• Title/Summary/Keyword: 런 아웃

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AN ADVANCED DISTURBANCE REJECTION CONTROL FOR REPEATABLE RUNOUT IN DISK DRIVE SYSTEMS (컴퓨터 하드디스크의 반복 런아웃에서 비롯된 외란의 효율적 제어)

  • 용부중
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.1
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    • pp.60-67
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    • 2000
  • An improved disturbance rejection control scheme is presented for minimizing the position error due to the repeatable runout disturbances in high density disk drive systems The proposed control algorithm is capable of attenuating repeatable disturbances which is one of the major detractors to hard disk drive quality and performance. This is achieved by a sys-tematic combination of an optimal feedback component and a feedforward preview component. The feedback component is designed where the emphasis is placed on robustness. The feedforward component is on the basis of a preview control comprised of a measured disturbance signals which leads to better disturbance rejection capabilites. The designed con-troller is applied as a plug-in module to a high density hard disk drive with a pre-existing conventional servo controller. Simulations have been carried out to demonstrate the effectiveness of this control scheme in the reduction of the periodic disturbances.

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High Speed Machining Considering Efficient Manual Finishing Part II: Optimal Manual Finishing Process and Machining Condition (고속 가공을 이용한 금형의 효율적 생산 제 2 부: 사상 공정 및 가공 조건의 선정)

  • Kim, Min-Tae;Je, Sung-Uk;Lee, Hae-Sung;Chu, Chong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.12 s.189
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    • pp.38-45
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    • 2006
  • In this work, optimal finish machining condition considering total time for mold or electrode manufacturing was investigated. First, manual finishing time according to the machining condition was analyzed for the work material. The effect of runout and phase shift of tool path on surface finish was also considered in those analyses. Secondly, optimal manual finishing processes were determined for various machining conditions. Finally, finish machining time and corresponding manual finishing time were taken into account for the estimation of the total time of manufacturing mold. Though small feed per tooth and pick feed reduced the manual finishing time, the finish machining time increased in such conditions. With a machining condition of feed per tooth of 0.2 mm and pick feed of 0.3 mm, the minimum total time of manufacturing mold was achieved in our machining condition.

Vibration Analysis of 1'HDD (1'HDD의 진동특성 분석에 관한 연구)

  • Han, Woo-Sup;Hong, Min-Pyo;Byun, Yong-Kyu;Koh, Jeong-Seok;Jeong, Seong-Weon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.352-357
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    • 2002
  • In recent years, the demand of mobile device, such as digital camera, camcoder and PDA, increases remarkably. So, requirements of the mobile information data storage used in the mobile devices increase noticeably also. 1' micro data storage is a kind of mobile storage ,which has a CF type II form factor, and the similar structure of the general 3.5' HDD. In this paper, we performed the vibration analysis of the 1' micro data storage, such as measurement of the NRRO of the disck, and modal analysis.

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NRRO analysis of HDD spindle ball bearings using the measured geometric imperfection (실측형상오차를 이용한 HDD 스핀들용 볼베어링의 NRRO 해석)

  • Kim, Young-Cheol;Choi, Sang-Kyu;Yoon, Ki-Chan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.369-374
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    • 2002
  • This paper presents theoretical analysis of the NRRO(non-repeatable run-out) for a ball bearing with geometric imperfection. The 3DOF dynamic analysis of a ball bearing using the Newton-Raphson method is performed to calculate the displacement of shaft center. Frequency and magnitude characteristics of radial and axial vibrations are investigated. The ball form errors of the ball, the inner race, and the outer race in a HDD spindle ball bearing are precisely measured. NRRO of a ball bearing is analyzed by using the measured waviness data. It is concluded that dominant components of radial vibrations are ${\Large}f_c\;and\;2{\Larg}f_b{\pm}{\Large}f_c$, and dominant component of axial vibrations is $2{\Large}f_b$. These are generated by the size error and the second waviness of the balls.

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Tool Fracture Detection in Milling Process (I) -Part 1 : Development of Tool Fracture Index- (밀링 공정시 공구 파손 검출 (I) -제1편 : 공구 파손 지수의 도출-)

  • 김기대;오영탁;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.5
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    • pp.100-109
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    • 1998
  • In order to increase productivity through unmanned machining in CNC milling process, in-process tool fracture detection is required. In this paper, a new algorithm for tool fracture detection using cutting load variations was developed. For this purpose, developed were tool condition vector which is dimensionless indicator of cutting load and tool fracture index (TFI) which represents magnitude of tool fracture. Through cutting force simulation, tool fracture index was shown to be independent of tool run-outs and cutting condition variations. Using tool fracture index, the ratio of the tool fracture to feed per tooth could be indentified.

