• Title, Summary, Keyword: 절삭속도

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Ball end milling of sculptured surface models by considering machinability (절삭성을 고려한 자유곡면 모형의 볼 엔드 밀링가공에 관한 연구)

  • 박천경;맹희영
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.2048-2061
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    • 1991
  • As compared with other cutting types, the ball end milling process causes a complexity in cutting system and a falling-off of machinability. In order to increase the productivity and efficiency in th NC machining of sculptured surfaces, this study carried out the qualitative linearized evaluation about the ball end milling system and applied their practical expressions to the technological processor at the cutter path planning stage. The evaluated expressions were proved to be adequate for practical use from an accuracy point of view and the estimation models were applied to sculptured surface machining processes for finding variable machining conditions. Consequently, it was recognized that variable machining conditions bring about the dispersion of force system and the reduction of machining time by more than 50%.

U$_3$Si 분말제조에서 chip 가공조건이 분말의 입도분포에 미치는 영향

  • 이돈배;박희대;장세정;조해동;이종탁;김창규;국일현
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.609-615
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    • 1995
  • Chip machining에 의한 U$_3$Si 분말제조시 절삭가공조건이 분말 입도 분포에 미치는 영향을 조사하기 위하여 U$_3$Si ingot를 선반에서 초경공구를 사용하여 절삭속도 및 이송속도를 변화시키면서 chip을 가공하였고, 가공된 chip의 형상을 광학현미경으로 관찰하고 칩의 크기를 측정하였다. 모든 절삭조건에서 톱니모양의 칩(saw toothed chip)이 형성되었으며, 일정한 절삭속도에서 공구의 이송속도를 변화시켰을 때 이송속도가 증가함에 따라 칩 두께의 증가와 함께 chip segment의 폭도 증가하여 chip segment 의 크기가 뚜렷이 증가함을 보였다. 또한 chip segment의 크기는 절삭속도 보다는 공구의 이송속도에 크게 영향을 받는 것을 알 수 있었고 분말의 입도 분포에도 크게 영향을 미치는 것으로 나타났다.

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Effects of Cutting Speed and Feed Rate on Axial Shape in Side Walls Generated by Flat End-milling Process (평엔드밀링 공정에서 절삭속도 및 이송속도가 측벽의 축방향 형상에 미치는 영향)

  • Kim, Kang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.5
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    • pp.391-399
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    • 2017
  • This paper presents the effects of the cutting speed and feed rate on the axial shape of flat end-milled down cut side walls. Experiments were performed using the cutting speed, tool diameter, and feed per tooth as variables, and the thrust force and axial shape were measured as the experimental results. The results of this study confirmed that a smaller feed per tooth, which is proportional to the value obtained by dividing the feed rate by the cutting speed, results in a higher axial shape accuracy. In addition, the axial shape can be simplified to a form in which two straight lines having different slopes meet at a singular point. Therefore, it was concluded that the shape accuracy could easily be estimated during the operation and improved by adjusting the feed per tooth.

Optimization of the constrained machining parameters problem by the SUMT (SUMT를 이용한 구속절삭조건의 문제에 관한 최적화)

  • 최경현;조규갑
    • Journal of the Korean Society of Marine Engineering
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    • v.19 no.3
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    • pp.70-76
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    • 1995
  • 생산스케쥴링의 기준이 되는 정보는 각 부품의 생산시간이나 생산비용인데, 이들은 고정된 값으로 취급되는 경우가 많다. 그러나, 실제적으로는 가공조건에 의하여 그 값들이 변화한다. 가공조거는 절삭깊이(depth of cut), 이송속도(feed rate), 및 절삭속도(cutting speed)로 구성되어 있다. 본 연구에서는 주어진 조건에 있어서 가공의 최적절삭조건을 최적이론의 하나인 페널티 함수이론(SUMT)을 이용하여 결정하는 할고리즘을 개발하였다. 알고리즘에서 목표함수(objective functions)로는 표면거칠기, 파워 소비, 등을 고려했다. 개발된 알고리즘 프로그램의 유용성을 증명하기 위해 선반가공의 예를 실행하여 그 결과를 예시하였다.

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Cutting Process Monitoring Using Tool Dynamometer in End-Milling Process (엔드밀 공정에서 공구 동력계를 이용한 절삭상태 감시)

  • 김홍겸;양호석;이건복
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.14-18
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    • 2001
  • Rise in cutting force causes tool damage and worsens product quality resulting in machining accuracy deterioration. Especially, fragile material cutting brings about breakage of material and worsens product surface quality. In this study, we trace the locus of cutting force and examine the machined surface corresponding to the cutting force loci. and build up a monitoring system for deciding normal operation or not of cutting process.

