• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.219-228
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• 1997

The objective of this paper is to provide an alternative framework for the integration of process planning and scheduling in cellular manufacturing. The concept of an integrated cellular manufacturing system is defined and the system architecture is presented. In an integrated cellular manufacturing system, there are three modules : the process planning module, the manufacturing-cell design module, and the cell-scheduling module. For each module, the tasks and their activities are explained.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.36-43
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• 1992

This paper presents a hierarchical real-time operation control and monitoring scheme of the FMS/CIM center which has been implemented at the Automation and Systems Research Institute of Seoul National University. The hierarchical structure of the whole scheme consists of three lavers. The upper layer is in charge of on-line scheduling, computer network control, shop-floor monitoring and command generation for AGV dispatching, machining, assembly, inspection, set-up, etc. The middle layer has six modules, which are installed in the FMS host computer with the upper layer and run on the multi-tasking basis. Each module is connected to one of six cell controllers distributed in the FMS model plant and transfers operation command down to each cell controller through the Ethernet/TCP-IP local area network. The lower layer is comprised of six cell control software modules for machining cell, assembly cell, inspection cell, set-up stations. AS/RS and AGV. Each cell controller reports the status of the manufacturing facilites to the middle layer as well as ecxecuting the appropriate sequence control of the manufacturing processes.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.4
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• pp.88-99
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• 1995

The demand for automatic manufacturing systems is increasing. Flexible Manufacturing System(FMS) is usually considered as a soluting for the shop floor automation. One of the difficulties in FMS is the communications problem. Since various machineries with different communications protocoles are included, applying a unified scheme is almost impossible. Therefore, a systematic approach is a key point to solve the communication problem. A cell is difined as an automation unit where closely related for a job reside together. A cell is a messenger between upper level computers and lower level machine equipment. In this research, the fonctions of the cell are defined to have more capabilities than conventional cells since a cell can be often a total manufacturing system is a small to medium sized factory. The cell conducts communications with different machines through the communications schemes established here. A set of software system has been developed according to the defined communication. The software has been tested for a simulation and real experiments for proof.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.5
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• pp.614-621
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• 1999

In this paper, the analytical appproaches are presented for jointly determining the profit-miximizing configuration of the fault-tolerance real time modular cell manufacturing system. The transient(time-dependent) analysis of Markovian models is firstly applied to modular cell manufacturing system from a performability viewpoint whose modeling advantage lies in its ability to express the performance that truly matters - the user's perception of it - as well as various performance measures compositely in the context of application. The modular cells are modeled with hybrid decomposition method and then availability measures such as instantaneous availability, interval availability, expected cumulative operational time are evaluated as special cases of performability. In addition to this evaluation, sensitivity analysis of the entire manufacturing system as well as each machining cell is performed, from which the time of a major repair policy and the optimal configuration among the alternative configurations of the system can be determined. Secondly, the recovery policies from the machine failures by computing the minimal number of redundant machines and also from the task failures by computing the minimum number of tasks equipped with detection schemes of task failure and reworked upon failure detection, to meet the timing requirements are optimized. Some numerical examples are presented to demonstrate the effectiveness of the work.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.724-730
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• 2010

A load cell is a converter that generates voltage signals when a certain force is effected in a given direction. An essential measurement device for electronic scales that indicate weight by numbers. These load cells are being applied in various areas such as daily life, distribution, laboratory and industrial. Recently the study to manufacture load cells in a more simple method while increasing performance is being persisted. In this study based on the comparison of load cells manufactured through single surface processing using strain gauges. Those manufactured through dual surface processing using strain gauges. Ultimately persist a more simple method of load cell manufacturing while increasing its performance. The elements that were compared were linearity, hysteresis, creep and eccentricity which are short tenn performance factors. The conclusion was that single surface processing showed almost identical data as that of dual surface processing, and the load cell error rate(0.005%) also excess regulation. The manufacturing time was shortened while mass-production was possible. Which indicates a development in the weighing industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.422-425
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• 1997

Computer Integrated Manufacturing (CIM) is undoubtedly one of the most influential concepts to have been introduced into the manufacturing world in recent times. The successful CIM application is greatly depended on the way of the approach to given manufacturing environments. This paper reports a new approach in building CIM systems trough the development of a poen cell controller.

• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.114-125
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• 2003

In this paper, we deal with the problem of modeling of agent-based robot manufacturing cell. Its role is becoming increasingly important in automated manufacturing systems. For Object Oriented & Queueing Petri Nets (OO&QPNs), an extended formalism for the combined quantitative and qualitative analysis of different systems is used for structure and performance analysis of mobile robotic cell. In the case study, the OO&QPN model of a mobile robotic cell is represented and analyzed, considering multi-class parts, non-preemptive priority and alternative routing. Finally, the comparison of performance values between Shortest Process Time (SPT) rule and First Come First Serve (FCFS) rule is suggested. In general, SPT rule is most suitable for parts that have shorter processing time than others.

• IE interfaces
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• v.10 no.3
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• pp.189-196
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• 1997

This paper presents a cell formation approach for a cellular manufacturing system to minimize the inter-cell moves considering operation sequences. Two new factors are introduced: (1)flow-similarity(FS) for integrating direct/indirect inter-machine flow and similarity (2)machine cell-part moves (CPM) for exactly computing inter-cell moves. FS is used for combining machines and CPM is used for assigning the parts to the preliminary machine cells. In addition, we develop an aggregated heuristic algorithm to form manufacturing machine cells and assign the parts to those cells based on these concepts. We use performance criterion called total inter-cell moves(TICM), which is the total material flow between internal cells and external cells. Results of computational tests on a number of randomly generated test problems show that the suggested heuristic is superior to existing methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.636-639
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• 2002

In the paper, a Visual factory model for a optical-components manufacturing process is built. The optical-components manufacturing process is composed of 3 operation processes; optical sub assembly process, package assembly process, and fiber assembly process. Each process is managed not a batch mode, which is one of most popular manufacturing styles to produce a great deal of industrial output, but though a modular cell. In the processes, a modular cell has to be processed independently of the other cells. Optimization for the composition of assembly cell in the optical-components system is made by the Visual factory model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.380-385
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• 1993

The demand for automatic manufacturing systems is incerasing. Computer Integrated Manufacturing(CIM) technology is believed to be a solution for the problem to enhance productivities and flexibilities. Although researches on CIM have been conducted treendously, application of the technology is not widely accepted yet. The CIM research on the shop floor starts with the Flexible Manufacturing System(FMS). One of the crucial obstacles to the FMS is the lack of excellent strategies for efficient operations. The aim of this research is constructing an automation scheme in the low level of factories where various machinaries are involved. An operating strategy is established for an automation unit named as a cell which resides between the upper level computers and manufacturing shop floor. The cell is defined to fit into the total manufacturing system. The defined cell has more functions than conventional cells. A scheduling scheme is adopted for the shop floor operations. A set of software has been developed and tested through simulations and shop floor experiments.