• Title/Summary/Keyword: Diamond Turning

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The Study on Ultra-Precision Cutting Characteristics Evaluation of Non-Ferrous Metals Using Attractor Quadrant Method (어트랙터 사분면법을 이용한 비철금속의 초정밀 절삭특성 평가에 관한 연구)

  • 고준빈;김건희;윤인식
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.6
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    • pp.20-26
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    • 2003
  • This study proposes the construction of attractor quadrant method for high-precision cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to Perform cutting Processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics and attractor quadrant characteristics. In quantitative quadrant feature extraction, 1,309 point in the case of A17075 (one quadrant) and 1,406 point (one quadrant) in the case of brass were proposed on the basis of attractor reconstruction. Proposed attractor quadrant method can be used for high-precision cutting characteristics evaluation of non-ferrous metals.

Ultra-precision single point diamond turning (SPDT) on an aspheric metal secondary mirror (초정밀 단일점 다이아몬드 터닝을 이용한 비구면 금속 부반사경 가공)

  • Kim, E. D.;H. S. Yang;Kim, G-H.
    • Proceedings of the Optical Society of Korea Conference
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    • 2001.02a
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    • pp.96-97
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    • 2001
  • A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT) . Without a conventional polishing process, the surface texture of R$\sub$a/=2.8 nm, and the form error of R$\sub$a/=0.05 λ has been stably achieved In a laboratory condition. (omitted)

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Wear of Single Crystal Diamond(SCD) Tools in Ultra Precision Turning of Electro-Nickel Plated Drum (전해니켈도금된 대면적 롤금형 가공시 단결정 다이아몬드공구의 마모에 관한 연구)

  • Lee, D.Y.;Hong, S.H.;Kang, H.C.;Choi, H.Z.;Lee, S.W.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.7
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    • pp.621-628
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    • 2009
  • Nickel-phosphorus alloys are attractive materials for diamond turning applications such as fabrication of large optics and other high precision parts. It is also well-known that the higher phosphorus content of the alloys minimizes the diamond tool wear. Due to the weakness of electoless nickel plating that the phosphorus contents is limited to 13-14% (wgt), increased attention has been paid at electro-nickel plating which enables the alloys with 15-16% phosphorus. In this study, experiments were carried out to observe the wear characteristic of single crystal diamond tools in micro-grooving of electro-nickel plated drums. The experiments shows that long distance (50km) machining of micro-grooving on electro-nickel plated drum is possible with a single crystal diamond tool without any significant tool wear and defective machined surface.

Admittance Model-Based Nanodynamic Control of Diamond Turning Machine (어드미턴스 모델을 이용한 다이아몬드 터닝머시인의 초정밀진동제어)

  • Jeong, Sanghwa;Kim, Sangsuk
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.154-160
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    • 1996
  • The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface cnotours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated dapth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in additn to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamoneter. Based on the parameter estimation of cutting dynamics and the admitance model-based nanodynamic control scheme, simulation results are shown.

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Tool Holder Design and Cutting Force Measurement of Diamond Turning Process (다이아몬드 터닝의 미세 절삭력 측정을 위한 tool holder 설계 및 절삭력 측정)

  • Jeong, S.H.;Kim, S.S.;Do, C.J.;Hong, K.H.;Kim, G.H.;Rui, B.J.
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.507-512
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    • 2001
  • In this work, tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. Tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces.

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System identification and admittance model-based nanodynamic control of ultra-precision cutting process (다이아몬드 터닝 머시인의 극초정밀 절삭공정에서의 시스템 규명 및 제어)

  • 정상화;김상석;오용훈
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1352-1355
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    • 1996
  • The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

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Machining of Corner-cube Pattern on Accumulated Cu-Thin Plates (적층된 구리 박판의 코너 큐브 패턴의 가공)

  • Lee, Joon-Yong;Bae, Chan-Yeol;Kim, Chang-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.3
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    • pp.109-114
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    • 2016
  • This study presents the optimal hardness range for a coated layer of a workpiece when the diamond tool cuts the corner-cube pattern on the coated plates using an ultra-precision diamond-turning machine. Two kinds of coated plates, which have the hardness range of 211~328 Vickers hardness, are used on the first experiments. The form accuracy for the corner-cube pattern could be achieved through the following experiments using the accumulated thin copper plates in second experiments, having optimal 265~275 Vickers hardness based on the basic first experiments without tool wear. When the number of machining adjustments was increased to seven times, having machining depth was reduced successively in second experiment, a fine surface could be achieved without tool wear.

Construction of 2-3 Dimensional Attractor System for Cutting Characteristics Evaluation of Metals (금속의 절삭성 평가를 위한 2-3차원 어트랙터 시스템의 구축)

  • Yun In Sik;Lee Jong Dae
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.2
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    • pp.8-13
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    • 2005
  • This study proposes the construction of 2-3 dimensional attractor system for cutting characteristics evaluation of metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to perform cutting processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in attractor characteristics. Constructed 2-3 dimensional attractor system in this study can be used for cutting characteristics evaluation of metals.