• International Journal of Precision Engineering and Manufacturing
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• 제8권3호
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• pp.64-70
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• 2007

Of all the rapid tooling (RT) methods currently available, thick-layer laminated tooling is the most suitable for large-scale, low-cost dies and molds. Currently, the determination of a lamina's contour or profile and the associated slicing algorithms are based on existing rapid prototyping (RP) data manipulation technology. This paper presents a new adaptive slicing algorithm developed exclusively for profiled edge laminae (PEL) tooling PEL tooling is a thick-layer RT technique that involves the assembly of an array of laminae, whose top edges are simultaneously profiled and beveled using a line-of-sight cutting method based on a CAD model of the intended tool surface. The cutting profiles are based on the intersection curve obtained directly from the CAD model to ensure geometrical accuracy. The slicing algorithm determines the lamina thicknesses that minimize the dimensional error using a new tool shape error index. At the same time, the algorithm considers the available lamination thicknesses and desired lamina interface locations. We demonstrate the new slicing algorithm by developing a simple industrial PEL tool based on a CAD part shape.

• 한국정밀공학회지
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• 제15권10호
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• pp.34-40
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• 1998

The burr produced on piece part edges in machining operations must be removed for most parts to function effectively. Although considerable cost have been expended in improving deburring methods, little energy has been applied toward minimizing burrs. This study has been carried out to prevent the burrs produced on pure aluminium under various working condition and specimen shape in turning operations. The computer image processing system was used for measurement of size of burr, such as burr length, burr depth and burr area. The size of burr showed a decreasing tendency with the increase of rake angle and side cutting angle but it increased rapidly with the increase of depth of cut and the cutting speed has no effect on size of burrs. The size of burr rapidly decreased with the increase of edge angle and burrs are not occurred if edge angle is over 80$^{\circ}$.

• 정보처리학회논문지A
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• 제10A권2호
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• pp.157-164
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• 2003

최근 볼륨 그래픽스가 의료 영상의 해석 도구로서 주목을 받아 오고 있다. 볼륨 그래픽스에서는 가시화를 위하여 복셀로 정의된 물체가 필요하다. 이 때문에 기하학적인 방법으로 정의한 다각형 및 곡면을 복셀 기반의 물체로 변환시키는데 이를 복셀화(voxelization)라고 한다. 기하학적인 물체를 복셀화하면 기하학적 물체 데이터를 샘플링 데이터와 함께 단일화된 방법으로 볼륨 렌더링할 수 있다. 본 논문에서는 큐브의 단면을 이용한 복셀화의 한 기법을 제안한다. 그리고 개인용 컴퓨터 환경에서 이 기법을 구현한 후에 단순한 기하학적인 데이터를 이용해서 평가하여 논리적인 타당성을 조사한다. 이 기법은 변환된 복셀로부터 정확한 법선 벡터를 계산할 수 있고 복셀간에 구멍(hole)이 발생하지 않고 다해상도(multi-resolution) 표현이 가능한 특성을 가지고 있다.

• 한국기계가공학회지
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• 제12권6호
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• pp.159-166
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• 2013

In order to develop the optimum shape of an MQL carbide end-mill suitable for high speed machining of wing ribs which are a detailed part of larger wing structures, using a new material Al-Li alloy, a new MQL carbide end-mill is created that has various quantities of holes, hole sizes, and hole locations. A theoretical machining graph is generated using the hammer test and FRF simulation, and a machining test is performed in order to verify the machining stability in the high speed machining area. The optimum configuration of the MQL carbide end-mill is also presented through comparing the chattering, machining noise and cutting conditions, including the maximum cutting depth, rpm, and feed rate per teeth, for each cutter.

• 대한산업공학회지
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• 제39권3호
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• pp.149-155
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• 2013

Electric discharging machining (EDM) is commonly adopted to machine the precise and tiny part when it is difficult to meet the productivity and the tolerance by the conventional cutting method. The die-sinking EDM method works well to machine the micro-parts and the perpendicular wall of die and mould, whereas EDM drilling, called super drill, is excellent to machine the deep and narrow hole regardless the material hardness and the hole location. However, the electrode wear is rapid compared to the conventional cutting tool and makes it difficult to control the electrode feeding and to machine precisely. This paper presents an efficient method to estimate the electrode wear using hole pass-through experiment while the stochastic method is used to compensate for the estimation model. To validate the proposed method, the commercial EDM drill machine is used. The experiment result shows that the electrode wear amount can be predicted very precisely.

