• 한국공작기계학회논문집
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• 제11권3호
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• pp.51-56
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• 2002

In order to achieve high precision machine tools, Performance enhancement of feed drive systems is required. One of the important technical issues is how to decrease thermal expansion of ball screw in proportion to the increase of machining speed. When measuring force of stretch of ball screw, since not only actual expansion and the value of bending have to be considered, it is impossible to define the exact value of expansion. In addition, support bearings of ball screw gain considerable force in axial direction. It also generates thermal expansion on the ball screw, and deteriorates the performances of the hearings. In conclusion, it is impossible to give the pretension enough to absorb all the elongation due to thermal expansion generated during machine is running. If given bed column and saddle are all bent to chance machine accuracy, and the support bearings of ball screw is damaged.

• 한국생산제조학회지
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• 제8권2호
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• pp.62-72
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• 1999

In this study, the griding machine bed was designed and analyzed by using epoxy-granite. Finite element technique was employed to design and analyze the composite bed structure. Von Mises stress and relative displacements between a tool and a workpiece were checked to compare a cast iron bed structure with a composite bed structure. Dynamic features of structures were also studied according to the process of modal analysis through natural frequency and mode shape measurement. Another improved model was also designed using the accumulation of knowledge based on the use of the structural analysis and experiments. Comparing with the cast iron bed structure, the composite bed structure maintains better functions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1191-1194
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• 1995

A conversational programming system for turning processes was studied to enhance the user friendlness of an NC by adopting man-machine interface functions through Visual C $^{++}$ programming tool under the Windows 95 environment. Shop floor programming performance was incorporated in the developed CAM module. In order to increase flexibility of the man-machine interface, graphic based programmin tool have been developed. An NC turning machine equipped whit an open architecture PCNC was used as a test bed of the system. Perfomance of the system was verified through case studies..

• 한국생산제조학회지
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• 제7권2호
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• pp.29-39
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• 1998

A conversational programming system for turning processes was studied to enhance the user friendliness of a NC Lathe by adopting man-machine interface functions through Delphi programming tool under the Windows 95 environment. Functions of tool collision checking were developed through zone limitation algorithms. Final shape of workpiece was generated by means of tree structure algorithm. Shop floor programming performance was incorporated in the developed CAM module. In order to increase flexibility of the man-machine interface, graphic based programming tools have been developed. A NC turning machine equipped with an open architecture PCNC was used as a test bed of the system. Performance of the system was verified through case studies.

• 한국공작기계학회논문집
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• 제16권3호
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• pp.37-43
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• 2007

Recent technological developments in machine tools have been focused on high speed, low vibration machining and high precision machining. And the concern with multi-functional machining has been increased for the last several years. Multi-tasking machines are widely used in machine tool industries. Laser multi-tasking machine has been developed for high precision and fewer vibration machining. The purpose of this study is to evaluate the effects of structural reinforcement on Laser multi-tasking machine which is comprehensively combined turning center and laser machine. Up to date, for the structural stability evaluation of a multi-tasking machine, the analysis model has been considered only the weight of the upper parts. The positions of upper parts on multi-tasking machine have not been considered in the model. So, the results of the present FE model have revealed some difference with measurement data in case of multi-tasking machine. Design of the machine and structural analysis is carried out by FEM simulation using the commercial software CATIA V5. In the result of the structural analysis, effectiveness of reinforcement of the bed was confirmed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.15-19
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• 2002

With the rapid development of industrial technologies, the demand for high precision products has been increasing drastically. For this reason, the need for developing of high performance machine tool, which can ensure high precision, is desired in the industrial fields. Technologies on the spindle system manufacture, guideway manufacture, error compensation, design of bed structure, protection against vibrations, and system integration are core technology for developing of high precision machine tools. Especially, among these, design of spindle system, which is leading precision and manufacturing technique. is one of the most important technologies. A high speed and high precision spindle system, which will be used for final machining of ferrule, is designed considering the effect caused by thermal, cutting torque, cutting farce, and work-piece materials. The detail process of analysis is presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.37-41
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• 2002

This study has been focused on the development of an open architecture CNC system and integration of core application technology for machine tool such as a remote monitoring/diagnosis system, NURBS interpolation, and cutting process simulation. To do this, we have developed a comprehensive CNC software including the basic HMI, screen editor, ASF, and visual builder. As a control hardware system for machine tool, the universal I/O module and CNC main unit have been developed. Then the remote monitoring/diagnosis system and NURBS interpolation have been implemented in the CNC software. The cutting simulation software will be used for enhancing the productivity of machine tools. Through a simulator and test bed, the whole technology has been verified.

• 한국정밀공학회지
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• 제7권2호
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• pp.74-84
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• 1990

The machine tool structures for ultra-precision machining muxt be manufactured with materials which have high static and dynamic stiffness, high damping, a long term dimensional and thermal stability. This study aims at the development of new composite material Epoxy-Granite which exhibits the satisfactory characteristics as a material of ultra-precision mchine tool bed. The Epoxy-Granite testpieces that use epoxy resins as a binder and granite particles as a aggregate have been manufactured so as to examine the material properties about mechanical, thermal and damping characteristics. Experiments were carried out to obtain the proper manufacturing conditions of Expoxy-Granite specimens by varying the several testing conditions such as types of epoxy resins, particle sizes of granite and mixture ratio of epoxy resin and aggregate. Also, when Epoxy-Granite was compared with cast iron, GRANITAN which was imported from CMS of U.K. and granite materials, it has exhibited the superior or almost the same mechanical and damping properties and thermal conductivity, except for the thermal expansion.

• 대한기계학회논문집
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• 제17권5호
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• pp.1183-1192
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• 1993

본 연구에서는 다음과 같은 두가지 관점에서 공구경로 최적화를 위한 기존 방 법의 문제점을 검토하고 이의 개선 방안을 제시하였다. 첫째, 기존의 공구경로 산출 방법에서는 고려되지 않는 공구대의 공구 장착 현황(turret configuration)이 최적화 과정에서 고려되어야 한다. 둘째로, 제작과 관련한 구속조건(manufacturing con- straints)이 최적화 과정에 직접 반영되어야 한다.

• 한국기계가공학회지
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• 제20권2호
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• pp.38-44
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• 2021

To cater to the transition from single-color to multicolor/multi-material printing, this paper proposes a cartridge-replacing type multi-nozzle Fused Depositon Modeling(FDM) three-dimensional (3D) printer. In the test printing run, tool change failure/wobble/layer shift occurred. It was confirmed that improper support was the cause of this tool change failure. As a solution, spline and electromagnetic cartridges were designed. Wobble was caused by machine vibration and the motor stepping out. To minimize wobble, an additional Z-axis was installed, and the four-point bed leveling method was used instead of the three-point bed leveling method. The occurrence of layer shift was ascribed to the eccentricity of the Z-axis lead screw. Therefore, slit coupler was replaced with an Oldham type. In addition to the mechanical supplementation, the control environment was integrated to prevent accidents and signal errors due to wire connections. Before the final test printing run, a rectifier circuit was added to the motor to secure precise control stability. The final test printing run confirmed that the wobble/layer shift phenomenon was minimized, and the maximum error between layers was reduced to 0.05.