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저순도 알루미나 예비소결체 절삭시의 공구 수명

  • 이재우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.247-247
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    • 2004
  • 세라믹의 완전 소결체는 높은 경도와 취성을 가지기 때문에 연삭과 같은 입자가공이 행해지게 되어, 가공능률이 매우 낮고, 복잡한 형상 창성이 어렵다. 완전소결된 세라믹의 절삭가공에서는, 공구수명이 짧고, 가공속도가 매우 늦어 일반의 부품가공에 적용하기 어렵다. 또한 소결이 전혀 행해지지 않은 성형체의 절삭가공은 공작물의 강도가 약하기 때문에 가공속도, 가공능률, 부품의 척킹 및 치수 정밀도 등에 문제가 있다고 할 수 있다 이러한 문제 때문에 엔지니어링 세라믹의 고능률, 고품위 절삭에 관한 연구가 필요하다.(중략)

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A Study of New Quick Tool-Life Testing Method (II) - The Developement a New Testing Method of Step-Cutting - (새로운 急速 工具壽命 試驗法에 관한 硏究 II)

  • 오양균;정동윤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.1
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    • pp.154-159
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    • 1987
  • In the previously reported Part I, the behavior of the flank wear for carbide tool was studied as a preceeding step to present a simple method for Quick Tool-Life Testing, and the following general equation was obtained $W_{f}$ =(a+bt) $V^{m}$ . In this study the following step-cutting formula for the constants a, b and m in the above general model is derived by using step-cutting data [a numerical formula] To check the validity of the above formula, the comparison is made between the tool-life equation inferred in this method and that inferred in the conventional tool-life testing method, when the wear criterion is 0.3mm. The equation obtained in the present method is V(T')$^{0.57}$=1763 whereas the equation obtained in the conventional tool-life testing method is V(T)$^{0.56}$=1605 The results of the above two formula are satisfactory and also verify the validity of the present research.earch.

Monitoring Machining Conditions by Analyzing Cutting-Force Vibration (절삭력 진동 분석에 의한 가공조건 모니터링)

  • Piao, Chunguang;Kim, Ju Wan;Kim, Jin Oh;Shin, Yoan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.9
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    • pp.839-849
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    • 2015
  • This paper deals with an experimental technique for monitoring machining conditions by analyzing cutting-force vibration measured at a milling machine. This technique is based on the relationship of the cutting-force vibrations with the feed rate and cutting depth as reported earlier. The measurement system consists of dynamic force transducers and a signal amplifier. The analysis system includes an oscilloscope and a computer with a LabVIEW program. Experiments were carried out at various feed rates and cutting depths, while the rotating speed was kept constant. The magnitude of the cutting force vibration component corresponding to the number of cutting edges multiplied by the frequency of rotation was linearly correlated with the machining conditions. When one condition of machining is known, another condition can be identified by analyzing the cutting-force vibration.

The Milling Characteristics of Cutting Type Rice Milling Machine Depending on the Number of a Cutting Roller's Air Vent and Blowing Velocity (절삭식 정미기의 절삭롤러 통풍구 수와 송풍속도에 따른 정백특성)

  • Cho, Byeong Hyo;Kang, Sin Hyeong;Won, Jin Ho;Lee, Hee Sook;Kang, Tae Hwan;Lee, Dong Il;Han, Chung Su
    • Food Engineering Progress
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    • v.21 no.2
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    • pp.110-115
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    • 2017
  • This study aimed to identify milling characteristics depending on the number of a cutting roller's air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be $38{\pm}0.5$ in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and $14.6^{\circ}C$ which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.

Adaptive Optimization of Turning Operation Using a GAs (유전알고리듬을 이용한 선삭공정의 적응최적화)

  • 김도균;고태조;김희술
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.806-811
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    • 1994
  • 최근의 절삭가공 생산시스템은 무인자동화,고속화,정밀화로 대별되면서 생산성을 극대화시킬려는 방향으로 연구 가 진행되고 있다. 종래의 CNC화된 기계가공시스템에서는 절삭속도,이송속도 그리고 절삭깊이 등과 같은 절삭 조건은 On-line으로 조절되는 장치를 갖지 않고 Off-line으로 프로그래머의 경험이나 절삭가공의 데이터 핸드북을 통하여 결정되어진다. 이러한 절삭조건은 절삭률 즉 생산성의 측면에서 최적의 값이 될 수가 없다. 이는 프로그래머가 측면에서 최적의 값이 될 수가 없다. 이는 프로그래머가 공구의 마모나 표면거칠기, 또는 공작기계의 부하 등을 고려하여 극적으로 NC프로그램을 짜기 때문이다. 이러한 문제점 때문에 현재 개발되어지고 있는 대부분의 적응제어시스템은 실용화가 되지못하고 있는 실정이어서 효휼적인 적응시스템의 개발은 필수적이다. 따라서 본 연구에서는 무인자동화 가공시스템에서 생산성을 최대화하기 위하여 사용하는 ACO 시스템에서 발생하는 상기의 문제를 해결하여 실용화할 수 있는 가공 최적화 시스템을 개발함을 연구의 목적으로 하고 있다.

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