• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1991년도 추계학술대회 논문집
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• pp.95-100
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• 1991

From a manufacturing standpoint it would be desirable to monitor the degradation of drawing die, that is essential for the maintenance of quality, the evaluation of product integrity and the reducing scrap. Acoustic emission is powerful method in monitoring fine wire drawing process, especially in detecting the die fracture at early stage. Experiments at so suggested that acoustic emission signals contained valuable information regarding the stage of a drawing process such as the surface appearance of products and the condition of lubrication. Using these informations makes AE monitoring techniques a possible tool in monitoring the drawing process operation. In order to approach this, this paper discusses the nature of acoustic emission signals produced in drawing process under various conditions. Experimental results are presented which illustrate the effects of wire and die material, lubricants, and drawing speed on the generation and the mean voltage level of acoustic emission signals. The results from these tests give controlling factors of acoustic emission generation.

• 소성∙가공
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• 제9권6호
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• pp.624-630
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• 2000

Typical automotive opening parts, i. e. hood trunk lid and door, are made through the press operations such as drawing, trimming, flanging, and hemming. The dimensional accuracy of stamped panels is mainly dependent on the drawing operation. However, the gap between outer panels and opening parts, which is important to the appearance quality of the assembled body, is directly influenced by the flanging and hemming operation. In this study, the relation between the design parameters of the hemming operation and the defect of roll-in is shown. The effects of some design parameters on the gap are examined using CAE. furthermore, the simulated results of the hemmed part of tailgate comer are shown and discussed.

• 한국해양공학회지
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• 제31권2호
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• pp.141-154
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• 2017

A production management system is developed to enhance both the information and productivity of ship and offshore plant deckhouse floor outfitting. The functions of the production management system for the deckhouse floor outfitting were reviewed based on a literature survey of several production management systems with respect to the ship building and architecture fields. This study investigated numerous daily production reports and their application to actual work places to utilize the system development. The developed scanned drawing-based production management (SDPM) system minimizes any loss and/or distortion of work information between the workshop and management office when applying a scanned production drawing to the daily report. The SDPM system increases the data objectivity, as well as intuitiveness of the information generation by adopting an efficient user interface, which makes it possible to perform image annotations on the scanned drawing for the daily production report while simultaneously interacting with the production management database. Applying the system operation to actual deckhouse floor covering work verified that it was feasible to use the SDPM system for production management in the ship outfitting work process.

• 한국정밀공학회지
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• 제13권5호
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• pp.53-59
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• 1996

Warm deep drawing of single-action dies using local heating has appeared to be an alternative attractive production method of multi-operation die sets generally used at room temperature in deep drawing of rectangular cup. Uniaxial tensile tests and deep drawing tests of various materials are carried out and the effect of temperature on tensile properties and drawability are examined at temperatures up to 200 .deg. C under three kinds of lubricants of teflon film, vinyl film and drawing oil. Good formability is achieved when punch and die temperature were differentiated intentionally in order to get large tensile strength(TS) at punch shoulder protion and small TS at die side. Throughout the experiments, it has been shown that the limiting drawing height of STS316L was increased with heating die and blank holder at 100 .deg. C, but that of STS430 wasn't. When vinyl or teflon film was attached on the plates, the drawability was increased considerably.

• 전기학회논문지
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• 제59권5호
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• pp.854-859
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• 2010

Distribution Automation System(DAS) is designed to improve operational efficiency by acquisition and control of remote data using its components such as central computation units, communication network and feeder remote terminal units. A conventional human machine interface of the DAS adopts a schematic diagram which is made by drawing power equipments on the geographic information system map. The single line diagram is more useful than the schematic diagram for the main tasks of distribution system operation such as protective relay coordination, service restoration and loss minimization. Since the configuration of the distribution line is changed according to the relocation of the open tie switches, the auto-drawing algorithm based on the connection between the sections and the switches is an essential technique. This paper proposes a new auto-drawing algorithm for a single line diagram of distribution systems based on tertiary tree and collision avoidance method. The feasibility of the proposed algorithm has been testified for various cases using practical distribution system with 12 feeders.

