• Title/Summary/Keyword: on-the-machine

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An experimental study on the generative elements of feed errors in CNC cylindrical grinding machine (CNC 원통연삭기 이송오차의 발생요인에 관한 실험적 연구)

  • Ko, Hai-Ju;Jung, Yoon-Gyo
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.1
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    • pp.62-69
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    • 1993
  • The accuracy of machine tools is the major factor concerned with the acuracy of the processed work. The feed errors of feed system in machine tool, therfore, make the machining errors of work directly on processing. In this point, this study focused on the generative elements of feed errors in CNC cylindrical grinding machine, such as supporting method of ball screw, the effect of pitch and yaw error and the position detecting method in servo system when operating its shaft of grinding wheel head. Furthermore, in order to improve the driving accuracy of this machine tool, feed errors are measured by a laser interferometer. Results obtained in this study provide some useful informations to attain high accuracy of CNC machine tool.

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A Study on Measurement of Dynamic Accuracy Using Grid Encoder in NC Machine Tools (Grid Encoder를 이용한 NC공작기계 동적정밀도 측정에 관한 연구)

  • 이찬호;이방희;김성청
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.378-381
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    • 2003
  • Efficient development of method on a performance evaluation for machine tools has been regarded as the most important work for accuracy and quality enhancement to every user and manufacturer. A evaluation method of accuracy for machine tools has been studied recently according to the rapid increase of interest in precision machine tools. To this point of view, the circular interpolation test of machine tools is recognized as the most useful method to distinguish a dynamic accuracy of NC machine tools by ISO and ANSI/ASME, etc. In this paper, we have studied and developed the form measurement system with grid encoder to analyse the final accuracy of NC machine tools. we have analyzed the servo system error and geometric error of NC machine tools through measuring a dynamic error signal by this system. and then we verified the experimental result and enhanced the reliability by means of comparing the characteristics of the developed system with the kinematic ball-bar system.

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Measurement of Tool Wear using Machine Vision in Flat End-mill (머신비젼을 이용한 평 엔드밀 공구의 마모측정)

  • Kim, Tae-Young;Kim, Eung-Nam;Kim, Min-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.1
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    • pp.53-59
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    • 2011
  • End milling is available for machining the various shape of products and has been widely applied in many manufacturing industries. The quality of products depends on a machine tool performance and machining conditions. Recognition characteristics of the cutting condition is becoming a critical requirement for improving the utilization and flexibility of present-day CNC machine tools. The measurement of tool wear would be performed by coordinate-measuring machine(CMM). However, the usage of CMM requires much time and cost. In order to overcome the difficulties, on-line measurement(OLM) system was applied for a tool wear measurement. This study shows a reliable technique for the reduction of machining error components by developing a system using a CCD camera and machine vision to be able to precisely measure the size of tool wear in flat end milling for CNC machining. The CCD camera and machine vision attached to a CNC machine can determine tool wear quickly and easily.

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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Two-Phase Approach for Machine-Part Grouping Using Non-binary Production Data-Based Part-Machine Incidence Matrix (수리계획법의 활용 분야)

  • Won, You-Dong;Won, You-Kyung
    • Korean Management Science Review
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    • v.24 no.1
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    • pp.91-111
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    • 2007
  • In this paper an effective two-phase approach adopting modified p-median mathematical model is proposed for grouping machines and parts in cellular manufacturing(CM). Unlike the conventional methods allowing machines and parts to be improperly assigned to cells and families, the proposed approach seeks to find the proper block diagonal solution where all the machines and parts are properly assigned to their most associated cells and families in term of the actual machine processing and part moves. Phase 1 uses the modified p-median formulation adopting new inter-machine similarity coefficient based on the non-binary production data-based part-machine incidence matrix(PMIM) that reflects both the operation sequences and production volumes for the parts to find machine cells. Phase 2 apollos iterative reassignment procedure to minimize inter-cell part moves and maximize within-cell machine utilization by reassigning improperly assigned machines and parts to their most associated cells and families. Computational experience with the data sets available on literature shows the proposed approach yields good-quality proper block diagonal solution.

