• Title/Summary/Keyword: Offset contour

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Development of Contour Offset Algorithm(COA) in nRP Process for Fabricating Nano-precision Features (복셀 차감법에 의한 나노 복화공정 정밀화)

  • 임태우;박상후;양동열;이신욱;공홍진
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.6
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    • pp.160-166
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    • 2004
  • In this study, a new algorithm, named as Contour Offset Algorithm(COA) is developed to fabricate precise features or patterns in the range of several micrometers by nano replication printing(nRP) process. In the nRP process, a femto-second laser is scanned on a photosensitive monomer resin in order to induce polymerization of the liquid monomer according to a voxel matrix which is transformed from the bitmap format file. After polymerization, a droplet of ethanol is dropped to remove the unnecessary remaining liquid resin and then only the polymerized figures with nano-scaled precision are remaining on the glass plate. To obtain more precise replicated features, the contour lines in voxel matrix should be modified considering a voxel size. In this study, the efficiency of the proposed method is shown through two examples in view of accuracy.

An Algorithm to Speed Up the Rapid Prototyping (쾌속조형의 속도를 향상시키기 위한 알고리즘)

  • Ko, Min-Suk;Chang, Min-Ho;Wang, Gi-Nam;Park, Sang-Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.3
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    • pp.157-164
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    • 2008
  • While developing physical prototype from CAD model, rapid prototyping mainly focuses on two key points reducing time and material consumption. So, we have to change from a traditional solid model to building a hollowed prototype. In this paper, a new method is presented to hollow out solid objects with uniform wall thickness to increase RP efficiency. To achieve uniform wall thickness, it is necessary to generate internal contour by slicing the offset model of an STL model. Due to many difficulties in this method, this paper proposes a new algorithm that computes internal contours computing offset model which is generated from external contour using wall thickness. Proposed method can easily compute the internal contour by slicing the offset surface defined by the sum of circle swept volumes of external contours without actual offset and the circle wept volumes. Internal contour existences are confirmed by using the external point. Presented algorithm uses the 2D geometric algorithm allowing RP implementation more efficient. Various examples have been tested with implementation of the algorithm, and some examples are presented for illustration.

A New Offset Algorithm for Closed 2D Lines with Islands (섬을 가진 2차원 직선 폐곡선에 대한 새로운 오프셋 알고리듬)

  • Kim Hyun-Chul;Lee Sung-Gun;Yang Min-Yang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.2 s.245
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    • pp.141-148
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    • 2006
  • In this paper, a new offset algorithm for closed 2D lines with islands is introduced and the result is illustrated. The main point of the proposed algorithm is that every point is set to be an offset by using bisectors, and then invalid offset lines, which are not to be participated in offsets, are detected in advance and handled with an invalid offset edge handling algorithm. As a result, raw offset lines without local invalid loops are generated. The proposed offset method is proved to be robust and simple, moreover, has a near O(n) time complexity, where n denotes the number of input lines. In addition, the proposed algorithm has been implemented and tested with 2D lines of various shapes.

Study for Development of the Fabrication System of Brain Model for Surgery Emulation (모의수술용 뇌모형 제작시스템 개발을 위한 연구)

  • 염상원;방재철;엄태준;주영철;김승우;공용해;천인국;김범태
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.298-298
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    • 2000
  • This paper presents the optimization technique to analyze the effect of the design parameters of rapid prototyping system for human brain model fabrication. The optimization method considers the functional relationships among the design parameters such as thickness gap, shrink rate, and laser speed that govern the operation of fabrication system. This paper applies a discrete optimization technique as the optimization method to determine the dominant parameter values. Additional study includes manner of complement surface image of ellipse which approximates the brain model using the adaptive slicing and the offset contour. According to the parameters tuning and interaction of effect, more suitable parameter values can be obtained by enhanced 3D brain model fabrication.

