6시그마 프로세스를 이용한 정류자(Commutator) 압입 공정개선에 관한 연구

정선환,최성대,양세영 한국기계가공학회 2005 한국기계가공학회지 Vol.4 No.2

Recently 6 quality control is an most important strategy to many enterprises in order to be a top company in the world, because it is an excellent scientific method to achieve the best quality control for their management and products. SY company is a small and medium one that has the quality problem for a long time such as occurring cracks on the surface of commutator at his assembly line while being assembled a rotor shaft and commutator of DC motor. This research was started to improve this problem by 6 process, and as the results of this study, first, to find three vital fews, second, to get an achievement of about 21% improvement for the fracture strength of commutator, and third, to be recognized to change into 6 quality control in SY company.

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.

다축 절삭가공용으로의 육관절 산업용 로봇의 적용평가

정선환,최성대,권현규,최은환,Cheong, Seon-Hwan,Choi, Seong-Dae,Kweon, Hyun-Kyu,Choi, Eun-Hwan 한국기계가공학회 2003 한국기계가공학회지 Vol.2 No.4

The stiffness of multi-articulated industrial robots is very weak, because their structure is an articulated type with some links and joints. Thus it is known that cutting processes for metals are not accepted in machine shop well, but they have a lot of merits for cutting processes, for example, drilling, tapping, and engraving etc, because of the characteristics of their high degree of freedom. The temptation of cutting aluminium was carried out to investigate the feasibility and the limitations or constraints for cutting metals on them. First the mode shapes of 6 degree of freedom welding robot were taken and analysed, and next the cutting processes were practically carried out on it. The results of study were found out to show the feasibility of cutting processes at drilling under 6mm of tool diameter, as well as to have some limitations and constraints, for examples, feed rate, depth of cut and cutting force etc.

절삭가공을 위한 다축 로봇의 강성보강에 관한 연구

정선환,최성대,권현규,최은환,Cheong, Seon-Hwan,Choi, Seong-Dae,Kweon, Hyun-Kyu,Choi, Eun-Hwan 한국기계가공학회 2004 한국기계가공학회지 Vol.3 No.2

Generally industrial multi-articulated robots are used for parts assembly, welding, and painting processes. The high flexibility of them is very useful to not only parts assembly, welding, and painting processes, but also machining processes. But because of machining processes to need a high stiffness of machine structure, so machining is usually not tried at them, except deburring processes now. During past three years the works are carried out to improve the stiffness of a industrial multi-articulated robot With some gas spring as a first idea in this research area. As a result of that stiffness was significantly up, and found and investigated the machining possibility at it.

6시그마를 이용한 유연승강부품에 관한 연구

정선환,최성대,조규열 한국기계가공학회 2006 한국기계가공학회지 Vol.5 No.2

This study was carried out to install the lifting force of a two hinge type stand mechanism by 6 Sigma process in advance. This unit is designed for the display device 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 coil springs and disc springs as a torque generator. The 6 Sigma process was applied to select two key factors among 7 elements to lift the head unit and to find out applicable tolerance securing the 3.4 ppm of defects as well as what deviation of lifting force we can expect between calculation and experiment at the design stage of development. The result of this study can be applied to various units for the optimization of the smooth lift.

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.

라인센터의 성능향상을 위한 동특성 해석

정선환,최성대,권현규,손재률,Cheong, Seon-Hwan,Choi, Seong-Dae,Kweon, Hyun-Kyu,Shon, Jae-Yool 한국기계가공학회 2003 한국기계가공학회지 Vol.2 No.2

Recently, the machine tools have been needed for high speed and accuracy to increase productivity. The most Important thing to get a more stabilized machine is to know the frequency response which has an effect on manufacture a lot. This problem should be considered seriously by many researchers. There are many application programs about FEM but Just using FEM program to get information of the object is not enough to put our confidence in the stability of the machine tool design. Therefore, the purpose of this research is to make a study for proving one of the ways to design to produce stabilized a machine more efficiently by comparing FRT method and FEM. At these two tests, we can learn about the frequency response area causing resonance and we can reconfirm the result to trust.

수직축 풍차의 자기동 성능 개선

정선환,최성대,최명수,손재율,맥이사 알렉산더,김신호 한국기계가공학회 2006 한국기계가공학회지 Vol.5 No.4

The inherent problem of a Darrieus wind turbine is its inability to self-start. Usually, a motor is used to provide angular acceleration until lift forces are produced in the airfoil blades or up until the turbine can already sustain its speed on its own. This paper describes a method of improving the self-starting of an H-type Darrieus vertical axis wind turbine (VAWT) by incorporating a helical Savonius turbine thus utilizing a drag-lift combination. The effect of each turbine in the combination relative to each other is investigated by testing a prototype windmill consisting of three NACA 0015 airfoil blades combined with a Savonius rotor with a helix angle of 180 degrees and whose swept area equals 30% of the entire turbine.

라인센터의 성능향상을 위한 구조설계

정선환,최성대,권현규,최언돈,손재률,Cheong, Seon-Hwan,Choi, Seong-Dae,Kweon, Hyun-Kyu,Choi, Un-Don,Shon, Jae-Yool 한국기계가공학회 2003 한국기계가공학회지 Vol.2 No.3

Recently, the field of the engineering has been studied about optimum design continuously. Verified data by comparison with simulation and dynamic characteristic analysis enables the design of a machine tool to be modified easily and effectively concerning to the mode shape of the vibration. Especially, BC-500 Line Center has got some problems causing vibration which mainly come from Column and ATC part. So it is necessary to solve those problems by the two kinds of method such as changing structural design and reinforcing with ribs. In this paper, column and ATC part of BC-500 Line center are modified by an optimum design by the analysing method of FEM to avoid vibration. As a result, a more stable machine tool was designed by this simulation as optimum condition.

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