• 한국정밀공학회지
• /
• 제11권6호
• /
• pp.117-126
• /
• 1994

This paper describes an application step of a $R^{-{\theta}}$ method which measures circular movements in machining centers. The detection of composite errors of circular movements and a high precision cutting method in machining centers were investigated by the analysis of data measured by $R^{\theta }$method which can detect the rotating angle and is applicable to variable measuring radius. When the error by squareness error and unbalance of position-loop-gain were mixed, the detection method of each error was proposed. Although the errors by squarenss error and backlash compensation were mixed, the errors by squareness error be detected. If the errors by unbalance of position-loop-gain and backlash compensation were mixed, the errors by unbalance of position-loop-gain could not detected. A high precision cutting mehod, which uses the NC program compensated by using feed-back data from error measured by the $R^{\theta }$method, was proposed.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 1998년도 추계학술대회 논문집
• /
• pp.259-262
• /
• 1998

DNC(Distributed Numerical controller)는 제품을 생산하기 위해 현장용 컴퓨터를 이용하여 공작기계 및 주변장치를 제어하고 감시한다. 본 논문에서는 SFC/OP(Shop Floor Control/point of Production) 시스템과 연계시키기 위한 DNC 시스템의 구조를 제시한다. 본 시스템은 도면 정보를 유기적으로 연결하여 작업절차서를 조회하고, 작업절차서 및 NC 프로그램/공구 보정 데이타를 인덱스 데이터베이스화하고, 소재·지그·공구를 연계한다. 또한 생산정보를 빠르고 능동적으로 현장 작업자에게 전달하고, 기계의 상태정보를 기계로부터 직접 수집함으로써 실시간 모니터링이 가능하다. 분석 및 설계단계에서는 실시간으로 발생하는 이벤트를 처리하기 위해 상태전이도(State Transition Diagram)를 사용한다. 서버 DBMS(Database Management System)로 관계형 데이터베이스를 채택한 Oracle을 사용하였고, 프로그램 개발도구로는 Developer 2000, Microsoft Visual C++ 5.0을 사용하여 구현한다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.975-978
• /
• 2001

For machining auto-mobile cam, the developed biarcs-fitting method eliminates the ridge problems in conventional straight-line fitting approximation or single-arc fitting of curve tool path where it leaves ridges of tool marks on the machined surface of the workpiece. The powerful advantage of this biarc method is demonstrated by applying it to the numerically controlled machining of a curved cam profile, also verified by using a CNC simulating program for auto-mobile cam profile. As a result, this algorithm may be used in CNC milling and turning for cam profile machining with short block line.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.1032-1035
• /
• 2000

Increasing demands on precision machining with computerized numerical control (CNC) machines have necessitated that the tool to move not only position error as small as possible, but also with smoothly varying feedrates in space. This paper presents a new high precision interpolation algorithm for 3-dimensional (3D) Non-Uniform Rational B-Spline (NURBS) curve in the reference-pulse CNC technique. Based on the minimum path error strategy, real-time NURBS interpolator was developed in software and this was implemented with a PC-NC milling machine. The several experimental results have shown that the proposed NURBS interpolator is useful for the high precision machining of complex shapes. It is expected that this algorithm can be applied to the CNC machines for the machining of 3D free-form surfaces.

• 대한기계학회논문집A
• /
• 제29권6호
• /
• pp.895-903
• /
• 2005

In this paper, we present a cutter location (CL) surface deformation approach for constant scallop height tool path generation from triangular mesh. The triangular mesh model of the stereo lithography (STL) format is offset to the CL surface and then deformed in accordance with the deformation vectors, which are computed by the slope and the curvature of the CL surface. In addition, the tool path which is computed by slicing the deformed CL surface is inversely deformed by those same deformation vectors to a tool path with a constant scallop height. The proposed method is implemented, and a tool path generated by the proposed method is tested by simulation and by numerical control (NC) machining. The scallop height was found to be constant over the entire machined surface, demonstrating much better quality than that of mesh slicing, under the same constraints for machining time.

