초정밀 금형가공기를 이용한 비구면 렌즈 가공특성 연구

백승엽,이하성,강동명,Baek, Seung-Yub,Lee, Ha-Sung,Kang, Dong-Myeong 한국금형공학회 2007 한국금형공학회지 Vol.1 No.1

The fabrication of precision optical components by deterministic CNC grinding is an area of great current interest. Replacement of the traditional, craftsman driven, optical fabrication process is essential to reduce costs and increase process flexibility and reliability. Moreover, CNC grinding is well suited to the fabrication of complex shapes such as aspheres, making it possible to design optical systems with fewer components and reduced weight. Current technology is capable of producing surfaces with less than 2 microns peak to valley error, 50 nm rms surface roughness, and less than 1 micron subsurface damage. Bound abrasive tools, in which the abrasive particles are fixed in a second (matrix) material, play an important part in achieving this performance. In this paper, the factors affecting the ultra-fine surface roughness and profile accuracy of machined surfaces of aspheric parts has been analyzed experimentally and theoretically and on ultra-precision aspheric grinding system and precise adjusting mechanism have been designed and manufactured. In the paper we report the results of experiments and modeling performed to examine the effects of machinability, occurring during grinding of optical surfaces, on the tool surface profile. Profiles of machined surface were measured by using SEM. In order to optimize grinding conditions of aspheric lens processing, we performed experiments by design of experiments.

철도차량 차체 가스용접 이음재의 가속수명예측과 신뢰도 평가

백승엽,Baek, Seung-Yeb 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.1

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of a railroad car and vehicles structure.However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weld, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, $({\Delta}{\sigma}_a)_R-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test(ALT) was conducted. From the experimental results, an acceleration model was derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

파우치 포장 장비의 변형량 및 응력해석

백승엽,최승건,정연승,장영주,Baek, Seung-Yub,Choi, Seung-Geon,Jung, Yeon-Seung,Jang, Young-Ju 한국금형공학회 2016 한국금형공학회지 Vol.10 No.1

Beverage industry is the largest in the domestic packaging market. Usually, beverage is packed in palstic, glass, can and paper bags. However, the cost of these packaging methods are very high and the recycling are not easy to handle. Pouch packaging method is one of the packaging method to solve the drawbacks of former beverage containers. The pouch packaging methods are difficult to control, it requires a number of processes. A vertical form-fill-seal machine which is self-developed is the capable of processing in a single apparatus. In this paper, in order to develop a pouch equipment, the structure analysis was carried out for the main unit. The stress and deformation of feed unit which removes the air inside the pouch while feeding down has been analyzed. It receives the greatest impact from the rolling part. And also, the sealing unit has been analyzed. The analysis result shows that the stress and the deformation was slight to be applicable to the actual system.

HDM을 이용한 잔류응력측정과 압축·인장 잔류응력이 인가된 재료의 피로수명평가

백승엽,Baek, Seung Yeb 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.2

This paper Investigated the characteristics of residual stress in weld is composed of typical specimens, are investigated by using three dimensional thermal elasto-plastic FEM analysis. Numerically calculated residual stresses in the gas welds were then compared with experimental results obtained by the hole-drilling method. Using the stress amplitude (${\sigma}a$)R at the hot spot point of gas weld, the relations obtained as the fatigue test results for typical specimens having various dimensions and shapes were systematically rearranged to obtain the (${\sigma}a$)R-Nf relationship. It was found that more systematic and accurate evaluation of the fatigue strength of plug- and ring-type gas-welded joints can be achieved by using (${\sigma}a$)R.

금형부품의 품질향상을 위한 표면처리에 관한 연구

백승엽,이하성,강동명,Baek, Seung-Yub,Lee, Ha-Sung,Gang, Dong-Myung 한국금형공학회 2008 한국금형공학회지 Vol.2 No.5

Micro Electrochemical Machining(Micro ECM) has traditionally been used in highly specialized fields such as those of the aerospace and defense industries. It is now increasingly being applied in other industries where parts with difficult-to-cut material, complex geometry and tribology such as compute. hard disk drive(HDD) are required. Pulse Electrochemical Micro-machining provides an economical and effective method for machining high strength, high tension, heat-resistant materials into complex shapes such as turbine blades of titanium and aluminum alloys. Usually aluminum alloys are used bearings to hard disk drive in computer. In order to apply aluminum alloys to bearing used in hard disk drive, this paper presents the characteristics of Micro ECM for aluminum alloy.

