• 산업경영시스템학회지
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• 제22권53호
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• pp.45-54
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• 1999

Manufacturing today is becoming increasingly competitive. If a company is to exist and successfully compete, it must pay very careful attention to production management, total quality assurance and total proactive maintenance issues. Overall machine performance, repair efficiency, system level utilization, productivity and quality of output need to be optimized as possible. To accomplish that objective, the behavior of manufacturing equipment and systems need to be monitored and measured continuously if it is possible. Then early warning of possible failure should be generated and proacted on that type of the situation to improve overall operation performance of manufacturing environment. In this paper, Proactive maintenance framework using performance-based reliability structure as enabler technology is proposed. Its paradigm enables one to maximize system through-put and product quality as well as resources in the performance domain. In the case of inadequate knowledge of the failure mechanics, this empirical modeling concept along with performance degradation knowledge can serve as an important product and process improvement tool. The real-time framework extension to proposed framework uses on-line performance information and is capable of projecting the remaining useful period.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1812-1816
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• 2011

본 연구에서는 약액 주입 후 미 도포로 인한 복합적인 공정불량을 예방하기 위하여 100nm 이하의 나노 반도체 제조공정에서 필수적인 스피너(spinner) 장비를 위한 약액 흐름제어 시스템을 개발하였다. 본 연구개발을 통하여 실시간으로 상태요소들을 감시할 뿐만 아니라 상태요소의 비정상적 변화나 웨이퍼 가공불량이 발생할 경우 해당 유니트를 정지시킴과 동시에 원격지에 있는 엔지니어에게 경보를 전송함으로써 즉각적인 대처가 가능하여 모듈의 수율을 향상시킬 수 있을 것으로 기대된다. 또한 세부 동작 시퀀스를 제어하기 위한 H/W와 S/W 시스템을 생산라인에 실장하고 성능점검 및 인증을 수행한 결과 5가지의 유형별 비정상적 프로세스를 정확히 검출하였다.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.195-204
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• 2017

Predicting the failure life of automated manufacturing systems can reduce overall downtime, maintenance costs, and total plant operation costs. Therefore, there is a growing interest in fatigue failure mechanisms as the safety or service life assessment of manufacturing systems becomes an important issue. In particular, fretting fatigue is caused by repeated tangential stresses that are generated by friction during small amplitude oscillatory movements or sliding between two surfaces pressed together in intimate contact. Previous studies in fretting fatigue have observed size effects related to contact width such that a critical contact width exists where there is drastic change in the fretting fatigue life. However, most of them are the two-dimensional finite element analyses based on the plane strain assumption. The purpose of this study is to investigate the contact size effects on the three-dimensional finite element model of a finite width of a flat specimen and a cylindrical pad exposed to fretting fatigue. The contact size effects were analyzed by means of the stress and strain averages at the element integration points of three-dimensional finite element model. This study shows that the fretting fatigue life of manufacturing systems can be predicted by three-dimensional finite element analysis based on SWT critical plane model.

• 한국생산제조학회지
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• 제8권4호
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• pp.112-122
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• 1999

In realistic control systems the nonlinear saturation attributes of the control actuator due to physical limitations should be taken into account This nonlinear saturation of actuators may cause not only deterioration of the control performance but also a large overshoot during start-up and shut-down. As the overshoot increases the system may become oscillatory unstable. in this paper the supervisor implementation which guarantees good performance for saturation operation and prevents reset wind up is presented, Moreover the sufficient conditions of the stability for saturated system using supervisory control with a dynamic controller are provided in the continuous-time and in the discrete-time domain Numerical example is illustrated to depict the efficiency of supervisory control for a typical satuaurated production-distribution system controlled by a discrete-time dynamic controller and to validate basic results by simulation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.590-596
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• 2010

Maglev vehicles levitated and propelled by electromagnet as non-contact between vehicle and guide rail is environmentally friendly transport system which have many advantages like ride comfort and guide way construction costs. As a goal of commercial operation at Incheon International Airport in 2012, development of vehicle is underway and proto-vehicle is test running at KIMM. The maglev bogie system of proto-vehicle, like railway vehicle, has functions to support weight of vehicle, transfer force of brake and propulsion and improve ride comfort through insulation of vibration and improve curve negotiation capability. The main components of a bogie are two modules consisted of electromagnetic, frame and linear motor, two tie beams to connect two modules and steering system to improve curve negotiation capability. The purpose of this paper is to describe general specification, structure, manufacturing process, performance testing, ride comfort of proto-vehicle and bogie system.

