• 유기물자원화
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• 제18권3호
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• pp.87-91
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• 2010

목재 및 비목재 재료는 여과재료로 광범위하게 사용되고 있다. 작은 입자(${\sim}5{\mu}m$)를 여과하는데 사용될 수 있는 구조를 가지기 때문이며, 상대적으로 원가가가 저렴한 재료이다. 이 화이버 필터는 비점오염원을 여과하는데 있어서 목재 및 비목재 재료의 몇 가지 물리적 성질, 특히 입자의 여과에 관하여 주목을 받는 차별화되는 특성을 가지고 있다. 또한, 이들 재료는 각각의 섬유들이 가지는 다양성과 형태로 인하여 비정형성과 복잡한 다공성구조를 형성한다.

• 한국정밀공학회지
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• 제23권9호
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• pp.47-53
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• 2006

An Experiment was carried out to find the scheme far minimization of burr formation on inclined exit surface in drilling. Several drills with different geometry are used for drilling the workpiece with inclined exit surface. Step drills are specified with step angle and step size. The influence of the inclination angle of exit surface on burr formation was observed, which enables to analyze the burr formation mechanism on inclined exit surface. Along the edge on the inclined exit surface, burrs are formed by the bending deflection to feed direction and also burrs are formed in exit direction of cutting edge. To minimize the burr formed in feed direction, the corner angle which is formed by the inclination angle and step angle must be large enough not to be bent to burr. By decreasing step angle of drill and decreasing the distance between two axes of two holes, burr formation at the intersecting holes can be minimized. Burr formation mechanisms are analyzed according to the drill geometries and cutting conditions. Several schemes far burr minimization on inclined exit surface were proposed.

• 한국정밀공학회지
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• 제19권9호
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• pp.166-171
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• 2002

The objective of this paper is to investigate the effect of clearance and the configuration of die system on burr formation by FEM analysis and experimental tests. Compared with casting, forging and machining, shearing has been known, especially in heavy or mass-production industries, as a very economical and fast way to obtain the desired shape Recently, the shearing process becomes widely used in the small and light electronic component manufacturing industries. When shearing a part of sheet metal, the burr formed on the cutting edge is usually unavoidable. The burr would not only degrade the precision of products but also causes additional cost for the deburring process. In this paper, the influence of shearing parameters such as clearance and configurations of the lower pad (ejector) on burr formation is investigated by using the experimental and numerical approach. From the experimental results, it has been shown that the more narrow clearance gives the smaller burr height and the higher shearing forces. The removal of lower holder also makes the sheared surface integrity and the dimensional accuracy become worse. The FEM results (using DEFORM-2D) show good agreement with the experimental results.

• 한국정밀공학회지
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• 제20권12호
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• pp.25-33
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• 2003

A burr has been defined as undesirable projection of material formed as a result of plastic flow from a cutting or shearing operation. It is unavoidable in all kinds of machining operation. As a result, burr makes troubles on manufacturing process due to deburring cost, quality of products and productivity. In this study, the primary interest is about exit burr. The burr formation mechanism in each type of burr is classified. Data bases are developed to predict burr formation result. In the milling operation, we develop an algorithm to analyze the burr formation mechanism by the geometrical analysis on the multi featured workpiece with multi cutting path. The algorithm includes three steps, i. e., the feature identification, the cutting condition identification, and the analysis on exit burr formation. We can predict which portion of workpiece would have the exit burr in advance so that we can manage to find a way to minimize the exit burr formation in an actual cutting. Also, this algorithm can be implemented in a commercial CAM package so that we can simulate the NC code to review the burr formation in advance.

