• Title/Summary/Keyword: High Speed Precision Machining

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A Fundamental Study on the Internal Grinding of Tungste Carbide Materials for Metal Mould to Improve the Machining Performance (금형용 초경합금재의 내면연삭 가공능률향상에 관한 기초적 연구)

  • 허성중;이규천;김영일;김원일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.39-43
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    • 1996
  • This paper described on the effect of residual stocks in internal grinding of tungsten carbide materials in order to improve the grinding efficiency as well as grinding accuracy. Though the fundamental investigation is carried out for tungsten carbide materials using electroplated diamond wheel, the residual stock after grinding process is effective to the grinding effciiency. The obtained results are as follows: (1) Under the depth of cut(t) is constant and decreasing the workpiece velocity(Vw), the resiudal stock after grinding is increased, but the difference is little less than the difference by table speed. (2) Increasing the wheel velocity, the residual stock after grinding is decreased. Therefore in order to minimize the residual stock, the wheel velocity should be increased as far as possible. (3) The surface foughness and out-of roundness increased with depth of cut and table speed, and decreased with wheel velocity, but it may as well adopt as much as polssible under the dimensional tolerance which is required for high efficiency grinding. (4) In order to remove residual stock, the spark-out grinding shoule be done, and it also can be improved about 20 .approx. 25% throughout spark-out grinding, and the number of optimal spark-out times were within 10 times.

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Design of A Small Thin Milling Cutter Considering Built-up Edge (구성인선을 고려한 소형 박판 밀링공구의 설계)

  • Jung, Kyoung-Deuk;Ko, Tae-Jo;Kim, Hee-Sool
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.5
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    • pp.130-136
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    • 2001
  • Generally, a metal slitting saw is plain milling cutter with thickness less than 3/16 inch. This is used for cutting a workpiece that high dimensional accuracy and surface finish is necessary. A small thin milling cutter like a metal slitting saw is useful for machining a narrow groove. In this case, built up edge(BUE) is severe at each tooth and affects the surface integrity of the machined surface and tool wear. It is well known that tool geometry and cutting conditions are decisive factors to remove BUE. In this paper, we optimized the geometry of the milling cutter and selected cutting conditions to remove BUE by the experimental investigation. The experiment was planned with Taguchi method based on the orthogonal array of design factors such as coating, rake angle, number of tooth, cutting speed, feed rate. Response table was obtained from the number of built-up edge generated at tooth. The optimized tool geometry and cutting conditions could be determined through response table. In addition, the relative effect of factors was identified bh the analysis of variance (ANOVA). Finally, coating and cutting speed turned out important factors for BUE.

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Design and Performance Test of High-speed Swivel Tool Head (고속 회전형 공구헤드의 설계 및 성능시험)

  • Kim, In-Hwan;Koo, Ja-Ham;Hur, Nam-Soo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.5
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    • pp.57-63
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    • 2014
  • At present, a high-speed swivel tool head of a small size is required to improve the productivity of CNC automatic lathes. Hence, there is growing interest in shorter machining times with higher cutting speeds. However, an increase in the rotation speed of a swivel tool head also has adverse effects, such as vibration and noise caused by the swivel tool head system. In this work, the fatigue life and contact pressure of a swivel tool head bearing system driven by gears were calculated. Based on the calculated results, a prototype swivel tool head was manufactured and its static and dynamic characteristics, i.e., the vibration, noise and precision, were measured using a reliability testing device which allows the application of cutting force to the end of the swivel tool head.

축방향 하중을 받는 앵귤러 콘택트 볼베오링의 수명특성에 관한 실험적 연구

  • Hwang, Pyung;Kwon, Sung-In
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1996.05a
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    • pp.53-59
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    • 1996
  • The new trends in main spindle design of Machining Center are focused on high-speed, high-precision and high-stiffness. As a main spindle bearing, the angular-contact ball bearing is well used. A rolling bearing is usually only a small part of a larger mechanical system, but its performance can have a great influence on the functioning of the whole machine. This work is about fatigue life tester design and monitoring of defected rolling-element bearings. The major work is done via experiments and the vibration signal is analysised by means of frequency spectrum technique. By analyzing the frequency spectrum, it is possible to view the condition of the bearings.

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The Effect of Surface Roughness on Cutting Tool Shape in CNC Lathe C-Axis Turn-mill Machining (CNC선반 C축 Turn-mill 가공에 있어서 절삭공구형상이 표면 거칠기에 미치는 영향)

  • Lee, Soon-kwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.4
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    • pp.62-68
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    • 2017
  • Since the aircraft parts industry is a high-value-added industry, mass production order production, and the hundreds of thousands. Therefore, parts produced However, since these parts require high reliability and stability, a high degree of precision is required. In Korea, there on the roughness of the machined surface in cutting process. However, research on the surface roughness characteristic obtained by which is widely used for aircraft parts is still insufficient in Korea. The purpose of this study is to investigate the effect of turning tool rotation speed and X axis feed rate on the surface roughness of cutting tools in CNC lathes during cutting of aluminum alloy 7075.

