共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Dexel-Based Direct Slicing of Multi-Material Assemblies 总被引:5,自引:3,他引:2
Slicing is an important procedure in rapid prototyping (RP) pre-processing, and can be grouped into two categories: direct
slicing and adaptive slicing. At present, investigations into the use of both direct and adaptive slicing methods are taking
place. However, not many direct slicing approaches have been reported in the literature. The methods are also restricted to
some solids in CSG or some CAD systems. Also, approaches on adaptive slicing are too complicated. The method proposed in this
paper employs dexel encoding for direct slicing multi-material (MM) assemblies in RP. One advantage of using a dexel model
is that Boolean operations can be performed simply on 1D line segments. Dexels can also be easily converted to tool paths
in RP machines. Compared to the ray representation of CSG trees, dexel models can be extended to represent MM assemblies with
material properties. Therefore, the method has high potential for direct slicing. In this paper, traditional dexel models
are first extended for rapid manufacturing single solid and MM assemblies. Compared to other adaptive slicing approaches,
a much more efficient and simple dexel model, for adaptive refinement in the building direction is then developed. To further
improve the surface finish, a layerwise refinement approach is also discussed. Finally, the computational complexity of the
proposed method is studied. 相似文献
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Ying Tie Ruyu Ma Ming Ye Dongmei Wang Chengtao Wang 《The International Journal of Advanced Manufacturing Technology》2006,28(3-4):302-306
This paper presents a non-uniform, periodic closed B-spline approximation algorithm for the fabrication of a medical pelvic
model, based on rapid prototyping, and also gives the finite element evaluation of the pelvic model. Rapid prototyping (RP),
when used in fabricating medical prosthesis, has a strict requirement for closeness and impermeability of STL files. Incorrect
data structure in STL files will cause the subsequent slicing process not to proceed. The non-uniform periodic closed B-spline
curve approximation method was applied to processing CT data. The precision and size of STL files was improved to optimize
the RP model of the pelvis. Finally, the model of the pelvis was evaluated with the finite element method. Results suggest
that a high similarity has been achieved in terms of shape, size and biomechanical properties of the pelvic model and the
normal one, which validates our argument that rapid prototyping with non-uniform, periodic closed B-spline algorithm is suitable
for the fabrication of a pelvic model, which will prove to be significant in the design of pelvic prostheses . 相似文献
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一种基于STEP的CAD模型直接分层方法 总被引:1,自引:0,他引:1
提出了一种基于产品模型数据交换标准的3维计算机辅助设计实体模型直接分层方法,零件的原始计算机辅助设计模型以产品模型数据交换标准中性文件的格式输入分层系统,系统提取其几何拓扑信息并重建计算机内部几何模型。用户选择零件的制作方向并指定分层厚度后,系统自动对计算机辅助设计模型进行直接分层,分层结果可直接送到各种快速成型系统加工。基于产品模型数据交换标准的计算机辅助设计模型直接分层不依赖任何特定的计算机辅助设计系统,通用性、灵活性好,而且产品模型数据交换标准文件的数据量大大小于STL文件,有利于网络化设计与制造环境下的数据传输与交换。 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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介绍了快速成形加工中常用的SLC数据模型的构成,提出了SLC数据模型下快速成形扫描路径的生成算法以及数据点的排序方法。采用VC++编程实现了扫描路径的生成,并通过风机叶片和车标模型两个实例,分析了扫描路径生成过程中零件切层厚度、扫描间距对扫描路径长度的影响。 相似文献
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作为快速成型技术中必不可少的环节,根据对零件制造精度和装配要求及效率的侧重不同,多年来多种分层算法已被国内外学者开发出来。在同等加工条件下,根据加工精度要求和层厚变化的不同,将分层算法大致分为等层厚分层算法和适应性分层算法两类。从常用的立体光刻(STL)模型、原始计算机辅助设计(CAD)模型和点云数据3种数据模型入手,简述了两类分层算法的研究和发展;介绍了采用斜边的分层算法、基于区域划分的混合算法、曲面分层算法等先进分层算法;讨论了分层算法中待解决的问题:直接分层算法的文件格式标准和轮廓的精确拟合等问题。最后,总结得出了分层算法未来的研究方向和趋势。 相似文献
9.
