• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.47-51
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• 1992

Automatic detection of tool breakage during NC machining is a key issue not only for improving productivity but to implement the unattended manufacturing system. In this paper, we develop a vibration sensor-based tool breakage detection system for NC milling processes. The system obtains the time-domain vibration signal from the sensor attached on the spindle bracket of our CNC machine and declares tool failures through the on-line monitoring schemes. For on-line detection, our approach is to use the PSC(statistical process control) methods being increasingly used for on-line process control. The main thrust of this paper is to propose and compare the performance of SPC methods including : a) X-bar control scheme, b) S control scheme, c)EWMA (exponentially weighted moving average) scheme, and d) AEWMA (adaptive exponentially weighted moving average) scheme. The performance of the control schemes are compared in terms of the type 1 and 2 error calculated from the experiment data.

• 한국CDE학회논문집
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• 제13권2호
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• pp.153-161
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• 2008

This paper proposes an efficient algorithm for deriving inverse kinematics equation of 5-axis machine. Because the joint order and direction of 5-axis machine are different for each type of machine, each type of machine needs its own inverse kinematics equation for post-processing of NC data. Also derived inverse kinematics equation may cause problems of indeterminate and inconsistent solution. In order to resolve these problems, we have developed a generic method to derive direct kinematics equation by considering orthogonal joints of 5-axis machines. Using this method, we also have proposed a general algorithm for deriving inverse kinematics equation for various types of 5-axis machines.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.92-96
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• 1993

Modern NC machine tools require a more and more exact monitoring and control of cutting process. A very important parameter is tool wear used to optimize cutting data and to change tools at the right time. In this study, a real-time multi-tool fracture method is proposed for measuring crater from fringe patterns generated by uni-shadow-moire. An optical technique using laser for non-contact measurement of tool fracture is presented. The technology in which the tool is illuminated by a beam of He-Ne laser and then the image of tool fracture CCD camera.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.106-111
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• 1998

NC code has to be made after changing the drawing information to DXF file, the converting file. Arranging the information ordered irregularly when DXF file is made decrease the unnecessary time of rapid feed during working and the DATA capacity when the information is changed. This CAM program can be used easely for the beginner of the minor enterprises. The connection of operations and the use of GUI increase business efficiency.

• 한국생산제조학회지
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• 제5권3호
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• pp.66-72
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• 1996

The applicability of a new method, termed the whirling motion concept, for the improvement of the surface finish in milling three-dimensional sculptured surfaces has been investigated. A method for implementing this concept o conventional NC machines that utilize a suitably configured attachment has been proposed. The tool path equation for the ball-end milling process, based on the surface-shaping system, has been obtained. Both results of the computer simulation and the experiment verified the proposed approach.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.192-195
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• 2006

본 논문에서는 다이 플레이트(Die Plate)를 제작할 때 생산성 향상을 위해서 3D CAD/CAM 시스템을 적용하였다. 사용된 3D CAD/CAM 소프트웨어는 UG NX 3.0이며 생성된 NC 코드는 CNC밀링 및 와이어 컷 방전가공기에 전송되어 다이 플레이트를 자동 가공한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.149-154
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• 1996

The applicability of a new method, termed the whirling motion concept, for the iprovement of the surface finish in milling three-dimensional sculptured surfaces has been investigated. A method for implementing this concept on conventional NC machines that utilize a suitably configured attachment has been proposed. The tool path equation for the ball-end milling process, based on the Surface-Shaping system, has been obtained. Both results of the computer simulation and the experiment verified the computer simulation and the experiment verified the proposed approach.

• 열처리공학회지
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• 제18권1호
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• pp.29-40
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• 2005

Formation of nanocrystalline ferrite was investigated using milled powders obtained by planetary ball milling of chips, which were made by high speed mechanical cutting of a low carbon steel(0.15%C-1.1%Mn-0.01%Ti). After 4 hour milling the chips were changed to powders of $50{\mu}m$ in average size, and with increasing milling time the powders were refined to about $3{\mu}m$ for 128 hour and showed more equiaxed shapes. Nanocrystalline(nc) region appeared in the surfaces of powders milled for 1 hour, and the 4 hour milled powders were almost filled with nc region. Hardness of nc region was much higher than that of work-hardened(WH) region. With increasing milling time, ferrite and cementite in pearlite were severely deformed and lamellar spacing was decreased, and then cementites began to disappear after 4 hour milling due to dissolution into ferrite. Deformation bands formed in lightly work-hardened region showed large width and similar crystallographic orientations. Spacing of deformation bands was decreased with deformation and the layered microstructure consisting of narrow deformation bands subdivided into variously oriented small grains was formed by more deformation, and eventually this structure seemed to be evolved to the nc structure by further deformation. It is also conjectured the growth of nc ferrite grains occurred through the coalescence of nanocrystalline ferrites rather than the nucleation and growth of recrystallized grains.

• 한국기계가공학회지
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• 제16권5호
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• pp.47-54
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• 2017

This study examines the implementation of a kinematic machining tool to evaluate the interference and collision phenomenon of 5-axis machining of wing ribs from airplanes, particularly for a large-size model airplane. We develop a machine simulation model of a parallel kinematic machining tool that can operate in a virtual space, which is equivalent to the authentic conditions in the field. The investigation of the simulation function elements indicates the necessity to generate the 6-axis machining, which attaches an angle head to the main axis of the machine. Using an NC program for the wing ribs, we attempt to verify the correspondence and conformity between the machine simulation model and the actual equipment.

• 대한기계학회논문집
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• 제15권6호
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• pp.2048-2061
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• 1991

본 연구에서는 이와 같은 구비조건과 문제점들을 해소하기 위하여 Fig.1과 같 이 볼 엔드 밀링의 절삭성과 경제적 절삭 속도식을 실용식의 형태로 표현하여 절삭조 건의 최적화를 위한 구속조건으로 설정하였고, 이를 자유곡면의 절삭경로 산출과정에 서 구속조건을 만족하면서 부품당의 생산비를 최소로 하는 스핀들속도와 이송속도를 결정하는 데에 적용하였다. 그리고 이는 실험모형에의 적용예를 통해 계산시간과 정 확도 및 절삭효과 등에 있어서 실용화의 가능성을 검토하였다. 이때 절삭력계를 해 석 함에 있어서는 기하학적 절삭 파라미터들에 대해 무차원적으로 정의된 절삭작용 누 적계수(accumulating coefficient)들을 이용하여 절삭력계를 선형화 된 실용식으로 표 현하였으며, 절삭 상수들과 절삭작용 누적계수들의 선형적 표현에 의해 평균 절삭력계 를 계산한 후, 토크 패턴 모델에 의해 절삭력 집중비를 구함으로써 실 절삭계의 주변 력(peripheral force), 드러스트, 토크, 동력 등을 예측하였다. 또한 절삭속도의 결 정에 있어서는 경제적 절삭속도 예측모델을 설정하여 가공비를 최소로 하는 절삭속도 를 선정토록 하였다.