• 제목/요약/키워드: Process

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장치산업에서 공정개선을 위한 공정변동 탐지에 관한 연구 (A study on detecting process variation for process improvement in the process industry)

  • 최형주
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제13권4호
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    • pp.273-285
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    • 2013
  • Because process variations have direct influence on yield rate in process industry, it is very important to understand process variations that occur accidentally. In process industry, quality variation due to the activities of process improvement and maintenance and chance effect such as change of work environment and difference in staffs' craftsmanship are mixed with each other, therefore it is difficult to actually detect minute process variations. In this study, objective and rational methods of detection that can detect minute process variations in process industry were designed referring to various methodologies of process management, and they were verified through similar examples.

Problems of Special Causes in Feedback Adjustment

  • Lee Jae June;Cho Sinsup;Lee Jong Seon;Ahn Mihye
    • 한국품질경영학회:학술대회논문집
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    • 한국품질경영학회 2004년도 품질경영모델을 통한 가치 창출
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    • pp.425-429
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    • 2004
  • Process adjustment Is a complimentary tool to process monitoring in process control. Process adjustment directs on maintaining a process output close to a target value by manipulating another controllable variable, by which significant process improvement can be achieved. Therefore, this approach can be applied to the 'Improve' stage of Six Sigma strategy. Though the optimal control rule minimizes process variability in general, it may not properly function when special causes occur in underlying process, resulting in off-target bias and increased variability in the adjusted output process, possibly for long periods. In this paper, we consider a responsive feedback control system and the minimum mean square error control rule. The bias in the adjusted output process is investigated in a general framework, especially focussing on stationary underlying process and the special cause of level shift type. Illustrative examples are employed to illustrate the issues discussed.

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반용융 알루미늄 합금의 Thixoforming 공정에서 점도의 변화가 유도특성에 미치는 영향 (Effect of Viscosity Variation on Flow Characteristic in Thixoforming Process of Semi-Solid Aluminium Alloys)

  • 강충길;이유철
    • 소성∙가공
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    • 제8권2호
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    • pp.188-199
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    • 1999
  • Semi-Solid Forming Process(Thixoforming, Rheocasting) is a novel forming process which has some advantages compared with conventional die casting, squeeze casting and hot/cold forging. In this study. Thixoforming process was selected as analysis processing in terms of billet handling and easiness of automation process. The Thixoforming process consists of reheating process of billet, billet handling, filling inot the die cavity and solidification of SSM part. In filling process, two rheology models which were Newtonian and Non-Nettonian model (Ostwald-deWaele)were verified with experimental results. The Ostwald-deWaele model shows the good agreement to the real flow and filling phenomena in die cavity. To give a boost the economical efficiency of Thixoforming process and to ensure the good forming result, reheating device coupled die set was proposed and the initial billet temperature for system that was found from experimental resluts. This study presents an overview of application of numerical analysis for simulation of semi-solid metal forming process to reduce the lead time for development of manufacturing part in industrial field.

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유리 마이크로 렌즈 어레이 성형을 위한 유리 마이크로 성형 공정 최적화 (Optimization of Glass Micro Molding Process for Glass Microlens Arrays)

  • 배형대;최민석;강신일
    • 정보저장시스템학회논문집
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    • 제2권4호
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    • pp.236-239
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    • 2006
  • Glass micro molding process is the most suitable process for fabricating high precision glass microlens amy at low cost. A new glass micro molding process was proposed. Tungsten carbide mold was fabricated by imprinting and sintering process to overcome the difficulties of the conventional process. In the glass micro molding process, process conditions such as processing temperature and compression force were changed. Geometrical properties of the replicated glass microlens array were measured and compared at variety process conditions. The condition of glass micro molding process was optimized. The experimental result showed that developed process was effective to produce a glass microlens array.

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TMMi 기반 자동차 제어 SW 테스팅 프로세스 구축에 관한 연구 (A Study on Implementation of Automobile Control Software Testing Process Based on TMMi)

  • 장진욱
    • 한국IT서비스학회지
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    • 제8권3호
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    • pp.159-169
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    • 2009
  • The issue of method of software testing process implementation has recently been in the spotlight in korea and some vendor make every effort to improve the software testing process through the evaluation of TMMi. The level of software process is at initial level, nevertheless, so the high quality of software is not guaranteed. This paper apply to the TMMi Level2 Assessment criteria of Automobile control software testing process. The test policy and strategy, test planning, test monitoring and control, test design and execution, test environment goal. The result need to emerge development process connection on the test policy and strategy process, test planning process etc. Also, the study analyzed the infra structure to reach the repeated level via key process area. As the result the process implementation in organization suggests the policy development and the implementation activity. Finally, the practical can refer to this paper in order to implementation the software testing process.

