• 산업경영시스템학회지
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• 제43권1호
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• pp.143-150
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• 2020

To enhance the effectiveness of the FMS (flexible manufacturing system), it is necessary for the manufacturing control system to be upgraded by integrating the cyber and the physical manufacturing systems. Using the CPPS (Cyber-Physical Production System) concept, this study proposes a 4-stage vertical integration and control framework for an aircraft parts manufacturing plant. In the proposed framework, the process controller prepares the operations schedule for processing work orders generated from the APS (advanced planning & scheduling) system. The scheduled operations and the related control commands are assigned to equipments by the dispatcher of the line controller. The line monitor is responsible for monitoring the overall status of the FMS including work orders and equipments. Finally the process monitor uses the simulation model to check the performance of the production plan using real time plant status data. The W-FMCS (Wing rib-Flexible Manufacturing Control & Simulation) are developed to implement the proposed 4-stage CPPS based FMS control architecture. The effectiveness of the proposed control architecture is examined by the real plant's operational data such as utilization and throughput. The performance improvement examined shows the usefulness of the framework in managing the smart factory's operation by providing a practical approach to integrate cyber and physical production systems.

• 아태비즈니스연구
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• 제14권2호
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• pp.1-15
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• 2023

Purpose - This study investigates whether the inventory levels of Korean manufacturing firms increased or decreased from 2000 to 2019. We also explore the relationship between inventory levels and firm performance. Design/methodology/approach - We use panel data on KOSPI-listed firms in the manufacturing industry. We measure days in inventory as a proxy for inventory levels, and firm performance is measured by return on assets, return on sales, and EBITDA ratio. The panel data regression method is employed in our analysis. Findings - We find that days in inventory of Korean manufacturing firms significantly increased from 2000 to 2019, especially for raw materials and finished goods inventory. In addition, while days in inventory of large- and medium-sized firms were less than those of small-sized firms, the change in days in inventory of large- and medium-sized firms was positively significant over time. Moreover, the increase in days in inventory was more prevalent among industries related to foods, clothes, chemicals, and transportation. Finally, we show that the days in inventory are negatively related to firm performance. Research implications or Originality - While the Korean manufacturing industry has enormously grown over the last 20 years and managing inventory is critical in the manufacturing industry, our findings counter-intuitively show that the days in inventory of the Korean manufacturing industry had been gradually increased. We speculate that the increase in days in inventory is due to the Korean manufacturing firms' heavy reliance on global supply chains.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1020-1023
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• 1996

Fieldbus provides real-time data communication among field devices in the process control and manufacturing automation systems. This paper presents an implementation method of Profibus in the experimental model of manufacturing automation system. The manufacturing automation system considered in this paper consists of robots, NC machines, sensors, conveyers and PCs. The application task programs are developed on the basis of FMS/FMA7 communication services which are provided by Profibus application layer. The communication and application programs are developed in the real-time environment.

• International Journal of Precision Engineering and Manufacturing
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• 제3권2호
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• pp.5-14
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• 2002

Internet becomes very common tool far communication and data sharing. Virtual readily(VR) on web browser, and virtual prototyping and virtual manufacturing is widely used in many engineering fields. The reduction of overall development process and error minimization during data conversion becomes very crucial where sharing data via Internet and VR. This paper deals with the advantage and disadvantage of VRML format used in RP(Rapid Prototyping), and a software for RP data preparation is developed. If VRML format as an international standard for VR, is replaced with STL format, the weak points of STL formal can be overcome and the technique related to virtual prototyping and virtual manufacturing can be addressed more systematically by sharing the data. The system developed in this work shows a good window to get access to a mare realistic observation of an object for an RP system from a long remote sites in a more systematic way.

• 한국생산제조학회지
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• 제9권2호
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• pp.80-86
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• 2000

Although polishing process take 30-50% of whole process of manufacturing die and mold it has not been fully automat-ed yet. Considering current trend of manufacturing it is necessary to study on polishing automation. To accomplish automation reliable database must be developed. For developing it polishing mechanism should be defined and a general empirical formula that can be applied widely should be created. In this paper it is found that polishing process must be separated into 2 process such as removing cusp and getting fine surface process and the polishing parameter which is com-posed of major machining parameters and normalization of data can be applied efficiently in making reliable database.

