• 한국생산제조학회지
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• 제5권4호
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• pp.82-89
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• 1996

In this study, to choose the drilling m/c with analysis model for dynamic design of machine tool strctures, are used substucture syntheis method for reduction to degrees of freedom of dynamic model and analysis evaluation of substructures The dynamic factors of substurctures are examined by substructure synthesis method. And that dynamic design of structures for energy balancing are performed. The computer program for calculated of the dynamic and energy distribution analysis was developed. Result of numerical analysis by developed program obtained to conclusion as following. The design of machine tool structures by dynamic avoid the resonances, and are known to considered based on the energy balancing. These methods can be used effectively for the performance evaluation, design modification and improvement of dynamic performance evaluation, design modification and improvement of dynamic performance of machine tools.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.430-434
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• 2001

Virtual manufacturing system is integrated computer model that represents the precise and whole structure of manufacturing system and simulates its physical and logical behavior in operation.[1] A virtual machine is computer model that represents a CNC machine tool and one of core elements of virtual manufacturing system. In this paper, it is emphasized that a virtual machine must be web-based system for serving information to all attendants in a real machine tool without the restriction of time or location, and then in the fault diagnosis, one of important modules of a virtual machine, the methods of both using the controller signal and web-based expert system are proposed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.188-188
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• 2004

Modal testing and analysis is a primary tool for obtaining reliable models to represent the dynamics of structures. When a structure is tested in order to collect measured data in modal testing, we usually use attached accelerometers to pick up the response data. Change in modal parameters due to the mass of transducers in modal testing is a well-known problem. The disadvantages are the shift of measured modal frequencies and the change of modal shapes, which can cause inaccurate results in further analysis. Modal analysis methods in frequency domain are based on a set of measured frequency response functions(FRF).(omitted)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.42-45
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• 2002

In this paper, multiphase optimization of machine Tool structure is presented. The final goal is to obtain 1) light weight, 2) statically and dynamically rigid. and 3) thermally stable structure. The entire optimization process is carried out in three phases. In the first phase, multiple static optimization problem with two objective functions is treated using Pareto genetic algorithm. where two objective functions are weight of the structure and static compliance. In the second phase, maximum receptance is minimized using simple genetic algorithm. And the last phase, thermal deflection to moving heat sources is analyzed using Predictor-Corrector Method. The method is applied to a high speed line center design which takes the shape of back-column structure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.97-101
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• 1993

In this work, the imaginary part of the inner modulation transfer function of the cutting dynamics is introduced for tool wear monitoring. Time-series method is utilized to construct the generalthree dimensional cutting dynamics whose imaginary part of the inner modulation transfer funcition shows the proportionality to tool wear at the natural frequency of the machine tool dynamics. This modelis reduced to single-input single- output model without altering the proporitonality characteristics to tool wear and implemented to the dual computer system in which one computer performs measurement while the other calculates the imaginary part of the inner modulation transfer function of th cutting dynamics by the batchleast square method. The values of the imaginary part at the natural frequencyof the machine tool structure in the cutting direction are compared to the one calculated during machining with a brand new tool to decide the current stants of the tool. The experiments shows the relevance of the proposed concept.

• 한국정밀공학회지
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• 제9권2호
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• pp.61-68
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• 1992

To meet the requirements for accuracy, productivity and reliability of machine tools, it is necessary to evaluate the chatter-free machining performance and to improve the dynamic performance of machine tools. In order to perform dynamic design of machine tools reasonably and effectively, the joint parts must be modelled accurately because their characteristics affect significantly on the total characteristics of machine tool. In this paper, an approach which identifies the effect of joint parts on the performance of total machine tool structure was proposed. That uses the experimental modal analysis, the finite element method and the sensitivity analysis method. The effectiveness of this approach was confirmed by applying it to structures with bearing joints. And as a result of the application, the change of dynamic characteristics of bearing joints was indentified.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.63-67
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• 2000

A tool holder system has been designed to measure cutting forces in diamond turning. This system includes a 3-component piezo-electric tranducer. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. This system will aid to the development of Fast Tool Servo (FTS)

• 한국정밀공학회지
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• 제26권6호
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• pp.68-73
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• 2009

One of the traditional optical methods to monitor a tool is a CCD sensor-based vision system which captures an aspect of the tool in real time. In the case using the CCD sensor, specific lens-modules are necessary to monitor the tool with higher resolution than its pixel size, and a microprocessor is required to attain desired data from captured images. Thus theses additional devices make the entire measurement system complex. Another method is to use a pair of an optical source and a detector per measuring axis. Since the method is based on the intensity modulation, the structure of the measurement system is simper than the CCD sensor-based vision system. However, in the case measuring the three dimensional position of the tool, it is difficult to apply to micro machine-tools because there may not be space to integrate three pairs of an optical source and a detector. In this paper, in order to develop a tool-origin measurement system which is employed in micro machine-tools, the improved method to measure a tool origin in x, y and z axes is introduced. The method is based on the intensity modulation and employs one pair of an optical source radiating divergent beams and a quadrant photodiode to detect a three dimensional position of the tool. This paper presents the measurement models of the proposed tool-origin sensor. The models were verified experimentally The verification results show that the proposed method is possible and the induced models are available for design.

• 한국기계가공학회지
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• 제17권2호
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• pp.103-108
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• 2018

In interrupted cutting, the workpiece has a groove that impacts both the cutting tool and the workpiece. Therefore, cutting tool damage occurs rapidly. In this study, I performed interrupted cutting of carbon steel for machine structures (SM20C) using an uncoated carbide tool (SNMG120404, P20), and observed tool damage, cutting chip shape, and the workpiece surface. Results: Under the specific cutting conditions of feed rate = 0.066 mm/rev, cutting speed = 120 m/min, and depth of cut = 0.1 mm; and feed rate = 0.105 mm/rev, cutting speed = 120 m/min, and depth of cut = 0.2 mm, the observed tool damage was small. Similar chip shape was observed (Expt. No. 1, 3, 7). Workpiece damage was observed (Expt. No. 3, 5, 7, 9).

• 한국정밀공학회지
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• 제28권9호
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• pp.1011-1017
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• 2011

Servo control loops are a core part in the control architecture of machine tools. Servo control loops manage acceleration, velocity and position of all the axes in a machine tool based on commands. The performance of servo control loops sets the basis for quality of production paris and cycle time reduction. First, this paper presents a general control architecture of machine tools and several control schemes in literature, which can be applicable to machine tools control; including Zero Phase Error Tracking Control (ZPETC) and Cross Coupling Control (CCC). After that, modem control strategies to mitigate the problem of high speed machining are reviewed. In high speed machining, high accelerations excite the machine structure up to high frequencies, thereby exciting the structure's modes of vibration. These structural vibrations need to be damped if accurate positioning or trajectory following is required. Input shaping is an attractive option in dealing with structural vibrations. The advantages and drawbacks of using input shaping technique for machine tools are discussed in detail.