파인세라믹의 연삭잔류균열깊이에 관한 실험적 연구

정윤교 國立 昌原大學校 産業技術硏究所 1994 産技硏論文集 Vol.8 No.-

The application of advanced ceramics as a substitute for classical is increasing because of their excellent properties. It is, however, not easy to grind these materials because they are strong, hard and brittle. In this study, representative advanced ceramics are ground and grinding mechanism is discussed in terms of the grinding force, grinding energy and surface roughness. The depth of the residual crack after grinding and critical grain load is estimated on the basis of the indentation theory. Furthermore, the propriety for results obtained is investigated by observation of a grinding profile.

CNC工作機械 移送誤差의 發生要因에 관한 實驗的 硏究

鄭潤敎,高亥柱 國立 昌原大學校 産業技術硏究所 1992 産技硏論文集 Vol.6 No.-

The accuracy of machine tools is the major factor concerned with the accuracy of the processed work. The feed errors of feed system in machine tool, therefore, make the machining errors of work directly on processing. In this point, this study focused on the generative elements in feed errors of CNC cylindrical grinding machine, such as supporting method of ball screw, the effect of pitch and yaw error and the position detecting method in servo system when operating its shaft of grinding wheel head. Furthermore, in order to improve the accuracy of this machine tool, feed errors are measured by a laser interferometer. Results obtained in this study provide some useful informations to attain high accuracy of CNC machine tool.

파인세라믹의 고능율 크리프피-드 연삭

정윤교 國立 昌原大學校 産業技術硏究所 1990 産技硏論文集 Vol.4 No.-

Advanced ceramics have some excellent properties which are suitable for mechanical components. It is, however, quite difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness, Now, creep-feed grinding is well known as an effective technology to increase the productivity of form grinding. In this study, creep-feed grinding is carried out for representative advanced ceramics, such as Al₂O₃, SiC, and Si₃N₄. The grinding force, surface roughness, chipping size and grinding rato are experimentally investigated. In addition, some proposals are made to resolve adverse effects in creep-feed grinding. Experimental results show that a resinoid bonded diamond wheel with grooves on the grinding surface. which is proposed in this study, has an excellent performance. Furthermore. the influence of the grinding fluid on the creep-feed grinding is investigated.

스크류유량계 개발에 있어서의 역공학 및 성능평가에 관한 연구

김종윤,황종대,이상열,정윤교 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

This research presents a modeling and a manufacturing method of screw type flow meter. This paper introduces the efficient design and manufacturing method of screw type flow meter using reverse engineering and test technology. The methods introduced this paper utilize the reverse engineering that is increasing accuracy of modeling and manufacturing of reverse model. And then it can be used in performance test with hydraulic test equipment. Hence this can be used in the basic document for development of the quite accurate flow meter.

고능율 와이어컷 방전가공조건에 관한 실험적 고찰

배성한,정윤교 國立 昌原大學校 産業技術硏究所 1993 産技硏論文集 Vol.7 No.-

Wire-cut electric discharge machining is technique in the midst of development, and the factors of effect on working characteristic are various. Purpose of this study is to obtain efficient machining condition for metal mold of satisfactional quality from experimental study in wire-cut electric discharge machining with alloy tool steel STD11. In this study, the effect of peak discharge current[Ip], gap voltage[Vg], and spark cycle[T] on machining speed[F], kerf width[G], and surface roughness[Ra] in wire-cut electric discharge machining are discussed mainly. It is found that F is function of Ip, Vg, T and expressed ad F = {α*Ip*(V-Vg)+β}/T[mm/min]. Relationship between Ra and F can be written as Ra=γ*F+δ[μm]. G is proptioned to Ip and Vg but is not connected with T. If the average roughness of metal mold is, therefore, decided, the machining speed and efficient machining conditions can be calculated.

절삭조건과 AE 신호들과의 관계에 관한 실험적 연구

조종래,정윤교,원종식 창원대학교 공작기계기술연구센터 1999 연구업적집 Vol.1 No.1

This paper investigates the relationship between cutting conditions and Acoustic Emission(AE) signals; AEavg, AErms, AEmode, as the base working to monitor the tool wear with in-process. For this purpose. cutting tests were conducted on a CNC lathe with comprehensive cutting conditions. It is known that AEavg and AErms are increased as the increasing of cutting velocity and depth of cut respectively. The new parameters, derived from AEavg and AErms, which may be used for the in-process detection of tool wear is discussed. It is also known that AEmode may also be applied for in-process monitoring to make the self diagnosis system because of its stability to the variation of cutting conditions.