Development of a precision machining process for the outer cylinder of vacuum roll for film transfer (필름 이송을 위한 진공 롤 외통의 정밀가공 공정개발)

  • Eui-Jung Kim;Ho-Sang Lee
    • Design & Manufacturing
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    • v.18 no.2
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    • pp.1-8
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    • 2024
  • Unlike the roll-to-roll process that uses a steel roll and a nip roll, a vacuum roll can hold and transfer a thin film using a single roll. To precisely manufacture a vacuum roll, a thin outer cylinder must be machined, which is assembled on the outside of the roll and contacts the film via vacuum pressure. In this study, the effects of jaw width and chucking force on the deformation of the outer cylinder during the turning process were investigated using analysis, and a precision machining and burr removal process was developed. The deformation of the outer cylinder decreased almost linearly with increasing jaw width and increased with higher chucking force and larger cylinder diameter. Additionally, the deflection due to the weight of the outer cylinder was approximately three times greater than that caused by film tension. For the machined outer cylinder, a burr removal experiment was conducted, and concentricity and cylindricity were measured. Using a device that removes burrs by rotating a wheel connected to the main shaft at high speed, it was found that burrs generated on the inner diameter could be removed very efficiently. On the vacuum side, the concentricity errors of the inner and outer diameters were 0.015 mm and 0.014 mm, respectively, and on the opposite side, they were 0.006 mm and 0.010 mm, respectively. Additionally, the measurement of Total Indicator Runout (TIR) according to the angle showed that the maximum cylindricity of the outer and inner diameters was 0.02 mm and 0.025 mm, respectively. Finally, through burr-height measurement at the hole boundary, it was found that the heights were within 0.05 mm.

An Experimental Study on the Lapping of Titanium Alloy (티타늄합금의 래핑가공에 관한 실험적 연구)

  • Park, Ji-Ho;Kim, Won-Il
    • Journal of the Korean Society of Industry Convergence
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    • v.8 no.1
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    • pp.25-29
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    • 2005
  • Titanium specially has high specific strength, excellent mechanical properties as fatigue strength and fracture ductility, good corrosion resistance, and therefore are broadly applied to the various fields. It is required the developmennt for the skills of wire-cut electrical discharge machining(WEDM), but the WEDMed surface was found to be worst due to the attached components of wire. Therefore precision maching method like lapping is necessary for getting high quilty surface. Roughness of lapped surface, surface hardness to each process depth and improved method of surface shape were stuided experimentally, by changing of grain size of diamond lap material and lapping pressure with constant speed in lapping process.

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Analysis of 2 step gear reducer in machine tool spindle (공작기계 주축용 2단 치차 감속기 해석)

  • 장영도;장희락;여진욱
    • Proceedings of the KAIS Fall Conference
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    • 2001.11a
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    • pp.99-103
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    • 2001
  • Though the research and the development in the field of machine tool was focused on high precision and high speed machine these days, traditional gear reduction device has been used to increase the cutting force which was transmitted from power source, motor In this study, analysis of 2 step gear reducer used in machining center spindle was carried out by using APM WinMachine which is commercial software for the analysis of machine element and system. For the analysis of this device, first of all, the analysis of power source and the transmitting of it were carried out. Then, machine elements like gear, shaft, bearing, and the forth, was analyzed in the view point of life time, static strength, stiffness, fatigue failure, etc. Consequently, we can estimate them and introduce new idea of the design modification of reduction device by this study.

Effect of Unbalance on Vibration and Machining of Al6061 Aluminum Alloy in Precision Rotator (정밀회전체의 언밸런스 변화에 따른 진동과 Al6061 알루미늄 합금 가공에 미치는 영향)

  • Kim, Min Soo;Kim, Jung Tae;Park, Seok Woo;Jeong, Dong Uk;Choi, Sun Ho;Koo, Bon Heun;Yoon, Sang Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.3
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    • pp.76-82
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    • 2021
  • At present, with the development of precision instruments, high dimensional accuracy of workpieces must be ensured. In particular, for the aluminum alloys used in automobiles, the surface roughness of the workpiece is extremely important. The dimensional accuracy and surface roughness of the workpiece is considerably affected by the rotational accuracy of the rotor. Therefore, to enhance the rotational accuracy, various variables such as those related to the components such as bearings, motors, and end mills, rotational speeds, and vibrations must be considered. In this study, the difference in the quality of the workpieces was compared considering the weight imbalance and rotational speed as variables.

Modeling of Cutting Parameters and Optimal Process Design in Micro End-milling Processes (마이크로 엔드밀링 공정의 절삭계수 모델링 및 최적 공정설계)

  • Lee, Kwang-Jo;Chung, Sung-Chong
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.3
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    • pp.261-269
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    • 2009
  • Micro end-milling process is applied to fabricate precision mechanical parts cost-effectively. It is a complex and time-consuming job to select optimal process conditions with high productivity and quality. To improve the productivity and quality of precision mechanical parts, micro end-mill wear and cutting force characteristics should be studied carefully. In this paper, high speed machining experiments are studied to construct the optimum process design as well as the mathematical modeling of tool wear and cutting force related to cutting parameters in micro ball end-milling processes. Cutting force and wear characteristics under various cutting conditions are investigated through the condition monitoring system and the design of experiment. In order to construct the cutting database, mathematical models for the flank wear and cutting force gradient are derived from the response surface method. Optimal milling conditions are extracted from the developed experimental models.

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