• Title/Summary/Keyword: Dressing Current

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Selecting Optimal Dressing Parameters of Ultra-precision Centerless Grinding Based on the Taguchi Methodology (다구찌 방법론에 근거한 초정밀 센터리스 연삭의 최적 드레싱 가공 조건 선정)

  • Chun Y.J;Lee J.H.;Lee E.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.108-113
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    • 2005
  • In this study, rotary type diamond dressing system for ultra-precision centerless grinding for ferrule was developed at the first time and experiments were conducted with AE sensor and hall sensor system to verify the optimum dressing condition for ultra-precision centerless grinding for ferrule. The correlations with the condition of dressing are evaluated by AE signal analysis with root mean square (RMS) and frequency analysis. And current signals from hall sensor are also studied as a factor of dressing optimum condition selection. Dressing process was conducted to investigate the effects of depth of cut, rotating speed, and the number of overlap to select the optimum condition of rotary dressing system of ultra-precision centerless grinding machine for ferrule fabrication. In order to verify the optimum condition of dressing, AE and current signals were compared with the surface quality of dressing wheel and grinding wheel for ultra-precision ferrule grinding. All of these experiments were completed by Taguchi Methodology to reduce experimental time. Hence, the optimum condition of rotary dressing system for ultra-precision centerless grinding for ferrule fabrication can be selected following to the experiment result from signals of AE and hall sensor.

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A study on the analysis of grinding mechanism by using optimum in-process electrolytic dressing (최적 연속 전해드레싱에 의한 연삭기구의 규명에 관한 연구)

  • Lee, Eun-Sang;Kim, Jeong-Du
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.8
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    • pp.1298-1310
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    • 1997
  • In recent years, grinding techniques for precision machining of brittle materials used in electric, optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of brittle materials. However, the present dressing system cannot have control of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process electrolytic dressing were proposed. This system can carry out optimum in-process dressing of superabrasive wheel, and give very effective control according to unstable current and gap increase. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of brittle materials.

Reducing the Non Grinding Time in Grinding Operations(2nd report) -Decision of Dressing Chance and Depth by the Direct Measurement of Grinding Wheel Surface- (연삭가공에 있어 비가공 시간 단축에 관한 연구(II))

  • KIM, Sun Ho;AHN, Jung-Hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.8
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    • pp.101-107
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    • 1997
  • In general, grinding is one of the final machining processes which determines the surface quality of machined products. Since the ground surface is affected by the states of grains and voids on the grinding wheel surface, the wheel should be dressed before the machined surface deteriorates over a quality limit This paper describes a systematic approach to decide a proper dressing chance and an optimal dressing depth for the working grinding wheel. An eddy current sensor and a laser displacement sensor are used to measure the loading on the working wheel surface and the topography of the dressed wheel surface respec- tively. The dressing chance can be properly decided through the relational locus between the amount of handing and the machined surface roughness. An optimal dressing depth to guarantee the less wheel loss and the higher wheel surface quality is decided through the analysis of the variance of topography for the dressed wheel surface, which decreases at three different rates according to the accumulated dressing depth.

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Dressing Chance Detecting System by the Direct Observation (직접관찰법에 의한 드레싱 시기 검출 시스템)

  • 김성렬;김선호;황진동;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.477-481
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    • 2002
  • Grinding which is the final finishing step in the machining processes plays an important role fur precision manufacturing because it directly affect the product quality. Since the ground surface is affected by the states of grains and voids on the grinding wheel surface, the wheel should be dressed before the machined surface deteriorates over a quality limit. This paper describes a systematic approach to decide a proper dressing chance. A fabricated eddy current sensor and CCD camera are used to measure the loading on the working wheel surface and to visualize the wheel surface states respectively. The dressing chance can be properly decided through the relation between the variation of the thresholding image of the wheel and the machined surface roughness as the variation of the eddy current sensor output is greater than the detected value previously.

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Development of Grinding Dressing System by Using Inprocess Electrelytic Dressing (정밀연삭기의 전해드레싱 시스템 개발사례)

  • 김정두
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.03a
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    • pp.196-202
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    • 1998
  • Recently, developments in the frontier industry have brought a rapid increase in the use of brittle materials such as silicon wafer, ferrite, sintered carbide, MgO single crystal and die steel. Because of high hardness and brittleness the cracking and chipping are apt to generate in the grinding of brittle materials, but have replaced gradually the high precision grinding. In this study, the optimum system of in-process electrolytic dressing controlled by computer was developed for improving the defects, and could maintain the optimum dressing condition at all times. The control of in-process dressing was simplified using this system, was able to maintain a stable dressing current and was unrelated to the change of dressing condition according to the variation of gap and oxide layer. Therefore, the optimum in-process electrolytic dressing system was constructed and the analysis of grinding mechanism with this system was studied.

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The Trial Construction of Optimum In-Process Electrolytic Dressing System and the Control Characteristics (최적 연속전해드레싱 시스템의 개발과 제어특성)

  • 김정두;이은상
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.3
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    • pp.680-687
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    • 1995
  • In recent years, grinding techniques for precision machining of brittle materials used in electric, optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of brittle materials. But the present dressing system cannot have control of optimum dressing of the superabrasive wheel. This study has proposed a new optimum in-process electrolytic dressing system. This system can carry out optimum in-process dressing of superabrasive wheel, and give very effective control according to gap increase.

A Study on the Analysis of Grinding Mechanism and Development of Dressig System by using Optimum In-process Electrolytic Dressing (최적 연속 전해드레싱에 의한 연삭기구의 규명 및 시스템 개발에 관한연구)

  • 이은상
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.04a
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    • pp.96-101
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    • 1997
  • In recent years, grinding techniques for precision machining of brittle materials used in electric, optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The present dressing system cannot have controll of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process electrolytic dressing were proposed. This system can carry out optimum in-process dressing of superabrasive wheel, and give very effective control according to unstable current and gap increase. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of brittle materials.

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Development of Optimum In-process Electrolytic Dressing System in the UItraprecision Grinding (초정밀 연삭용 최적 연속 전해드레싱 시스템의 개발에 관한 연구)

  • 이은상
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1995.03a
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    • pp.82-103
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    • 1995
  • In recent years grinding techniques for precision machining of brittle materials used in electric optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasibve wheel makes possible the effective precision grinding of brittle materials. But the present dressing system cannot have control of optimum dressing of the superabrasive wheel. This study has proposed a new optimum in-process dressing of superabrasive wheel and give very effective control according to gap increase.

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A Study on the Ultraprecision Grinding for Brittle Materials With Electrolytic Dressing (전해드레싱에 의한 경취재료의 초정밀 연삭에 관한 연구)

  • 김정두;이연종;이창열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1486-1496
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    • 1993
  • The diamond wheel with superabrasive is required for mirror-like surface grinding of brittle materials. But the conventional dressing mothod can not apply to the diamond wheel with superabrasive. Recently electrolytic dressing method was developed for cast-iron bonded diamond wheel with superabrasive. This technique can take replace of lapping and polishing. Using the electrolytic dressing, the surface roughness of workpiece was improved largely and grinding force was very low and the continuity of the grinding force was also very improved. In this study, the purpose is the realization of mirror-like surface grinding of ferrite with electrolytic dressing of metal bonded diamond wheel. For application of ultraprecision grinding for brittle material, superabrasive wheel, air spindle and inprocess electrolytic dressing were used. In addition, the effects of pick current and pulse width on ground surface were investigated, and the suitable dressing conditions for ferrite were found out.