• Title/Summary/Keyword: Shape of Machined Surface

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Prediction and analysis of the machined surface accuracy in end milling (엔드 밀링의 가공 표면 정밀도 예측과 해석)

  • 고정훈;윤원수;조동우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.1018-1022
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    • 2000
  • Enhancement of the accuracy of products and productivity are essential to survive in a global industrial competition. This trend requires tighter dimensional tolerance specifications. To actively cope with the rapid change of the workpiece material and cutter geometry, a general method that can predict and analyze the machined surface is needed. Surface generation model for the prediction of the topography of machined surfaces is developed based on cutting force model considering cutter deflection and runout. This paper presents the method that constructs the three-dimensional machined surface error following the movement of a cutter, irrespective of the variations of cutting conditions. In addition, the effects of the cutting forces and the kink shape on the machined surface are extensively investigated.

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A Closer Look at the Effect of Particle Shape on Machined Surface at Abrasive Machining (입자연마가공에서의 입자 형상의 영향에 대한 고찰)

  • Kim, Dong-Geun;Sung, In-Ha
    • Tribology and Lubricants
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    • v.26 no.4
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    • pp.219-223
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    • 2010
  • Despite the increasing need of nanometer-scale accuracy in abrasive machining using ultrasmall particles such as abrasive jet and chemical mechanical polishing(CMP), the process mechanism is still unknown. Based on the background, research on the effects of various process parameters on the machined surface at abrasive machining was motivated and performed by using finite element analysis where the effect of slurry fluid flow involved. The effect of particle shape on the machined surface during particle-surface collision was discussed in this paper. The results from FEA simulation revealed that any damage or defect generation on machined surface by the impact may occur only if the particle has enough impact energy. Therefore, it could be concluded that generation of the defects and damage on the wafer surface after CMP process was mainly due to direct contact of the 3 bodies, i.e., pad-particle-wafer.

A Study on the Precision of a Machined Surface in Thrust Internal Grinding (스러스트 내면 연삭가공의 가공면 정도에 관한 연구)

  • Choi, Hwan;Seo, Chang-Yeon;Seo, Young-Il;Lee, Choong-Seok
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.5
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    • pp.73-79
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    • 2016
  • In this paper, the grinding characteristics in thrust internal grinding have been studied using vitreous CBN wheels with a machining center. Grinding experiments have been performed according to grinding conditions such as wheel feed speed, cut depth, workpiece speed, rate of grinding width and number of grinding passes. The machining error, shape of machined surfaces, grinding force, and surface roughness have been investigated though these experiments. Based on the experimental results, the grinding characteristics on the machined surface in the internal thrust grinding are discussed.

A Study on the Mechanical States of Machined Surface by Considering Cutting Edge (절삭날을 고려한 절삭가공면의 기계적 성질에 관한 연구)

  • Kim, Joo-Hyun;Woo, Hee-Sun;Chang, Yoon-Sang
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.7
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    • pp.188-195
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    • 1999
  • Cutting edge plays an important role in generating machined surface. In order to consider the geometric effects of the cutting edge on mechanical states, the concept of ploughing force and stagnation point was introduced which explains the generating mechanism of machined surface during cutting. The effects of edge radius and nose radius of cutting tool on the distribution of residual stresses of the machined surface having several hardness were studied. Good machined surface having high compressive residual surface stresses can be achieved if cutting tools having large edge radius and small nose radius are used for cutting work materials having high hardness with high depth of cut. The magnitude of edge radius and the hardness of work material also affected the shape of the chip in orthogonal cutting.

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Multi-signal characteristics for condition monitoring of micro machined surface (미세가공면의 상태 감시를 위한 다중신호특성에 관한 연구)

  • Jang, Su-Hoon;Park, Jin-Hyo;Kang, Ik-Soo;Kim, Jeong-Suk
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.1
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    • pp.31-36
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    • 2009
  • Micro-machining technology has been adopted for shape accuracy of micrometer and sub-micrometer scale, surface roughness of tens nanometer in industries. In micro-machining process the quality of machined surface is derived from machining condition and tooling. This paper investigates AE(acoustic emission) and cutting force signals according to machined surface quality related to machining condition. Machined surface quality was analyzed by the AE and cutting force parameter which reflect surface morphology. The characteristics of signal were extracted for process optimization by monitoring both the tool condition and the machined surface texture in micro end milling process.

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A Study on the Forging Prototype Manufacture of Aluminium 7050 Alloys (Al7050합금의 단조 시제품 제작에 관한 연구)

  • Kang, Seong-Ki;Lee, Jea-Kun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.4
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    • pp.39-45
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    • 2012
  • In this paper, process conditions are investigated for elimination of the grain coarsening and improved material flow during forging process by both of experiments and FEM analysis. Particular interest has been given to understand role of preform shape on the grain coarsening behavior and magnitude of the hammer forging load. As the results of FEM simulation by using DEFORM-3D, the simulated forging loads were 2,200ton in the case of a machined bar which is machined from 65mm to 60mm diameter, and below 1,900ton in the case of machined preform, respectively. The use of preform has been beneficial for reduction of the forging load and elimination of the grain coarsening. However, in the case of as received bar and the round bar, which was machined to 2.5mm thickness in surface layer, some degree of local grain coarsening behavior has been observed. The optimized preform shape could be properly designed by applying the FEM simulation.

A study on the machinability of Carbon Fiber Reinforced Plastics on tool shape (공구형상에 따른 CFRP(Carbon Fiber Reinforced Plastics) 복합재료의 절삭 특성에 관한 연구)

  • Shin, Bong-Cheul;Kim, Kyu-Bok;Ha, Seok-Jae;Cho, Myeong-W
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.799-804
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    • 2011
  • CFRP(Carbon Fiber Reinforced Plastics) has been used many industries aerospace, automobile, medical device and building material industries, etc. Because it is lighter than other metals and has good properties, such as rigidity, strength and wear. CFRP may be cured integrity. However, it needs postprocessing similar to drilling or endmilling for shape cutting and combination of various material. In this paper, tool dynamometer and accelerometer used to signal analysis for machining properties under various cutting conditions and tool shape changes. In addition, microscope used to verify the machined CFRP surface. As the results, it was found that the cutting force and the vibration were decreased in the increasing of cutting edge (2-flute < 4-flute < composite tool), and the good machined surface can be obtained in this experiments.

A Study on the Virtual Machining CAM System : Prediction and Experimental Verification of Machined Surface (실 가공형 CAM 시스템 연구: 가공형상의 예측 및 실험 검증)

  • 김형우;서석환;신창호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.961-964
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    • 1995
  • For geometric accuracy in the net shape machining, the problem of tool deflection should be resolved in some fashion. In particular, this is crucial in finish cut operation where slim tools are used. The purpose of this paper is to verify the validity and effectiveness of the prediction model of the machined surface. Experimental results are presented for the cut of steel material with HSS endmill of diameter 6mm on machining center. The results shows that 1) the machining error due totool deflection is serious even in the low cutting load, 2) by using the mechanistic simulation model with experimental coefficients, the machining error was predicted with maximum prediction error of 10% which was significantly reduced to the desired level by the path modification method.

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Shape Design and Machinability Evaluation of Flat End mill for High Speed Machining of GC250 Material (회주철(GC250)의 고속가공을 위한 엔드밀공구의 형상 설계 및 가공성 평가)

  • 이상용;김전하;강명창;김정석;강호연
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.292-296
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    • 2002
  • In the present investigation, the improvement of processing efficiency in the high speed machining of GC250 is explored. This study is to evaluate the tool performance in difficult-to-material using the new developed tool. Tool performance evaluation are conducted by tool wear, surface roughness, chattering in machined surface. The tool wear of A type was smaller than B type. In type B tool the chatter mark was observed in machined surface. The good surface roughness was obtained in type A tool. Consequently, the tool performance of A type is better than B type.

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An Experimental Study for Machined Patterns of Friction Surface on Disc Brake Rotor in Performance Aspect (디스크 브레이크 로터 마찰면 가공 형태에 따른 성능 변화 연구)

  • Jung, Taeksu;Cha, Bawoo;Hong, Yunhwa;Kim, Cheongmin;Hong, Younghoon;Cho, Chongdu
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.4
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    • pp.471-479
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    • 2016
  • Cross-drilling and slotting on the frictional surface of a brake rotor are methods used for improving the performance of the brake system. These shapes have particular advantages, such as the shaving effect of a slotted shape, which maintains a clean pad-to-rotor contact surface, and the venting effect of a drilled shape, which provides passageways for the gas to escape. In order to understand the effect of the machined pattern on the brake performance aspect, an experimental method is adopted along with the dynamometer test. The cross-drilled rotor, slotted rotor, and mixed pattern rotor with cross-drilling and slotting machining are prepared and tested in terms of friction coefficient, temperature, braking torque, and noise.