• Title/Summary/Keyword: Workpiece Vibration

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Effect of Unbalance on Vibration and Machining of Al6061 Aluminum Alloy in Precision Rotator (정밀회전체의 언밸런스 변화에 따른 진동과 Al6061 알루미늄 합금 가공에 미치는 영향)

  • Kim, Min Soo;Kim, Jung Tae;Park, Seok Woo;Jeong, Dong Uk;Choi, Sun Ho;Koo, Bon Heun;Yoon, Sang Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.3
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    • pp.76-82
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    • 2021
  • At present, with the development of precision instruments, high dimensional accuracy of workpieces must be ensured. In particular, for the aluminum alloys used in automobiles, the surface roughness of the workpiece is extremely important. The dimensional accuracy and surface roughness of the workpiece is considerably affected by the rotational accuracy of the rotor. Therefore, to enhance the rotational accuracy, various variables such as those related to the components such as bearings, motors, and end mills, rotational speeds, and vibrations must be considered. In this study, the difference in the quality of the workpieces was compared considering the weight imbalance and rotational speed as variables.

Evaluation of Cutter Orientations in 5-Axis High Speed Milling of Turbine Blade (터빈블레이드의 5축 고속가공에서 최적가공경로의 선정)

  • Lim T. S.;Lee C. M.;Kim S. W.;Lee D. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.53-60
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    • 2002
  • Recently, the development of aerospace and automobile industries brought new technological challenges, related to the growing complexity of products and new geometry models. High speed machining using 5-Axis milling machine is widely used for 3D sculptured surface parts. 5-axis milling of turbine blade generates the vibration, deflection and twisting caused from thin and cantilever shape. So, the surface roughness and the waviness of workpiece are not good. In this paper, The effects of cutter orientation and lead/tilt angle in 5-Axis high speed ball end-milling of turbine blade were investigated to improve the geometric accuracy and surface integrity. The experiments were performed at lead/tilt angle $15^{\circ}$ of workpiece with four cutter directions such as horizontal outward, horizontal inward, vertical outward, and vertical inward. Workpiece deflection, surface roughness and machined surface were measured with various cutter orientations such as cutting direction, and lead/tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle.

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Feed Directional Dynamic Characteristics of the Machine Tool System (공작기계 계 의 이송방향 동특성에 관한 연구)

  • 이종원;조영호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.7 no.1
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    • pp.36-45
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    • 1983
  • In order to characterize the machine tool feed-drive dynamics, thread cutting experiments are performed with cutting conditions and slide-way lubrication varied. During the experiments, the carriage, tool post and tail stock accelerations in the feed direction are measured, and analyzed by employing the spectral analysis method. It is found that the tool post vibration in the feed direction during thread cutting operation is mainly due to those of the carriage and the workpiece. Other structure-related vibrations show little effects on the tool post vibration. The characteristics of the carriage vibration is shown to be fairly consistent, except the vibration amplitude, regardless the variations in cutting condition and lubrication within the experimental range. The experimental results suggest that the feeddrive system can be modelled as a 2 DOF damped oscillatory system.

Machining of Micro Structure using Elliptical Vibration Grooving Machine (타원궤적 진동절삭 가공기를 이용한 미세 형상 가공)

  • Kim, Gi-Dae;Loh, Byoung-Gook
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.11
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    • pp.45-51
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    • 2008
  • Successive micro-scale V-grooves and a grid of pyramids were machined by elliptical vibration tufting (EVC) to investigate feasibility of using EVC as an alternative method of creating micro-molds to photo-lithography and electroforming, which have been commonly employed. An elliptical vibration grooving machine was developed which consists of two orthogonally-arranged piezoelectric actuators, a diamond cutting tool, and a motorized xyz stage. The micro-scale features were machined on materials of copper, duralumin, nickel, and hastelloy and it was found that EVC significantly reduces cutting resistance and prohibits generation of side burrs and rollover burrs, thus resulting in improving machining qualify of micro-molds in ail experimented workpiece materials.

Virtual Dynamic Machining System for Chatter Detection and Avoidance (채터진동 검출 및 회피를 위한 가상 동적 가공시스템 구축)

  • Kim, H.;Jo, M.H.;Koo, J.Y.;Lee, J.H.;Kim, J.S.
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.3
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    • pp.273-278
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    • 2014
  • This study presents a chatter vibration avoidance program for the milling process. Chatter vibration has a negative effect on workpieces and spindle-tools. When chatter vibration occurs, the cutting tool is loaded dynamically, a chatter pattern is generated on the workpiece, and the tool life is reduced. The developed program is composed of various modules such as an FFT analyzer, an impact test analyzer, a chatter vibration indicator, and a spindle speed recommender. The proposed program is verified using an AISI D2 cutting experiment in milling process. The effect of chatter vibration on the machining condition can be simulated by the suggested method, and successfully exploited to avoid chatter vibration.

