• Title, Summary, Keyword: Grinding Mechanism

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3-D Form Generation Mechanism in the Centerless Grinding Process (II) -Thrufeed Grinding- (무심 연삭 공정의 3차원 형상화기구 (II) -관통 연삭-)

  • Kim, Kang;Joo, Jong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.5
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    • pp.137-144
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    • 1998
  • A mathematical model for investigating the form generation mechanism in the centerless thrufeed grinding process is described. The length of the contact line and the magnitude of the grinding force between the grinding wheel and workpieces vary with the change of the axial location of the current workpiece during grinding. Thus, a new coordinate system and a grinding force curve of previous and/or following workpieces are introduced to treat the axial motion. Experiments and computer simulations were carried out using three types of cylindrical workpiece shapes. To validate this model. simulation results are compared with the experimental results.

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Development of a Parallel-Serial Robot Arm for Propeller Grinding (프로펠러 연삭작업을 위한 병렬-직렬 로보트 암 개발)

  • Lee, Min Ki;Choi, Byung Oh;Jung, Jong Yoon;Park, Kun Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.2
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    • pp.146-158
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    • 1996
  • This paper develops a robot arm for propeller blade grinding. The grinding work requires a high stiffness robot arm to reduce deformation and vibration which are generated during machining operation. Conventional articulated robots have serial connecting links from the base to the gripper. Thus, they have very weak structure to the stiffness for grinding operation. Stewart Platform is a typical parallel robotic mechanism with very high stiffness but it has small work space and large installation space. This research proposes a new grinding robot arm by combining parallel mechanism with serial mechanism. Therefore, the robot has large range of work space as well as high stiffness. This paper introduces the automatic system for propeller grinding utilizing the robot and the design of proposed robot arm.

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A Study on the Behaviors of Abrasive Grains in CBN Wheel (CBN 숫돌의 입자거동에 관한 연구)

  • 김희남
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.91-95
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    • 1996
  • One must observe abrasive grain of grinding wheel and know their behaviors to understand the grinding mechanism. The behaviors of abrasive grain on the wheel surface. such as shapes distributions and changes were studied to make the grinding mechanism clear but the behaviors of abrasive grains on CBN wheel are not known enough. From this paper the working surface of a grinding wheel is observed by photography in which a picture of a wheel surface is taken by the camera through the microscope on the grinding machine and analyzed with the computer.

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Kinematics and Design of CNC Drill Grinding Machine (CNC 드릴 연삭기 구조 및 설계)

  • 강성균
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.555-559
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    • 1996
  • Based on the general drill grinding mechanism, termed the helical grinding system, the conceptual design of 5 axes CNC drill grinding machine is proposed. Unique determination of the grinding parameters for precise production of the desired flank geometry is discussed by utilizing a mathematical model. Also, different combinations of grinding parameters are mentioned in order to produce various drill geometries (conical, cylindrical, and planar drill) on the single proposed CNC machine. A manual helical grinding machine has been fabricated and consequently helical drills have been ground in order to check the feasibility of the proposed grinding mechanism and its functionality.

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Structural Characteristic Analysis of a High-precision Centerless Grinding Machine with a Concrete-filled Bed

  • Kim, Seok-Il;Cho, Jae-Wan
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.4
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    • pp.34-39
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    • 2006
  • High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a structural characteristic analysis and evaluation were carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffness values of the centerless grinding machine were estimated based on the relative displacements between the GW and RW caused by grinding forces. The simulated results illustrated that a concrete-filled bed considerably improved the structural stiffness and accuracy of a high-precision centerless grinding machine.

Structural Characteristic Analysis of a High-Precision Centerless Grinding Machine with Concrete-Filled Bed (콘크리트 층진 베드를 적용한 초정밀 무심 연삭기의 구조 해석)

  • Kim Seok Il;Cho Jae Wan
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.2
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    • pp.172-179
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    • 2005
  • A high-precision centerless grinding machine has been recognized as a core equipment performing the finish outer-diameter grinding process of ferrules which are widely used as fiber optic connectors. In this study, in order to realize the high-precision centerless grinding machine, the structural characteristic analysis and evaluation are carried out on the virtual prototype consisted of the steel bed, hydrostatic GW and RW spindle systems, hydrostatic RW feed mechanism, RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffnesses of centerless grinding machine are estimated based on the relative deformations between GW and RW caused by the grinding forces. And the simulated results illustrate that the concrete-filled bed has the considerable effect on the improvement of the structural stiffness of centerless grinding machine.

3-D Form Generation Mechanism in the Centerless Grinding Process (I) -Infeed Grinding- (무심 연삭 공정의 3차원 형상화기구 (I) -인피드 연삭-)

  • Kim, Kang;Joo, Jong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.5
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    • pp.128-136
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    • 1998
  • A mathematical model for investigating the form generation mechanism in the centerless infeed grinding process is described. For 3-D modeling of form generation, contact points are assumed to be on least squares contact lines at the grinding wheel, regulating wheel, and work-rest blade. Using force and deflection analysis, the validity of this assumption is shown. Based on the 2-D simulation model developed in the previous work and the least squares contact line assumption, a 3-D model is presented. To validate this model, simulation results were compared with the experimental works. The experiments and computer simulations were carried out using three types of cylindrical workpiece shapes with varying flat length. The experimental results agree well with the simulation. It can be seen that the effect of flat end propagated to the opposite end through workpiece reorientation.

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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.

Grinding Mechanism and Case Study on Double-Disc Grinding of Ferrous Sintered Material

  • Tanaka, Masaru;Yoshimoto, Akinori;Ohshita, Hideo;Hashimoto, Toshihiko
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.877-878
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    • 2006
  • The sintered parts are mainly used for automobile industry, and a part of air conditioners. In automobile industry, the application range of sintered parts is very broad and use for a driving and a lubricating system. And air conditioner uses them for compressor. Grinding of compressor and pump parts is very difficult these days, because these parts use High hardness materials and require high precision grinding. Tool life has to be extended to decrease production cost. We analyzed processing mechanism and developed new grinding wheels for Double Disk Grinding. And, we introduce new truing technology that improved tool-life and precision.

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Thermal Characteristic Analysis of a High-Precision Centerless Grinding Machine for Machining Ferrules

  • Kim, Seok-Il;Cho, Jae-Wan
    • International Journal of Precision Engineering and Manufacturing
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    • v.8 no.1
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    • pp.32-37
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    • 2007
  • The outer diameter finishing grinding process required for ferrules, which are widely used as fiber optic connectors, is carried out by high-precision centerless grinding machines. In this study, the thermal characteristics of such a machine, for example, the temperature distribution, temperature rise, and thermal deformation, were estimated based on a virtual prototype and the heat generation rates of heat sources related to normal operating conditions. The prototype consisted of a concrete-filled bed. hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The reliability of the predicted results was demonstrated using temperature characteristics measured from a physical prototype. The predicted and measured results indicated that this particular high-precision centerless grinding machine had very stable thermal characteristics.