• 제목/요약/키워드: Sculptured Surfaces

검색결과 72건 처리시간 0.034초

자유곡면에서 사각형 쉘요소의 자동생성 (Automatic Generation of Quadrilateral Shell Elements on Sculptured Surfaces)

  • 박상준;채수원;고병천
    • 한국자동차공학회논문집
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    • 제3권6호
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    • pp.145-153
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    • 1995
  • An algorithm for the automatic generation of quadrilateral shell elements on three-dimensional sculptured surfaces has been developed, which is one of the key issues in the finite element analysis of structures with complex shapes such as automobile structures. Mesh generation on sculptured surfaces is performed in three steps. First a sculptured surface is transformed to a projection plane, on which the loops are subdivided into subloops by using the best split lines, and with the use of 6-node/8-node loop operators and a layer operator, quadrilateral finite elements are constructed on this plane. Finally, the constructed mesh is transformed back to the original sculptured surfaces. The proposed mesh generation scheme is suited for the generation of non-uniform meshes so that it can be effectively used when the desired mesh density is available. Sample meshes are presented to demonstrate the versatility of the algorithm.

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5-축 CNC 밀링으로의 자유곡면 가공에 관한 연구 (I) 공구축 방향의 벡터와 포스트 프로세싱 (A Study on the Machining of Sculptured Surfaces by 5-Axis CNC Milling (l) Cutter Axis Direction Verctor and Post-Processing)

  • 조현덕;전용태;양민양
    • 대한기계학회논문집
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    • 제17권8호
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    • pp.2001-2011
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    • 1993
  • This study deals with the machining of sculptured surfaces on 5-axis CNC milling machine with end mill cutter. The study (I) has the following contents. In 5-axis CNC milling, CL-data consist of CC-data and cutter axis direction vector at the CC-point. Thus, in machining of the sculptured surface on 5-axis CNC milling machine, determination of the direction vector of the milling cutter is very important. The direction vector is obtained by the fact that bottom plane of the milling cutter must not interfere with the free-form surface being machined. The interference is checked by the z-map method which can be applied in all geometric types of the sculptured surfaces. After generating NC part programs from 5-axis post-processing algorithms, sculptured surfaces were machined with 5-axis CNC milling machine (CINCINNATI MILACRON, 20V-80). From these machining tests, it was shown that the machining of the free-form surfaces on 5-axis CNC milling machine with the end mill has smaller cusp heights and shorter cutting time than on 3-axis CNC milling machine with the ball-end mill. Thus, 5-axis CNC end milling was effective machining method for sculptured surfaces. The study (II) deals with the prediction of cusp height and the determination of tool path interval for the 5-axis machining of sculptured surfaces on the basis of study(I).

자유곡면으로부터 단면정보를 이용한 황삭계획에 관한 연구 (A study on roughing planning by 2D criss sectional information generated from sculptured surfaces)

  • 안대건;최홍태;이석희
    • 한국경영과학회:학술대회논문집
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    • 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
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    • pp.187-196
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    • 1994
  • This study deals with roughing planning by cross sectional information generated from sculptured surfaces. Bicubic Bezier surface is adopted as sculptured surfaces in this paper. The system consists of 3 pstyd : 1) modeling sculptured surface, 2) reconstruction of cross-section in 2D coordinates, 3) determination of roughing tool path with structural data. The system is developed by using BIM-PC in the environment of Auto CAD R11, AutoLISP and MetaWare C. The proposed system shows an efficient algorithm for roughing planning with cross sectional information.

5-축 CNC 밀링으로의 자유곡면 가공에 관한 연구 (II) 커섭 높이 예측과 공구경로 결정 (A Study on the Machining of Sculptured Surfaces by 5-Axis CNC Milling (ll) The Prediction of Cusp Heights and Determination of Tool Path interval)

  • 조현덕;전용태;양민양
    • 대한기계학회논문집
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    • 제17권8호
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    • pp.2012-2022
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    • 1993
  • For the machining of the sculptured surfaces on 5-axis CNC milling machine, the milling cutter direction vector was determined in the study (I) with 5-axis post-processing. Thus, it was possible to cut the sculptured surfaces on five-axis CNC milling machine with the end mill cutter. Then, for smooth machined surfaces in five-axis machining of free-from surfaces, this study develops an algorithm for prediction of cusp heights. Also, it generates tool path such that the cusp heights are constrained to a constant value or under a certain value. For prediction of the cusp height between two basis points, a common plane, containing the line crossing two basis points and the summation vector of two normal vectors at two basis points, is defined. The cusp height is the maximum value of scallops on the common plane after end mill cutter passes through the common plane. Sculptured surfaces were machined with CINCINNATI MILACRON 5-axis machining center, model 20V-80, using end mill cutter. Cusp heights were verified by 3-dimensional measuring machine with laser scanner, WEGU Messtechnik GmbH.