A study on the chatter vibration characteristics simulation for cutting tooling of turning machine tool (터닝센터에서의 툴링과 채터 특성 시뮬레이션 연구)

  • Hwang, Joon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.6
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    • pp.274-278
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    • 2014
  • Machining performance is often limited by chatter vibration at the tool-workpiece interface. Chatter vibration is a type of machining self-excited vibration which originated from the variation in cutting forces and the flexibility of the machine tool structure. Cutting tooling method is one of major factor to chatter vibration in turning process. Even though lots of cutting tooling methods are developed and used in machining process, precise analysis of cutting tooling effect in view of chatter vibration behavior. This study presents numerical and experimental approaches to verify and effects of various cutting tooling geometry and clamping method on the onset of chatter vibration. Acquired knowledge from this study will apply the optimal geometry design of cutting tooling and adjusting of machining process.

Cutting Force by Chip Former in Machining (절삭가공에서 칩포머에 의한 절삭저항)

  • Choi, Won-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.7 no.4
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    • pp.325-330
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    • 2004
  • The forces acting on the tool are an important aspect of maching. For those concerned with the manufacture of machine tools, a knowledge of the forces in needed for estimation of power reguirements and for the design of machine tool elements tool-holders and fixtures, adequately rigid and free from vibration. The force reguired to form the chip is dependent on the shear yield strength of the work material un der cutting conditions which are cutting speed, workpiece, feedrate, insert type. In this study, FG, ML, MP, MC, C, RT inserts were investigated in turning using SM45C, SCM4, SKD11, SUS316, materials. The diameter of materials was 60mm, 80mm, 110mm. This paper presents MP were lowest and SKD11 were largest of the workpiece in cutting forces.

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Optimum Shape Design of Cemented Carbide Micro-Drill in Consideration of Productivity

  • Kim, Gun-Hoi;Kwon, Ji-Yong;Lee, Sung-Goo
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.264-268
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    • 2003
  • Recently reduction of industrial products in size and weight has been increased by application of micro-drills in gadgets of high precision and a great interest of a micro-drilling has been raised. Due to the lack of tool stiffness and the chip packing, the micro-drilling requires not only the robust tool structure which has not affected by vibration but also effective drilling methods designed to prevent tool fracture from cutting troubles. This paper presents an optimum design shape of a 0.15 mm micro-drill associated with a new manufacturing process to improve the production rate and to lengthen the tool life and suggestions on the micro-drilling characteristic properties associated with the tool life and workpiece quality.

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Optimum Shape Design of Cemented Carbide Micro-drill in Consideration of Productivity (생산성을 중시한 초경합금 소재 마이크로 드릴의 최적 형상설계)

  • 김건회
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.3
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    • pp.133-140
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    • 2004
  • Recently reduction of industrial products in size and weight has been increased by application of micro-drills in gadgets of high precision and a great interest of a micro-drilling has been raised. Due to the lack of tool stiffness and the chip packing, the micro-drilling requires not only the robust tool structure which has not affected by vibration but also effective drilling methods designed to prevent tool fracture from cutting troubles. This paper presents an optimum design shape of a 0.15 mm micro-drill associated with a new manufacturing process to improve the production rate and to lengthen the tool life and suggestions on the micro-drilling characteristic properties associated with the tool life and workpiece quality.

Magnetic Abrasive Polishing Technology with Ceramic Particles (세라믹 입자를 이용한 자기연마가공 기술 사례)

  • Kwak, Tae-Soo;Kwak, Jae-Seob
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.12
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    • pp.1253-1258
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    • 2013
  • Ceramic particles as polishing abrasives are often used in a magnetic abrasive polishing process because they have strong wear resistance. Non-ferromagnetic ceramic abrasives should be mixed with ferromagnetic iron particles for controlling the mixture within a magnetic brush during the polishing process. This study describes the application of the ceramic particles for the magnetic abrasive polishing. The distribution of the magnetic abrasives attached on a tool varies with magnetic flux density and tool rotational speed. From the correlation between abrasive adhesion ratio in the tool and surface roughness produced on a workpiece, practical polishing conditions can be determined. A step-over for polishing a large sized workpiece is able to be selected by a S curve, and an ultrasonic vibration assisted MAP produces a better surface roughness and increases a polishing efficiency.