• Title/Summary/Keyword: END

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A Study on the Optimization of Slot Cut in the End Milling Processes (엔드밀에 의한 슬롯가공의 최적화에 관한 연구)

  • Choi, Jong-Guen;Kim, Hyung-Sun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.6
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    • pp.38-43
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    • 2006
  • A slot cut in end milling processes is one of the laborious works because the cutting force is likely to deflect the tools excessively, then to make large errors or to fracture the tool. This difficulty is owing to the poor stiffness of slender shaped end mills. Though, in most cases, additional finish cuts are followed after rough cuts, the accuracy of rough cuts is still important because it affects the final accuracy after finish cuts and productivity. The accuracy in slot cuts depends on the tool stiffness and the cutting conditions including depth of cut and feed. In order to meet the desired accuracy, diameter of end mill and cutting allowance have to be selected carefully. This study suggests several guidances for selecting the end mill diameter and the slot cut allowance to improve machining accuracy and productivity in slot end millings. Some experiments were done with the various cutting parameters of tool diameter, depth of cut and feed.

Simulation of surface profile using accelerometer in high speed end milling (고속 엔드밀 가공시 가속도계를 이용한 표면형상 시뮬레이션)

  • 이기용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.321-325
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    • 2000
  • To obtain precise surface and high productivity, high speed end milling has been studied recently. Though high speed end milling is explicitly effective for precision surface generation geometrically, tool deflection, chatter vibration and frequency characteristics of end milling system deteriorate the theoretical surface. In this study, simulation algorithm and programming method are suggested to simulate machined surface using acceleration signal in high speed end milling. This simulation is conducted by considering vibrational effect of spindle system which was not considered by other researchers. Between simulated results and experiment results, good agreements were obtained.

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End-to-End Performance of VoIP based on Mobility Pattern over MANETs

  • Kim, Young-Dong
    • Journal of information and communication convergence engineering
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    • v.7 no.3
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    • pp.309-313
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    • 2009
  • In this paper, end-to-end VoIP(Voice over Internet Protocol) performance is evaluated by simulation with NS-2 simulation tool. There are many results studied and published for VoIP performance over TCP/IP networks. But, almost all of them were focused on wired or wireless Internet environments. About MANET (Mobile Ad Hoc Network), VoIP is currently studying several points of research. In this paper, analysis of VoIP performance is done with focusing on the mobility of MANETs. MOS(Mean Opinion Score), network delay, packet loss rates are considered as end-to-end QoS performance parameters.

Simulation of Machined Surface Considering Acceleration Signal in High Speed End Milling (고속 엔드밀 가공시 가속도 신호를 고려한 가공표면의 시뮬레이션)

  • Lee, Gi-Yong;Gang, Myeong-Chang;Lee, Deuk-U;Kim, Jeong-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.2
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    • pp.228-234
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    • 2001
  • To obtain precise machined surface and high productivity in machining, high speed end milling has beed studied recently. Though high speed end milling is explicitly effective for precision surface generation geometrically, tool deflection, chatter vibration and frequency characteristics of end milling system deteriorate the theoretical surface. In this study, simulation algorithm and programming method are suggested to simulate machined surface using acceleration signal in high speed end milling. This simulation is conducted by considering vibrational effect of spindle system which was not considered by other investigators. Good agreements were obtained between simulated results and experimental results.

The Shear and Friction characteristics Analysis of End-milling (엔드밀링의 전단특성 및 마찰특성 해석)

  • Lee, Y.M.;Song, T.S.;Shim, B.K.
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.724-729
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    • 2000
  • In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting model. According to this analysis, when cutting SM45C steel, 72% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

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A Study on the Static Rigidity of the End Mill (엔드밀의 정적 강성에 관한 연구)

  • 이상규;고성림
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.9-14
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    • 1996
  • The deflection of an end mill is very important in machining process and cutting simulation because it affects directly workpiece accuracy, cutting force, and chattering. In this study, the deflection of the end mill was studied both experimentally and by using finite element analysis. And the moment of inertia of radial cross sections of tile helical end mill is calculated for the determination of the relation between cross section and rigidity of tile tools. Using tile Bernoulli-Euler beam and and the concept of equivalent diameter, a deflection model is established, which includes most influence from tool geomety parameters. It was found that helix angle attenuates the rigidity of the end mill.

