• 한국자동차공학회논문집
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• 제3권3호
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• pp.19-28
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• 1995

The explicit scheme for finite element analysis of sheet metal forming problems has been widely used for providing practical solutions since it improves the convergency problem, memory size and computational time especially for the case of complicated geometry and large element number. The explicit schemes in general use are based on the elastic-plastic modelling of material requiring large computation time. In the present work, rigid-plastic explicit finite element method is introduced for analysis of sheet metal forming processes in which plane strain normal anisotropy condition can be assumed by dividing the whole piece into sections. The explicit scheme is in good agreement with the implicit scheme for numerical analysis and experimental results of auto-body panels. The proposed rigid-plastic explicit finite element method can be used as robust and efficient computational method for prediction of defects and forming severity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.818-821
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• 2004

With a rapid development in the area of micro and ultra precision technology, the micro surface machining of small size parts are explosively increased. Especially, to improve efficiency of various beams in lens and reflector, non-rotational symmetric form and several mm level heights changeable surface can be machined at a time. These geometric complex 3D surface cannot be machined by general short stroke FTS. The long stroke FTS if firmly needed to move directly several mm and have nm level positioning accuracy for the complex surface form. The long stroke FTS used linear motors to drive moving unit long and fine, aero static bearings to decrease friction and moving errors in guide way, optical linear scale with nm level resolution to measure position of FTS. Furthermore, to increase the performance of acceleration of FTS, the light material, such as AL is used for the structure and the high stiffness box type structure is selected. In this paper, the genetic algorithm approach is described to determine a set of design parameters for auto tuning. The authors have attempted to model the design problem with the objective of minimizing the error, such as variable pattern change. This method can give the better alternative than existing other method.

• 한국생산제조학회지
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• 제22권6호
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• pp.921-930
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• 2013

From an economic perspective, an enterprise's business activity depends on the efficient use of corporate resources for generating profits. However, on the enterprise side, it is difficult to measure and evaluate the effective use of each resource. This paper suggests an alternative for eliminating process inefficiencies in the consolidation of competitive power in auto parts manufacturing company A. Multitudinous process variables from company A's raw materials-to-shipment process are configured as input resources, and a Data Envelopment Analysis(DEA) is carried out to determine economical benefit of said resources' operation, as well as how products are manufactured. The DEA model offers a non-parametric approach to measuring relative efficiency using input and output factors. Furthermore, AHP is used for logically deciding the importance of each evaluation factor. In general, DEA models have been used for measuring efficiency of the service and public sectors. However, this study focused on measuring the efficiency of SMEs production lines.

• 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.

• 한국컴퓨터정보학회논문지
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• 제21권3호
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• pp.91-96
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• 2016

We have surrounded undesired living noises in our life. One of biggest noises coming out of range hood during cooking in the kitchen. A range hood is one of the most important appliances in the kitchen because it ventilates polluted air out during cooking, and maintains air quality in the kitchen. But current kitchen range hoods bring up some issues; First, the range hoods consume massive amount of standby power not in use condition. Second, current models have designed manual fan operating system with sudden onset of noise with starting. In this paper, we propose an auto control system entire processes from air ventilation to noise reduction. Our system is consist of three parts (Eco-sensors pack, Main Controller and Active Noise Controller); Eco-sensors pack detects air pollution of kitchen areas and sends the detection values to Main Controller. Main Controller determines operation of range hood by detected values. Active Noise Controller is located inside of the range hood. It received starting signals from Main Controller which elicits degrees of polluted air condition and fan operating speed from 1 to 3. Once Active Noise Controller detected the signals, it runs a ventilating fan until new value from Main Controller becomes 0. while the range hood works, A noise cancellation algorithm inside of Active Noise Controller become activated to reduce levels of noise. As a result, the proposed system clearly shows reduction in power consumption include standby power and decreases in levels of noise.

