• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.821-825
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• 1991

This paper presents an architecture and control logic of a Flexible Manufacturing Cell (FMC) which is one of the important elements under Computer Integrated Manufacturing (CIM) environment. To implement FMC, it is very important to develop a software which can control and monitor the overall system in an integrated environment. Our primary concern in this research is not to develop individual systems, but to integrate them in the hierarchical control level. Progress on the research of integrating CAD/CAM, Process Planning, Off-line Robot Programming and Simulation module into FMC control system is reported. FMC hardware system used here has an Automated Storage & Retrieval System (AS/RS), a conveyor system, a transfer robot, a CNC milling machine, a bar-code system, and an IBM PC/AT as Cell Control System (CCS). In order to demonstrate the operational result, the name plates, text-carved aluminium plates, are manufactured by this system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.368-373
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• 2015

Porous alumina ceramics with two different pore sizes were fabricated using hollow microspheres as the pore-forming agent. The relative density, total porosity, and microstructure of the obtained alumina ceramics were studied. It was found that the total porosity of sintered samples with different amounts of hollow microsphere content, from 2.0 to 4.0 wt%, was 69.3-75.6%. The interconnected and spherical cell morphology was obtained with 3.0 wt% hollow microsphere content. The resulting ceramics consist of a hierarchical structure with large-sized cells, and small-sized pores in the cell walls. Moreover, the compressive strength of the sintered samples varied from 8.3-11.5 MPa, corresponding to hollow microsphere contents of 2.0-4.0 wt%.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1250-1255
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• 1990

This paper discusses an optimal cyclic scheduling problem for a FMC (Flexible Manufacturing Cell) modeled by a two-machine flowshop with two machining centers with APC's (Automated Pallet Changers), an AGV (Automated Guided Vehicle) and loading and unloading stations. Cyclic production in which similar patterns of production is repeated can significantly reduce the production lead-time and WIP (Work-In-Process) in such flexible, automated system. Thus we want to find an optimal cyclic schedule that minimizes the cycle time in each cycle. However, the existence of APC's as buffer storage for WIP makes the problem intractable (i.e., NP-complete). We propose an practical approximation algorithm that minimizes, instead of each cycle time, its upper bound. Performances of this algorithm are validated by the way of computer simulations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.1-6
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• 2012

This paper addresses the issue of Renewable Energy for Electricity Storage device is one of the NAS (Sodium-Sulfur) battery will be about the module. For safety reasons, not the actual battery cells using a dummy cell in the module's operating temperature setting to examine the characteristics of the insulation vacuum of the wall temperature and external temperature changes measured over time. Upper and lower boundaries of the wall vacuum insulation characteristics cotton C intervals over time, average $5^{\circ}C$, but the temperature is rising, 4C section with little temperature change did not occur. On the other hand, about $3^{\circ}C$ in section 4D, and it was confirmed that the temperature rises. Wall vacuum insulation characteristics over time to look at the experiments and measurements are described.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.197-208
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• 1999

This paper presents an operation sequence-based approach for determining machine cell layout in a cellular manufacturing environment. The proposed model considers the sequence of operations in evaluating the intercell and intracell movements. In this paper, design of cellular layout has an objective of minimization of total material flow among facilities, where the total material flow is defined as a weighted sum of both intercell and intracell part movements. The proposed algorithm is developed by using genetic algorithm and can be used to design an optimal cellular layout which can cope with changes of shop floor situation by considering constraints such as the number of machine cells and the number of machines in a machine cell.

• Korean Management Science Review
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• v.24 no.1
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• pp.91-111
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• 2007

In this paper an effective two-phase approach adopting modified p-median mathematical model is proposed for grouping machines and parts in cellular manufacturing(CM). Unlike the conventional methods allowing machines and parts to be improperly assigned to cells and families, the proposed approach seeks to find the proper block diagonal solution where all the machines and parts are properly assigned to their most associated cells and families in term of the actual machine processing and part moves. Phase 1 uses the modified p-median formulation adopting new inter-machine similarity coefficient based on the non-binary production data-based part-machine incidence matrix(PMIM) that reflects both the operation sequences and production volumes for the parts to find machine cells. Phase 2 apollos iterative reassignment procedure to minimize inter-cell part moves and maximize within-cell machine utilization by reassigning improperly assigned machines and parts to their most associated cells and families. Computational experience with the data sets available on literature shows the proposed approach yields good-quality proper block diagonal solution.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.43-49
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• 2013

We have studied on ozonate water cleaning mechanisms to apply in manufacturing process of 156 mm silicon wafer which is used in the solar cell fabrication. We have analyzed contamination sources on wafer surface which causes poor quality and performance of products in fabrication process, and examined cleaning process using ozonate water to eliminate it. Using this novel technology particles are removed over 94%, and remained organic materials are removed more over 45%.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.45-62
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• 1998

This research is concerned with buffer management in a multi-cell FMS with an AGVS. Buffers in manufacturing systems are required to reduce blocking and starving caused by breakdowns, variability in process times, and diversity of part routing. Due to the high per unit buffer cost, which primarily consists of floor space and equipment costs, the total capacity of buffers in and FMS is very limited. Proper buffer management can provide a high system efficiency. This paper presents a buffer management model for a multi-cell FMS with an AGVS and a simulation study to compare the proposed model to a conventional buffer management model in a job shop FMS.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.13-19
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• 1999

In this paper, we suggests a WIP (Work In Process) of FMC (Flexible Manufacturing Cell) analysis methods based on the TPN (Time Petri Nets) unfolding. Unfolding of PN is a partial order-based method for the verification of concurrent system without the state space explosion. The aim of this work is to formulate the general cyclic state scheduling problem to minimize the WIP to satisfy economical constraints. The method is based on unfolding of the original net into the equivalent acyclic description.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1817-1824
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• 1999

How to efficiently and optimally schedule iterative is one of the critical issues in FMC(Flexible Manufacturing Cell). In this paper, we apply transformation rules to find the solution of the scheduling problem in FMC. These kinds of rules have already been applied for the analysis of autonomous Petri nets. Here in, transformation is intended to preserve the existence of at least one optimal solution for the scheduling problem. Some transformations rules to reduced TPN's size without changed the initial characteristics are proposed and applied to analyze the scheduling problem of FMC.