• Journal of Information Technology Applications and Management
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• 제15권1호
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• pp.243-260
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• 2008

To prevent low yields in the semiconductor industry is crucial to the success of that industry. However, to prevent low yields is difficult because of too many factors to affect yield variation and their complex relation in the semiconductor manufacturing process. This study presents a new efficient detection methodology for detecting abnormal yields including high and low yields, which can forecast the yield level of a production unit (namely a lot) based on yield-related feature variables' behaviors. In the methodology, we use C5.0 to identify the yield-related feature variables that are the combination of correlated process variables associated with yield, use SOM (Self-Organizing Map) neural networks to extract and classify significant patterns of past abnormal yield lots and finally use C5.0 to generate classification rules for detecting abnormal yield lot. We illustrate the effectiveness of our methodology using a semiconductor manufacturing company's field data.

• 한국산업융합학회 논문집
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• 제6권4호
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• pp.379-386
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• 2003

The goal of this research is to develop a Heel/Side Laster and control GUI(Graphic User Interface) for adaptive manufacturing. For this purpose, we have analyzed the working sequences of heel/side laster, and developed a control program that will facilitate the machineries with functions that are suitable for adaptive manufacturing. We also made it possible to modify the gluing path with simple manipulation of CAD data. By providing a user-friendly GUI, we made it possible for unskilled workers use the system without difficulty. In addition, we have developed a flexible environment where the already available CAD data can be modified and saved with ease. Automatic feeding and path control algorithms for thermoplastic cement were also implemented. By using the Heel/Side Laster for adaptive manufacturing, we are able to achieve increased productivity and work efficiency while improving the quality of the product with self-diagnosis and fine adjustment function.

• 산업공학
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• 제21권2호
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• pp.151-160
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• 2008

Defect size distribution is a probability density function for the defects that occur on wafers or glasses during semiconductor/LCD fabrication. It is one of the most important information to estimate manufacturing yield using well-known statistical estimation methods. The defects are detected by automatic optical inspection (AOI) facilities. However, the data that is provided from AOI is not accurate due to resolution of AOI and its defect detection mechanism. It causes distortion of defect size distribution and results in wrong estimation of the manufacturing yield. In this paper, I suggest a size conversion method and a maximum likelihood estimator to overcome the vague defect size information of AOI. The methods are verified by the Monte Carlo simulation that is constructed as similar as real situation.

• 기술혁신연구
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• 제6권2호
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• pp.80-100
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• 1998

The application of computers and information technologies progressed with remarkable pace has paved the way for technological innovation toward the efficient integration of various functions in a manufacturing system. Actually it is observed that the greater part of manufacturing companies already initiated significant efforts to integrate information systems and attained the level of integration to some extent. The purpose of this paper is to clarify the strategic direction that manufacturing firms are pursuing through integrating information systems. Using the extensive data gathered from Japanese manufacturers, it is attempted to find the differences in competitive priorities and action programmes between the companies with high and low-level system integration. Our empirical data reveals that the manufacturers with highly integrated system are focusing their competitive capabilities on the rapid design change and new product introduction, and accordingly they place a greater emphasis on the action programmes related to design, process and quality improvement. As a conclusion, highly integrated firms tend to pursue new product development strategy more intensively, thereby they want to be a preemptor in the new market through exploiting technological advantages of integrated manufacturing system.

• Journal of Information Technology Applications and Management
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• 제24권4호
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• pp.133-152
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• 2017

Smart factory has been regarded as a big opportunity for manufacturing industries. However, little literature has been studied for the current status of Korean smart factory. Our paper tries to find gaps between research and real world by summarizing the recent literature and cases in Korean context. As the present level of smart factory introductions in Korean small manufacturing firms is lower than what a variety of literature says, our study points out that more efforts, investments and government support are required to catch up with the knowhow and technologies of developed countries although real-time control, enhanced productivity have been obtained. In future research, we will continue the smart factory study with the accumulated real data.