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  • Title/Summary/Keyword: ceramic tool

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Investigation of Dispersion Stability of Conductive Nano Ink Using 1-Octanethiol Coated Copper Nano Powders (1-Octanethiol이 코팅된 나노 구리 분말을 이용한 나노 잉크의 분산도에 대한 연구)

  • Cho, Danee;Baik, Jong-Hwan;Park, Joong-Hark;Lee, Caroline Sunyong
    • Journal of the Korean Ceramic Society
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    • v.49 no.5
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    • pp.417-422
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    • 2012
  • Copper nano particles have been considered as the materials for conductive ink due to its good thermal, electrical conductivity and low cost. However, copper nanoparticles oxidize easily, decreasing dispersion stability and electrical conductivity. Therefore, it is important to develop a method to minimize oxidation of copper nano particles to improve its dispersion stability property in copper nano ink. In this study, copper nano particles were coated with 1-Octanethiol VSAM(Vaporized Self Assembled Multilayers) to prevent oxidation and coated copper powders were dispersed in conductive ink successfully by studying its relationship of different chain length of solvents to 1-Octanethiol coating layer to fabricate nano ink. Various alcohol solvents, such as 1-Hexanol, 1-Octanol, and 1-Decanol were used. The coating layer was observed using FESEM and TEM. Furthermore, dispersion of copper nano particles in nano inks, was characterized using Turbiscan analyzer, viscometer, and contact angle measurement tool.

Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • 김석일;조재완
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.416-423
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

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The Polishing Characteristics and Development of Ultrasonic Polishing System through Horn Analysis (혼 해석을 통한 초음파 폴리싱 시스템의 개발 및 연마특성)

  • 박병규;김성청;문홍현;이찬호;강연식
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.3
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    • pp.53-60
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    • 2004
  • We have developed and manufactured an experimental ultrasonic polishing machine with frequency of 20kHz at the power of vibration 1.7㎾ for effective ultrasonic polishing in processing of high hardness material. Design of the horn is performed by the FEM analysis. The following conclusions were empirically deduced through experimental results to clarify the major elements which affect the surface roughness during the ultrasonic process by following the experimental plans. The ultrasonic polishing machine has been developed in parts of structure part, ultrasonic generator, vibrator. We were able to process the high hardness material without difficulty as a result of ultrasonic polishing by utilizing the groove added step-type horn. Through analyzing by applying the experimental plans, the rotating speed of the horn was determined to be the major factor in influencing the surface roughness. In the case of ceramic, wafer, we were able to obtain good surface roughness when the feed rate and the ultrasonic output were higher. Because the load on slurry particle increases when the ultrasonic output is higher, the processed surface becomes worse in the case of optical glass.

Mechanical Properties of Metal/Ceramic FGM made by Thermal Spraying Method (용사법에 의해 제작된 금속/세라믹 경사기능 재료의 기계적 특성)

  • Kim, Y.S.;Nam, K.W.;Kim, H.S.;Oh, M.S.;Kim, K.S.
    • Journal of Power System Engineering
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    • v.2 no.3
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    • pp.41-48
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    • 1998
  • This study was aimed at development of fabrication process of functionally graded materials(FGM), consisting of metal and ceramic by thermal spraying method. NiCrAIY/Al2O3 FGM were made by using plasma spraying onto the SS400 carbon steel substrate. And mechanical properties such as microhardness, thermal shock resistance and adhesive strength of the coating layer were investigated. Adhesive strength was evaluated by acoustic emission method. It was resulted that NiCrAIY/Al2O3 FGM made by thermal spraying method showed excellent thermal shock resistance and adhesive strength compared to the other lamellar structures of sprayed coatings and that AE is useful tool to evaluate the defect of thermal sprayed coating layer.

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Predict of Surface Roughness Using Multi-regression Analysisin Turning of Plastic Mold Steel (플라스틱 금형강의 선삭 가공시 중회귀분석을 이용한 표면거칠기 예측)

  • Bae, Myung-Il;Rhie, Yi-Seon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.4
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    • pp.87-92
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    • 2013
  • In this study, we carried out the turning of plastic mold steel(STAVAX) with whisker reinforced ceramic tool(WA1) and analyzed ANOVA(Analysis of Variance) test. Multi-regression analysis was performed to find influential factors to surface roughness and to derive regression equation. Results are follows: From ANOVA test and confidence interval analysis of surface roughness, We found that influential factors to surface roughness was feed rate, cutting speed and depth of cut in order. From multi-regression analysis, we derived regression equation of STAVAX. it's coefficient of determination(R2) was 0.945 and It means that regression equation is significant. From experimental verification, we confirmed that surface roughness was predictable by regression equation. Compared with former research, we confirmed that increase of feed rate is the main cause of the growing of surface roughness and cutting force.

Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • Kim Seok-ll;Cho Jae-Wan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.30-37
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

Modeling and Analysis of Thermal Effects of Underwater Laser Drilling for Ceramics (세라믹에 대한 수중 레이저 드릴링의 열영향 모델링 및 해석)

  • Kim, Teak Gu;Kim, Joohan
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.12
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    • pp.1265-1271
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    • 2013
  • In this work, modeling and analysis of thermal effects laser drilling under water for ceramics were presented. Laser is a unique tool for machining ceramics due to the characteristic of non-contact material removal. However, ablation by a laser often induces a thermal effect on the material and an increased heat-affected-zone or deposition of debris can be observed on the machined parts. The underwater surrounding improved a heat transfer rate to cooling down the machined part and could prevent any deposition of debris near the machined surfaces and edges. The heat modeling was applied to obtain the temperature distributions as well as temperature gradients between the material and surroundings. The cooling effect of the underwater laser drilling was improved and a more stable temperature distribution was calculated. The actual laser drilling results of ceramic laser drilling were presented to verify the effects of underwater laser drilling.

A Study on the Grinding Characteristics of Ceramics (세라믹 재료의 연삭 특성에 관한 연구)

  • 정을섭;김성청;김태봉;소의열;이근상
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.3
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    • pp.86-92
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    • 2002
  • In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel far ceramic materials. Normal component of grinding resistance of Al2O3 was less then that of Si3N4 and ZrO2. This seems to be the characteristics of ceramic tools on work pieces both of high hardness. For the case of Si3N4 and ZrO2, as the mesh number of wheel increases, the surface roughness decreases. For the case of Al2O3, the surface roughness does not decreases. Specific binding energy decreases as the material removal rate per unit time increases. For the case of Si3N4 and ZrO2, grinding is carried out by abrasive wear processes. For the case of Al2O3, grinding is carried out by grain shedding process due to brittle fracture.

Indentation Damage of Porous Alumina Ceramice

  • Ha, Jang-Hoon;Lee, Chul-Seung;Kim, Jong-Ho;Kim, Do-Kyung
    • Journal of the Korean Ceramic Society
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    • v.41 no.1
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    • pp.19-23
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    • 2004
  • The Hertzian indentation contact damage behavior of porous alumina with controlled pore shape was investigated by experiments. Porous alumina ceramics containing well-defined pore shape, size and distribution were prepared by incorporation of fugitive spherical starch. Porous alumina with isolated pore structure was prepared with porosity range up to 30%. The indentation stress-strain curves of porous alumina were constructed. Elastic modulus and yield stress can be obtained from the stress-strain relationship. Impulse excitation method for the measurement of elastic modulus was also conducted as well as Hertzian indentation and was confirmed as a useful tool to evaluate the elasticity of highly porous ceramics. Elastic modulus of the inter-connected pore structure is more sensitive to porosity than that of the isolated pore structure. When the specimen had isolated pore structure, higher yield point was obtained than it had inter-connected pore structure. This study proposed that the elastic modiulus of porous ceramics is strongly related to not only porosity, but also the structure of pore.

Grinding Characteristics and Wear Behavior of Diamond Wheel in Ceramic Grinding (세라믹 연삭에서 다이아몬드 휠의 연삭 특성 및 마멸 거동)

  • 박병규;문홍현;김성청
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.8-14
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    • 2003
  • The characteristics of grinding and wear behavior of diamond wheel for grinding ceramic materials was investigated in this study. In case of Si3N4, the wear of wheel was large, the finding force was relatively stable and the fluctuation of surface roughness n small. On the other hand in case of Al2O3 and ZrO2, the wear of wheel and surface roughness were decreasing, the grinding force was increasing. During grinding with vitrified bond wheel, Si3N4 shows renewal of cutting edge while Al2O3 and ZrO2 show glazing phenomenon of cutting grains. We have found that it possible to observe the behavior of grinding wheel by grinding ratio, grinding resistance, surface roughness and cutting edge ratio. Through the grinding experiments, it was found that grinding life of diamond wheel is 20 times for Si3N4, and 40 times fir Al2O3 and ZrO2.