HUMAN-MACHINE INTERACTION IN NUCLEAR POWER PLANTS

  • YOSHIKAWA HIDEKAZU
    • Nuclear Engineering and Technology
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    • v.37 no.2
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    • pp.151-158
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    • 2005
  • Advanced nuclear power plants are generally large complex systems automated by computers. Whenever a rare plant emergency occurs the plant operators must cope with the emergency under severe mental stress without committing any fatal errors. Furthermore, The operators must train to improve and maintain their ability to cope with every conceivable situation, though it is almost impossible to be fully prepared for an infinite variety of situations. In view of the limited capability of operators in emergency situations, there has been a new approach to preventing the human error caused by improper human-machine interaction. The new approach has been triggered by the introduction of advanced information systems that help operators recognize and counteract plant emergencies. In this paper, the adverse effect of automation in human-machine systems is explained. The discussion then focuses on how to configure a joint human-machine system for ideal human-machine interaction. Finally, there is a new proposal on how to organize technologies that recognize the different states of such a joint human-machine system.

Comparison of Machine Learning Tools for Mobile Application

  • Lee, Yo-Seob
    • International Journal of Advanced Culture Technology
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    • v.10 no.3
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    • pp.360-370
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    • 2022
  • Demand for machine learning systems continues to grow, and cloud machine learning platforms are widely used to meet this demand. Recently, the performance improvement of the application processor of smartphones has become an opportunity for the machine learning platform to move from the cloud to On-Device AI, and mobile applications equipped with machine learning functions are required. In this paper, machine learning tools for mobile applications are investigated and compared the characteristics of these tools.

A Study on Machine Failure Improvement Using F-RPN(Failure-RPN): Focusing on the Semiconductor Etching Process (F-RPN(Failure-RPN)을 이용한 장비 고장률 개선 연구: 반도체 식각 공정을 중심으로)

  • Lee, Hyung-Geun;Hong, Yong-Min;Kang, Sung-Woo
    • Journal of the Korea Safety Management & Science
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    • v.23 no.3
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    • pp.27-33
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    • 2021
  • The purpose of this study is to present a novel indicator for analyzing machine failure based on its idle time and productivity. Existing machine repair plan was limited to machine experts from its manufacturing industries. This study evaluates the repair status of machines and extracts machines that need improvement. In this study, F-RPN was calculated using the etching process data provided by the 2018 PHM Data Challenge. Each S(S: Severity), O(O: Occurence), D(D: Detection) is divided into the idle time of the machine, the number of fault data, and the failure rate, respectively. The repair status of machine is quantified through the F-RPN calculated by multiplying S, O, and D. This study conducts a case study of machine in a semiconductor etching process. The process capability index has the disadvantage of not being able to divide the values outside the range. The performance of this index declines when the manufacturing process is under control, hereby introducing F-RPN to evaluate machine status that are difficult to distinguish by process capability index.

A Study on the Dynamic Behavior and Comparative Analysis of a Suspension Type Pulsator/Drum Type Washing Machine (현가형 펄세이터 세탁기와 드럼형 세탁기의 동특성 해석 및 비교 분석)

  • 최진영;이종민;이주상;박노철;박영필
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.1134-1139
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    • 2003
  • Vibration problems are an intrinsic characteristic in a washing machine owing to rotation working mechanism. Therefore, a right comprehension of working principle and the analysis on dynamic behavior of a washing machine is essential to design anti-vibration or vibration reduction. In this paper, we choose two kinds of a washing machine: a suspension type pulsator/drum type washing machine. Each the structure and working principle of a washing machine is discussed briefly and the dynamic behavior of it is investigated, then, the vibration detection problems of transient or excessive vibration is tented in each category. Some vibration experimented results in a washing machine are presented also.

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Improvement of Form Accuracy in Curved Dies and Molds Using Compensation of Finishing Tool (연마 공구의 압력 보정에 의한 곡면 금형의 형상 정밀도 향상)

  • 임동재;정해도;안중환;안대균
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.866-869
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    • 2000
  • The finishing process for die is an important process because it has influence on final quality of products. And it is difficult to automatize finishing process so that the process has depended on expert's skill until now. However, recently a study on development of die automatic finishing machine has been progressed, and actually this machine is applied to fabrication of die. But die automatic finishing machine has the problems such as low supply rate and high machine price. In this paper 3-axis machine was applied to the die finishing. And to improve form accuracy of die finishing path was regenerated. The finishing path considered tilting of finishing tool. and variation of machining force with contacting point between finishing and workpiece.

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