• Title/Summary/Keyword: Tailstock

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Machine tool identification under actual cutting process by DDS analysis (DDC방식에 의한 공작기계 절삭 특성 규명)

  • ;;Lee, Chong Won
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.5 no.4
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    • pp.303-311
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    • 1981
  • Machine tool dynamics is investigated under actual working conditions. Experimental evaluation of cutting dynamics in a lathe is made with cutting conditions and cutting positions varied. The thrust force and the toolpost and tailstock accelerations during turning process are modelled and analyzed by employing Dynamic Data System methodology. It is found that two acceleration signals are good enough to replace the thrust force, when used for machine tool identification under cutting process and for chatter detection.

A study on the chucking alignment error analysis in coaxial grinding of ferrule (페룰 동축연삭시 척킹 오차 해석)

  • 김동길;김영태;이상조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.9-14
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    • 2002
  • Ferrule is widely used as fiber optic connecters. In fiber-optic communications, the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin, pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule center is investigated in the case where cone-shaped center pins and round circle hales which make contact with each other near the edge of the holes, using homeogenous coordinate transformation and numerical analysis. The obtained results are as follows: The alignment errors between center pins alone do not affect the rotation accuracy of ferrule. The alignment errors between center holes cause a sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers increase in proportion to the center pin angle in the case of a fixed alignment errors

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Prediction of Form Accuracy during Traverse Grinding of Slender Workpiece Using the Cylindrical Prunge Grinding Data (원통연삭 실험자료를 이용한 트래버스 연삭공정중의 형상예측)

  • 박철우;이상조
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.3
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    • pp.174-183
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    • 2000
  • Non-Parallelism the axial direction occurs during grinding process of long slender shafts. The reason for the axial error is due to elastic deformation of the components, accumulation phenomenon of the grinding and wheel wear during the grinding process. The accumulation phenomenon, the size generation mechanism and the wheel wear process during traverse grinding result in complicated process at each step on the wheel surface. The grinding system stiffness obtained from the stiffness of the center on the tailstock and the workpiece varing according to the relative position of the wheel and the workpiece. Further more, the value of wheel wear increases as the grinding process advances. The above mentioned issues make the shape generation process during traverse grinding quite complicated. This research analyzes the shape generation process in the direction of the work spindle. First, the formulation of the grinding system stiffness was conducted and the simulation analysis method of the traverse grinding was established. Also, a measuring system for assessing the dimensinal accuracy of the workpiece has been developed.

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A study on the chucking system in coaxial grinding of ferrule (페룰 동축 연삭시 척킹 시스템에 관한 연구)

  • Kim, Dong-Kil;Lee, Sang-Jo;Ahn, Geon-Jun;Kwak, Chol-Hun
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.987-991
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    • 2003
  • Ferrule is widely used as fiber optic connecters. In fiber-optic communications, the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin, pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule center is investigated in the case where cone-shaped center pins and round circle holes which make contact with each other near the edge of the holes, using homeogenous coordinate transformation and numerical analysis. The obtained results are as follows: The alignment errors between center holes cause a sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers increase in proportion to the center pin angle. The relationship between center pins displacement in coaxial grinding and grinding accuracy was explained.

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Effects of Cutting Conditions on Surface Roughness in Turning (선삭시 절삭조건이 표면거칠기에 미치는 영향 분석)

  • Lee, Sin-Yeong;Kim, Hong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.8
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    • pp.139-149
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    • 2001
  • The effects of the cutting conditions on the surface roughness of workpiece in turning were studied in this paper. The workpieces made of carbon steel SM20C and SM45C were tamed without the support of the tailstock center. Cutting conditions were changed in three or flour steps in each parameter and cutting fluid was used. The surface roughness results of tests were measured and the effects of the cutting conditions were analyzed by the method of analysis of variance. The summary of the experimental research is as follows. The main parameters were cutting speed, fred-rate, depth of cut, and the interactions between speed and fled-rate, speed and depth of cut, and fred and depth of cut. As cutting speed increased, surface roughness showed lower value. The surface roughnesses of feed-rate 0.102 mm/rev and 0.147 mm/rev were better than those of feed-rate 0.05 mm/rev and 0.2 mm/rev.

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A Study on the Chucking of Ferrule using Cone-type Centers and Ball-type Centers in Co-Axial Grinding - Chucking Error Analysis (원추형 센터와 볼형 센터를 이용한 페룰 동축 연삭시 척킹에 관한 연구-척킹 오차 해석)

  • 김동길;박성준;김영태;이상조
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.40-49
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    • 2003
  • Ferrule is widely used as fiber optic connecters. In fiber-optic communications. the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin. pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule centers are investigated in the case where the ferrule is chucked with the cone-shaped center pins and bail centers, With homogeneous coordinate transformation and numerical analysis, the obtained results are as follows: In the case of cone-type center, the alignment errors between center pins alone do not affect the rotation accuracy of ferrule. The alignment errors between center holes cause sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers is proportional to the center pin angle. In the case of ball-type center, the displacements of ferrule centers has similar pattern as cone-type center, and the alignment errors art proportional to ball diameters.

Practical Turret Stiffness Calculation Model to Modify Lathe Structure (선반 구조변경을 위한 현장용 공구대 강성계산모델)

  • Heo, Seong-Hyeok;Kim, Su-Jin
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.5
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    • pp.19-24
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    • 2017
  • In this research, a practical stiffness calculation method is developed and applied for modifying the height of the headstock, turret, and tailstock of a CNC lathe to enlarge the turntable diameter. The casting structure is assumed to be a rigid body and the linear motion element to be an elastic spring to simplify the turret stiffness calculation model. The stiffness of the sliding guide and ball screw of the original lathe is measured with a push tester and LVDT sensor, and the turret stiffness of the modified lathe is predicted and compared with experimental results to verify the model. The measured stiffness of the original turret is $0.17kN/{\mu}m$ and that of the modified turret is $0.11kN/{\mu}m$, i.e., an 18% difference from the predicted result. The verified stiffness calculation model can be used to develop another modified lathe.

A Study on Performance Improvement of Whirling Machines (Whirling machine의 성능 개선을 위한 연구)

  • Lee Jung-Ki;Yang Woo-suk;Son Jea-seok;Han Hui-duck;Kim Han-soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.10 s.241
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    • pp.1416-1429
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    • 2005
  • In order to meet the increasing competitive pressures coupled with higher demands for component quality, whirling machines have been at the cutting edge of the automobile industry for more than 25 years. The hard whirling process can save on machining time and operation elimination. Hard whirling is done dry, without coolant. The chips carry away nearly all of the heat during cutting, leaving the workpiece cool and minimizing any thermal geometry variations. The surface finish and profile accuracy are close to grinding quality. Whirling machines usually consist of four major parts; 1) loading system that requires the necessary axial speeds, 2) head stock that needs high precision clamping and positioning system at the chuck and tailstock, 3) whirling unit that demands the high cutting speeds and cutting power fer cutting deep thread profiles and 4) unloading system that requires an easy workpiece unloading. Also, capabilities of the whirling machine can be improved by attaching a vision system to the machine. Most of whirling machines in Korean automobile industry are imported from the Leistritz company, Germany and the Hasegawa company, Japan. Tn this paper, a basic research will be performed to improve and enhance the existing whirling machines. Finally, a new Korean whirling machine will be proposed and developed.