• 제목/요약/키워드: Offset Mesh

검색결과 33건 처리시간 0.026초

옵셋 다면체를 이용한 5축 가공경로 생성 (5-Axis Tool Path Generation from Offset Polyhedral Mesh)

  • 김수진;양민양
    • 대한기계학회논문집A
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    • 제30권6호
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    • pp.678-683
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    • 2006
  • In this paper, the 5-axis tool path that has been generated from the original surface is, newly generated from the offset polyhedral mesh. In this approach, the interference check between two solid models can be simplified to that of offset polyhedral mesh and axis line. The tool path computation and interference check based on the offset mesh is simpler and faster than that based on the original surface. But 5-axis tool path generation using this approach is able to apply only for ball endmill and still takes longer time than 3-axis tool path generation.

임의의 구멍을 포함하는 B-Spline 곡면상에서의 자동 삼각 요소망 생성 (Automatic Triangular Mesh Generation Over B-Spline Surfaces Including Arbitrary Holes)

  • 김근호;양현익
    • 한국CDE학회논문집
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    • 제9권1호
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    • pp.1-10
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    • 2004
  • In the process of finite element analysis, mesh generation is tedious job which consumes tremendous time. Therefore, the automation of well shaped mesh generation from the minimal boundary input data is desirable to improve reliability and accuracy of the analysis and also to reduce the process time of the entire design process. The automation of triangular mesh generation has been relatively well treated due to its robustness and ease of handling when compared to rectangular element mesh generation. In this study, the offset method developed previously for generating plane rectangular element mesh has been corrected and modified to generate triangular element mesh on the B-spline surface having arbitrary holes. The result shows that the generated triangular mesh has the average aspect ratio over 0.9. The designed arbitrary surface shape has been interactively constructed by non-uniform B-spline theory for triangular mesh generation.

잔삭 가공을 위한 펜슬커브 생성 (Pencil Curve Computation for Clean-up Machining)

  • 박태종;박상철
    • 한국CDE학회논문집
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    • 제11권1호
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    • pp.20-26
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    • 2006
  • This paper presents a procedure to compute pencil curves from a triangular mesh which is offset with the radius of a given ball-end mill. An offset triangular mesh has numerous self-intersections caused by an abundance of invalid triangles, which do not contribute to the valid CL-surface. Conceptually, we can obtain valid pencil curves by combining all intersections tying on the outer skin of the offset triangular mesh, i.e., the valid CL-surface. The underlying concept of the proposed algorithm is that visible intersections are always valid for pencil curves, because visible intersections lie on the outer skin of the offset model. To obtain the visibility of intersections efficiently, the proposed algorithm uses a graphics board, which performs hidden surface removal on up to a million polygons per second.

SIMS 분석조건이 Bismuth Titanate 박막의 깊이방향 조성 해석에 미치는 영향 (Effect of Surface Charging on the SIMS Depth Profile of Bismuth Titanate Thin Film)

  • 김재남;이상업;권혁대;신광수;전웅;박병옥;조상희
    • 분석과학
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    • 제14권6호
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    • pp.486-493
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    • 2001
  • 본 연구는 SIMS를 이용한 bismuth titanate 박막의 깊이방향 분석에 있어서 mesh grid를 사용한 경우와 사용하지 않은 경우, offset voltage를 사용한 경우와 사용하지 않은 경우 등 분석조건에 따른 charging effect 그리고 검출한계의 특성을 검토하고자 하였다. 결과에 따르면 -40 V의 offset voltage를 사용하였을 경우는 charging effect의 감소는 물론 검출한계도 낮출 수 있었으나 mesh grid를 사용하였을 경우에는 charging effect는 다소 줄일 수 있었으나 반면 검출 한계는 오히려 높아졌다. O- 일차이온을 적용한 경우는 -40 V의 offset voltage를 사용하였을 때와 동일한 효과를 얻을 수 있었다.

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삼각망 곡면의 3축 라운드엔드밀 가공을 위한 공구경로 생성 (Toolpath Generation for Three-axis Round-end Milling of Triangular Mesh Surfaces)

  • 정연찬
    • 한국정밀공학회지
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    • 제26권2호
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    • pp.133-140
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    • 2009
  • Presented in this paper is a method to generate round-endmill toolpaths for sculptured surfaces represented as a triangular mesh model. The proposed method is applicable in toolpath generation for ball-endmills and flat-endmills because the round-endmill is a generalized tool in three-axis NC (numerical control) milling. The method uses a wireframe model as the offset model that represents a cutter location surface. Since wireframe models are relatively simple and fast to calculate, the proposed method can process large models and keep high precision. Intersection points with the wireframe offset model and a tool guide plane are calculated, and intersection curves are constructed by tracing the intersection points. The final step of the method is extracting regular curves from the intersection curves including degenerate and self-intersected segments. The proposed method is implemented and tested, and a practical example is presented.