자유곡면으로 이루어진 Cavity의 가공경로생성 (Tool Path Generation of a Die Cavity Defined by Sculptured Surfaces)

  • 전용태;박세형
    • 한국정밀공학회지
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    • 제10권3호
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    • pp.161-167
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    • 1993
  • This paper deals with a new method for the machining of a die cavity defined by sculptured surfaces. In machining die cavities or pockets, process planners have been faced with some troulbes. One of the troubles ius to rebove a great deal of material within a given boundary while avoiding cutter interference. Cutter interference is a ciritical problem in NC machining of a die cavity. Even though this cavity machining has been implemented in many CAM systems, most of them can handle limited shapes of cavities or pockets. In this paper, a procedure has been developed to machine die cavity or pocket of a sculptured surface. The offset surfaces of the part surfaces and boundary surfaces are determined to calculate the intersection curves. These intersection curves form a FACE on the part surface, and the interference free tool pathe is generated by eliminating the points outside the FACE when computing the cutter contact (CC) data. Additionally, the cutter location (CL) data obtained from the CC data convert to an NC data. The NC data generated through this algorithm are verified on the CINCINNATI milling machine. A propotype die cavity machining system has been implemented in FORTRAN language and FIGARO graphics library on IRIS workstation.

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자유 곡면의 다축 NC 가공시 간섭 없는 공구 접근 자세 영역 (Interference-Free Tool Approach Directions in Multi-Axis NC Machining of Sculptured Surfaces)

  • J.G. Kang
    • 한국정밀공학회지
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    • 제14권7호
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    • pp.108-115
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    • 1997
  • In this paper, an algorithm of computing interference-free tool approach directions(visibility cone) with consideration of tool volume at an arbitrary point of a sculptured surface is developed. The surface is first approximated into a polyhedron with smaller subpatches and the tool approach directions are evenly sampled so as to test accessibility. Then the visibility cone is computed by testing if each approach direction is interfered by other surface subpatches. The results are represented as the binary spherical map which transform geometric information on sphere into aogebraic one. The developed algorithm is implemented and tested by several sculptured surfaces, convincing it can be easily used as a tool for not only interference- free tool approach directions but also determining process planning of multi-axis NC machining of sculp- tured surfaces

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분할가공법에 의한 자유곡면가공 (machining of sculptured surfaces using partition machining method)

  • 이태휘;이상조
    • 대한기계학회논문집A
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    • 제21권12호
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    • pp.2114-2120
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    • 1997
  • This paper presents precision machining of sculptured surfaces with a flat end cutter as follows; tool path generation using partition machining method and elimination interference. These days many researchers are getting interested in flat end cutter having a good cutting performance as machine tool for machining sculptured surfaces. It can get low curvature surfaces and have a much better material removal rates and longer tool life. Partition machining method is the first submitted in this paper. It is a new method of tool path generation, which means the way to map surfaces under the normal vector and then to cut them partially.

역공학(Reverse Engineering)을 위한 자유곡면 형상의 NURBS Approximation (Reverse Engineering for Sculptured Surfaces by Using NURBS Approximation)

  • 조재형;조명우
    • 한국정밀공학회지
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    • 제19권8호
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    • pp.108-115
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    • 2002
  • In measuring step for reverse engineering of sculptured surfaces, computer vision system is used to simplify the complicated surface by boundary edge detection method that minimizes the measuring error. The measured data by Coordinate measuring machine is clouded data points of surfaces which is segmented surface using image process. In this research, the measured data is approximated as NURBS surfaces by new suggested algorithm. The position and number of control points, selection of parametric values and compensation of weight factors are proposed. Finally, surface model is simulated and improved resulting performance is obtained.

자유곡면 가공을 위한 CAD/CAM 시스템 (An Integrated System for Computer-Aided Design and Manufacturing of Sculptured Surface)

  • 김광수;최영환
    • 대한산업공학회지
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    • 제17권1호
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    • pp.37-49
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    • 1991
  • This report describes an integrated approach to sculptured surface design and manufacture, and a software package for it on a multi-axis NC milling machine. The integrated software consists of four parts : (1) surface fitting procedure for generating the characteristic polyhedron from 3 dimensional CMM data, (2) surface description for generating the mathematical representation of sculptured surfaces. (3) tool path generation for approximating the surface representation into a sequence of linear cutter paths, and (4) tool control for generating the corresponding joint variable values. This integrated approach is generally applicable to sculptured surface manufacturing where multi-axis milling machines are necessary to produce smooth three-dimensional surfaces.

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자유곡면의 경사도에 따른 볼엔드밀링 이송속도의 최적화 연구 (Optimization of Ball End Milling Feedrate considering Variation of Slopes in the CNC Machining of Sculptured Surfaces)

  • Maeng, Hee-young;Yoon, Jang-sang
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.209-214
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    • 2003
  • This study presents the analysis of ball end milling machinability and its application to the determination of the optimum feedrate in the CNC machining process of sculptured surface. The methods which estimate the cutting force system is approached experimentally. The estimation strategy, named technological processor, was applied to the machining process of sculptured surface for finding optimum variable feedrate. From the result of practical implementation for the test model, it is ascertain that the technological processor have brought the dispersion of force profiles. As compared with conventional imposing of cutting conditions, the machining time has reduced by more than 60%.

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