지능형 주축 설계 기술

황영국(Young-Kug Hwang) 한국정밀공학회 2014 한국정밀공학회 학술발표대회 논문집 Vol.2014 No.10월

꼭지점 계획을 이용한 주축 사이즈와 베어링간 길이 결정

황영국(Young-Kug Hwang),이춘만(Choon-Man Lee) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.10

The spindle is the main component in machine tools. The static and dynamic stiffness of the spindle directly affect the machining productivity and surface integrity of the workpiece. The static and dynamic stiffness of the spindle depend on the shaft size, bearing arrangement, bearing span length, and so on. Therefore, the selection of shaft size and bearing span length are important to improve the spindle stiffness. This paper presents an determination of shaft size and bearing span length in spindle design step. In order to select the optimal bearing and built-in motor locations with constraint conditions, the extreme vertices design was applied. The results show that extreme vertices design is usable for spindle design with design constraints.

공작기계용 고속ㆍ고능률 주축을 위한 가변예압량 결정에 관한 기초연구

황영국(Young-Kug Hwang),이춘만(Choon-Man Lee) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.10

Modern machine tool spindles simultaneously require high stiffness and fast rotation characteristics for high speed, highly efficient processing, as well as for a wide range of use rotation. In order to this, a variable preload technology is needed so that the bearing that can apply a greater preload to raise the stiffness of the spindle at the low speed range and a smaller preload at the high speed range to reduce heat generation, as opposed to greater stiffness, and to allow high speed rotation. This paper propose the algorithm for determining the variable preload. For determination of a variable preload, the bearing life, rigidity, and the gyroscopic slip were considered as the constraint conditions. The bearing life was calculated by simultaneously considering the spindle rotational speed and external load.

Polygalacturonase를 검출하기 위한 종이 기반의 효소결합 면역반응 센서 제작

황영국 ( Young-kug Hwang ),김지관 ( Ji-kwan Kim ),이영환 ( Young Hwan Lee ),최영수 ( Young-soo Choi ) 한국센서학회 2021 센서학회지 Vol.30 No.5

In this paper, we describe the fabrication of a paper-based enzyme-linked immunosorbent assay (ELISA) to detect polygalacturonase (PG), which is used as a biomarker to determine whether a plant is infected with a disease. The proposed paper-based ELISA can analyze the concentration of PG in a short time using a small sample compared to the traditional ELISA, which is generally performed using a well plate. To increase the resolution of the sensor, we optimized the dilution ratio of the HRP-conjugated goat anti-rabbit IgG antibody and the dilution ratio of the anti-PG and HRP-conjugated goat anti-rabbit IgG antibodies. Furthermore, for quantitative analysis of PG concentration, Delta RGB analysis was conducted to detect color changes in the sensing window displayed by the PG samples at various concentrations. Based on the experiment, the fabricated paper-based ELISA could measure at least 0.25 μg of PG and the measurement range was 0.25-2 μg. Therefore, the paper-based ELISA for detecting PG is expected to be able to determine the presence or absence of disease in crops at the infection stage in the future.

꼭지점계획법을 이용한 주축 치수 결정에 관한 연구

황영국(Young-Kug Hwang),이춘만(Choon-Man Lee) 한국생산제조학회 2009 한국생산제조학회지 Vol.18 No.2

The spindle is the main component in machine tools. The static and dynamic stiffness of the spindle directly affect the machining productivity and surface integrity of the workpiece. The static and dynamic stiffness of the spindle depend on the shaft size, bearing arrangement, bearing span length, and so on. Therefore, the selection of shaft size and bearing span length are important to improve the spindle stiffness. This paper presents the determination of shaft size and bearing span length in spindle design step. In order to select the optimal bearing and built-in motor locations with constraint conditions, the extreme vertices design was applied. The results show that extreme vertices design is usable for spindle design with design constraints.

유한요소법을 이용한 주축 인터페이스부의 정강성 특성

황영국(Young-Kug Hwang),정원지(Won-Jee Chung),이춘만(Choon-Man Lee) 한국생산제조학회 2007 한국생산제조학회지 Vol.16 No.1

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems such as the run-out errors and reduced stiffness must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an analysis of static stiffness in the main spindle interface. Finite element analysis is performed by using a commercial code ANSYS according to variation of cutting force, clamping force and rotational speed. From the finite element results, it is shown that the rotational speed and clamping force mostly influence on the variation of the static stiffness in the main spindle interface.

전자석을 이용한 주축용 베어링의 예압 조절 장치에 관한 연구

황영국(Young-Kug Hwang),김웅(Woong Kim),이춘만(Choon-Man Lee) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.5

In today's machining environment, heavy cutting at a low speed and light cutting at a high speed, as are often performed on a single machine tool, must be carried out successively for highly efficient machining as well as high speed machining. Therefore, current machine tool spindles require great stiffness and high speed rotation performance simultaneously. To that end, a preload device is needed so that the bearing that can apply a greater preload to raise the stiffness of the spindle at the low-speed range while a smaller preload at the high-speed range to reduce heat generation as opposed to greater stiffness and to allow high-speed rotation. In this study, the new concept of an automatic variable preload device that can adjust the preload applied to spindle bearing using electromagnetic was proposed. A prototype for the automatic variable preload device using electromagnetic was created. With the prototype, it was confirmed that the preload device based on the proposed structure worked properly.

MQL 선삭가공에서 절삭력과 표면거칠기 향상에 관한 연구

황영국(Young-Kug Hwang),정원지(Won-Jee Chung),정종윤(Jong-Yun Jung),이춘만(Choon-Man Lee) 한국생산제조학회 2006 한국생산제조학회지 Vol.15 No.4

At present, industry and researchers are looking for ways to reduce the use of lubricants because of ecological and economical reasons. Therefore, metal cutting is to move toward dry cutting or semi-dry cutting. One of the technologies is known as MQL(Minimum Quantity Lubrication) machining. This research presents an investigation into MQL machining with the objective of deriving the optimum cutting conditions for the turning process of SM45C. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed rate, oil quantity and so on, with MQL and flood coolant. The surface roughness and cutting force results of tests were measured and the effects of cutting conditions were analyzed by the method of Analysis of Variance(ANOVA). From the experimental results and ANOVA, this research proposed optimal cutting conditions to improve the machinability in MQL turning process.

리니어모터 구조 최적화를 통한 성능 향상 [1]

황영국(Young Kug Hwang),이춘만(Choon Man Lee),은인웅(In-Ung Eun) Korean Society for Precision Engineering 2008 한국정밀공학회지 Vol.25 No.5

고속 주축에서 클램핑력 및 회전수 변화에 따른 주축 인터페이스 접촉률 변화에 관한 연구 (1)

황영국(Young Kug Hwang),이춘만(Choon Man Lee),정원지(Won Jee Chung) Korean Society for Precision Engineering 2006 한국정밀공학회지 Vol.23 No.3

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evolution of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.