다중해상도해석을 위한 Boundary를 가지는 비정규 메쉬의 Normal 메쉬화 방법 (Normal Meshes for Multiresolution Analysis on Irregular Meshes with a Boundary)

  • 강성찬;이규열;김태완
    • 한국CDE학회논문집
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    • 제6권3호
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    • pp.184-192
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    • 2001
  • In this paper we present a remeshing algorithm for irregular meshes with boundaries. The irregular meshes are approximated by regular meshes where the topological regularity is essential for the multiresolutional analysis of the given meshes. Normal meshes are utilized to reduce the necessary data size at each resolution level of the regularized meshes. The normal mesh uses one scalar value, i.e., normal offset value which is based on the regular rule of a uniform subdivision, while other remeshing schemes use one 3D vector at each vertex. Since the normal offset cannot be properly used for the boundaries of meshes, we use a combined subdivision scheme which resolves a problem of the proposed normal offset method at the boundaries. Finally, we show an example to see the effectiveness of the proposed scheme to reduce the data size of a mesh model.

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그리비어 옵셋을 이용한 메탈 그리드 메쉬 필름 제작 기법 (Fabrication Method of Metal Grid Mesh Film Using the Gravure Offset Printing)

  • 김정수;김동수
    • 한국정밀공학회지
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    • 제31권11호
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    • pp.969-974
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    • 2014
  • Previously fabricated electronic devices were used for vacuum manufacturing processes such as conventional semiconductor manufacturing. However, they are difficult to apply to continuous processes such as roll-to-roll printing, which results in very high device manufacturing and processing costs. Therefore, many developers have been interested in applying continuous processes to contact printing or noncontact printing technologies and they proposed various continuous printing techniques instead of conventional batch coating. In this paper, we proposed improved gravure offset printing process as one of the contact printing technique. We used etching pattern geometry with soft core blanket roll for printing of ultra fine line below the 10um.Using this technique we obtained flexible metal grid mesh film as transparent conductive film.

평면변형률 상태 하에서 유한요소해석을 이용한 균열닫힘 거동 예측 및 평가 (Finite Element Analysis of Fatigue Crack Closure under Plane Strain State)

  • 이학주;송지호;강재윤
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.202-207
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    • 2004
  • An elastic-plastic finite element analysis of fatigue crack closure is performed for plane strain conditions. The stabilization behavior of crack opening level and the effect of mesh size on the crack opening stress are investigated. In order to obtain a stabilized crack opening level for plane strain conditions, the crack must be advanced through approximately four times the initial monotonic plastic zone. The crack opening load tends to increase with the decrease of mesh size. The mesh size nearly equal to the theoretical plane strain cyclic plastic zone size may provide reasonable numerical results comparable with experimental crack opening data. The crack opening behavior is influenced by the crack growth increment and discontinuous opening behavior is observed. A procedure to predict the most appropriate mesh size for different stress ratio is suggested. Crack opening loads predicted by the FE analysis based on the procedure suggested resulted in good agreement with experimental ones within the error of 5 %. Effect of the distance behind the crack tip on the crack opening load determined by the ASTM compliance offset method based on the load-displacement relation and by the rotational offset method based on the load-differential displacement relation is investigated. Optimal gage location and method to determine the crack opening load is suggested.

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솔리드 STL 모델의 옵셋 방법 (Offset of STL Model Generated from Solid Model)

  • 김수진;양민양
    • 한국정밀공학회지
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    • 제22권9호
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    • pp.202-211
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    • 2005
  • This paper introduces and illustrates the results of a new method fer offsetting triangular mesh by moving all vertices along the multiple normal vectors of a vertex. The multiple normal vectors of a vertex are set the same as the normal vectors of the faces surrounding the vertex, while the two vectors with the smallest difference are joined repeatedly until the difference is smaller than allowance. Offsetting with the multiple normal vectors of a vertex does not create a gap or overlap at the smooth edges, thereby making the mesh size uniform and the computation time short. In addition, this offsetting method is accurate at the sharp edges because the vertices are moved to the normal directions of faces and joined by the blend surface. The method is also useful for rapid prototyping and tool path generation if the triangular mesh is tessellated part of the solid models with curved surfaces and sharp edges. The suggested method and previous methods are implemented on a PC using C++ and illustrated using an OpenGL library.

스윕라인 알고리즘을 이용한 공구경로의 생성 (Tool-Path Generation using Sweep line Algorithm)

  • 성길영;장민호;박상철
    • 한국정밀공학회지
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    • 제26권1호
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    • pp.63-70
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    • 2009
  • Proposed in the paper is an algorithm to generate tool-path for sculptured surface machining. The proposed algorithm computes tool path by slicing offset triangular mesh, which is the CL-surface (Cutter Location surface). Since the offset triangular mesh includes invalid triangles and self-intersections, it is necessary to remove invalid portions. For the efficient removal of the invalid portions, we extended the sweep line algorithm. The extended sweep line algorithm removes invalid portions very efficiently, and it also considers various degeneracy cases including multiple intersections and overlaps. The proposed algorithm has been implemented and tested with various examples.