• 대한기계학회논문집A
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• 제22권2호
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• pp.476-481
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• 1998

It is generally known that in high speed work with more than 1000 m/min cutting speed, according to the work material phenomenon of tool wearing is increased due to the some produced neat and as a result this makes the cutting work impossible. In this study, the high speed cutting is possible because of the different cutting from the presently known fact. That is, most of generated heats influence on the quantity flowing in chip greatly. Therfore, this study aims at the behavior of cutting heat generated at high speed cutting. It makes clearly the euqntity of heat flowing in chip, work materal, tool, and inflowing ratio. The cutting mechanism varies by the changing of cutting depth, slant face and contact area through this study. And it is exammined that the influence of heat of all parts is greatly due to the change the contact length of clearance face. It is confirmed from the exp[eriment that the inflowing heat ratio influences the cutting speed greatly and the heat of clearance face can not be disregarded.

• International Journal of Advanced Culture Technology
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• 제9권1호
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• pp.224-241
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• 2021

According to data from the National Police Agency, 75.5 percent of dead traffic accidents in Korea are truck accidents. About 1,000 people die in cargo truck accidents in Korea every year, and two to three people die in cargo truck accidents every day. In the survey, Korean cargo workers answer poor working conditions as an important cause of constant truck accidents. COVID 19 is increasing demand for non-face-to-face logistics. The inefficiency of the Korean transportation system is leading to excessive work burden for small logistics The inefficiency of the Korean transportation system is causing excessive work burden for small individual carriers. The inefficiency of the Korean transportation system is also evidenced by the number of deaths from logistics industry disasters that have risen sharply since 2020. Small and medium-sized Korean Enterprises located in CIPs (Connected Industrial Parks) often do not have smart access certification systems. And as a result, a lot of transportation time is wasted at the final destination stage. In the logistics industry, time is the cost and time is the revenue. The logistics industry is the representative industry in which time becomes money. The smart access authentication system architecture proposed in this paper allows small logistics private carriers to improve legal stability, and SMEs (Small and Medium-sized Enterprises) in CIPs to reduce logistics transit time. The CIPs smart access system proposed in this paper utilizes the currently active Mobile OTP (One Time Password), which can significantly reduce system design costs, significantly reduce the data capacity burden on individual cell phone terminals, and improve the response speed of individual cell phone terminals. It is also compatible with the OTP system, which was previously used in various ways, and the system reliability through the long period of use of the OTP system is also high. User customers can understand OTP access systems more easily than other smart access systems.

• 소성∙가공
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• 제10권3호
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• pp.193-199
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• 2001

Forming more than two parts of sheet metal in a single stamping operation lowers production costs, reduces weight, and heightens dimensional accuracy. The tailored blank (TB) is a laser-welded or mash-seam-welded sheet metal with different thicknesses, different strengths, or different coatings. Recently, automotive manufacturers have been interested in tailored blanks because of their desire to improve the rigidity, weight reduction, crash durability, and cost savings. Therefore the application to auto-bodies has increased. However, as tailored blanks do not behave like un-welded blanks in press forming operations, stamping engineers no longer rely on conventional forming techniques. Field try-outs are very important manufacturing processes for an economic die-making. In the field try-outs, the rounded geometries of tool and the drawbead shape and size in die face are generally modified when the forming defects can not be removed by the adjustment of forming process parameters. In this study, the field try-outs of tailored door inner panel are introduced and evaluated. The behaviours of laser tailored blank associated with different thickness combinations in the forming process of door inner panel are described focusing on terms of experimental investigations on the formability.