• 한국생산제조학회지
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• 제21권1호
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• pp.116-122
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• 2012

The purpose of this study is on the development of 3-D conductive pattern fabrication system using laser. For development 3-D direct patterning system, we used the dynamic focusing, the laser power stabilizer and the auto aligning techniques. These technologies are already used commercially. However operation and control integrated system for 3-D direct patterning are not yet developed. The objective of this paper is to introduce laser direct structuring and develop the operating and integration system. Also we implemented new application of laser direct structuring.

• 산업공학
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• 제11권2호
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• pp.159-176
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• 1998

In the motor manufacturing system with the properties of short delivery and order based production, the process plan is performed individually for each order by the expert of process plan after the completion of the detail design process to satisfy the specification to be required by customer. Also it is hard to establish the standard process plan in reality because part routings and operation times are varied for each order. Hence, the production planner has the problem that is hard to establish the production schedule releasing the job to the factory because there occurs the big difference between the real time to be completed the process plan and the time to be required by the production planner. In this paper, we study the decision supporting system for the process plan based on knowledge base concept. First, we represent the knowledge of process planner as a database model through the modified POI-Feature graph. Then we design and implement the decision supporting system imbedded in the heuristic algorithm in the client/server environment using the ORACLE relational database management system.

• 한국정밀공학회지
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• 제14권11호
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• pp.147-153
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• 1997

Fault diagnosis technique in machining system which is one of engineering techniques absolutely necessary to automation of manufacturing system has been proposed. As a whole, diagnosis process is explained by two steps: sensor data acquisition and reasoning current state of system with the given sensor data. Flexible disk grinding process implemented in milling machine was employed in order to obtain empirical manufacturing process information. Resistance force data during machining were acquired using tool dynamometer known as sensor which is comparably accurate and reliable in operation. Tool status during the process was analyzed using influnece diagram assigning probability from the statistical analysis procedure.

• 대한안전경영과학회지
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• 제16권4호
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• pp.1-9
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• 2014

The occupational health and safety accidents were continuously increased during handling, usage and manufacturing the chemical materials according to increase of small and medium sized enterprises in domestic industries. These accidents mainly resulted from insufficient occupational health and safety management and deteriorative facilities and focused on corresponding operation to minimize the damage of accidents after occurrence. But, it was required that we grasped the occurrence causes of occupational health and safety risk in handling, usage and manufacturing the chemical materials and develop the adequate corresponding operation and system according to the possible occurrence of occupational health and safety risk. This study deals with the development of risk assessment model to derive the risk and important risk of occupational health and safety and then help to construct the self-controlled occupational health and safety system for small and medium sized enterprises handling the chemical materials.

• 한국기계가공학회지
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• 제19권11호
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• pp.87-93
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• 2020

A key component of aviation safety is to eliminate the errors in commercial aircraft air data systems to ensure stable aviation operation. Although the technical aspects such as the maintenance and inspection play a pertinent role, human errors are expected to have a similar or even larger influence on the aviation safety. Aviation maintenance and inspection tasks are often performed by a complex organization, in which individuals perform a variety of tasks in an environment involving time pressure, sparse feedback, and complex conditions. These situational characteristics, combined with the general tendency of human error, may lead to various types of errors, which may have critical consequences such as accidents and loss of life. For instance, if an amber message "IAS DISAGREE" is displayed on the primary flight display while the aircraft is rolling on the runway to takeoff, the crew immediately performs a rejected takeoff operation and troubleshoots the air data system. This paper proposes alternative approaches to address the occurrence of defects due to the human factors involved in the practical processes of the air data system of commercial aircraft.