• Title, Summary, Keyword: End effect

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Simulation of Machined Surface Considering Acceleration Signal in High Speed End Milling (고속 엔드밀 가공시 가속도 신호를 고려한 가공표면의 시뮬레이션)

  • Lee, Gi-Yong;Gang, Myeong-Chang;Lee, Deuk-U;Kim, Jeong-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.2
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    • pp.228-234
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    • 2001
  • To obtain precise machined surface and high productivity in machining, high speed end milling has beed studied recently. Though high speed end milling is explicitly effective for precision surface generation geometrically, tool deflection, chatter vibration and frequency characteristics of end milling system deteriorate the theoretical surface. In this study, simulation algorithm and programming method are suggested to simulate machined surface using acceleration signal in high speed end milling. This simulation is conducted by considering vibrational effect of spindle system which was not considered by other investigators. Good agreements were obtained between simulated results and experimental results.

A Study for Energy Separation of Vortex Tube using Air Supply System (I) - the effect of diameter of cold end orifice - (공기공급 시스템에 적용되는 Vortex Tube의 에너지 분리특성에 관한 연구(I) -저온출구 orifice의 직경변화에 의한 영향-)

  • 이병화;추홍록;상희선
    • Journal of the Korean Society of Safety
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    • v.13 no.4
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    • pp.9-18
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    • 1998
  • The vortex tube is a simple device for separating a compressed gaseous fluid stream into two flows of high and low temperature without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air supply system. The phenomena of energy separation through the vortex tube was investigated experimentally. This study is focused on the effect of the diameter of cold end orifice diameter on the energy separation. The experiment was carried out with various cold end orifice diameter ratio from 0.22 to 0.78 for different input pressure and cold air flow ratio. The experimental results were indicated that there are an optimum diameter of cold end orifice for the best cooling performance. The maximum cold air temperature difference was appeared when the diameter ratio of the cold end orifice was 0.5. The maximum cooling capacity was obtained when the diameter ratio of the cold end orifice was 0.6 and cold air flow ratio was 0.7.

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Optimization of outer core to reduce end effect of annular linear induction electromagnetic pump in prototype Generation-IV sodium-cooled fast reactor

  • Kwak, Jaesik;Kim, Hee Reyoung
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1380-1385
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    • 2020
  • An annular linear induction electromagnetic pump (ALIP) which has a developed pressure of 0.76 bar and a flow rate of 100 L/min is designed to analysis end effect which is main problem to use ALIP in thermohydraulic system of the prototype generation-IV sodium-cooled fast reactor (PGSFR). Because there is no moving part which is directly in contact with the liquid, such as the impeller of a mechanical pump, an ALIP is one of the best options for transporting sodium, considering the high temperature and reactivity of liquid sodium. For the analysis of an ALIP, some of the most important characteristics are the electromagnetic properties such as the magnetic field, current density, and the Lorentz force. These electromagnetic properties not only affect the performance of an ALIP, but they additionally influence the end effect. The end effect is caused by distortion to the electromagnetic field at both ends of an ALIP, influencing both the flow stability and developed pressure. The electromagnetic field distribution in an ALIP is analyzed in this study by solving Maxwell's equations and using numerical analysis.

Thrust Performance Improvement of a Linear Induction Motor

  • Lee, Hyung-Woo;Park, Chan-Bae;Lee, Byung-Song
    • Journal of Electrical Engineering and Technology
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    • v.6 no.1
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    • pp.81-85
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    • 2011
  • The end effect of a linear induction motor (LIM) has been known for several decades, especially in high speed operation. The exit part of the primary is not dealt as extensively as the entry part because of its minor effect. However, the exit part is one of the keys to weaken the dolphin effect, which occurs in high speed operation. In this paper, the concept of the virtual primary core is introduced, and chamfering of the primary outlet teeth is proposed to minimize the longitudinal end effect at the exit zone. For this, LIM for the high-speed train is designed and analyzed by using finite element method. Results confirm that chamfering can improve thrust performance effectively.

EFFECT OF TOP END CONDITION OF FUEL BED CONTAINER ON DOWNWARD SMOLDER SPREAD

  • Sato, Kenji;Sakai, Yasuhiro
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • pp.146-153
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    • 1997
  • An experimental study was performed of natural-convection downward smolder spread across a sawdust bed peripherally enclosed with an insulating container, to examine the effect of the open- ing condition at the top end on downward smolder spread. Experiments were conducted by using relatively coarse sawdust and 25-cm-long cylindrical container The variations of temperature profiles along the bed axis with time were determined far different opening conditions and were com-pared with those in smolder spread from open top to open bottom. It was shown that the smolder zone initiated from open top toward closed bottom penetrates the bed with keeping high peak temperature like the case of open top to open bottom spread, although mean spread rate is smaller. This indicates that the downward smolder zone can be sustained stably if sufficient air or oxygen Is supplied from the back of it by natural convection even if upward draft entering from the bottom of the bed is absent. When the top end was partially closed by mounting a cover after stable smolder spread had begun from open top toward open bottom, the temperature at the peak decreased more than 200 K and the smolder zone became to spread with thickening residue. In this case, the shape of temperature profiles continuously changed or decayed until end-effect at the open bottom end enhanced the reaction. The temperature at the shrunk peak, free from the end-effect, was almost identical with the temperature at the exothermic oxidative-degradation zone in smolder spread from open top to open bottom. from these results, it can be inferred for natural-convection downward smolder spread that the oxidation reaction of the char is very sensitive to the oxygen supply by natural convection in the space above the smolder zone, and that the top end opening condition strongly alters the completeness of reactions, structure, and behavior of the smolder zone.

