• 제목/요약/키워드: edge chipping

검색결과 33건 처리시간 0.021초

MR Polishing을 이용한 커버글라스의 굽힘강도 향상에 관한 연구 (A study of minimizing edge chipping of coverglass using MR Polishing)

  • 이정우;김지훈;임동욱;하석재
    • Design & Manufacturing
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    • 제16권1호
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    • pp.50-54
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    • 2022
  • Coverglass of electronic equipments is thinner and slimmer, so the glass must have good bending strength. In these days, the polishing edge of glass is used by solid tool like grinding wheel. But solid tool leave micro crack or edge chipping in edge of glass. MR polishing is an optimal method by polishing edge of glass. MR polishing is used MR fluid that is a liquid tool. MR polishing doesn't leave tool path or residual stress, micro crack and edge chipping unlike grinding wheel polishing. In this paper, the results of grinding and MR polishing were compared and analyzed to improve bending strength by minimizing edge chipping of cover glass. It was derived that the depth and size of cracks have a significant influence on the bending strength of the glass edge. The edges of the glass using MR grinding were analyzed to have a better surface and higher bending strength than the glass using abrasive wheel grinding. It was confirmed that MR polishing had an effect on strength improvement by effectively removing cracks in the specimen.

사파이어 의료용 나이프의 연삭가공에서 지그의 탄성계수가 날 부 형상에 미치는 영향 : 제2보 탄성계수와 치핑 현상의 검증 (Effect of the Elasticity Modulus of the Jig Material on the Blade Edge Shape in the Grinding Process of Sapphire Medical Knife - Part 2 Verification of the Chipping Phenomenon and Elastic Modulus of the Jig Material)

  • 신건휘;강병욱;곽태수
    • 한국기계가공학회지
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    • 제16권5호
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    • pp.63-68
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    • 2017
  • This study determines the selection of an appropriate jig material for the blade edge of the medical sapphire knife. The physical properties of the jig material affects the edge shape and chipping phenomenon in machining of the medical sapphire knife. If a grinding wheel is used, brittle workpieces such as sapphire are easily damaged by the propagation of cracks because the grinding force significantly increases. It is important to constantly maintain the grinding force in the grinding process of the brittle materials. The grinding force can be kept constantly by inducing the elastic deformation of the Jig material because the elastic deformation of brittle work-piece is negligibly low. The chipping phenomenon may be reduced by selecting the proper Jig material. Aluminum, copper, stainless steels and carbon steel were used as Jig materials. The experiment was conducted using a cast iron grinding wheel, which was installed on a conventional grinding machine with the ELID grinding system. The thickness and width of the chipping area were measured using an optical microscope and FE-SEM to analyze the shape of the blade edge. According to the experiment result, the chipping phenomenon decreased, and the sharp edge was formed when the jig materials with low elastic modulus were used.

영상처리를 이용한 초정밀가공용 다이아몬드 공구의 마멸 측정 (Wear Mwarsurement of Single Crystal Diamond Tool Using Image Processing)

  • 양민양
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 춘계학술대회 논문집
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    • pp.135-139
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    • 1996
  • In this a paper, a new method to measure the wear of the single crystal diamond(SCD) tool using image processing is presented. To increase resoultion, high magnifying lens is used and to enlarge the measurement field of view, a image region matching method is applied. The shape of SCD tool is modeled by mathematical analysis. Cutting edge chipping and wear are calculated by the model. This method is proved to be efficient in detecting a few micron of wear and cutting edge loss by chipping along the whole cutting edge.

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사파이어 의료용 나이프의 연삭가공에서 지그의 탄성계수가 날 부 형상에 미치는 영향 (Effect of the Elasticity Modulus of Jig Material on Blade Edge Shape in Grinding Process of Sapphire Medical Knife)

  • 신건휘;이득우;곽태수
    • 한국기계가공학회지
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    • 제16권2호
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    • pp.102-107
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    • 2017
  • This study focuses on the effect of the elasticity modulus of jig material on blade edge shape in the grinding process of a sapphire medical knife. The ELID grinding process was applied as the edge-grinding method for sapphire material. Carbon steel and copper have been selected as the hard and soft jig materials, respectively. The blade edge created by ELID grinding was measured by a surface roughness tester and optical microscope. The shape of the ground edge and surface roughness were compared using the measurement results. As a result, it was found that chipping in the blade edge of the sapphire knife occurred more than in the case of jig material with a high-elasticity modulus because of the high normal force in the grinding process. Moreover, the maximum height surface roughness, $R_{max}$,of the ground surface was higher in the case of the jig material with a high-elasticity modulus due to the difference in elasticelongation. It was considered to lead to chipping from the notch effect.

무 알칼리 유리의 연마 조건에 따른 영향 (Effect of Polishing Grinding Conditions on Alkali-free Glass)

  • 박영희;홍민성
    • 한국생산제조학회지
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    • 제25권6호
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    • pp.440-444
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    • 2016
  • Owing to the introduction of various IT devices with emphasis on portability and design, the TFT (thin film transistor liquid crystal display) panel applied to IT devices has the same shape as the product, and the portability requirement of IT devices has resulted in a need for panels with higher rigidity. In this study, the effect of grinding conditions such as the feed rate and edge speed of edge grinding on the surface roughness and chipping of the machined surface is investigated using a metal bond wheel. During edge grinding of alkari-free glass, weak mechanical property of glass results in big chipping owing to generation of tensile stress at the end of grining operation. The results of this study show that the grinding characteristics of alkali-free glass are obtained and meet industry requirements.

