共查询到19条相似文献,搜索用时 187 毫秒
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基于STL模型支撑生成算法的研究 总被引:4,自引:0,他引:4
针对快速成型制造中须对零件加支撑的需求,提出一种新的支撑生成方法。它首先提取零件待支撑区域的关键特征(如悬吊点、下棱线、待支撑下表面的轮廓线等),同时指出各种支撑的基本构件实质就是单边对应的多边形支撑面,并采用了局部斜板支撑的方案实现其生成算法,在此基础上生成零件的特征支撑;然后采用对生成的特征支撑STL模型分层后分区扫描填充加强支撑线来实现对待支撑下表面内部区域的有效支撑。应用表明:该方法实现了对成型零件关键特征的准确支撑和对待支撑面域的有效支撑,生成支撑效果良好。 相似文献
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光固化快速成形自动支撑技术研究 总被引:9,自引:1,他引:8
对光固化快速成形中自动支撑问题进行了研究,提出了基于STL模型的待支撑特征识别方法,实现了对待支撑面、悬吊线和悬吊点的提取。根据待支撑特征投影区域的几何特征,将其分为细小区域、细长区域以及环形区域等,针对各类区域的形状特点采用不同的填充算法进行二维支撑填充,提出了三点法确定支撑的生长起始点和终止点的方法,开发出了支撑自动生成软件。实际应用表明该技术可以解决人工加支撑时由于支撑不合理所造成的制作失败及精度降低等问题,节省了Stereolithography加工时的数据预处理时间,提高了快速成形的效率。 相似文献
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为了解决双面数控渐进成形中板材件无支撑悬空区域存在变形的问题,提出一种背板辅助的双面数控渐进成形方法。该方法以背板对板材的支撑作用,抑制板材件非成形区的非理想变形,进而提高成形质量。研究了面向复杂板材件基于背板的双面数控渐进成形策略和对于一个给定待成形板材件标准模板库模型自动生成所需背板计算机辅助设计模型的算法。该算法根据板材件类型的不同,通过提取待成形板材件标准模板库模型的特征轮廓,采用顶点偏置方法生成出背板计算机辅助设计模型,并采用数值模拟和实际成形实验对所提背板辅助双面数控渐进成形方法进行了验证和评估。有限元分析和实验结果表明,双面数控渐进成形中背板的使用能够有效提高成形件的成形质量,具有可行性和可应用性。 相似文献
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为解决数控渐进反向成形过程中板材与支撑之间形成密闭空腔,腔内空气不断被压缩而产生的对板材的反作用力影响板材件成形质量和成形精度问题,提出一种可由待成形板材件的CAD模型自动生成带有通气孔特征的支撑体三角网格模型的方法。给出了计算支撑体空腔体积与空腔内压强的算法、自动识别复杂板材件凹部数量与位置的算法,及其在合适的位置生成通气孔进而生成带有通气孔的支撑体三角网格模型的算法。应用实例表明,所提算法能够自动生成带有通气孔的支撑体。成形实验表明,板材件成形过程中密闭空间的形成会导致成形件鼓包变形甚至破裂,而带有通气孔的支撑体能够有效地解决上述问题。 相似文献
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由于目前尺寸链自动生成存在着人机交互过多,实用性不强,并且主要集中在二维的情况。提出了一种以图论为基础,基于UG的三维空间尺寸链自动生成的方法。通过人机交互对装配体进行自由度的约束,使用UG/OPEN API函数对零件模型进行信息提取;利用图论理论,构建尺寸公差、形位公差和装配邻接表,建立了公差图结构。在此基础上,提出了基于特征面要素的搜索算法,该算法减少了不必要的人机交互,真正意义上实现了三维空间尺寸链的自动生成。通过实例验证了该算法,证明有效。 相似文献
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S. H. Sun H. W. Chiang M. I. Lee 《The International Journal of Advanced Manufacturing Technology》2007,34(7-8):702-701
Slicing a 3D graphic model into layers of 2D contour plots is an essential step for all rapid prototyping (RP) machines. Various
methods are available, such as stereo lithography (STL) file slicing, direct slicing and adaptive direct slicing. Amongst
these, adaptive direct slicing is the most advanced for its capability of adapting the slicing thickness according to the
curvature of any contour. In this study, an adaptive direct slicing method complete with the algorithm for calculating the
thickness of each layer is proposed. As an illustration of the method, the algorithm was programmed within the commercial
CAD software package, PowerSHAPE. The method was shown to be fast and accurate in comparison with STL file slicing and direct
slicing, which both used a constant layer thickness.