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A MORPHOLOGIC CHARACTERISTICS STUDY OF CROWN OF LINGUAL SURFACE WITH NORMAL OCCLUSION IN KOREAN ADULTS (한국인 성인 정상교합자 치관의 설측면 특징에 관한 연구)

  • Yu, Hyung-Seog;Park, Young-Chel
    • The korean journal of orthodontics
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    • v.22 no.3 s.38
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    • pp.675-690
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    • 1992
  • The purpose of this study was to obtain the lingual morphology (size, angulation, contour, eminence) of adults with normal occlusion in order to provide the basic data for lingual bracket and lingual arch form in Korean. The subjects (Male: 50, Female: 50) were selected who have normal occlusion and dental casts were prepared. Tooth size, angulation, arch width, horizontal contour, lingual eminence were measured for all 28 teeth both upper and lower arch. The results were as follows: 1. Measuring items of all individual teeth for adults with normal occlusion were obtained. 2. In comparison tests, there was a statistically difference between intermolar widths $(\underline{6}\;to\;\underline{6})$ before occlusal reduction and intermolar width $(\underline{6}\;to\;\underline{6},\underline{7}\;to\;\underline{7})$ after occlusal reduction only all the other measuring items showed no statistically differences. 3. There was small variation in horizontal contour of lingual surface on lower incisors and upper and lower bicuspids. The other teeth showed somewhat greater variations. 4. There was offset between canine and bicuspid in upper arch while there was no prominent offset in lower arch.

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3D-Contour Machining for Die Manufacturing in a Motor Industry (자동차 산업의 금형제작을 위한 3차원 윤곽가공)

  • Ju, Sang-Yoon;Nam, Jang-Hyun
    • IE interfaces
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    • v.9 no.2
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    • pp.119-128
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    • 1996
  • A procedure is presented for a 3D-contour machining without cutter interferences. The 3D-contouring machining along a spatial curve is often required for manufacturing trimming and flange dies in motor industries. Input data for the machining contour is a spline curve with polynomial vector equation provided by CATIA system. Points are sampled on the contour curve and line segments and helical curves are approximated from the point data. Cutter interference is checked on the approximated spline and all of interference curves are substituted with interference-free helical curves for a tool path generation. The non-machined curve areas are locally machined by tools with smaller diameters. A tool radius offset is considered for generating NC data to be free with tool size.

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Contour Parallel Offset and Tool-Path Linking Algorithm for Pocketing Using Pairwise Intersection Approach (Pairwise Intersection 방식을 이용한 윤곽 오프셋 및 공구경로 연결 알고리즘)

  • Huh, Jin-Hun;Kim, Yeoung-Il;Jun, Cha-Soo
    • Korean Journal of Computational Design and Engineering
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    • v.11 no.5
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    • pp.375-383
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    • 2006
  • Presented in this paper is a new fast and robust algorithm generating NC tool path for 2D pockets with islands. The input shapes are composed of line segments and circular arcs. The algorithm has two steps: creation of successive offset loops and linking the loops to a tool path. A modified pairwise technique is developed in order to speed up and stabilize the offset process, and the linking algorithm is focused on avoiding thin-wall cutting and minimizing tool retractions. The proposed algorithm has been implemented in C++ and some illustrative examples are presented to show the practical strength of the algorithm.

A neural network extracting the induced stimuli for the perception of subjective contours (주관적 윤각 인식을 위한 유도 자극 추출 신경망)

  • 정은화;홍경호;김욱현
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.3
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    • pp.37-47
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    • 1997
  • Human observers perceive a contour where no line or edge is given (subject contour), such as the border between gratings of thin lines offset by half a cycle. Subjective contours occur in a wide variety of circumstances in nature. A common factor in all such figures in the perception of a surface(contour) occuluding part of a background, i.e. subject contours are always accompanied by subject surfaces. Some examples about these kinds of figures are given by kanizsa trangle or square. Ph;ysiological observations are reported in which the perceptual phenomenon that some simple examples of subject contours are perceived as images (gigures; contours) through physiological experiments was investgated. In this paper, we proposed a neural network extracting the induce dstimuli for the perception of subject contours based on the visual mechnism. This visual mechnism is proposed by hubel & wiesel's paper.

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