• 제목/요약/키워드: ceramic tool

검색결과 224건 처리시간 0.029초

초음파 가공에 의한 미세 에어홀 가공 기술 (Micro-machining of Glass Air Hole using Ultrasonic Machining)

  • 김병희;전성건;남권선;김헌영;전병희
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 춘계학술대회 논문집
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    • pp.48-52
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    • 2004
  • Ultrasonic machining is effective for machining of extreme hard and brittle materials, including glass, ceramic, carbide, graphite. The major machining principle involves the direct hammering as well as the impact of abrasive panicles on the workpiece. Also, it involve cavitation erosion. The general workpiece is flat side. This study attempted micro hole machining of a curved surface of glass tube. Ultrasonic machining is fault of the slow machining speed. An experiment does and got 16 seconds validity machining time as increasing the processing speed. Moreover, entrance crack and surface roughness was similar both machining speed is slow and fast. Several micro hole of glass tube machined using one micro tool, but tool wear is infinitesimal.

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주축 변위 센서를 이용한 절삭력 측정에 관한 연구 (A Study on Cutting Force Measurement Using Cylindrical Capacitance-Type Spindle Displacement Sensor)

  • 김일해;박만진;장동영;한동철
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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    • pp.89-94
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    • 2001
  • A cylindrical capacitance-type spindle displacement sensor was designed and tested in the hard turning as a way to develop a sensor that can estimate cutting forces without using a tool dynamometer. The displacement sensor was installed between the face of spindle cover and the chucking element, and measured pure radial motion of the spindle. Ceramic inserts and tool steel workpieceof 65 Rc were used during the hard turning tests. The signals from the sensor showed the same pattern of cutting force variations as those from the tool dynamometer. The research results showed that the developed sensor could be utilized as an effective and cheap on-line sensing device to estimate cutting forces.

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중절삭시 공구마모에 의한 절삭상태변수의 변화 (Cutting state parameter variations caused by tool wear in hard turning)

  • Jang, Dong-Young;Hsiao, Ya-Tsun;Kim, Il-Hae;Kim, Woo-Jung;Han, Dong-Chul
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 춘계학술대회 논문집
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    • pp.653-657
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    • 2000
  • Machining performance in hard turning of hardened AISI M2 steel has been studied. Ceramic tools were used in the cutting tests without coolants and workpiece was prepared by heat treatment to increase its hardness up to Rc 60. Cutting state parameters such as cutting forces, temperature, and tool wear were measured in the experiments and effects of tool wear on cutting states were investigated.

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초정밀 가공 기계의 진동 특성 해석 (Analysis on the Vibration Characteristics of Ultra Precision Machine Tools)

  • 김성걸;박영일;김석현
    • 산업기술연구
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    • 제14권
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    • pp.119-125
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    • 1994
  • Ultra-precision machine tool equipped with the diamond bite tip is used to machine optical products, drums of VTR or computer hard disk. It needs nano technology in the surface roughness of workpiece. To perform the nano scale machining, ultra-precision machine tool must be designed and manufactured in consideration of the vibration characteristics. In this paper, using the finite element analysis, we investigate the modal parameters of the ultra-precision machine tool structures, which use cast iron, granite and alumina ceramic for the bed materials. To verify the numerical results, we manufacture a model of ultra-precision machine tool using granite bed and perform impulse test. Through the theoretical and experimental analyses, we could compare and estimate the vibration characteristics of the three models for the ultra-precision machine tools.

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HSS공구와 PVD 코팅기술의 영향 (Impact of PVD Coating Technology on HSS Tool)

    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.899-904
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    • 2001
  • The impact of PVD coatings can be summed up in practical terms: this technology historically complements the best designed tool substrates to enhance cutting performance. PVD coatings are now incorporated in 25% of all HSS tools. The functionality is to extend the machining speed range, improve wear resistance at the cutting edge, and reduce friction at chip/tool contact areas to allow easier chip evacuation. These translate to a larger safe zone, as discussed in the failure mode diagram, for better productivity and higher reliability in machining operations of the customer. PVD coatings therefore represent an enabling technology that extends the application range of cutting tools in response to modern industrial needs. PVD coatings prolong the product life cycle of HSS tools and help this "mature" material to hold its territory against the advent of the newer hardmetal and ceramic tool materials. There is a lot of competitive life left particularly in PVD coated HSS endmills, drills, threading/tapping tools. PM HSS technology further increases the possibilities.ibilities.

