• Title/Summary/Keyword: Workpiece Rotation Speed

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Effect of Surface Roughness on Cutting Conditions in CNC lathe C-Axis Milling Arc Cutting (CNC선반 C축 밀링 원호가공에서 절삭조건이 표면 거칠기에 미치는 영향)

  • Shin, Kuk-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.4
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    • pp.99-105
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    • 2014
  • The domestic airline industry undertakes the production of finished products by assembling existing self-described components via a design process which involves assembly and production steps, after which many of the finished products are exported. However, high reliability and stability must be guaranteed, because customers require high-precision components at the time of manufacturing. In the aircraft parts industry, the mass production of high-value-added parts is limited. Therefore, a small production scale depending on the part is used, as many types of conventional CNC lathe machines with X-axis and Z-axis as well as Z-axis and C-axis CNC milling are used. The parts also rely on high-pressure air to increase production. The most important factors are good stability during processing, as high-precision parts are required, as noted above. It was found that as the C-axis rotation speed increased, the diameter of the cutting tool decreased with a decrease in the surface roughness, while the workpiece rotation speed increased with an increase in the surface roughness.

A Study on the Flat Surface Zone of the Flexible Disk Grinding System (유연성 디스크 연삭가공 평면가공구간에 대한 연구)

  • Yoo, Song-Min
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.125-132
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    • 2007
  • Inherent dynamic interaction between flexible disk and workpiece creates partially non-flat surface profile. A flat zone was defined using minimum depth of engagement. Several key parameters were defined to explain the characteristics of the zone. Process conditions including disk rotation speed, initial depth of cut and feed speed were varied to produce product profile database. Correlation between key factors was examined to find the characteristic dependencies. Trends of key parameters were displayed and explained. Higher flat zone ratio was observed for lower depth of cut and higher disk rotation speed. Ratio of minimum depth of cut against target depth of cut increased for higher feed speed and disk rotation speed but was insensitive to the depth of cut variation. The process transition was visualized by continuously displaying instantaneous orientation of the deflected disk and the location of key parameters were clearly marked for comparison.

A Study on the Optimum Design of Power Vice-Strengthening Device (파워바이스 증력장치 최적설계에 관한 연구)

  • Lee, Gyung-Il;Jung, Yoon-soo;Kim, Jae-Yeol
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.6
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    • pp.69-74
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    • 2017
  • In the current machining industry, machining precision is necessary and machining is being carried out. In this ultra-precision machining industry, the fixation of the workpiece is very important and the degree of machining depends on the degree of fixation of the workpiece. In ultra-precision machining, various methods, such as using a vise chuck or the like and using bolt nut coupling, are used for fixing a workpiece to an existing machine tool. In particular, when the precision gripping force of the jig is insufficient during machining of the ultra-precision mold parts, the machining material shakes due to the vibration or friction, and the machining precision is lowered. In the ultra-precision machining of power transmission parts, such as gears, the accuracy of the product is then determined. In addition, the amount of heat generated during machining has a significant effect on the machining accuracy. This is because the vibration value changes according to the grasp force of the jig that fixes the workpiece, and the change in the calorific value due to the change in the main shaft rotation speed of the ultra-precision machining. The increase in the spindle rotation speed during machining decreased the heat generation during machining, and the machining accuracy was also good, and it was confirmed that the machining heat changed according to the fixed state of the workpiece and the machining accuracy also changed. In this study, we try to optimize the driving part of the power vise by using structural analysis, rather than the power vise, using the basic mechanical-type power unit.

Characteristics of Feed Mechanism in NC Lathe (수치제어선반의 이송특성에 관한 연구)

  • 여인완;박철우;이상조
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.7
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    • pp.104-118
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    • 1998
  • In this paper, the motion of ballscrew and shape of workpiece are the main objective variables varying with load conditions. To verify feed mechanism in NC lathe, the monitoring system is designed and cutting condition variables are spindle speed depth of cut and feed. During machining, rotation number of ballscrew motion of ballscrew in direction to gravity center and cutting force are measured. After machining, the roughness of workpiece is measured.