• 한국산학기술학회논문지
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• 제3권2호
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• pp.126-130
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• 2002

본 논문은 쾌속제작법을 이용한 임의형상을 가공하는 새로운 방법의 개념을 소개하고 있다. 본 시스템은 레이저 절단, 이송. 적층, 소결의 단계를 통하여 세라믹재료로 된 임의형상을 가공할 수 있다. 시스템을 구성하는 주요장비로는 레이저 발생장치, X-Y테이블, 이송시스템, 그리고 전기로 등이 있다. 이 시스템을 사용하면 표면의 거칠기가 매끄러운 형상을 상대적으로 짧은 시간에 제작할 수 있는 장점이 있다. 또, 2차 공정을 거치지 않고, 바로 물체를 제작할 수 있어 효율성이 높다고 할 수 있다. 제작된 모형은 바로 조립되어 사용될 수 있기 때문에 응용분야가 다양하다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2001년도 학술발표회 논문집(I)
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• pp.52-59
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• 2001

Methods to measure and estimate transpiration of a forest composed of evergreen broad-leaved trees (Pasania edulis Makino) are studied. Heat pulse velocity has been measured along with soil moisture and micrometeorological factors at the Fukuoka Experimental Forest, the Research Institute of Kyushu University Forests in Fukuoka, Japan (33$^{\circ}$38'N, 130$^{\circ}$31'E, alt. 75m). Tree cutting measurement was conducted to convert the heat pulse velocity into sap flow and transpiration. A big leaf model to calculate transpiration and Interception loss is examined and the estimated values are compared with the measured values obtained from the heat pulse measurement. The results show that 1) Pasania edulis Makino posessing radial pore structure had relatively high water content and high heat pulse velocity even within the central part of the stem near the pith, 2) the heat pulse velocity was well correspond to the water uptake in the tree cutting measurement, 3) the estimation of sap flow based on the heat pulse velocity is accurate, and 4) the big leaf model using the parameters obtained from measurement of a portable photosynthesis system in one day in summer gives reasonable estimation of transpiration independent of seasons and weather.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.666-672
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• 2008

Train wheels are the most important part of the high-speed rail system with supporting body, running stably and safely. Wheel exchange and fix plan is computed by the worker who managing entire Train Maintenance Process based on his know-how so that this system is losing its reliability and accuracy. And predicting of the wheel's lifetime is absolutely difficult matter because of uncertainty between trains like mileage of the type of trains, condition of operation, curve section and wheel's cutting pattern. Therefore workers always used to hold many wheels. For this reason, the cost of stock is soar when the level of stock was normal. If the stock is sufficient, the cost of stock will rise. On the other hand, If the stock is deficient, we would have trouble that the plan of the train maintenance process will be failed. Thus this paper aimed at application that "Wheel Managing System" which is able to predict wheel's life-cycle and demands under the RIMS(Rolling-Stock Information Maintenance System) with analysing wheel exchanging and cutting status considering economical or stable aspects.

• 한국생산제조학회지
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• 제23권1호
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• pp.94-101
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• 2014

Recently, in order to reduce the time required to replace an optical jumper cord, many researchers are using a field-installable connector and applying the ferrule polishing method, ferrule mechanical contact method, or ferrule fusion contact method. However, the process of arranging the length of the optical fiber, i.e., inserting the optical fiber into the ferrule by hand and checking its cross section, takes 60% of the time required for the entire process, which increases the overall cost. Therefore, in order to make this task more cost-effective, we will develop an automated inspection system with automatic cross-sectional arrangement of a field-installable connector. This system will be able to decrease the failure rate from 10% to 2% compared with the conventional method when cutting the optical fiber inserted into the ferrule. It will also improve the productivity by decreasing the test time by 28% compared with the conventional method. Our studies showed that it was possible to reduce the production costs and improve the quality of a field-installable connector, and we expect it to dominate the market.

• 한국산림과학회지
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• 제81권1호
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• pp.21-29
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• 1992

본(本) 연구(硏究)는 강원도(江原道) 인제군 기린면 진동리 소재(所在) 천연(天然) 혼효임분(混淆林分)의 구조(構造) 파악(把握)을 통하여 작업종(作業種) 결정(決定)을 위한 기초자료(基礎資料)를 제공(提供)하기 위하여 실행(實行)되었다 이를 위하여 대상(對象) 임분(林分)의 직경(直徑), 분포(分布), 수고(樹高) 분포(分布), 그리고 경급별(徑級別) 재적(材積) 분포(分布)가 분석(分析)되었고 이를 이용(利用)하여 택벌임(擇伐林)의 가능성(可能性)이 검토(檢討)되었다. 1. 직경(直徑) 분포(分布)는 전형적(典型的)인 택벌임(擇伐林)에서 볼 수 있는 지수감소형(指數減少型) 구조(構造)를 나타냈고 수고(樹高) 분포(分布)에서도 택벌림(擇伐林)으로 유도(誘導)될 수 있는 높은 가능성(可能性)을 보였는데 이는 이 대상(對象) 임분(林分)이 자생(自生) 천연림(天然林) 특유(特有)의 복층림(複層林) 구조(構造)를 소유(所有)하고 있기 때문이다. 그러나 경급별(徑級別) 재적(材積) 분포(分布)에서는 택벌(擇伐) 임형(林型)에 이르지 못한 미성숙(未成熟) 구조(構造)를 보이고 있는데 그 이유(理由)는 30cm 이상(以上)의 경급(徑級)에서의 본수(本數)의 부족(不足)에 기인(起因)한 것으로 판단(判斷)된다. 이러한 구조상(構造上)의 부확실성(不確實性)은 앞으로의 연구에서 밝혀져야 하는데 특(特)히 직경(直徑)과 재적(材積) 생장율(生長率)의 추정(推定)에 의한 미래(未來) 임분(林分) 구조(構造)의 파악(把握)이 시급(時急)한 것으로 보인다.