• 한국지능시스템학회논문지
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• 제10권5호
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• pp.459-465
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• 2000

본 논문에서는 CCD 카메라에서 나오는 NTSC 신호를 분석하여 근거리에서 초점을 맞출 수 있도록 렌즈의 동작을 제어하는 방법을 제안한다. 카메라와 물체의 거리가 약 1미터 이하로 가까워지면 자동 초점 기능을 갖춘 카메라는 영상의 전체적인 초점보다는 가장 근접한 미세 부분을 기준으로 초점을 맞추어서 영상을 획득한다. 이러한 문제를 해결하기 위해, 어닐링 알고리즘을 이용하여 CCD 카메라 렌즈에 내장된 모터를 영상의 전체적인 신호에 따라 제어하여 근거리에서 처리대상에 가장 적합한 영상을 획득하는 방법을 제안한다. 이러한 CCD 카메라 초점 제어 기술은 눈의 홍채를 이용한 인식 시스템에서 사용될 목적으로 개발되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.834-840
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• 2001

Gear is general mechanical elements that used for power transmission between two shafts that interval is comparatively short. and it delivers big power as accurate ratio of speed. The profile of Spur gear which is the most basic factor is divided into Trochoidal fillet curve and Involute curve. Involute curve is used a lot of a shaped curve of machine parts such as a gear, a scroll compressor and a collar of centrifugal pump. However, It is poor to study the modeling of Trochoidal fillet curve and the three dimensions model shaped mathematical curve. This paper describes a mathematical model of profile shifted involute gear. and this model is based on Camus's theory. We draw three dimensions gear have accurate mathematical function using ADS, VisualLISP. and To check accuracy and perfection, we make a program of checking Interference. and use for this study.

• 한국기계가공학회지
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• 제6권1호
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• pp.62-70
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• 2007

The development of new materials that are light-weight, yet high in strength has become vital to the machinery, aircraft and auto industries. However, there are a lot of problems with developing such materials that require expensive tools, and a great deal of time and effort. Therefore, the improvement of fatigue strength and fatigue life are mainly focused on by adopting residual stress. The fatigue crack growth rate of the Shot-peened material was lower than that of the Un-peened material. And in stage I, threshold stress intensity factor of the shot-peen processed material is high in critical parts unlike the Un-peened material. Also, fatigue crack growth exponent and number of cycle of the Shot-peened material was higher than that of the Un-peened material. That is concluded from effect of da/dN. And Fatigue life shows more improvement in the Shot-peened material than in the Un-peened material. And compressive residual stress of surface on the Shot-peen processed operate resistance force of fatigue crack propagation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.450-454
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• 1997

This system is the automatic boiler tube bending equipment which has four heads for bending the tube and the carriage for moving the tube. The system consists of two frames for transporting each moving parts, high-frequency heating equipment for heating the tube in hot bending, control panel for inputting the job data operating, remote control unit for concetration and distribution of input/output, and the monitoring system which can establish unmanned operationby receiving the bending job data via LAN form a design teamwhich produces the job data and schedule based on master production plan and diagnoses bending data change, input, whole system status, and system malfunctions. By employing this system, 30% of production improvement was achieved was achieved comparing to the existing bending system.

• 한국생산제조학회지
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• 제23권4호
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• pp.345-349
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• 2014

In this study, an age-hardened 6061-T6 alloy sheet was used, which is commonly utilized for auto parts. The junction strength characteristics in relation to the stirring speed and welding speed were studied in accordance with the friction stir welding rotation of the tool pin. Micro hardness measurements of A type and B type pins, for a welding speed of 400 mm/min and a tool rotational speed 3000 rpm, were obtained as Hv104 and Hv111, respectively. For a welding speed of 200 mm/min and a tool rotational speed of 2000 rpm, we obtained Hv48 and Hv50 for A and B type pins, respectively. Microstructure observation showed that the stirring portion was fine and uniform, which occurred because of its plastic deformation. In the thermomechanically affected zone, partial recrystallization was present because of the plastic deformation. The crystal grains in the heat affected zone were coarsened due to the heat generated by friction stir welding.