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A Study on the End Mill Wear Detection by the Pattern Recognition Method in the Machine Vision (머신비젼으로 패턴 인식기법에 의한 엔드밀 마모 검출에 관한 연구)

  • 이창희;조택동
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.4
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    • pp.223-229
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    • 2003
  • Tool wear monitoring is an important technique in the flexible manufacturing system. This paper studies the end mill wear detection using CCD camera and pattern recognition method. When the end mill working in the machining center, the bottom edge of the end mill geometry change, this information is used. The CCD camera grab the new and worn tool geometry and the area of the tool geometry was compared. In this result, when the values of the subtract worn tool from new tool end in 200 pixels, it decides the tool life. This paper proposed the new method of the end mill wear detection.

Nonlinear Analysis of End-to-End Anastomosis Using Sub-modeling (Sub-modeling을 이용한 end-to-end 문합의 비선형 해석)

  • 한근조;안성찬;심재준
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.192-198
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    • 2003
  • A finite element analysis of end-to-end artery/PTFE anastomosis has been presented in this study to evaluate the distribution of compliance and stresses in the vicinity of the anastomosis due to any mismatch in compliance characteristics. The artery wall was assumed to be made of linear isotropic material in this simplified model and a nonlinear analysis and convergency study with respect to increasing meshed element numbers were performed with a mean artery pressure loading of the artery-PTFE model. Also, sub-modeling method was Introduced to progress the accuracy of the finite element analysis. The results are as follow : 1. A hypercompliant zone on the artery side was observed around 4.Omm from the anastomosis and a high hoop stresses in the wall of artery and PTFE was dominant. 2. An artery displays large deformation so that nonlinear analysis and sub-modeling method was used. 3. An anastomosis with the thinner thickness and larger diameter PTFE (B type) could reduce the compliance disagreement.

Internet Governance and Users (인터넷 거버넌스와 이용자)

  • Kim, Borami
    • Review of Korean Society for Internet Information
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    • v.14 no.3
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    • pp.95-100
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    • 2013
  • Having taken actions for 2 years, Net Neutrality User Forum has realized Net Neutrality as a international issue of future Internet. Although the Internet design principle (layering, module, IP protocol) has enabled the end users to communicate each other without any additional permission or interference, in the reality, the end users have been tracked by both companies and governments, and the communications could be blocked, or restricted by surveillance devices, such as DPI, which could change the whole Internet design principle. Given that the Internet is a large community of the equal end-users based on end-to-end principle, it's essentially the issues of the whole Internet users, rather than of one nation, and we should focus on developing the transparent and participatory ways in Internet governance. The current Internet governance discussion have taken placed in ICANN, IGF, etc., in bottom-up processes of multistakeholderism to reflect the views of end-users. However there have been the controversial issues in Internet Governance, such as the position of government as a stakeholder, global north-south problem, transparency, so we have faced the debate on the new or evolving frame of Internet governance.

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Shear and Friction Characteristics in Down-End Milling with Different Helix Angles (하향엔드밀링시 헬릭스각에 따른 전단 및 마찰특성변화)

  • 이영문;장승일;서민교;손정우
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.17-24
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    • 2004
  • In end milling process, undeformed chip thickness and cutting forces vary periodically with phase change of the tool. Recently, a model has been proposed to simulate the shear and friction characteristics of an up-end milling process in terms of the equivalent oblique cutting to this. In the current study, a down-end milling process has been replaced with the equivalent oblique cutting process. And shear and tool-chip friction characteristics variation of SM45C steel has been studied using the end-mills of different helix angles. The specific shear and friction energy consumed with helix angle of $50^{\circ}$ is somewhat larger than those of$30^{\circ}$ and $40^{\circ}$. The specific shear energy consumed is about 76-77% of the specific cutting energy regardless the helix angles.