• 제목/요약/키워드: TurnTool

검색결과 162건 처리시간 0.031초

Cylindrical Grinding Integrity - A Review on Surface Integrity

  • Alagumurthi, N.;Palaniradja, K.;Soundararajan, V.
    • International Journal of Precision Engineering and Manufacturing
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    • 제8권3호
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    • pp.24-44
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    • 2007
  • Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operation of discrete components. The inherent high cutting temperature in grinding if not controlled may lead to rapid tool wear, which in turn will lead to dimensional inaccuracy. The very nature of the grinding mechanism in material removal impairs the grounded surfaces by inducing residual stress, micro cracks and other thermal damages at the machined surface. This paper is an attempt to review some of the surface integrity issues in cylindrical grinding taken up and reported by number of researchers over the years. This review may have been planned to be useful to the researchers and other professionals interested to work on grinding.

칩브레이크 선정을 위한 Taguchi 방법의 적용 (Application of Taguchi Method for the Selection of Chip Breaker)

  • 전준용
    • 한국생산제조학회지
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    • 제7권3호
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    • pp.118-125
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    • 1998
  • Chip control is a major problem in automatic machining process, especially in finish turning operation. In this case, chip breaker is one of the important factors to be determined. As unbroken chips are grown. these deteriorate the surface roughness. and proces automation can not be carried out. In this study to get rid of chip curling problem while turning internal hole. optimal chip breaker is selected from the experiment. The experiment is planned with Taguchi's method that is based on the orthogonal arrary of design factors. From the response table. cutting speed, feedrate, depth of cut and tool geometry turn to be major factors affecting chip formation. Then, optimal chip breaker is selected. and this is verified as good enough for chip control from the experiment.

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반도체 수율 향상을 위한 통계적 공정 제어에 전문가 시스템의 적용에 관한 연구 (Applying Expert System to Statistical Process Control in Semiconductor Manufacturing)

  • 윤건상;최문규;김훈모;조대호;이칠기
    • 한국정밀공학회지
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    • 제15권10호
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    • pp.103-112
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    • 1998
  • The evolution of semiconductor manufacturing technology has accelerated the reduction of device dimensions and the increase of integrated circuit density. In order to improve yield within a short turn around time and maintain it at high level, a system that can rapidly determine problematic processing steps is needed. The statistical process control detects abnormal process variation of key parameters. Expert systems in SPC can serve as a valuable tool to automate the analysis and interpretation of control charts. A set of IF-THEN rules was used to formalize knowledge base of special causes. This research proposes a strategy to apply expert system to SPC in semiconductor manufacturing. In analysis, the expert system accomplishes the instability detection of process parameter, In diagnosis, an engineer is supported by process analyzer program. An example has been used to demonstrate the expert system and the process analyzer.

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박판 성형 공정에서 스프링백의 강건 설계 (Robust Design of Springback in Sheet Metal Forming)

  • 김경모;인정제
    • 한국기계가공학회지
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    • 제12권2호
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    • pp.41-48
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    • 2013
  • Springback is a very typical dimensional discrepancy phenomenon, which occurs usually on the final stamping parts after the tool loading is removed. Variation of springback leads to amplified variations and problems during assembly of the stamped components, in turn, resulting in quality issues. The variations in the properties of the incoming material and process parameters are the main causes of springback variation. In this research, a robust design methodology which combines orthogonal array based experimental design and design space reduction skim to reduce the springback variation for advanced high strength steel parts in sheet metal forming is suggested. The concept of design space reduction is adapted in the experimental design setup to improve the quality of the obtained solution. The effectiveness of the proposed procedures is illustrated through a robust design of springback in metal forming process of a cross member of auto body.

Optimal Underwater Coverage of a Cellular Region by Autonomous Underwater Vehicle Using Line Sweep Motion

  • Choi, Myoung-Hwan
    • Journal of Electrical Engineering and Technology
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    • 제7권6호
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    • pp.1023-1033
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    • 2012
  • An underwater planar covering problem is studied where the coverage region consists of polygonal cells, and line sweep motion is used for coverage. In many subsea applications, sidescan sonar has become a common tool, and the sidescan sonar data is meaningful only when the sonar is moving in a straight line. This work studies the optimal line sweep coverage where the sweep paths of the cells consist of straight lines and no turn is allowed inside the cell. An optimal line sweep coverage solution is presented when the line sweep path is parallel to an edge of the cell boundary. The total time to complete the coverage task is minimized. A unique contribution of this work is that the optimal sequence of cell visits is computed in addition to the optimal line sweep paths and the optimal cell decomposition.

무궁화위성 추적 안테나 바이어스 추정 연구 (A Study on Koheasat Tracking Antenna Bias Estimation)

  • 박봉규;탁민제;안태성
    • 한국항공우주학회지
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    • 제31권1호
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    • pp.58-66
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    • 2003
  • 본 논문에서는 무궁화위성을 대상으로 추적 안테나의 바이어스를 추정하기 위한 방안들을 제시하고 있다. 먼저 거리, 방위각, 앙각에 이어 선회시선거리를 포함하는 배치필터를 구성하였으며 시뮬레이션을 통하여 바이어스 추정성능 변화를 분석하였다. 또한 결과를 보완하기 위하여 정밀하게 보정된 타 추적 안테나의 정보를 이용하여 대상 안테나의 바이어스를 정확하게 예측하기 위한 방안을 제시하였다. 마지막으로 안테나 바이어스 추정 결과를 분석하고 평가할 수 있도록 안테나 바이어스간의 상관관계에 대한 분석을 수행하였다.

