평판디스플레이용 유연승강유니트의 힌지기구 설계

정선환(Seon-Hwan Cheong),최성대(Seong-Dae Choi),조규열(Gyu-Yeol Cho) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.3

This study was carried out to minimize the lifting force of a two hinge type stand mechanism. This unit is designed for the display devices in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with a coil spring and disc springs as a torque generator. The maximum and the minimum torque value should be calculated initially for the smooth lift. And the reasonable torque distribution is necessary to prevent any auto lift and auto dropping at any position because the torque generated by coil spring is more sensitive than disc spring in tilting the position. Therefore, the analysis of the coil spring is requisite to issue the specific torque value depending on the distorted angle with securing reliability of a long time storage condition. After the theoretical torque value was calculated, the evaluation was carried out by making a proto-type sample, then distorted angle was updated by experiment. The result of this study can readily be applied to various units for the optimization of the smooth lift.

�作業의 回轉精度 解析

鄭璿煥 金烏工科大學校 1986 論文集 Vol.7 No.-

Tapping accuracy mainly depends on the runout of main spindle and tapping holder. If there were a passive controlled tapping holder to compensate the components of error motion due to those runouts, tappping holder accuracywould be maintained in high accuracy. To design a such tapping holder, the rotational accuracy of internal thread tapping must be found. In this paper, the ratational accuracy of internal thread tapping is studied. As the result of this study, a design consideration of tapping holderusing machining centers and milling machines is suggested as follow; the components of pure radial motion and axial error motion are domained to have influence on the rotational accuracy of internal thread tapping.

COBOL 프로 그래밍을 위한 자동화 도구의 설계 및 구현

鄭善煥 건국대학교 1989 論文集 Vol.5 No.-

The general automatic tool is used to provide to a programmer a good software development environment by assisting him with the operation of computers or part of the work for developing software. The control system of the automatic tool for COBOL PROGRAMMING in this thesis preserves, in the text files, the program information by replacing the information with formation is made by a programmer through proper programming sentences. The program through a dialogue with the computer. This series of course is repeated in the control system until a target program is completed. The general automatic tool implemented in this thesis produces information files through screen-oriented menus. And thus even a nonprofessional programmer as well as a professional programmer can program with ease using this method. Furthermore, this general automatic tool enables an easy production and maintenance of a program by generating the target program through the feedback of a proto type.

旋削加工時 削切出口에서 發生하는 超硬工具의 破損機構에 關한 硏究

鄭璿煥 金烏工科大學校 1982 論文集 Vol.3 No.-

This paper deals with the failures of carbide tools during the exit phase in turning. The main emphasis of the present study was to classify and analyze the cause of tool failures at exit without the additional complications of wear. So, each cutting edge was used for only one cut in the experiments. Cutting test were performed with different exit angles, "ø". It was observed that the exit angle "ø" significantly affects the nature and probability of fracture at exit, but the entrance angle θ was found to have no effect on the failure. Three major types of tool failure were observed at exit in these "single-cut experiments." : i) Fracture at exit associated with fracture of the last portion of the workpiece. ii) Chip-tool adhesion and subsequent flaking off of tool material from the rake face on applying a small force to remove the welded chip. iii) Built-up-edge and subsequent chipping when small force was applied on the BUE after the cut.

工科技術敎育에 關한 硏究 : 工高出身學生만을 對象으로 한 工學技術敎育 -機械ㆍ電子- 硏究 A study on the engineering technology education for the students with the background of Technical High School education in mechanical and electronic fields

鄭璿煥 金烏工科大學校 1981 論文集 Vol.2 No.-

Korean industry is now changing rapidly from the type of labour-intensive industry to technology-intensive industry. This shift is away from a dependence upon the light-to-medium manufacture of textiles and clothing to the medium-to heavy manufacturing of a more sophisticated pattern. This growing sophistication results in a change in the numbers and kinds of workers needed in industry. They must master and keep abreast with the processes necessary for ultimate production. The gap between skilled workers and engineers of more abstract engineering fields needs a new type of workers such as technicians or technologists in the technology spectrum of Korean industry. The 4-year program of engineering technology education to bring up engineering technologists started from United States of America in the 1960's at first. There also developed, in several universities, 4-year curricula that were not engineering but technical in content. These were generally manufacturing-or production-oriented, and not connected with the engineering departments. In Korea, Kum-oh Institute of Technology opened on March, 1980 first started for the specialized engineering education to educate engineering technologists with the background of Technical High School education. The purpose of this thesis is to reaffirm the educational goal of K.I.T. and develop a relevant program to bring up engineering technologists in Korea.