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적층형 세라믹 액츄에이터의 전기-기계거동 (Electro-mechanical properties of Multilayer Ceramic Actuators)

  • 정순종;고중혁;송재성;홍원표;최원종
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 춘계학술대회 논문집
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    • pp.478-481
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    • 2004
  • This study presents the combined effect of electric Held application and mechanical compressive stress loading on deformation in a multilayer ceramic actuator, designed with stacking alternatively 0.2(PbMn$\_$1/3/Nb$\_$2/3/O$_3$)-0.8(PbZr$\_$0.475/Ti$\_$0.525/O$_3$) ceramics and Ag-Pd electrode. The deformation behaviors were thought to be attributed to relative 180$^{\circ}$domain quantities which is determined by pre-loaded stress and electric field. The non-linearity of piezoelectricity and strain are dependent upon the young's modulus resulting from the domain reorientation.

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세라믹 연삭에서 다이아몬드 숫돌 마멸에 관한 연구 (A Study on the Diamond Wheel Wear in Ceramic Grinding)

  • 공재향;유봉환;소의열;이근상;유은이
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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    • pp.344-348
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    • 2001
  • In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness after using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous grinding of ceramics, cutting edge ratio of resinoid bond wheel decreases. For the case of vitrified bond wheel, cutting edge ratio does not change.

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Coated $Si_3N_4$-TiC ceramic 공구의 마모 특성 (Wear characteristics of coated $Si_3N_4$-TiC ceramic tool)

  • 김동원;권오관;이준근;천성순
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1988년도 제7회 학술강연회초록집
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    • pp.43-48
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    • 1988
  • 보호피막을 입히는 방법으로는 화학증착법과 물리증착법이 주로 사용되고 있다. 고온 분위기에서 기체 상태인 반응물의 화학반응을 통하여 원하는 물질을 증착시키는 화학증착법은 물리증착법에 비해 점착성(adhesion)이 우수하고, 보호피막층의 성분조절이 용이하며, 반응물이 기체상태이므로 대량생산이 용이하여 보호피막 증착법으로 많이 사용되고 있다. $Si_3N_4$-TiC ceramic 표면에 TiC, TiN 및 Ti(C, N) coating을 함으로써 얻을 수 잇는 장점들은 표면층의 경도를 증가시키며, steel과의 마찰계수의 감소 및 coating 층 자체가 고온에서 고체 윤활제로 작용하여 마찰열의 상당한 감소를 얻을 수 있으며, 또한 coating층 자체가 비교적 안정한 화합물로 피삭재내의 성분원소들에 대한 diffusion barrier로 작용되며, 내식성을 증가시킬 수 있다. 본 연구에서는 각 증착층의 미소경도, 열충격저항, steel과의 마찰계수를 측정하였으며, 최종적으로 절삭시험을 통하여 증착층들의 내마모성을 조사, 규명하였다.

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$Si_3N_4$-TiC ceamic 공구에 화학증착된 TiC, TiN 및 Ti(C, N)에 관한 연구 (A study on the chemically vapor deposited TiC, TiN, and Ti(C, N) on $Si_3N_4$-TiC ceramic tools)

  • 김동원;김시범;이준근;천성순
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1988년도 제7회 학술강연회초록집
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    • pp.39-42
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    • 1988
  • 요업체 절삭공구(ceramic tool)는 공구강이나 초경제품에 비해 고속 절삭 작업이 가능하며 생산성을 높일 수 있기 때문에 최근 주목을 받고 있다. 본 실험에서 모재(substrate)로 사용된 $Si_3N_4$-TiC ceramic은 요업체 공구중에서 파괴인성이 우수하며, 주철이나 초합금을 절삭할 때 우수한 성능을 나타낸다. 그러나 요업체 절삭공구중에서 경도가 낮은 편에 속하며, Fe,Mn,O와 $Si_3N_4$가 화학적 반응을 일으켜서, steel을 절삭할 때 상면 마모(crater wear)가 심하게 발생하기 때문에 우수한 성능을 나타내지 못하고 있는 실정이다. 따라서 이러한 단점을 보완하기 위해 공구의 표면에 보호피막(protective coating)을 입히는 것은 필수적이다. 본 연구에서는 반응변수들이 TiC 및 TiN 증착층의 증착속도, 미세구조, 화학적 조성 및 증착층과 substrate 사이의 interface를 조사하여 각 증착층의 최적증착조건을 규명하고자 한다.

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Hexagonal 인서트용 열간압출 금형설계 (Die Design of Hot Extrusion for Hexagonal Insert)

  • 권혁홍;이정로
    • 한국공작기계학회논문집
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    • 제11권1호
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    • pp.32-37
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    • 2002
  • The use of hexagonal ceramic inserts for copper extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper the data on the loading of the tools is determined from a commercial FEM package as the contact stress distribution on the die-workpiece interface and as temperature distributions in the die. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the design and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads.