• Title/Summary/Keyword: Machined

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A Study on Plastic Strain Distribution of Machined Surface (기계가공면의 소성스트레인 분포에 관한 연구)

  • ;飯野 豊
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.111-117
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    • 2000
  • The plastically deformed layer in a machined surface must be considered in precision machining process. Therefore the analysis of the machined surface, including the plastic deformation and strain distribution should be carried out quantitatively. The subsequent recrystallization technique was presented for analysis of the plastically deformed layer in the machined surface, and the technique was successfully applied to determine the plastic strain in the machined surface. This investigation is to evaluate the plastic strain in the distance 0.1mm from the machined surface, and in particular, to find the effect of shear angle, shear strain, cutting energy etc. on the plastic strain.

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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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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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Properties of a Helical Gear Due to the Manufacturing Process - Forged versus Machined Product (헬리컬기어 제조공정에 따른 특성 비교 -단조품과 기계가공품-)

  • Jung, H.C.;Kang, B.S.;Lee, I.H.;Choi, S.T.;Sin, S.J.;Kang, S.H.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.21 no.1
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    • pp.67-74
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    • 2012
  • Although high productivity is possible, cold forged helical gears have not been widely used due to difficulty in achieving mechanical properties as well as dimensional accuracy of the product. Confidence in the gear characteristics also is very important in heavy-duty gear applications. Therefore, the properties of forged gears must be compared to the properties of conventional machined gears. The properties might be different due to the different fabrication processes. In this study, machined and forged products both before and after heat-treated have been compared by measuring the residual stress and involute curve of the tooth. Characteristics of hardness and microstructure were also compared. Additionally, tooth fracture strength was compared for the heat-treated products. Moreover, the tooth strength and the fracture pattern were compared between the machined and forged gears. The forged gear showed decreased changes in residual stress and decreased changes in dimensions when compared to the machined gear before and after heat treatment. The forged gear was over 10% better than the machined gear in tooth strength.

Machined Surface Prediction and Experimental Verification for Virtual Machining CAM System (실가공형 CAM 시스템의 구현을 위한 가공면 예측 및 실험검증)

  • 정대혁;서석환
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.3
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    • pp.247-258
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    • 1999
  • With the contemporary CAD/CAM system, where the tool path is generated and verified purely based on the geometric operation, geometric accuracy of the machined surface cannot be guaranteed dut to the cutting mechanics, meaning that the cutting mechanics should be incorporated in some fashion. In this paper, we incorporate the instantaneous cutting force and the tool deflection phenomena in predicting the machined surface for the finish-cut and milling operation. For the given NC dat including cutting conditions, the developed algorithm computes cutting force and deflection amount along the tool trajectory, and outputs the 3D graphic model of the machined surface together with error analysis. The validity and accuracy of the presented method has been tested by the actual cutting experiments. Experimental results and accuracy enhancement method together with implementing architecture of the VMCS (Virtual Machining CAM System) are discussed in the paper.

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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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The OMM system for machined form and surface roughness measurement concerned with volumetric error (기계 체적오차가 고려된 가공형상-거칠기 측정 OMM 시스템)

  • 이상준;김선호;김옥현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.681-686
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    • 2000
  • Machining information such as machined form and surface roughness accuracy is an important factor for manufacturing precise parts. To this regard, OMM(On the Machine Measurement) has been issued for last several decades to alternate with CMM. In this research, measuring system consisting of a laser probe is developed for machined form and surface roughness measurement on the machine tool. The obtained machined form accuracy is compared with reference one defined in CAD model. The measured surface roughness data is compared with measured master surface beforehand. Furthermore, using the pre-defined volumetric error map approach compensates the geometric accuracy of the machine tool. The overall performance is compared with CMM, and verified the feasibility of the measurement system.

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Effect of Heat Treatment on the Surface Machined by W-EDM (고온 열처리가 와이어 컷 가공면에 미치는 영향)

  • Choi, K.K.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.15 no.8 s.89
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    • pp.539-543
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    • 2006
  • Experimental studies are carried out in order to investigate the effects of heat treatment on the surface machined by W-EDM. In this work, two ways of heat treatment after W-EDM are considered. As a comparison, the machined surface by a traditional method such as milling/grinding is also considered. Thereby, specimens are prepared by four different machining methods. Those are (1) milling and then grinding, (2) wire-cut electric discharge machining (W-EDM), and (3) low temperature heat treatment or (4) high temperature heat treatment after W-EDM. The resulting surface roughness are measured and the changes of surface microstructures are investigated using the scanning electron microscope (SEM) with energy dispersive X-ray spectrometer (EDS). In general, heat treatment after W-EDM result in smoother surface and better chemical composition at the machined surface. Especially, high temperature tempering could remove defects in the thermally affected zone, which cause an overall deterioration of the surface machined by W-EDM.

The OMM System for Machined Form and Surface Roughness Measurement Concerned with Volumetric Error (기계 체적오차가 고려된 가공형상-거칠기 측정 OMM 시스템)

  • 이상준;김선호;김옥현
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.7
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    • pp.232-240
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    • 2000
  • Machining information such as machined form and surface roughness accuracy is an important factor for manufacturing precise parts. To this regard, OMM(On the Machine Measurement) has been issued for last several decades to alternate with CMM. In this research, measuring system consisting of a laser probe is developed for machined form and surface roughness measurement on the machine tool. The obtained machined form accuracy is compared with reference one defined in CAD model. The measured surface roughness data is compared with measured master surface beforehand. Furthermore, using the pre-defined volumetric error map approach compensates the geometric accuracy of the machine tool. The overall performance is compared with CMM, and verified the feasibility of the measurement system.

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Prediction of the Surface Machined by EDM Using Iterative Discharge Simulation (연속방전 시뮬레이션을 이용한 미세방전가공 표면의 예측)

  • Kim T.G.;Min B.K.;Lee S.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.509-510
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    • 2006
  • Simulation of micro electrical discharge machining (micro-EDM) process using finite element analysis is proposed. Multiphysics model which has three steps; heat transfer analysis, structural analysis and electric field analysis is developed for simulation. Machined surface for successive five discharges is simulated using developed multiphysics model. Machined surface roughness was simulated under two discharge conditions and the simulated results are compared with actual machined surfaces. From the comparison it is demonstrated that the model can accurately predict the machined surface with the error less than $0.5{\mu}m$.

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