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Signal Characteristics of Measuring System for Condition Monitoring in High Speed Machining (고속가공에서 상태 감시를 위한 계측시스템의 신호특성)

  • Kim, Jeong-Suk;Kang, Myung-Chang;Kim, Jeon-Ha;Jung, Youn-Shick;Lee, Jong-Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.3
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    • pp.13-19
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    • 2003
  • The high speed machining technology has been improved remarkably in die/mold industry with the growth of parts and materials industries. Though the spindle speed of machine tool increases, the condition monitoring techniques of the machine tool, tool and workpiece in high speed machining ate incomplete. In tins study, efficient sensing technology in high speed machining is suggested by observing the characteristics of cutting force, gap sensor and accelerometer signal also, machinability of high-speed machining is experimentally evaluated sensing technique to monitor the machine tool and machining conditions was performed.

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Effects of cutter runout on end milling forces I -Up and milling- (엔드밀링 절삭력에 미치는 공구형상오차 I -상향 엔드밀링-)

  • 이영문;최원식;송태성;권오진;백승기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.985-988
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    • 1997
  • In end milling process, the undeformed chip section area and cutting forces vary periodically with phase change of the tool. However the real undeformed chip section area deviates from the geometrically ideal one owing to cutter runout and tool shape error. In this study ,a method of estimating the real undeformed chip section area which reflects cutter runout and tool shape error was presented in up end milling process using measured cutting forces. Size effect was identified from the analysis of specific cutting resistance obtained by using the modified undeformed chip section area.

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A Study on the Charactistics of Machined Surface due to Cutter Runout (커터 런 아웃과 가공표면 생성에 관한 연구)

  • Hwang, J.;Lee, K. Y.;Shin, S. C.;Chung, E. S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.873-877
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    • 1997
  • This paper presents experimental results to know the charcteristics of machined surface due to cutter runout. Cutter runout is a common but undesirable phenomenon in multi-tooth machining such as end-milling process because it introduces variable chip loading to insert which results in a accelerated tool wear, amplification of force variation and hence enargement vibration amplitude. To develop in-proess cutter runout compensation system, set-up the micro-positoning mechanism which is based on piezoelectric translator embeded in the work holder to manipulate the depth of cut in real-time. And feasibility test of system was done under the various experimental cutting conditions. This results provide lots of information to build-up the precision machining technology.

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An Experimental Study on the Runout Characteristics of Spindle State Monitoring Using an Optical Fiber Displacement Sensor (광 파이버 변위 센서를 이용한 주축 모니터링 시 나타나는 런아웃 특성에 대한 실험적 고찰)

  • 신우철;박찬규;정택구;홍준희;이동주
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.472-477
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    • 2003
  • Spindle state monitoring is getting more and more important according to the technology trend of spindle that is accurate and automated. Spindle state monitoring is to measure the state of rotation vibrations. The spindle rotation error motion detected by sensing device includes rotation object's unbalance, external forced vibrations, shape error of spindle, as well as measuring error of monitoring device. In this paper, we have inspected the runout characteristics. Also, we introduce the way to exclude the runout element that appear while you monitor a spindle state.

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Development of Automatic Cam Profile Measurement System (자동 측정이 가능한 전용 캠 프로파일 측정 시스템 개발)

  • Jeong, Hwang-Young;Lee, Hyun-Seok;Park, Tae-Min;Shin, Woo-Cheol;Koh, Jun-Bin;Hong, Jun-Hee
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.1
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    • pp.106-112
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    • 2008
  • In this paper, It does the profile measurement of the cam of diesel engine SOHC of the actual object. It uses the measurement of run-out method. This method is that the surface of the object is measured by the sensor when the object rotate, and calculated and displayed by the computer the signal which acquired by sensor. When we acquire the signals, we have two error because of motion and contacting between cam and probe. In this paper, we compensate the motion error while simply liner equation. And we have a solution that we change the figure of probe when we have a contacting error. We compared the data measuring on developed automatic cam profile measuring system with the data measured on CMM.