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Chucking Compliance Compensation by Using Linear Motor (리니어 모터를 이용한 척킹 컴플라이언스 보상)

  • Lee, Seon-Gyu;Lee, Jin-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.1
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    • pp.15-22
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    • 2002
  • This paper introduces a compensating system for machining error, which is resulted from chucking with separated jaws. In machining the chucked cylindrical workpiece, the deterioration of machining accuracy, such as out-of-roundness is inevitable due to the variation of the radial compliance of the chuck workpiece system which is caused by the position of jaws with respect to the direction of the applied force. To compensate the chucking compliance induced error, firstly roundness profile of workpiece due to chucking compliance after machining needs to be predicted. Then using this predicted profile, the compensated tool feed trajectory can be generated. And by synchronizing the cutting tool feed system with workpiece rotation, the chucking compliance induced error can be compensated. To satisfy the condition that the cutting tool feed system must provide high speed and high position accuracy, brushless linear DC motor is used. In this study, firstly through the force-deflection experiment in workpiece chucked lathe, the variation of radial compliance of chuck workpiece system is obtained. Secondly using the mathematical equation and cutting experiment result, the predicted profile of workpiece and its compensation tool trajectory are generated. Thirdly the configuration of compensation system using linear motor is introduced, and to improve the system performance, PID controller is designed. Finally the tracking performance of system is examined by experiment. Through the real cutting experiment, roundness is significantly improved.

Mirror Surface ELID Grinding of Large Scale Diametral Silicon Wafer with Straight Type Wheel (스트레이트 숫돌에 의한 대직경 Si-wafer의 ELID 경면연삭)

  • 박창수;김경년;김원일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.946-949
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    • 2001
  • Mirror surface finish of Si-wafers has been achieved by rotary in-feed machining with cup-type wheels in ELID grinding. But the diameter of the workpiece is limited with the diameter of the grinding wheel in the in-feed machining method. In this study, some grinding experiments by the rotary surface grinding machine with straight type wheels were conducted, by which the possible grinding area of the workpiece is independent of the diameter of the wheels. For the purpose of investigating the grinding characteristics of large scale diametral silicon wafer, grinding conditions such as rotation speed of grinding wheels and revolution of workpiece are varied, and grinding machine used in this experiment is rotary type surface grinding m/c equipped with an ELID unit. The surface ground using the SD8000 wheels showed that mirror like surface roughness can be attained near 2~6nm in Ra.

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Characteristic of Mirror Surface ELID Grinding of Large Scale Diametrical Silicon Wafer with Rotary Type Grinding Machine (로타리 연삭에 의한 대직경 Si-wafer의 ELID 경면 연삭특성)

  • 박창수;김원일;왕덕현
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.5
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    • pp.58-64
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    • 2002
  • Mirror surface finish of Si-wafers has been achieved by rotary in-feed machining with cup-type wheels in ELID grinding. But the diameter of the workpiece is limited with the diameter of the grinding wheel in the in-feed machining method. In this study, some finding experiments by the rotary surface grinding machine with straight type wheels were conducted, by which the possible grinding area of the workpiece is independent of the diameter of the wheels. For the purpose of investigating the grinding characteristics of large scale diametrical silicon wafer, grinding conditions such as rotation speed of grinding wheels and revolution of workpieces are varied, and grinding machine used in this experiment is rotary type surface grinding m/c equipment with an ELID unit. The surface ground using the SD8000 wheels showed that mirror like surface roughness can be attained near 2~6 nm in Ra.

A Study on Surface Magnetic Abrasive Polishing (자기연마장치를 이용한 폴리싱)

  • 류한선;고태조;김희술;이상욱
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1836-1839
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    • 2003
  • This paper describes the surface polishing characteristics of a flat and free surface ferromagnetic substance(SM45C) that magnetic abrasive polishing processed. The effects of the various working factors on the surface roughness are clarified by experiments respectively, such as magnetic flux density. rotation speed of magnetic head. working gap, feed rate of workpiece. diameter of magnetic abrasives. and shape of workpiece. On the basis of these experiments, the polishing mechanism is discussed and the characteristics of the polishing process are described. In addition, it is found experimentally that die & mold surfaces are also polished precisely by this process

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A Study on the Characteristics of Zerodur Grinding using Ultra-Precision Machine (초정밀가공기를 이용한 Zerodur의 연삭 특성에 관한 연구)

  • 김주환;김건희;한정열;김석환;원종호
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.405-409
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    • 2003
  • We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed depth of cut and feed rate were altered while grinding the workpiece surfaces of 20m in diameter. Surface roughness is measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness better than 0.02${\mu}{\textrm}{m}$ Ra and the form accuracy of around 0.2${\mu}{\textrm}{m}$ PV.

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A Study on the Characteristics on Ultra-Precision Grinding of a Zerodur (Zerodur의 초정밀 연삭 특성에 관한 연구)

  • Kim, Geon-Hee;Park, Yo-Chang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.4 no.1
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    • pp.13-17
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    • 2005
  • We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and a range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed, depth of cut and feed rate were altered while grinding the workpiece surfaces of 20mm in diameter. Surface roughness was measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness smaller than $0.2{\mu}m$ Ra.

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