• Title/Summary/Keyword: tool position

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Determination of Parameters for 3-Dimensional Electrical Discharge Machining by a Tool Electrode Surface (공구전극곡면에 의한 3차원 방전가공조건의 결정)

  • 주상윤;이건범
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.1
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    • pp.27-33
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    • 2000
  • This paper presents a method for determining machining parameters in 3-dimentional electrical discharge machining(EDM). The parameters are the peak value of currents, the pulse-on time, and the pulse-off time. It is known that they influence the performance of EDM more than the other else. The parameters are determined from the discharge area between a tool electrode and a work piece. The discharge area is directly influenced by the geometry of a tool surface and the tool discharge position. The discharge area on a tool discharge position is calculated from intersection curves between the tool surface and a horizontal plane. The grid search method is applied to determine the intersection curves. An example is introduced to show that the machining parameters are obtained from the surface geometry of a tool electrode.

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Performance Analysis of Free-Style Writing and Drawing using Ultrasonic Position System

  • Shin, Low-Kok;Park, Soo-Hong
    • Journal of information and communication convergence engineering
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    • v.6 no.1
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    • pp.6-9
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    • 2008
  • In future domestic context aware applications the location of mobile devices is often required. Ultrasonic technology enables high resolution indoor position measurements. A disadvantage of state-of-art ultrasonic systems is that several base stations are required to estimate 3D position. This study aims to evaluate the efficiency and effectiveness of using UPS as a 3D free-hand writing or drawing tool. The processes include the design and testing of UPS as an efficient 3D free-hand writing or drawing tool in the air. The paper will further explain the system architecture of the UPS and how to use GPS as 3D free-hand writing or drawing tool. The efficiency and effectiveness of the system was confirmed by a computer software simulation. The software will further display the result of drawing or writing from the user by graphics. As a result, it is possible to implement UPS as a 3D free-hand writing or drawing tool in the air.

A Study on the Error Compensation of Machine Tool Position Using Reference Artifact and On-machine probe (기준물을 이용한 공작기계 위치오차 보정기술에 관한 연구)

  • 조남규;박재준;정성종
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.20-25
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    • 2000
  • In this paper, a methodology of geometrical error identification and compensation for NC machine tool position. We have proposed a reference artifact with which, in measuring the coordinate system of NC machine, the robust coordinate systems are given. The coordinate system of the NC machine could be compensated successfully with the information obtained by measuring the reference artifact and our compensation algorithm. Monte Carlo simulation is used to evaluate coordinate referencing ability and, the uncertainties of the machine tool position is estimated and observed through the compensation process by simulation.

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Dwell time calculation algorithm in aspherical lens polishing with discrete annular tool path (이산 환형 방식의 비구면 렌즈 연마 경로에서 체재 시간 제산 알고리듬)

  • Lee Ho Cheol;Yang Min Yang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.2
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    • pp.14-20
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    • 2005
  • This paper describes a dwell time calculation algorithm for polishing tool path generation in the small toot polishing process of the axis-symmetrical lens. Generally dwell time control in the polishing machines means that small polishing tool stays for a dwell time at the specific surface position to get the expected polishing depth. Polishing depth distribution on an aspherical lens surface consists of the superposition of the local polishing depth at the each dwell position. Therefore, tool path generation needs each dwell time together with tool positioning data during the polishing tool movements on the aspherical lens surface. The linear algebraic equation of removal depth removal matrix and dwell time is formulated. Parametric effects such as the dwell d interval are simulated to validate the dwell time calculation algorithm.

Determination of Wear Limit and the Initial Setting Position of Tool for a Machining Process (절삭공정에서 가공공구의 초기위치와 마모한계 결정)

  • 이도경
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.17 no.31
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    • pp.91-98
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    • 1994
  • Most of machines are physically or chemically degenerated by continuous usage. There- fore, a preventive maintenance is necessary. Producing defects are caused by process shift in mean and variance which are due to three types of degeneration. We develope the function of process variance from the experimental data and determine the optimal tool wear limit and the initial setting position of tool by considering the percent defective cost and the preventive maintenance cost.

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항공기 부품, 무엇이 문제인가\ulcorner

  • CHO, HYO-SANG
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.1
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    • pp.15-16
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    • 1997
  • 공작기계의 기본은 POSITION ACCURACY이다. XYZ 3축 직선운동 복합으로 거의 모든 형태를 표현할 수 있다. 3축 각각의 직선운동만 정확하면 정밀한 절삭가공이 된다는 뜻이다. 직선운동의 정확도를 기하기 위하여 볼스크류 를 쓰고 기아도 그라인딩을 한다. POSITION ACCURACY는 NC-CONTROLLER를 사용하면서 극대로 증가한다. 이것이 공작기계의 원리이다. 항공기의 조립은 공작기계가 갖고 있는 X Y Z 3축의 복합만으로는 STROKE가 짧아 표현할 수 없는 상당히 긴 STROKE이면서 공간의 위치가 요구된다. 이를 찾는 방법은 지극히 정밀한 LENS를 동원한 OPTICAL TOOL을 쓰는 것이 가장 용이하다. 항곡부품의 위치도 OPTICAL TOOL을 사용하는 것이 가장 용이하다. 물론 건축용 OPTICAL TOOL보다 항공용은 몇배 더 정밀하다.

