of a manufacturing system. Also a new control model, called MuLOM(Multi-Layered Operation Model), is suggested to represent the control behaviour for a holonic flexible manufacturing cell control system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.496-505
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• 1996

지역적으로 널리 분산되어있는 여러 생산지로 부터 원격으로 제조활동의 현황을 원격 및 실시간으로 감시하고 통제 및 관리하는 시스템을 초고속통신망을 이용해 구축하고 이에대한 시제품을 개발하는 것이 본 연구의 최종 목표이다. 본 논문에서는 원격감시 및 검사기술, 원격생산정보취합 및 추적기술, 원격 데이터베이스 설계 및 운영기술, 단말 및 망접속기술등에 대하여 설계하고 시제품 구현에 대한 방법을 소개한다.

• Journal of Computational Design and Engineering
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• 제2권4호
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• pp.253-260
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• 2015

Feature-based NC machining, which requires high quality of 3D CAD model, is widely used in machining aircraft structural part. However, there has been little research on how to automatically detect the CAD model errors. As a result, the user has to manually check the errors with great effort before NC programming. This paper proposes an automatic CAD model errors detection approach for aircraft structural part. First, the base faces are identified based on the reference directions corresponding to machining coordinate systems. Then, the CAD models are partitioned into multiple local regions based on the base faces. Finally, the CAD model error types are evaluated based on the heuristic rules. A prototype system based on CATIA has been developed to verify the effectiveness of the proposed approach.

• 한국CDE학회논문집
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• 제10권4호
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• pp.237-243
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• 2005

To increase the productivity and efficiency of an enterprise, all relevant product information should be provided to shop floor workers timely and in a unified form because shop floor workers are final consumers of most accumulated information generated from various departments of an enterprise. But, most existing enterprise information systems have an emphasis upon providing design/manufacturing information to office workers. Proposed in this study is the development of integrated design/manufacturing information system focused on providing cohesive information required to shop floor activities. For developing integrated information system, the functional requirements at the shop floor are identified and analyzed. Based on the extracted functional requirements, object-oriented system design and implementation is conducted. By using this system, shop floor workers can use all relevant information required to their daily operation in a integrated and unified form.

• 한국정밀공학회지
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• 제29권4호
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• pp.386-394
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• 2012

Recent trends in the flexible manufacturing systems are morphing cell control for the shop-wide production operation system and providing the integrated operation and execution system together with vendor-specific FMC/FMS platform. In these requirements, the shop-floor level operation system plays a role of coordinating the control activity of each cell, and has to provide flexibility for the complexity of mixed operations of various cells. This paper suggests a system architecture for the mixed environments of multi-cells and job shop, its corresponding enabling technologies based on comparative studies with other related studies and commercialized systems. This approach includes a process definition model considering the integration with upper BOM-BOP and external service modules, and reconfigurable device-level interface which provides dynamic interconnections with machine tools and cell controllers. The function modules and their implementation results are also described to provide the feasibility of the proposed approaches as the flexible shop-floor operation system for the multi-cell environments.

• Journal of Ship and Ocean Technology
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• 제8권4호
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• pp.45-55
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• 2004

How to achieve engineering collaboration among diverse engineering activities is one of the key topics in manufacturing fields nowadays. The infrastructure for collaborative engineering is essential, and it can be realized by information technologies and intelligent engineering applications in digital environments. Digital Manufacturing is a technology to facilitate effective product developments and agile productions by computer models representing the physical and logical schema and the behavior of real manufacturing systems including products, processes and factories. A digital factory as a well-designed and integrated digital environment is incorporated in it. In this paper, digital manufacturing is recommended as a good strategy for collaborative engineering, especially in product developments and productions. By business process analysis and some case studies, we suggested sophisticated digital models are very useful to concurrent and collaborative engineering. It is expected that digital manufacturing is a very good strategy for achieving dramatic time and cost savings in many engineering activities of many manufacturing industries, including machinery, automotive and shipbuilding.

• 대한기계학회논문집A
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• 제27권12호
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• pp.2028-2038
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• 2003

High-speed feed drive systems have been widely used in the manufacturing and semiconductor industries. Specifications for high-speed systems require more advanced capabilities than conventional feed drive systems. It is necessary to devise special design concepts to achieve the level of performance for high-speed feed drive systems. In this paper, an integrated design method is proposed for high-speed feed drive systems in which the interactions between mechanical and electrical subsystems ought to be considered simultaneously during the design process. Based on the integrated design method, a nonlinear optimal design procedure of mechanical subsystems considering the Abbe and radius errors is accomplished through the design process of electrical subsystems satisfying the control stability and the saturation condition of actuators as well as the relative stability. Both mechanical and electrical parameters are considered as design variables. Simulations and numerical case studies show that the integrated design method of high-speed feed drive systems creates results satisfying the desired performances of mechatronic systems.

• 한국경영과학회지
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• 제23권4호
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• pp.63-73
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• 1998

With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.