Comics with Drama: New Communication in Wedia

  • Hu, Jia-Wen;Tsang, Seng-Su
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권10호
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    • pp.4143-4159
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    • 2015
  • We-the-media (aka wedia) is a concept where the users of social networking sites, such as Facebook, turn into the broadcasters. This study used the popular application Bitstrips as the experiment tool. Facebook was used as the Wedia platform for publishing designed comics, then used the three elements of Goffman's dramaturgy model-role, scene and dialog-to analyze 265 comics created by 3 researchers and observe the audience's responses within 9 months. The results showed that people want to see a good story with positive dialogue, and prefer scene is school more than work. As all these elements are controllable, Wedia communication has the potential for more applications. We also found that including the elements of news, gambling and gift-giving tended to trigger greater response. Furthermore, We suggesting that such embedding of product information in web episodes (webisodes) with caricature could be a successful marketing strategy.

A Study on Google Classroom as a Tool for the Development of the Learning Model of College English

  • Lee, Jeong-Hwa;Cha, Kyung-Whan
    • International Journal of Contents
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    • 제17권2호
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    • pp.65-76
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    • 2021
  • The aim of this study was to explore the use of Google Classroom as a learning management system for College English. The study targeted 34 university students. They took part in various activities, such as writing reactions to video lectures, peer-editing essays, and recording video presentations, et cetera. For the study, a t-test was conducted to evaluate the English development of the students. The two essays that each student wrote were used as the data sources. The result (t=-5.854, p=.000) indicated an improvement in their English writing proficiency. In addition, a survey was conducted to gather students' feedback regarding their perceptions towards the course. The study covered five aspects of their experience: Google Classroom, language development, Quizlet, classroom experience, and essay-writing experience. From the results, students indicated a positive response to the program. The use of Google Classroom in an online learning setting accomplishes two things; it helped the students in the development of their English proficiency, and provided activities that students find interesting, which in turn stimulates their self-learning spirit.

Novel green Sr4ScAl3O10:Eu2+ phosphor prepared by the melt quenching technique

  • Toda, Kenji;Iwaki, Masato;Katsu, Minenori;Kamei, Shin-nosuke;Kim, Sun-Woog;Hasegawa, Takuya;Muto, Masaru;Yamanashi, Ryota;Sakamoto, Tatsuya;Ishigaki, Tadashi;Uematsu, Kazuyoshi;Sato, Mineo;Yoon, Dae-Ho
    • Journal of Ceramic Processing Research
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    • 제20권3호
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    • pp.276-279
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    • 2019
  • New green-emitting Sr4ScAl3O10:Eu2+ phosphor was prepared using a novel melt quenching synthesis method. The temperature of raw materials irradiated with the strong light of the Xe arc-lamp was rose up to about 2273 K, followed by a sharp drop in the temperature after turn off the lamp. This method is a useful tool for rapid screening of novel phosphor materials.

Numerical modeling of Si/$SiO_2$ etching with inductively coupled CF4 plasma

  • 양원균;주정훈
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.97-97
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    • 2010
  • 많은 플라즈마 공정 중에 건식 식각은 복잡하고 표면반응이 잘 알려지지 않은 등의 이유로 가장 어려운 분야 중의 하나이다. 이러한 이유로 식각 장치 디자인뿐만 아니라 플라즈마를 이용한 건식 식각의 공정 조건은 수많은 시행착오를 통해 시도되어 왔다. 이런 문제들을 극복하기 위해 많은 연구자들에 의해서 다양한 방법과 tool을 이용해 모델링이 시도되고 있다. 본 연구에서는 $CF_4$ 가스를 이용한 유도결합 플라즈마에 의해 Si와 $SiO_2$를 식각하는 것을 상용 프로그램인 전산모사 유체역학 시뮬레이터인 CFD-ACE+를 이용하여 모델링했다. 150 mm 직경의 웨이퍼에 대한 모델은 식각 속도 실험결과와 비교 하였다. Ar의 경우 20 mTorr에서 13.56 MHz, 500 W인가 시 2.0 eV의 전자온도와 $7.3{\times}10^{11}\;cm^{-3}$의 전자밀도가 계산결과와 상당히 일치하게 측정되었고, $CF_4$를 이용한 $SiO_2$ 식각에서도 식각 속도가 평균 190 nm/min로 일치했고 식각 균일도는 3% 였다. 450 mm 웨이퍼 공정용 장치의 모델 계산 결과에서는 안테나와 기판의 거리, 챔버의 단면적, 기판 지지대와 배기구와의 높이 등 기하학적인 구조와 각 안테나 턴의 위치 및 전류비가 플라즈마 균일도에 많은 영향을 주었으며, 안쪽부터 4 turn이 있는 경우 2번째, 4번째 turn에만 1:4의 전류비를 인가했을 때, 수십%의 전자밀도의 불균일도를 4.7%까지 낮출 수 있었다. 또한, Si 식각에서는 식각 속도의 분포가 F radical의 분포와 같은 경향을 보임을 확인했고, $SiO_2$ 식각에서는 전자 밀도의 분포와 일치함을 확인함으로써 균일한 식각을 위해서 두 물질의 식각 공정에서는 다른 접근의 시도가 필요함을 확인했다. 플라즈마의 준중성 조건을 이용해서 Poisson 방정식을 풀지 않고 sheath를 해석적 모델로 처리하는 방법과, Poisson 식으로 정전기장을 푸는 방법을 통해서 입사 이온의 에너지 분포를 비교하였다. 에너지 범위는 80~120 eV로 같지만, 실험에서는 IED가 낮은 에너지 쪽이 더 높게 측정됐고, 계산 결과에서는 높은 에너지 쪽이 높았다.

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