Direct slicing and G-code contour for rapid prototyping machine of UV resin spray using PowerSOLUTION macro commands 总被引:2,自引:1,他引:2
C. C. Chang 《The International Journal of Advanced Manufacturing Technology》2004,23(5-6):358-365
Rapid prototyping processes produce parts layer by layer directly from 3D CAD models. An important technique is required to slice the geometric model of a part into layers and to generate a motion code of the cross-sectional contour. Several slicing methods are available, such as slicing from sterolithgraphy (STL) files, tolerate-error slicing, adaptive slicing, direct slicing, and, adaptive and direct slicing. This paper proposes direct slicing from 3D CAD models and generating a G-code contour of each layer using PowerSOLUTION software (Delcam International, Birmingham, UK). PowerSOLUTION includes two main modules: PowerSHAPE is used to build 3D CAD models and PowerMILL is used to produce G-Code tool paths. It provides macro language, picture files and cutting paths for secondary development work.The authors used macro commands to write an interface generating direct slicing from 3D CAD models and G-code contours for all layers. Most well-known controllers in the market accept the G-Code. Therefore, it is easier to apply this scheme in a CNC-machining center to produce rapid prototyping such as laminated object manufacturing (LOM) for complex geometries. The interface was successfully applied the interface to the UV resin spray rapid prototyping (UVRS-RP) machine that was developed to produce RP. 相似文献
10.
面向快速成型制造的CAD平台内嵌式通用接口 总被引:1,自引:0,他引:1
面向快速成型设备的CAD平台中的内嵌式通用接口,可直接在CAD建模环境下零件模型实施自适应直接切片操作,同时生成以片层结构数据为单位的快速成型接口文件,该接口使用NURBS曲线对各截面的片层结构轮廓进行精确地解析重构;依据重构后的NURBS截面轮廓,自动填充功能可精确地生成快速成型设备的X,Y向栅线扫描路径。实验数据表明,与利用STL模型切片获得的得的多义线轮廓对比,经NURBS解析重构后的自适应直接切片轮廓与原始轮廓间的拟合误差降低98%以上,所需的NURBS线段数目减少77%以上。 相似文献
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Direct Slicing from PowerSHAPE Models for Rapid Prototyping 总被引:4,自引:2,他引:2
X. Chen C. Wang X. Ye Y. Xiao S. Huang 《The International Journal of Advanced Manufacturing Technology》2001,17(7):543-547
Rapid prototyping processes produce parts layer by layer directly from CAD models. An efficient method is required to slice
the geometric model of a part into layers. Several slicing methods are introduced in this paper: slicing from STL files; tolerate-errors
slicing; adaptive slicing; direct slicing; adaptive and direct slicing. PowerSHAPE is a powerful package for building models,
and it provided macro language and picture files for its secondary development work. To meet rapid proto-typing slicing demands,
the author proposes a direct slicing approach based on PowerSHAPE models. In this method, lines, arcs and Bezier curves are
used to describe the section contours. This approach can be used in stereolithography, selective laser sintering, fused deposition
modelling, and other rapid prototyping processes, e.g. laminated object manufacturing. It may be the future solution to existing
slicing problems. 相似文献
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M. Y. Zhou J. T. Xi J. Q. Yan 《The International Journal of Advanced Manufacturing Technology》2004,23(1-2):20-27
Adaptive slicing varies layer thickness by taking the geometry change of the CAD model in the build direction into account to improve surface finish. Direct slicing generates exact slice contours from the original CAD model and avoids an intermediate representation, known as an STL file. At present, most direct slicing approaches are restricted to some CSG solids or some CAD systems. In this paper, an approach toward adaptive direct slicing with non-uniform cusp heights independent of CAD systems for rapid prototyping is presented. First the geometry model is imported into the adaptive direct slicing system from CAD systems using the standard STEP format. Using OpenGL graphics libraries, the solid model is then displayed and the user is prompted to specify the allowable cusp height for each highlighted surface. Lastly, the CAD model is sliced adaptively with different cusp heights (tolerance requirements) for different surfaces. With non-uniform cusp heights, adaptive slicing has a higher efficiency. Implementation details and results are also presented. 相似文献
16.
STL File Generation with Data Reduction by the Delaunay Triangulation Method in Reverse Engineering 总被引:10,自引:0,他引:10
S.-M. Hur H.-C. Kim S.-H. Lee 《The International Journal of Advanced Manufacturing Technology》2002,19(9):669-678
Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and typical steps include
the scanning of a clay or wood model and the generation of manufacturing data such as an STL file.
A new approach to remove point data with Delaunay triangulation is introduced to deal with the size problems of the STL file
and the difficulties in the operation of the rapid prototyping (RP) process. The selection of a group of triangles, based
on the angle, is used for a robust and reliable implementation of the Delaunay triangulation method. The developed software
enables the user to specify the criteria for the selection of the group of triangles by the angle between triangles, the percentage
of reduced triangles, and the allowable area.
This approach can be used to reduce the measuring data from the laser scanner, thus save the handling time of point data during
the modelling process and is useful for verifying and slicing the STL model during the RP process. 相似文献
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研究了面向分层实体制造与数控铣削复合成形的基于STL模型的三维层生成算法。利用凹边在上下两个方向上的可见性确定分层位置,通过切割平面与各三角面片求交实现STL模型的分割,并把分割面三角网格化生成封闭的三维层。分层的结果可满足复合快速成形工艺要求。 相似文献