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A Study on the Control Method for the Tool Path of Aspherical Surface Grinding and Polishing (비구면 연삭 및 연마를 위한 공구 경로 제어에 관한 연구)

  • Kim, Hyung-Tae;Yang, Hae-Jeong;Kim, Sung-Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.1 s.178
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    • pp.113-120
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    • 2006
  • This paper proposed the control algorithm fur aspheric surface grinding and was verified by the experiment. The functions of the algorithm were simultaneous control of the position and interpolation of the aspheric curve. The non-linear formula of the tool position was derived from the aspheric equations and the shape of the tool. The function was partitioned by an certain interval and the control parameters were calculated at each control section. The movement in a session was interpolated with acceleration and velocity. The position error was feed-backed by rotary encorder. The concept of feedback algorithm was correcting position error by increasing or decreasing the speed. In the experiment, two-axis machine was controlled to track the aspheric surface by the proposed algorithm. The effect of the control and process parameters was monitored. The result showed that the maximum tracking error was under sub-micro level for the concave and convex surfaces.

A Development of Docking Phase Analysis Tool for Nanosatellite

  • Jeong, Miri;Cho, Dong-Hyun;Kim, Hae-Dong
    • Journal of Astronomy and Space Sciences
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    • v.37 no.3
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    • pp.187-197
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    • 2020
  • In order to avoid the high cost and high risk of demonstration mission of rendezvous-docking technology, missions using nanosatellites have recently been increasing. However, there are few successful mission cases due to many limitations of nanosatellites like small size, power limitation, and limited performances of sensor, thruster, and controller. To improve the probability of rendezvous-docking mission success using nanosatellite, a rendezvous-docking phase analysis tool for nanosatellites is developed. The tool serves to analyze the relative position and attitude control of the chaser satellite at the docking phase. In this tool, the Model Predictive Controller (MPC) is implemented as a controller, and Extended Kalman Filter (EKF) is adopted as a filter for noise filtering. To verify the performance and effectiveness of the developed tool for nanosatellites, simulation study was conducted. Consequently, we confirmed that this tool can be used for the analysis of relative position and attitude control for nanosatellites in the rendezvous-docking phase.

A Study of Machining Error Compensation for Tool Deflection in Side-Cutting Processes using Micro End-mill (측면가공에서 마이크로 엔드밀의 공구변형에 의한 절삭가공오차 보상에 관한 연구)

  • Jeon, Du-Seong;Seo, Tae-Il;Yoon, Gil-Sang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.128-134
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    • 2008
  • This paper presents a machining error compensation methodology due to deflection of micro cutting tools in side cutting processes. Generally in order to compensate for tool deflection errors it is necessary to carry out a series of simulations, cutting force prediction, tool deflection estimation and compensation method. These can induce numerous calculations and expensive costs. This study proposes an improved approach which can compensate for machining errors without simulation processes concerning prediction of cutting force and tool deflection. Based on SEM images of test cutting specimens, polynomial relationships between machining errors and corrected tool positions were induced. Taking into account changes of cutting conditions caused by tool position variation, an iterative algorithm was applied in order to determine corrected tool position. Experimental works were carried out to validate the proposed approach. Comparing machining errors of nominal cutting with those of compensated cutting, overall machining errors could be remarkably reduced.

Sub-micron Control Algorithm for Grinding and Polishing Aspherical Surface

  • Kim, Hyung-Tae;Yang, Hae-Jeong;Kim, Sung-Chul
    • International Journal of Control, Automation, and Systems
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    • v.6 no.3
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    • pp.386-393
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    • 2008
  • A position control method for interpolating aspherical grinding and polishing tool path was reviewed and experimented in a nano precision machine. The position-base algorithm was reformed from the time-base algorithm, proposed in the previous study. The characteristics of the algorithm were in the velocity control loop with position feedback. The aspherical surface was divided by an interval at which each velocity and acceleration were calculated. The theoretical velocity was corrected by position error during processing. In the experiment, a machine was constructed and nano-scale linear encoders were installed at each axis. Relation between process parameters and the variation of position error was monitored and discussed. The best result from optimized parameters showed that the accuracy was 150nm and improved from the previous report.