칼라 TV 생산 라인의 자동화 구축에 관한 연구

정선환,최성대,유종규 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

The Toyota Production System (TPS) developed by Toyota corporation is a management principle and production model to improve values added through eliminate of waste. Since the oil shock in 1970s, the TPS has drawn the worldwide attentions as a main factor of competitiveness of Japanese manufacturing system and has been studied and implemented in many countries regardless of size and types of industry. For the correspond to various customer's requirement, it is required to establish on time delivery procedure and to shorten lead time. Therefor it intended to establish TPS which is adopted to 7 losses reduction and JIT(Just In Time). In this paper, the automatic production line for color TV manufacturing by TPS was developed and proved tp push up two times of productivity, to reduce the 25 workers at a time, and to widen the flexibility of manufacturing from 14" to 25" TV

NC파트 프로그래밍을 위한 전문가시스템

정선환 대한기계학회 1994 대한기계학회논문집 Vol.18 No.11

An expert system for NC part programming of NC lathe (ESPP-1) is developed as a part of Computer-Adied Manufacturing system. Conventional computer-assisted part programming system essentially requires an NC part programmer who is an expert in NC part programming. But the developed ESSP-1 can allow an inexperienced person to make an excellent NC data for the NC Lathe without any problem, since the system has a knowledge base composed of EIA and ISO NC code, feed rate, spindle speed, machining coordinates selection, and tool selection etc., which were directly evoked from some skilled NC part programmers, and referenced some machining handbooks. This paper discusses the algorithm of the expert system for NC part programming of the NC lathe (ESPP-1) and the performance comparisons between the developed expert system and the conventional system.

LCD 모니터 힌지용 인장 스프링의 피로특성

정선환(Seon-Hwan Cheong),최성대(Seong-Dae Choi),김기만(Ki-Man Kim),변용근(Yong-Kun Byun),양승철(Seung-Cheol Yang) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.1

The spring is an important mechanical parts to improve the functions of precision machines, automobiles, ships, industrial machines, and IT devices etc.. The hinge mechanism for LCD monitors is very important to support and maintain the proper position of monitor panel, and the tension spring which is a major parts of hinge mechanism plays a significant roll to provide the supporting force positioning the monitor panel. In this paper, an analysis and experiment were carried out to investigate the fatigue characteristics of the tension spring of hinge mechanism, such as hardness test, fatigue test and fractography analysis. As a result of this study the SWPB with heat treatment and shot peening was found to have the optimal design conditions of tension spring for LCD monitor hinge mechanism.

친환경 온/오프 다이어프램 밸브 개발

정선환(Seon-Hwan Cheong),최성대(Seong-Dae Choi),김신호(Shin-Ho Kim) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.4

Currently, most of all valves using at the semiconductor & LCD manufacturing process are pack less type. Such valves are needed to have the functions to protect perfectly from the leakage of fluid by using bellows and diaphragm instead of the grand packing. But not only those valves made in Korea are not available at this point, but also advanced foreign manufacturers do not open enough their data on the basic technology. Otherwise although they open the data a little, they are almost data about stainless steel for pneumatic valves. In this paper, it was focused on the fluid valves for chemical & DI water based on the data of steel valves which are already using commercially. And also this study concentrated to collect the basic developing data of Eco-On/Off diaphragm valve by ourselves.

반도체 실리콘 웨이퍼 가공용 폴리싱머신의 구조해석에 관한연구

정선환(Seon-Hwan Cheong),최성대(Seong-Dae Choi),권현규(Hyun-Kyu Kwon),손현수(Hyon-Su Son) 한국기계가공학회 2006 한국기계가공학회 춘추계학술대회 논문집 Vol.2006 No.-

Although Korea is now the top nation to produce non-memory semi-conductors in the world, but there are lacked informations about the researches and developments for the domestic equipments to manufacture the accurate silicon wafer such as a lapping, and polishing machine. Therefore in this study, as the consideration to develop a domestic polishing machine in the future, some trials were carried out to take some basic design data being useful to improve the structure of a specified polishing machine for silicon wafer. It was focused in plate and frame part that is base part in a polishing machine. Through its' 3D modeling, and structural analysis, the problems were investigated the deformation and stress of major parts, and the improvement methods were proposed by the results of analysis. As results, the thermal deformation in plate that contacts directly with silicon wafer was dominated, and they were known that it was very important to review the design factors to get a stability of thermal, and a structural robustness, too.