An erratum to this article can be found at 相似文献
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S.-H. Huang L.-C. Zhang M. Han 《The International Journal of Advanced Manufacturing Technology》2002,20(5):363-367
Although the STL (stereo lithography) file format is the de facto standard for the rapid prototyping industries, there are
always some defects in STL files, many of which are difficult to correct. Instead of correcting the defects of bad STL files
by a manual, interactive and complex approach with an STL file correction program, an error-tolerance slicing algorithm for
STL files is proposed in this paper. With the detailed analysis of complex defects such as cracks and non-manifold facets,
a complete topological structure for the facets model with defects is built and the layer is sliced effectively. The badly
sliced contour is processed by crack-tracking and non-manifold facet travelling methods to obtain a correct contour in a relatively
easy 2D way. 相似文献
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A New Slicing Procedure for Rapid Prototyping Systems 总被引:7,自引:2,他引:5
Y.-S. Liao Y.-Y. Chiu 《The International Journal of Advanced Manufacturing Technology》2001,18(8):579-585
The current slicing rule of most rapid prototyping (RP) systems cannot ensure unilateral tolerances on the whole prototype
and often results in problems of overcut and undercut on the same part. This drawback leads to unsatisfactory precision of
the part in post processing. In order to reduce the above problems, a new slicing method is proposed in this paper. Based
on the geometry information in a stereolithography (STL) file, an algorithm is developed. The appropriate slicing rule is
selected according to the inner product of the normal vector and working direction of the part, together with the function
of the part to be manufactured. The STL file is cut into 2D sections and an accurate contour is calculated. After the slicing
computation, an appropriate working path is produced. The rules proposed in this paper have been verified. This work contributes
to the improvement of slicing rules in existing RP systems, especially in systems using uniform thickness slicing. It also
improves manufacturing efficiency and working tolerances. 相似文献
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Mohammad T. Hayasi Bahram Asiabanpour 《The International Journal of Advanced Manufacturing Technology》2009,45(1-2):170-180
This paper explains a new machine path generating system that its output is compatible with different rapid prototyping processes. The basis of this system is direct slicing from design-by-feature solid model. Slicing a computer-aided design (CAD) model through intersecting the model with the XY-plane at each Z increment is a well-known method of path generation. Slicing a CAD model is currently conducted through stereolithography (STL) file slicing, direct slicing, and additive direct slicing. A direct slicing approach inside a design-by-feature solid modeler is proposed. Autodesk Inventor solid modeler, as a design-by-feature solid modeler, is used for 3D solid modeling. The proposed system is implemented by Visual Basic codes inside Inventor. In this approach, first protrusion and subtractive features that form a model are extracted. Then, the intersection of each feature and the XY-plane is identified. Then, the internal and external loops are found. Depending on the specific rapid prototyping (RP) process requirements, internal or external hatch are also computed, respectively. Finally, a continuous path in required format is generated. The system reported in this paper has been successfully tested on several complex 3D models created in Inventor. The system offers customized output for different RP processes that need external or internal hatch pattern. The proposed approach for generating RP machine path through feature recognition inside design-by-feature solid modeler overcomes with the problems that are caused by imperfect STL files. Also, this system is capable of generating code compatible with major rapid prototyping processes. 相似文献
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快速成形容错切片中线段集合自适应连接方法 总被引:1,自引:0,他引:1
阐述了一种基于STL文件容错分层边界线段自适应连接的有效方法,将自适应方法应用于快速成形数据处理过程中,恰当地选择自适应变量、评价参数和约束条件,并进行数学公式推导。应用该方法实现了STL文件层面边界线的自适应连接。该方法比STL文件纠错方法减少了计算量和人工操作时间;与已有的裂缝跟踪方法相比,对于交叉情况,通过设不可连接端点的方法避免了全部拆分重新连接,提高了计算速度。该方法已在开发的数据处理软件中得到应用,运行情况良好。 相似文献