한국해양대학교

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高出力 다이오드 레이저를 이용한 窒化硅素세라믹의 레이저 豫熱旋削에 관한 硏究

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dc.contributor.author 이수진 -
dc.date.accessioned 2017-02-22T05:23:55Z -
dc.date.available 2017-02-22T05:23:55Z -
dc.date.issued 2010 -
dc.date.submitted 56932-07-09 -
dc.identifier.uri http://kmou.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002174596 ko_KR
dc.identifier.uri http://repository.kmou.ac.kr/handle/2014.oak/8653 -
dc.description.abstract Abstract Driven by development of science, factory automation is establishing itself widely since the Industrial Revolution. So, the interest in instrument life span and management time and cost increased, that on-going researches on materials like ceramics, plastics and new materials are in progress. In particular, the engineering ceramics which have been used long time by human being are one of the materials advantageous in various conditions with high strength, endurance at high temperature, abrasion resistance and corrosion resistance etc. However, due to high strength and high brittleness of ceramics, a finishing process required after sintering is difficult. Recently, the diamond grinding is generally considered as the only method economically feasible for machining of materials for industrial application. The grinding can produce products with excellent surface finishing and measurement precision, but has low material removal rate and insufficient machining flexibility, and thus is difficult to be applied to ceramics parts of complex shape. Accordingly, this study focused on laser assisted machining (LAM) of silicon nitride ceramic that efficiently removes the material through machining of softening zone by local heating. In this study, the textual characteristics of SSN and HIP treated silicon nitride ceramics by the temperature were researched as one of basic research on such laser machining. And, the effects of laser-assisted machining parameters were studied for cost reduction, and active application in processing of silicon nitride ceramics. Laser assisted machining of silicon nitride allows effective cutting using CBN tool by locally heating the cutting part to the softening temperature of YSiAlON using the laser beam. If silicon nitride is sufficiently preheated, the surface is oxidized and N2 gas is formed and escapes from the material, thereby making the cutting process more advantageous. During laser assisted machining, high power results in reduced cutting force and increased tool life, but excessive power brings oxidation of the surface. Increased feed rate also increases cutting energy during laser assisted machining and feed rate shows greater influence on cutting force than oxidation of the surface. Once appropriate cutting conditions are found by controlling the laser power and feed rate, silicon nitride ceramic can more efficiently be cut. The surface temperature and cutting force were measured by pyrometer and dynamometer at real time respectively. And the surface and cross section of material were observed with video microscope and SEM, and oxidation of surface was analyzed using EDS and XRD. Using the results of these experiments, mechanism of laser assisted machining was ascertained. -
dc.description.tableofcontents 목 차 Abstract 1. 서론 1 1.1 연구 배경 및 목적 1 1.2 연구내용 5 2. 이론적 배경 8 2.1 HPDL(High power diode laser)의 원리와 특성 8 2.1.1 HPDL의 특성 및 적용 10 2.1.1 HPDL의 발진원리 12 2.2 질화규소 세라믹의 특징 19 2.2.1 세라믹의 소결방법 및 종류 19 2.2.2 공업용 세라믹의 종류 및 특성 24 2.2.3 질화규소 세라믹의 특성 28 2.2.4 질화규소 세라믹의 적용 33 2.3 절삭이론의 기초 36 2.3.1 절삭공구의 구조와 형상에 따른 영향 36 2.3.2 절삭된 칩의 형태 39 2.4 세라믹의 레이저 예열선삭 42 2.4.1 기존의 세라믹 절삭가공 42 2.4.2 레이저 예열선삭의 개요 44 3. 실험 재료 및 방법 45 3.1 실험재료와 장치의 구성 45 3.1.1 실험재료 45 3.1.2 실험장치 49 3.2 실험 및 분석 방법 56 3.2.1 실험방법 56 3.2.2 분석방법 60 4. 실험 결과 및 고찰 62 4.1 질화규소 세라믹의 예열특성 62 4.1.1 출력에 따른 질화규소 세라믹의 조직적 변화 62 4.1.2 이송속도에 따른 예열된 질화규소 세라믹 표면의 산화 70 4.1.3 소결방법에 따른 질화규소 세라믹의 예열특성 77 4.2 HIP 처리된 질화규소 세라믹의 레이저 예열선삭 특성 80 4.2.1 파라메타 변화에 따른 시편의 표면관찰 80 4.2.2 절삭된 칩의 형상관찰 86 4.2.3 절삭력 및 절삭공구의 변화 91 4.3 소결방법에 따른 질화규소 세라믹의 예열선삭 특성비교 95 4.3.1 파단면을 이용한 조직적 관찰 95 4.3.2 절삭된 시편의 표면비교 97 4.3.3 절삭된 칩의 형상비교 105 4.3.4 절삭력 및 절삭공구 수명의 비교 108 4.4 세라믹의 종류 및 레이저열원에 따른 예열선삭의 가능성 평가 113 4.4.1 각종 세라믹의 레이저 흡수율에 따른 가공성 평가 113 4.4.2 CO2 레이저를 사용한 세라믹 예열선삭시의 절삭특성 117 4.5 질화규소의 절삭 메커니즘 및 조직적 거동의 규명 136 4.5.1 레이저조사에 의한 질화규소의 조직적 거동 및 결함발생 136 4.5.2 질화규소 세라믹의 레이저 예열선삭에 관한 열해석 152 4.5.3 질화규소 세라믹의 레이저 예열선삭 메커니즘 158 5. 결론 161 참고 문헌 164 -
dc.language kor -
dc.publisher 한국해양대학교 대학원 -
dc.title 高出力 다이오드 레이저를 이용한 窒化硅素세라믹의 레이저 豫熱旋削에 관한 硏究 -
dc.title.alternative A Study on Laser-assisted Machining of Silicon Nitride using High Power Diode Laser -
dc.type Thesis -
dc.date.awarded 2010-02 -
dc.contributor.alternativeName Lee -
dc.contributor.alternativeName Su Jin -
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기관시스템공학과 > Thesis
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