• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1287-1294
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• 2003

The wear process of end mill is so complicated process that a more reliable technique is required for the monitoring and controlling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for 4 cases using the high-speed-steel end mill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. As the cutter impacts the workpiece surface, a situation of farced vibration arises in which the dominant forcing frequency is equal to the tooth passing frequency of the cutter. The tooth passing frequency appears as a harmonics form, and end mill flank wear is related with the first harmonic. It is possible to detect end . mill flank wear. This paper proposed the new method of the end mill wear detection.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.42-46
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• 1993

This paper presents development of a pratical tool deflection compensation system in order to reduce the machining error by the tool deflection in the end-milling process. The system is a tool adapter which includes 2-axis force sensor for detecting tool deflection and 2-axis tool tilting device for adjusting tool position through computer interface in on-line process. In experiments, it is revealed that the force sensor applying parallel plate principle and strain gauge is proper to obtain dynamic process signal, and the tilting device using stepping motor and cam drive mechanism is suitable to have necessary action. By the system and control algorithm, it is possible to get precise machining surface profile without excessive machining error and overcut generated due to increased cutting force in more productive machining condition.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.281-286
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• 2004

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for using the high-speed steel end mill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.1
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• pp.51-58
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• 2005

The development of the high-efficiency machine-tools equipment and new cutting tool materials with high hardness, heat- and wear-resistance has opened the way to application of high-speed cutting process. The basic argument of using of high-speed cutting processes is the reduction of time and the respective increase of machining productivity. In this sense, the spindle units may be regarded as one of the most important units, directly affecting many parameters of high-speed machining efficiency. One of the possible types of spindle units for high-speed cutting is the air-bearing type. In this paper, we propose the mathematical model of the dynamic behavior of the air-bearing spindle. To provide the high-level of speed capacity and spindle rotation accuracy we need the adequate model of "spindle-bearings" system. This model should consider characteristics of the interactions between system components and environment. To find the working characteristics of spindle unit we should derive the equations of spindle axis movement under the affecting factors, and solve these equations together with equations which describe the behavior of lubricant layer in bearing (bearing stiffness equations). In this paper, the three influence coefficients are introduced, which describe the center of spindle mass displacement, angle of shaft rotation around the axes under the unit force application and that under the unit torque application. These coefficients are operated in the system of differential equations, which describes the spindle axis spatial movement. This system is solved by Runge-Kutta method. Obtained trajectories and amplitude-frequency characteristics were then compared to experimental ones. The analysis shows good agreement between theoretical and experimental results, which confirms that the proposed model of air-bearing spindle is correctis correct

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.4
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• pp.100-105
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• 2008

Cost reduction, time to market, and quality improvement of software product are critical issues to the software companies which try to survive in recent competitive market environments. Software Product Line Engineering (SPLE) is one of the approaches to address these issues. The goal of software product line is to maximize the software reuse and achieve the best productivity with the minimum cost. In software product line, software components are classified into the common and variable modules for composition work. In this paper, we proposed a dynamic composition process based on aspect-oriented programming methodology in which software requirements are classified into the core-concerns and cross-cutting concerns, and then assembled into the final software product. It enables developers to concentrate on the core logics of given problem, not the side-issues of software product such as transactions and logging. We also proposed useful composition patterns based on aspect oriented programming paradigm. Finally, we implemented a prototype of the proposed process using Java and Aspect to show the proposed approach's feasibility. The scenario of the prototype is based on the embedded analysis software of telecommunication devices.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.209-212
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• 2002

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for 4 cases using the high-speed steel slot drill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.311-314
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• 2001

The objectives of this paper include the development of an agile prototype of SFFS, the $CAFL^{VM}$(Computer Aided fabrication of Lamination for Various Material), which is suitable for the multi-item and small-quantity production and various material fabrication. This paper includes remodeling of the layer slices for the 2D cutting, supplementing information of the layer slices and developing process conditions to fabricate products of various shape. And also includes developing control hardware as well as software by enhancing BOF of the manipulator to 3 degree for the precise 2D cutting. It will generate optimal layer trajectory considering the dynamic characteristics of the laser beam. The system can be used as a competitive agile protype system in terms of various materials, fabrication speed, and accuracy by CAD modeling precise layer slicing, material development, robot path control, and optimization of the support structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.409-415
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• 2021

Medical waste management is becoming increasingly important, specifically in light of the current COVID-19 pandemic, as hospitals, clinics, quarantine centers, and medical research institutes are generating tons of medical waste every day. Previously, a traditional incineration process was utilized for managing medical waste, but the lack of landfill sites, and accompanying environmental concerns endanger public health. Consequently, an innovative sterilization shredding system was developed to resolve this problem. In this research, we focused on the design and numerical analysis of a shredding system for hazardous and infectious medical waste, to establish its operational performance. The shredding machine's components were modeled in a CAD application, and finite element analysis (FEA) was conducted using ABAQUS software. Static, fatigue, and dynamic loading conditions were used to analyze the structural stability of the cutting blade. The blade geometry proved to be effective based on the cutting force applied to shred medical waste. The dynamic stability of the structure was verified using modal analysis. Furthermore, an S-N curve was generated using a high cycle fatigue study, to predict the expected life of the cutting blade. Resultantly, an appropriate shredder system was devised to link with a sterilization unit, which could be beneficial in reducing the volume of medical waste and disposal time, thereof, thus eliminating environmental issues, and potential health hazards.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.101-108
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• 2001

In this study, the static and dynamic characteristics of endmilling process were modelled and the analytic realization of chatter mechanism was discussed. In this reward, We have discussed on the comparative assessment of recursive time series modeling algorithms that cal represent time machining process and detect the abnormal machining behaviors in precision endmilling operation. In this study, simulation and experimental works were performed to show the malfunctional behaviors. For this purpose, new recursive algorithm(RLSM) was adopted for the oil-line system identification and monitoring of a machining process, we can apply these new algorithms in real process for detection of abnormal chatter. Also, The stability lobe of chatter was analysed by varying parameter of cutting dynamics in regenerative chatter mechanics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.671-675
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• 2014

This paper presents a fabrication of hydrophilic Poly(dimethylsiloxane) (PDMS) with periodic wrinkling surface. The proposed periodic wrinkling surface was fabricated using the sequential processes of typical curing process of PDMS, cutting process, platinum deposition process, and wrinkling transfer process. The surface morphology of the fabricated wrinkling surface was observed by using optical and dynamic atomic force microscopy and discussed. The measured period and amplitude of wrinkling was about $2.2{\mu}m$ and $0.31{\mu}m$, respectively. And, the contact angles of water droplets on the wrinkled surface were measured in order to understand effect of the wrinkling surface on surface modification of hydrophobic PDMS. Our new finding was that the proposed wrinkling surface was hydrophilic and the measured contact angle was about $62^{\circ}$. Moreover, it was found out from the simple cell culture test that the fabricated wrinkling surface was more effective for cell spreading and adhesion than the case of native PDMS substrate.