• Journal of Welding and Joining
• /
• 제14권3호
• /
• pp.29-40
• /
• 1996

Electron beam 용접은 전자총에서 발생된 electron beam을 렌즈로 집속시켜 고 에너지의 열원을 얻는 것을 기본 원리로 하고 있다. Electron beam은 렌즈에 의해 매우 작게 집속(0.1 - 1mm.PHI.)시켜 높은 에너지밀도로 만들 수 있으므로 용접을 매우 깊게(수십 - 수백 mm) 할 수 있다. 이러한 용접 특성은 모재의 열변형을 최소로 하여 용접 부위가 원래의 성질을 잃어버리는 것을 최소화한다. 그러나, deep welding 의 경우 입력 파워 밀도가 너무 큰 관계로 계면 부위가 기계적 충격에 약하다는 단점 을 갖고 있다. Electron beam 용접은 서로 다른 금속을 filler material 없이 용접할 수 있으며 복잡한 구조의 용접이 가능하다. 또한 대부분의 electron beam 용접은 진공 중에서 이루어지기 때문에 공기의 영향을 받지 않는다는(산화 방식) 특성을 갖고 있다. 즉, 공기와의 접촉이 적기 때문에 산화가 방지되고 용접 순도가 매우 높다는 장점을 갖고 있다. 이는 반면 장치가 거대해지고 비싸다는 단점으로 작용한다. 1980년대 부터 이러한 단점의 극복을 위해서 대기중에서의 electron beam 용접에 관한 연구가 수행 되어 실용화 단계에 이루고 있다. 최근 전자, computer기술의 발달로 electron beam 출력을 더욱 더 정밀하게 조절할 수 있고, computer와 sensor의 결합으로 자동용접 위치 제어와 NC(Numerical Control) 작업대의 설치로 완전 자동화 용접 공정이 가능 하다. 그 결과 높은 용접 속도를 얻을 수 있으며 무인 생산 체계에로의 응용이 가능 하다.

• 한국CDE학회논문집
• /
• 제2권2호
• /
• pp.85-92
• /
• 1997

An axial flow fan design system has been made by integrating the self-developed programs and I-DEAS. By using the system, an axial flow fan was designed, manufactured and verified through the wind tunnel experiments in coorperation with a refrigerator appliance division. It has been shown that the optimal design without the ambiguity of the design parameters can be possible by the three-dimensional flow simulations using a self-developed CID code, FANS-3D. (Flow Analysis code using Navier Stokes aguations in Three-Dimensional curvilinear coordinates). By virtue of the fluency of the data flow, an optimally designed fan which satisfies design conditions can be selected in a short time and less cost. The manufacturing processes of a Mock-up and an injection molding die have been automated through the self-made interface programs which connnect from the start to the end. It has been shown that the newly developed fan by this system has a superior performance characteristics to an existing fan.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.1145-1151
• /
• 2022

A hybrid cutting using both plasma and end mill was developed for safe and efficient dismantling of nuclear facilities. In this cutting method, a moving arc plasma heats up the workpiece before milling. Thermally softened part of the workpiece is then removed quickly and deeply with an end mill. For the cutting experiments, a three-axis numerical control (NC) milling machine was combined with a commercialized arc plasma torch and used to cut 25 mm thick stainless steel plates. Experimental results revealed that pre-heating by arc plasmas can improve the cutting volume per unit time higher than 40% by reducing the cutting load and increasing the cuttable depth when using an end mill without cutting fluids. These advantages of a hybrid cutting process are expected to contribute to quick and safe segmentations of metal structures with radioactively contaminated inner surfaces.

• 조명전기설비학회논문지
• /
• 제19권7호
• /
• pp.67-72
• /
• 2005

WPAN(Wireless Personal Area Networks)에서는 현재 동작중인 PNC(Piconet Coordinator)가 피코넷을 떠나거나 종료하고자 할 때, 피코넷 내의 PNC 능력을 가진 디바이스에게 PNC 역할을 양도할 수 있다. 그러나 WPAN의 권고안에서는 PNC 핸드오버를 위한 PNC 후보 선택에 대해서는 디바이스 성능 정보를 비교하여 선택하는 방안만을 기술되어 있으며, 이에 대한 구체적인 선택 방법은 포함하고 있지 않다. 본 논문에서는 피코넷 NC가 피코넷 내의 다른 디바이스에게 PNC 기능을 양도하게 될 때에 피코넷의 데이터 처리성능을 최적화 될 수 있게 PNC 수용 디바이스 개수와 밀집도를 고려하여 PNC를 선택하는 방안에 대해 제안한다. 수치 해석의 결과에서 보면 디바이스들이 집중되어 있을수록 평균 데이터 처리량이 증가되는 것을 나타내었고, 최고 두 배까지 향상되었다. 따라서 PNC 후보 선발시 서비스 디바이스 개수와 밀집도를 같이 고려해야만 피코넷 성능을 높일 수 있다.

• International Journal of CAD/CAM
• /
• 제6권1호
• /
• pp.183-192
• /
• 2006

A CAD/CAM system has been developed for rapid prototyping (RP) of microfluidic devices based on excimer laser micromachining. The system comprises of two complementary softwares. One, the CAM tool, creates part programs from CAD models. The other, the Simulator Tool, uses a part program to generate the laser tool path and the 2D and 3D graphical representation of the machined microstructure. The CAM tool's algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD system, and process parameters (laser fluence, pulse repetition frequency, number of shots per area, wall angle), to automatically generate Numerical Control (NC) part programs for the machine controller. The performance of the system has been verified and demonstrated by machining a particle transportation device. The CAM tool simplifies part programming and replaces the tedious trial-and-error approach to creating programs. The simulator tool accepts manual or computer generated part programs, and displays the tool path and the machined structure. This enables error checking and editing of the program before machining, and development of programs for complex microstructures. Combined, the tools provide a user-friendly CAD/CAM system environment for rapid prototyping of microfluidic devices.