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.

고속, 고정밀 및 고생산성을 위한 머시닝 센터의 시스템 동정

정선환,노승훈 金烏工科大學校 1994 論文集 Vol.15 No.-

Machining center is one of the most important machine tools in the machine shop because of its productivity and high flexibility. This paper describes the system identification of the main spindle system of a machining center which was manufactured by a small and medium company in korea. The main spindle system greatly affects the cutting speed, accuracy, and productivity of the machine tools. The result shows that the main spindle system has acceptable dynamic performance in the current speed range, but it should be modified for the higher speed for the stable operation of the machine.

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

DFSS에 의한 FPD용 높이 조절기구 설계

정선환,최성대,조규열 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

This study was carried out to minimize the lifting force and to design the slim sized frame of a height adjustment mechanism. This unit is designed for the display devices in order to enhance the ergonomics for effective height adjustment as well as to achieve much slimmer frame for the pedestal. A tolerance analysis of 6 sigma was applied to achieve smooth lift at design stage not to change the tolerance specification of gap several times in a roller type of lifting mechanism at mass production stage. The specification of minimum gap and the target of production yield ratio were agreed with a quality team before tooling. A DFSS simulation on drawings had been done with reasonable tolerance and achievable standard deviation(σ) several times until the target spec of gap and yield ratio was met. Once tolerance and deviation(σ) were fixed tooling start was done successfully. A CAE method was applied to achieve a slim design. Design parameters were frozen when those parameters matched the reference strength data of standard model. Through those tolerance analysis and CAE simulation the number of tool modification was reduced and production yield ratio was raised up without arguing quality specification at production stage in the end.

�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.

Feed Back 제어를 이용한 감광액 공급용 정량제어 펌프 시스템 개발

김신호,정선환,최성대 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

This study was carried out to develope a flow control system using to supply PR(photo-resist) in the semi-conductor manufacturing process. The features of this system are to be able to measure the high viscosity and micro-flow. To meet above study object some ideas was induced to design a new concept valve with new material, multi-cross wheel, and new sealing method etc.. As the evaluations on the developed micro-flowmeter it was enough satisfied to use at the IT industries such as photo-resist process.

리사이클을 위한 평판 유리 파쇄 장치 개발

최성대,정선환,김잠규,김우재,김용선 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

At a point time, when demand is gradually increasing on LCD and PDP market all over the world, demand on glass which is key part of LCD and PDP is increasing, too. Hence, glasses are being cut by requested size for satisfaction on demands, the remain glass is making problems. This study is for designing installation of handling these remained glasses effectively and easily.

Instability of the Whirl of Rotors in Pinion Gear System

盧承勳,鄭璿煥 金烏工科大學校 1989 論文集 Vol.10 No.-

기어시스템의 불안정성 횡진동에 대한 연구는 실용적인 측면에서 대단히 중요하다. 본 연구에서는 로터시스템의 베아링에 의한 지지를 용수철에 의한 지지로 단순화 한후, 이상화된 모델에 대하여 불안정 구간을 예견하였다. 질량불균형과 외진가속도의 변화에 따른 임계강성도의 존재가 확인되었다.

고출력 다이오드 레이저를 이용한 SKD11 표면 열처리 특성

최성대,정선환,양승철,김잠규 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

An experimental investigation with high power diode laser system was carried out to study the effect of surface heat treatment on the SKD11. The surface heat treatment characteristics of the laser beam were evaluated using hardness tests, optical microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy(EDS). Results indicated that the Hardness were changed by beam size, focal length, feed rates. The micro grain structure was observed retained austenite grain at hardened zone and globular cementite grain at fine grain zone and base metal zone by optical microscopy. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected on the surface and the hardened surface intensity level was bigger than the unhardened surface. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected hardened surface and the hardened surface distributed plenty of carbon density than metal zone.

과학개념의 위계적 분석 및 그 적용을 통한 교수 효과와 과학교육과정 계열성의 타당화 평가 연구

정진우,조선형,임청환 한국교원대학교 과학교육연구소 1996 청람과학교육연구논총 Vol.6 No.1

The purpose of this study is to investigate the psychological hierarchy structure of science concepts and to determine the effective teaching order by comparing the teaching effects of the psychological hierarchy order with those of teaching order of the current text in order to inquire validating evaluation framework of science curriculum sequence. Key concepts were selected by tasks analysis in the seven units of elementary and secondary school curriculum. Concept formation tests were developed to evaluate each concepts achievement. The test items were made according to each of the concepts based on 12 prototype tasks developed by Frayer(1969). To identify the students' psychological hierarchy the test items were administrated to elementary and secondary school students. Ordering theory was used to identify the students' psychological hierarchy. Nonequivalent control group pretest-posttest design was used in this study as an experimental design. Teaching with psychological hierarchy order was applied tp experimental group and teaching with concept order described in the current text was applied to control group. The major results of this study are as followings: 1. The students' psychological hierarchy structures are different from logical hierarchy structures. 2. The science teachers' psychological hierarchy structures are different from not only logical hierarchy structures but also students' psychological hierarchy structures. 3. The mean score of experimental group applied psychological hierarchy order is significantly higher(p<.05) than the control group in the concept achievement.