• 대한조선학회논문집
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• 제31권3호
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• pp.31-37
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• 1994

선체 형상을 표현하기 위하여 Bi-Cubic B-spline이 가장 널리 사용되고 있다. B-spline곡선 곡면 정의에 있어서 입력 데이터가 불규칙하거나, 주어진 데이터의 갯수가 많은 경우, 또는 형상이 복잡한 경우에 주어진 형상의 부드러운 곡선 곡면(Smooth curves or surfaces)을 재현할 수 있는 역행렬을 구하기 어렵다. 이러한 문제점을 극복하기 위해 새로운 버텍스 산출법(ISE 방법: Image Surface Expansion Method)을 제시한다. 곡선정의를 이용하여 ISE방법을 검증하였고, 수렴성을 확인하였다. 또한 선체형상을 정의하였으며, Open Uniform B-spline으로 형성된 곡면과 비교하였고, ISE방법의 신뢰도를 검증하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.965-968
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• 1997

The objective of this study is to develop a rigid-thermoviscoplastic finite element program for the analysis of orthogonal cutting process. Deformation of the workpiece material is considered as rigid-viscoplastic and the numerical solution is obtained from the coupled analysis bctween plastic deformation and temperature field, including treament of temperature dependent material properties. The chip and the burr formation are simulated for the non-steady state orthogonal cutting using the developed program. To validate the program the predicted results at chip and burr format~on stage are compared with the published ones. The case of isothermal cutting process is also considered to study the thermal effect on the machining process.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(A)
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• pp.438-441
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• 2011

가상현실기반 충치치료 훈련 시스템에서 필수적으로 구현되어야 하는 부문은 절삭도구인 버(bur)를 이용하여 치아를 삭제하는 과정이다. 치아에 비하여 시술도구의 크기가 상대적으로 매우 작기 때문에 보다 정교한 충돌감지뿐만 아니라 치아 삭제에 따른 형태변형에 동기화된 정확한 충돌 모델이 요구된다. 따라서 본 논문에서는 디스턴스 필드를 이용한 볼륨 모델을 치아에 적용하고 이를 형태변형 시각화와 햅틱 렌더링에 함께 이용하는 실시간 충돌 모델을 제안한다. 또한 안정적인 햅틱 피드백을 위해 버의 포인트 쉘 생성 방법과 시간 응집도에 따른 점 접촉 모델 가속화 방법을 제시한다.

• 한국생산제조학회지
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• 제8권3호
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• pp.76-82
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• 1999

This study was carried out to verify finding performance of dental diamond bur and investigate the possibility of AE application in density field. Work pieces were made of acryl and bovine respectively for the experiments in this study. Grinding test was conducted to get the data of grinding resistance and specific finding energy of low different types of diamond bur by using tool dynamometer. AE signal was acquired to verify grinding process in the AE measuring system. AErms value was increased as the grinding velocity and depth were increasing, but it decreased as the feed rate was increasing. The case of the small value of AE signal is due to abnormal grinding in D type diamond bur. By analyzing AErms start and finish time of grinding working, abnormal grinding state can be confined. Abnormal state can be found through the behavior of AE signal in the finding working. As a result, it is expected that forecast of abnormal state is possible using AE equipments under real time process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.414-418
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• 1996

This paper aims at reviewing the possibility application over normal or abnormal, detection used by AE and the characteristics of grinding process. In this study, when diamond bur in dentistry with chosen grinding conditions were tuned at grinding. The variation of grinding resistance and AE signal is detected by the use of AE measuring system. The tests are carried out in accordance with diamond burs and workpiece: arcyl and cowteeth. According to the experiment results, the following can be expected; AE has the possibility to detect the state normality and abnormality. However, the grinding resistance measuring can find it difficult to detect it. It can be accurately excepted from AE occurrence pattern in contact start point of diamond but and cowteeth, grinding condition and derailment point. It is known that AErms is well compatible with grinding resistance.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.485-491
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• 1999

A burr is formed in every corner of parts as a result of machining, which produces undesirable edge geometry and influence deeply to surface quality of workpiece. Therefore these burrs must be removed certainly. The cost of removing these burrs is directly proportional to their size. Burrs have been among the most troublesome obstruction to high productivity and automation of machining processes. The proper selection of cutting condition and tool geometry will be helpful to reduce the occurrence of burrs. In paper will observe burr formation along helix angle in end milling and certificate experimentally mechanics relation of helix angle and burr formation.