• 열처리공학회지
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• 제20권2호
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• pp.72-77
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• 2007

Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

• 전자공학회논문지CI
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• 제45권1호
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• pp.1-10
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• 2008

본 논문에서는 기존에 얼굴 검출에 사용된 ICT(Improved Census Transform) 변환을 이용하여 눈, 코, 입 등의 얼굴 특징을 검출하는 하드웨어를 설계하였다. 파이프라인 구조를 이용하여 동작 속도를 높였고, ICT 변환, 메모리 공유, 동작 과정의 세분화를 통하여 메모리 사용량을 줄였다. 본 논문에서 사용한 알고리즘을 얼굴 검출 및 인식 분야에서 테스트용으로 주로 쓰이는 BioID 데이터베이스(database)를 이용하여 테스트한 결과 100%의 검출률을 보였고, 설계한 하드웨어의 결과도 이와 동일하였다. 또한 Synopsys사의 Design Compiler와 동부아남사의 $0.18{\mu}m$ library를 이용하여 합성한 결과 총 $376,821{\mu}m2$의 결과를 얻었고 78MHz의 동작 클럭 하에서 17.1msec의 검출 속도를 보였다. 본 논문은 소프트웨어 형태의 알고리즘을 임베디드 하드웨어로 구현함으로 인하여 실시간 처리의 가능성을 보였고, 저가격, 높은 이식성에 대한 가능성을 제시하였다.

• 한국생산제조학회지
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• 제24권5호
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• pp.508-513
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• 2015

In this study, the effect of the helix angle and rake angle of a flat end-mill in the milling of titanium alloy was investigated. Tool shape parameters such as helix angle and rake angle affect the cutting force, cutting zone temperature, vibration, and chip flow mechanism, which in turn determine tool life, surface integrity, and dimensional accuracy of the milling process. To investigate the effect of the helix and rake angles, a certain range of parameters was selected, and three-dimensional tool models were generated for finite element analysis (FEA) for each case. The cutting force and pressure on the tool flank face and rake face were investigated by FEA. Further, several tool models were proposed for machining tests. The cutting force characteristics were investigated by the machining tests.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.435-438
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• 2008

To verify the load equations, the load-stroke curves of the load equation that were analytically derived for sandwich plates were compared with those of the simulations in the case of the total thickness of 3 mm, the thickness of the face sheets of 0.5 mm, a gap between attachment points of 1.5 mm, and a thickness of the core element of 0.8 mm. The results of the comparisons showed that the overall analytic loads enable the prediction of the numerical loads irrespective of the change of the clearance, the radius of the die, and the radius ratio.

• 한국CDE학회논문집
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• 제9권4호
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• pp.286-293
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• 2004

Recently, hot processing using the heat source like laser machining and RFS was developed and spreaded gradually. In order to generate tool-path for the proper hot tool, a new tool-path linking algorithm is needed because tool-path linking algorithm for machining can't be applied. In this paper, zigzag tool-path liking algorithm was proposed to generate tool-path automatically for RFS. The algorithm is composed of three steps: 1) Generating valid tool-path element, 2) Storing tool-path elements and creating sub-groups, 3) linking sub-groups. Using the proposed algorithm, CAD/CAM software for the tool-path generation of hot tool was developed. The proposed algorithm was applied and verified for Venus's face and die of cellular phone case.

• 소성∙가공
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• 제14권1호
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• pp.57-64
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• 2005

This study deals with the cold forging process design for shaft in the main part of automobile motors with rectangular deep groove. In forging process, the accuracy and die lift is very important because it have influence on reduction of the production cost and the increase of the production rate. Therefore, it is necessary to develop the manufacturing process of shaft by cold forging., process variables are the cropped face angle of billet and the eccentric load of punch. The former is derived from cropping test, the latter is occurred by clearance between container and preform. Also, grooved preform select the process variable for decrease in punch deflection. We investigate that a deflection of punch and a deformation of preform to every process variables. Through this investigation, we suggest the optimal preform and process design, expect to be improved the tool life in forging process.

• 대한기계학회논문집
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• 제14권6호
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• pp.1474-1486
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• 1990

본 연구에서는 자동차용 표면처리 강판의 스탬핑 성형에 있어서 도금 종류별 도금층의 표면특성과 마찰, 윤활특성의 상관관계를 규명하고, 스탬핑 성형특성을 파악 하여 도금 종류별 최적 성형조건을 도출하고자 한다.