Edge chipping test (ECT)의 실험방법과 해석에 관한 문헌고찰 (Literature review on the experimental method and interpretation of the edge chipping test (ECT))

  • 송민규;고경호;허윤혁;박찬진;조리라
    • 대한치과보철학회지
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    • 제60권1호
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    • pp.9-18
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    • 2022
  • 임상에서 심미적 수복에 사용되는 세라믹 재료들은 성능에 대한 예측을 위해 실험실 연구가 필수적이다. 취성을 가진 세라믹의 물성 평가를 위해서는 파괴인성과 굽힘강도 등 전통적인 실험들이 사용되어 왔다. 하지만 이러한 실험은 실험의 하중조건, 실패 양상, 실패가 일어나는 하중 값이 사람의 교합력 범위나 임상에서의 실패와 유사하지 않다는 한계점이 있다. 반면 최근에 세라믹 부분파절을 연구하기 위해 도입된 edge chipping test (ECT)는 임상과 실패 양상이 비슷하고, 실패하중값도 사람의 교합력과 유사하여 세라믹 물성 연구에 유용하게 사용될 수 있다. 이 문헌고찰에서는 전통적인 세라믹 하중시험들의 의미와 한계점들을 살펴보고 ECT와 비교함으로써 보다 임상적으로 의미 있는 세라믹 재료들의 실험실 연구에 대해 고찰하고자 한다.

평 엔드밀 공구인선부 조도의 간접적인 측정법 (Indirect Method for Measurement of Tool Edge Roughness in flat End Mill)

  • 김전하;강명창;김정석
    • 한국정밀공학회지
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    • 제19권10호
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    • pp.92-98
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    • 2002
  • End mill is an essential tool to generate complex surface in workpiece and it has been developed with various materials and tool shapes. The most important factor to evaluate the performance of end mill is still the wear characteristics of flank face. In addition to the flank wear, the tool edge roughness generated by the chipping is another important factor in aspects of material property and machinability evaluation and affects the quality of machined surface. Up to now, there is no direct method for measurement of tool edge roughness. In this study, the tool edge roughness of flat end mill is indirectly measured along the axial direction of workpiece. The theoretical equation is derived in consideration of tool geometry. Finally, the optimal conditions to measure the tool edge roughness by the proposed method are presented through the theoretical review and experimental identification.

미세홈 가공시 전해 인프로세스 드레싱의 영향에 관한 연구 (A Study on the Effect of Electrolytic In-process Dressing in Slot Grinding)

  • 유정봉;이석우;정해도;최헌종
    • 한국정밀공학회지
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    • 제16권1호통권94호
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    • pp.18-25
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    • 1999
  • Chipping is an unavoidable phenomenon in the slot grinding process of hard and brittle materials. However, it should be reduced for the improvement of surface integrity in the manufacture of optical and semiconductor components. Electrolytic In-process Dressing (ELID) technique for metal bonded superabrasive grinding wheel has been developed for mirror surface grinding of hard and brittle materials. Electrically dressed wheel surface has sharply exposed abrasives and results in lower grinding force, higher grinding efficiency in grinding. The paper deals with a newly developed method for slot grinding using ELID and was implemented to improve grooved surface quality and decreases chipping size on the edge of the groove. As a result, we accomplished chipping-free grooves and obtained the clear ground surfaces on glass and WC.

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엔드밀 밀링공구의 가공특성검출 (Machining Characteristics Detection of Endmill Milling Tool)

  • 맹민재;조성산;정준기
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.678-682
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    • 1996
  • Acoustic emission(AE) is monitored during end milling with a sensor attached to the cutting fluid discharge nozzle. Cutting forces are also measured and compared with the AE signals to examine the reliability of the AE signals. It is demonstrated that the AE signals provide reliable informations about the cutting processes and tool states. Moreover, edge chipping and fracture of tools can be successfully detected using both the AE signals and cutting forces.

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$Si_3N_4-hBN$ 머시너블 세라믹의 R-curve 거동분석과 가공성 평가 (Evaluation of R-curve Behavior Analysis and Machinability of $Si_3N_4-hBN$ Machinable Ceramics)

  • 장성민;조명우;조원승;이재형
    • 한국정밀공학회지
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    • 제21권1호
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    • pp.61-70
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    • 2004
  • Generally, ceramics are very difficult-to-cut materials because of its high strength and hardness. The machining process of ceramics can be characterized by cracking and brittle fracture. In the machining of ceramics, edge chipping and crack propagation are the principal reasons to cause surface integrity deterioration. Such phenomenon can cause not only poor dimensional and geometric accuracy, but also possible failure of the ceramic parts. Ceramics can be machined with traditional method such as grinding and polishing. However, such processes are generally cost-expensive and have low material removal rate. Thus, in this paper, to overcome these problems. BN powder, which gives good cutting property, is added for the fabrication of machinable ceramics by volume of 5,10,15,20,25 and 30%. And, mechanical properties, R-curve behavior and machining tests are carried out to evaluate the machining properties of the manufactured machinable ceramics.