C^(++)과 신경망을 이용한 In-process 감시 시스템의 구축

조종래,정운교 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

Monitoring of the cutting trouble is necessarily required to do Factory Automation and Intelligent manufacturing system. Therefore, we constructed a monitoring system using neural network in order to monitor of the cutting trouble. From obtained result, it is shown that the cutting trouble can be monitored effectively by neural network

인서트형 밀링커터의 복합5축가공 기술개발에 관한 연구

황종대,정윤교 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This research presents a modeling and a manufacturing method of insert type milling cutters such as face cutter, flat endmill and ball endmill. The methods introduced in this paper adopts the multi-tasking 5-axis machining that is increasing machining accuracy of holder and position accuracy of bolting points. So this can be used in the basic document of the total package program that involves modeling and manufacturing module in various insert cutters.

화상에 의한 간상해에 Anti-prostaglandin이 미치는 영향

김용송,임정교,손윤경,서인수,손태중 慶北大學校 醫科大學 1991 慶北醫大誌 Vol.32 No.1

저자는 anti-prostaglandin의 화상독에 의한 간상해에 미치는 영향에 관하여 알아보고자 Sprague-Dawley계 흰쥐 수컷의 체표 30%에 3도 화상을 일으키고 생리식염수와 anti-prostaglandin제제인 flurbiprofen을 투여한 후 각각 5일과 10일 후 도살하여 간의 변화를 관찰하였으며 성적은 다음과 같다. 생리식염수를 투여한 실험군에서는 화상 5일 후 간세포에 mitochondria의 상해와 ER의 확장이 있었고 유동내에는 호중구 등 염증세포의 침윤이 있었다. 화상 10일 후에는 상기한 mitochondria의 상해가 거의 수복되고 ER의 확장도 감소되었으며 유동내의 염증세포도 거의 보이지 않았다. flurbiprofen을 투여한 실험군에서는 화상 5일후 mitochondria의 상해와 ER의 확장이 관찰되었으며 이는 화상 10일 후 까지 지속되었다. 이상의 성적으로 보아 중증화상후에 간은 화상독에 의하여 간세포 mitochondria의 상해를 주로하는 손상을 받게되나 이는 시간이 지나면 수복 가능한 가역적인 상해라 보아진다. 또한 anti-prostaglandin제제는 화상독에 의한 간세포상해에 거의 영향을 미치지 못할 것으로 생각된다. An ultrastructural study was carried out to investigate the effects of burn toxin to liver. Thermal burns wee tried on the skin of Sprague-Dawley rats with severity of 30% and 3rd degree. Flurbiprofen (a kind of anti-prostaglandin) and normal saline was administered every day after burn. The animals were sacrificed at 5 days and 10 days after burns and the livers were extracted for electron microscopic observation. The liver cells of saline intake groups at 5 days after burns were characterized by generalized mitochondrial injury, such as swelling, loss of cristae and membrase destruction. Dilatation of ER and lysosomal increase are also noted. The sinusoid revealed neutrophilic infiltration. At 10 days after burns the liver cells demonstrated nearly normal structure without mitochondrial injury. Mild dilatation of ER was seen. The flurbiprofen intake groups revealed that mitochondrial swelling, loss of critae and destruction of mitochondrial membrane with dilatation of ER and lysosomal increase at 5 days after burns. These features were continued to 10 days after burns. According to these results, it would be concluded that the effects of burn toxin to liver is characterized by mitochondrial injury and it is reversible change. And the anti-prostaglandin drugs may not be effective to inhibit the progressive injury induced by burn toxin.

스텝이송을 이용한 미세구멍가공

한진욱,이응숙,정윤교 國立 昌原大學校 産業技術硏究所 1995 産技硏論文集 Vol.9 No.-

Micro drilling is one of the most important machining types and its importance becomes more and more increased in the whole field of industry. Micro drilling, however, has few the case of practical application, because it requests high techniques; manufacturing micro drill, treating, chip, producing precise hole shape and progressing machining efficiency. Micro drilling has a technical problem; drill breakage from drill breakage from the lack of drill stiffness and the interruption of chip. It is, therefore, essential to select of proper cutting conditions and of step fed for the method solving the lack of stiffness and the interruption of chip. Especially, study on step feed is requested more than the present. The purpose of this paper is to investigate experimentally about cutting conditions which affect on tool life and round errors and to estimate about the efficiency of step feed.