• 소성∙가공
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• 제20권8호
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• pp.562-567
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• 2011

This paper deals with effects of certain important factors in a tube drawing operation, such as the use of a mandrel, die radius and tangential angle at die outlet, on the deformation behavior of a small-diameter seamless tube. Both experimental and finite element simulation studies are carried out to assess the effects of the above parameters. Experiments and finite element predictions are compared. The use of a mandrel simplifies the design of tube drawing, but also induces some difficulties from increased process complexity. The effects of die outlet tangential angle and radius are discussed in detail.

• 정보학연구
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• 제8권3호
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• pp.1-10
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• 2005

Cosine and Sine function is widely used for the arithmetic, translation, object drawing, Simulation and etc. of Computer Graphics in Natural Science and Engineering. In general, Cordic Algorithm is effective method since it has relatively small size and simple architecture on trigonometric function generation. However profitably it has those merits, the problem of operation speed is occurred. In graphic display system, the operation result of object drawing is quantized and has the condition that is satisfied with rms error less than 1. So in this paper, the proposed generator is composed of partition operation at each ${\pi}/4$ and basic Cosine, Sine function generator in the range of $0{\sim}{\pi}/4$ using the lower order of Tayler's series in an acceptable error range, that enlarge the range of $0{\sim}2{\pi}$ according to a definition of the trigonometric function for the purpose of having a high speed Cosine, Sine function generation. And, division operator using code partition for divisor three is proposed, the proposed function generator has high speed operation, but it has the problems in the other application parts with accurate results, is need to increase the speed of the multiplication.

• 대한기계학회논문집 C: 기술과 교육
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• 제2권2호
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• pp.125-130
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• 2014

기계제도 교과목은 기계공학 교육에서 매우 중요한 위치를 차지하고 있음에도 불구하고, 이론교육과 실습을 병행해야 하고 CAD 소프트웨어 기능 교육도 포함하고 있어서, 내실 있게 운영되기 힘든 교과목이다. 서울과학기술대 기계시스템디자인공학과에서는 기계제도 교육에 PBL 수업 방식을 도입하여 적용하고 있다. 학생들은 이론 수업에서 학습한 기계도면 작성의 규칙, 도면 독해와 작성법 등을 팀별 PBL 과제 수행을 통해 실제로 적용해 봄으로써, 도면 판독과 작성능력을 체득하게 되고 CAD 소프트웨어 활용 기능도 충실히 연습하게 된다. 본 논문에서는 그 동안 시도되었던 다양한 PBL 과제와 교육방법을 소개하고 그 효과를 분석해 보았다.

• 대한기계학회논문집A
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• 제30권11호
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• pp.1425-1432
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• 2006

Coating layers on a coated sheet steel frequently affect distributions of strain rate of sheets and deteriorate the frictional characteristics between sheets and tools in sheet metal forming. Thus, it is important to identify the deformation behavior of these coatings to ensure the success of the sheet forming operation. In this study, the technique using nano-indentation test, FE-simulation and Artificial Neural Network(ANN) were proposed to determine the power law stress-strain behavior of coating layer and the power law behavior of extracted coating layers was examined using FE-simulation of drawing and nano-indentation process. Also, deep drawing test was performed to estimate the formability and frictional characteristic of coated sheet, which was calculated using the linear relationship between drawing force and blank holding force obtained from the deep drawing test. FE-simulations of the drawing process were respectively carried out for single-behavior FE-model having one stress-strain behavior and for layer-behavior FE-model which consist of coating and substrate separately. The results of simulations showed that layer-behavior model can predict drawing forces with more accuracy in comparison with single-behavior model. Also, mean friction coefficients used in FE-simulation signify the value that can occur maximum drawing force in a drawing test.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 춘계학술대회 논문집
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• pp.109-117
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• 1994

This paper describes a method and a system for automatic generation of flanged cylinderical deep drawing process outlines. A process outline is a sequence of operation leading from the blank to the required finished part. The input is the dimension of final product and the output is the effective process outline to manufacture the product. That system is programmed by PROLOG language and is composed of facts and rules of manufacturing knowledge hierarchically.