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A Scale-Effect of O-Cell Pile Load Test with Variable End Plate (가변선단재하판을 이용한 양방향말뚝재하시험의 치수 효과)

  • Joo, Yong-Sun;Kim, Nak-Kyung;Kim, Ung-Jin;Park, Jong-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.884-890
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    • 2009
  • The bi-directional pile load test with variable end plate overcomes the shortcoming of the Osterberg cell test. It is possible that the ultimate bearing capacity of the bi-direction can be known by using the loading of the end plate and two step procedures. The first step is to confirming end bearing capacity with variable end plate and the second step is similar to the conventional O-cell test. In the study, To calculate ultimate capacity of bi-directional load test using model with the pile with variable end plate O-cell, operated with end plate of 3 type on sand layer according to the relative density, loose, medium and dense conditions.

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A Study on the cutting forces prediction using machining theory in end milling (절삭이론을 이용한 엔드밀 가공에서의 절삭력 예측에 관한 연구)

  • Jung, Sung-Chan;Kim, Kug-Weon
    • Proceedings of the KSME Conference
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    • pp.928-933
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    • 2004
  • A new approach for modelling and simulation of the cutting forces in end milling processes is presented. In this approach, the cutting forces in end milling are modelled based on a predictive machining theory, in which the machining characteristic factors are predicted from input data of fundamental workpiece material properties, tool geometry and cutting conditions. In the model, each tooth of a end milling cutter is divided into a number of slices along the cutter axis. The cutting action of each of the slices is modelled as an oblique cutting process. For the first slice of each tooth, it is modelled as oblique cutting with end cutting edge effect, whereas the cutting actions of other slices are modelled as oblique cutting without end cutting edge effect. The cutting forces in the oblique cutting processes are predicted using a predictive machining theory. The total cutting forces acting on the cutter is obtained as the sum of the forces at all the cutting slices of all the teeth. A Windows-based simulation system for the cutting forces in end milling is developed using the model. Experimental milling tests have been conducted to verify the simulation system.

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The Improved Quasi-3D FE Analysis on the AFPM Motor (개선된 Quasi-3D FEM을 통한 AFPM 전동기의 해석)

  • Woo, Dong-Kyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.773-776
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    • 2016
  • In the quasi-3D finite element(FE) anlysis, the overall characteristics of axial flux permanent magnet(AFPM) motor could be composed of each computation region. However, A drawback of quasi-3D FEM is not to consider the end effect on the stack end. To address this problem, an improved quasi-3D FE analysis which considers the end effect of the AFPM motor was proposed. From results the 3D FE analysis, the validity of the proposed method is verified.

Analysis of Working Factors for Improvement of Surface Roughness on High Speed End-Milling (엔드밀 고속 가공시 표면정도 향상을 위한 가공인자의 영향 분석)

  • 배효준;박흥식
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.6
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    • pp.52-59
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    • 2004
  • Recently the high speed end-milling processing is demanded the high-precise technique with good surface roughness and rapid time in aircraft, automobile part and molding industry. The working factors of high speed end-milling has an effect on surface roughness of cutting surface. Therefore this study was carried out to analyze the working factors to get the optimum surface roughness by design of experiment. From this study, surface roughness have an much effect according to priority on distance of cut, feed rate, revolution of spindle and depth of cut. By design of experiment, it is effectively represented shape characteristics of surface roughness in high speed end-milling. And determination($R^2$) coefficient of regression equation had a satisfactory reliability of 76.3% and regression equation of surface roughness is made by regression analysis.

Analysis of Cutting Edge Geometry Effect on Surface Roughness in Ball-end Milling Using the Taguchi Method (다구찌 방법을 통한 볼 엔드밀 절삭날 형상이 가공면 거칠기에 미치는 영향 분석)

  • Cho, Chul Yong;Ryu, Shi Hyoung
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.23 no.6
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    • pp.569-575
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    • 2014
  • In this study, the effect of cutting edge geometry, such as helix and rake angles, on surface roughness in ball-end milling is investigated by using the Taguchi method. A set of experiments adopting the $L_{27}(3^{13})$ design with an orthogonal array are conducted with special WC ball-end mills having different helix and rake angles. Analysis of variance (ANOVA) is performed to analyze the effects of tool geometry and machining parameters, such as cutting speed, feed per tooth, and depth of cut, on surface roughness. The ANOVA results reveal that helix and rake angles are critical factors affecting surface roughness; the interaction of helix angle and cutting speed is also important. This research can contribute to novel cutting edge designs of ball-end mills and optimization of cutting parameters.