비정규분포하에서의 효과적 공정관리를 위한 기술체계동향 연구 (A Study of Technology Trends for Effective Process Control under Non-Normal Distribution)

  • 김종걸;엄상준;김영섭;고재규
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2008년도 추계학술대회
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    • pp.599-610
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    • 2008
  • It is an important and urgent issue to improve process capability in quality control. Process capability refers to the uniformity of the process. The variability in the process is a measure of the uniformity of output. A simple, quantitative way to express process capability, the degree of variability from target in specification is defined by process capability index(PCI). Almost process capability indices are defined under normal distribution. However, these indices can not be applied to the process of non-normal distribution including reliability. We investigate current research on the process of non-normal distribution, and advanced method and technology for developing more reliable and efficient PCI. Finally we suggest the perspective for future study.

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Improvement Plan of Daily Work Accomplishment Index based Process Management based on Lean Construction Principles

  • Yoo, Dong Uk;Hong, Eun Hwa;Choi, Byung Sun;Chae, Myung Jin;Chun, Jae Youl
    • Architectural research
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    • 제20권4호
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    • pp.147-152
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    • 2018
  • As construction projects become larger, process plans become more complex, and inadequate process management leads to waste of time and resources. Effective process management requires process management techniques that can identify problems inherent in the process, continuously improve, and reflect interdependent process characteristics. In the field, the day's details by work type and work status are to be entered in the work daily report. However, even when important information is written, it is not directly linked to the overall process management. This study aims to propose specific process management and decision-making plan based on actual worker by visualizing and quantifying the information described in the existing work daily report. It is expected efficient process management to increase reliability and productivity through process management, which can increase the utilization of work daily reports and facilitates organic communication among participants.

네트 모델을 이용한 대체 공정 계획 생성 (Generation of Alternative Process Plan by Net Model)

  • 박지형;박면웅;강민형
    • 한국정밀공학회지
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    • 제14권1호
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    • pp.168-173
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    • 1997
  • A process planning system that generates alternative process plans offers multiple process plans for a part, thereby provides the flexibility to cope with the changes in shop floor status. In this paper, we intro- duce the concept of process net as a model for the generation of alternative process plans. We also show the usefulness of process net model in generating alternative process plans by implementing the developed sys- tem to construct process net, and devising an algorithm to generate alternative process plans for rotational parts.

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Integral constants of Transformed geometric Poisson process

  • Park, Jeong-Hyun
    • Journal of the Korean Data and Information Science Society
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    • 제9권2호
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    • pp.305-310
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    • 1998
  • In this paper, we introduce the conditions that the P-process has the intensity function which it is a standard form of gamma distribution. And we show that the transformed geometric Poisson process which the intensity function is a standard form of gamma distribution is a alternative sign P-process

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통계적 분석기법을 이용한 공정 운전 향상의 방법 (Process operation improvement methodology based on statistical data analysis)

  • Hwang, Dae-Hee;Ahn, Tae-Jin;Han, Chonghun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.1516-1519
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    • 1997
  • With disseminationof Distributed Control Systems(DCS), the huge amounts of process operation data could have been available and led to figure out process behaviors better on the statistical basis. Until now, the statistical modeling technology has been susally applied to process monitoring and fault diagnosis. however, it has been also thought that these process information, extracted from statistical analysis, might serve a great opportunity for process operation improvements and process improvements. This paper proposed a general methodolgy for process operation improvements including data analysis, backing up the result of analysis based on the methodology, and the mapping physical physical phenomena to the Principal Components(PC) which is the most distinguished feature in the methodology form traditional statistical analyses. The application of the proposed methodology to the Balst Furnace(BF) process has been presented for details. The BF process is one of the complicated processes, due to the highly nonlinear and correlated behaviors, and so the analysis for the process based on the mathematical modeling has been very difficult. So the statisitical analysis has come forward as a alternative way for the useful analysis. Using the proposed methodology, we could interpret the complicated process, the BF, better than any other mathematical methods and find the direction for process operation improvement. The direction of process operationimprovement, in the BF case, is to increase the fludization and the permeability, while decreasing the effect of tapping operation. These guide directions, with those physical meanings, could save fuel cost and process operator's pressure for proper actions, the better set point changes, in addition to the assistance with the better knowledge of the process. Open to set point change, the BF has a variety of steady state modes. In usual almost chemical processes are under the same situation with the BF in the point of multimode steady states. The proposed methodology focused on the application to the multimode steady state process such as the BF, consequently can be applied to any chemical processes set point changing whether operator intervened or not.

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