금형가공을 위한 초정밀 나노가공기의 구조해석

백승엽,김선용,Baek, Seung-Yub,Kim, Seon-Yong 한국금형공학회 2007 한국금형공학회지 Vol.1 No.1

As various manufacturing technology of optical glass is developed, the aspheric lenses are supplied to many fields. Electronic or measuring instruments equipped with aspheric lens have recently been used since aspheric lens is more effective than spheric one. However, it is still difficult manufacture glass lens because of high cost and the short life of core. The demands of the aspheric glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. For the mass production of aspheric lens, specific molds with precisely machined cores should be prepared. In order to obtain competitiveness in the field of industrial manufacturing, a reduction in the development period for the batch machining of products is required. It is essential to analyze the stress distribution and deformations of machining system which is used for manufacturing the aspheric lens using FEM software ANSYS. Finite element simulations have been performed in order to study the influence of machining system which is developed in this study on structures. It is very important to understand the structural behavior of machining system. This paper investigated the static analysis and dynamic analysis of machining system for aspheric lens to predict the damage due to loading.

프레스 금형을 이용한 석재판 고정장치 개발

백승엽,김선용,Baek, Seung-Yub,Kim, Sun-Young 한국금형공학회 2008 한국금형공학회지 Vol.2 No.4

The productive products are required diversification of product development and advanced for competitiveness. A lot of methods to fix architecture wrapping panels and stone materials are developed in domestic area very much. In this paper, it is very important that a fixing device of slate and molds were developed to reduce the production cost and improve safety. Therefore new model was suggested to reduce manufacturing cost and structure design and FEM analysis were performed to manufacture die press dies for mass production.

CT형 점용접 이음재의 피로설계에 관한 연구

백승엽,Baek, Seung-Yeb 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.2

Stress distribution and deformation on the CT-type(Cross Tension type) spot welded lap joint subjected to out of plane tensile load were investigated by finite element method. Using the maximum principal stresses at the nugget edge obtained by FEM analysis, evaluated the fatigue strength of the CT-type spot welded lap joints having various dimensions and materials. and also, the influence of the geometrical parameters of CT-type spot welded lap joints on stress distribution and fatigue strength must be evaluated. thus, in this paper, ${\Delta}P-N_f$ curve were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curve were systematically rearranged in the $\Delta\sigma-N_f$ relation with the hot spot stresses at the CT-type spot welded lab joints. It was found that the proposed $\Delta\sigma-N_f$ relation could provide a more reasonable fatigue design criterion for the CT-type spot welded lap joints.

자동차(自動車) 번호표(番號標)(보통 번호표(番號標)) 숫자(數字)의 가독성(可讀性)에 대한 연구(硏究)

백승엽,조암,Baek, Seung-Yeop,Jo, Am 대한인간공학회 1988 大韓人間工學會誌 Vol.7 No.1

The purpose of this study is to provide basic research data on the readability of the car number license plate in Korea by experimental procedure. This study is performed by the combination of color contrasts, character forms, and stroke widths. Additionally it is focused on the distance of distinct vision and misreading rate. The results of the this study are as follows: First, as to the color contrasts, the plate which has black on yellow contrast has better readability than current contrast between white and green (white character on green plate, vice versa). Second, as the character forms, it is showed that Quasigothic and NAMEL types have less misreading rates by 42.86% and 42.15%, respectively, than current Gothic type, and they also increase distance of distant vision by 4 meter. Third, as to the stroke widths, it is showed that 12 milli-meter and 14 milli-meter of stroke widths have less misreading rates by 63.94% and 65.33 %, respectively, than current 6 milli-meter of stroke width.

STS301L 용접종류별 이음재의 피로설계에 관한 연구

백승엽,Baek, Seung-Yeb 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.3

Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug type joint, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. And also, the influence of the geometrical parameters of gas welded joints on stress distribution and fatigue strength must be evaluated. the ${\Delta}P-N_f$ curves were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curves were rearranged in the ${\Delta}{\sigma}-N_f$ relation with the maximum stress at the edge of fillet welded joint.