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逆向工程设计理念适用于以自由曲面为主的产品,由测量系统取得物体外形点资料,配合CAD软件重建该物体模型进行设计,本文以高尔夫球头为例,介绍逆向工程中点数据的获取及整合处理,讨论了CAD系统结合逆向工程的建模和曲面分析技术,实现了复杂曲面零件三维重构,为曲面零件的逆向造型设计提供了途径。 相似文献
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自由曲面测量若干关键问题的研究 总被引:6,自引:0,他引:6
结合国内外研究现状 ,对自由曲面测量中曲面CAD模型已知时测点的自适应分布、测量路径优化、自由曲面形状误差评定和 CAD模型未知时的测量规划和测点数据处理等几个关键问题的实现方法进行了分析研究 ,并对测点的自适应分布做了仿真研究 ,证明了其有效性 相似文献
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为了获得已有自由曲面的CAD模型,这里通过对自由曲面的测量、特征提取及曲面构造的方法来定义出自由曲面的几何形状,并用该方法实现了对轿车门板自由曲面的反求,构造出该零件的CAD模型。 相似文献
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现代制造过程中,自由曲面的设计加工的日益广泛,如飞机机翼、汽车外形、模具工件表面等均为自由曲面。计算机技术与CAD/CAM技术的发展,使得对自由曲面产品的设计加工变得更加容易。本次研究以一件自由曲面的工艺品为例,首先用激光扫描仪扫描模型,获取其表面点云数据,再将点云数据导入Geomagic Studio逆向建模,然后在UG里面对模型进行修改并在UG加工模块中生成了模型的数控加工代码,最后在三坐标铣床上加工,验证了代码的正确性。以上实例表明,用逆向工程技术对自由曲面产品进行NURBS曲面重构,再结合CAD/CAM技术,能有效的对现有复杂曲面产品二次设计,缩短产品开发周期,提高加工效率。 相似文献
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曲面可以具体的分为规则的曲面与自由的曲面其依据就是对于标准的数学模型是否可以进行适用.若是依据特征对曲面进行分类,又可以对CAD模型进行已知和未知的曲面划分.对曲面进行测量是为了给予曲面在进行精度检验以及反求的时候提供保证.利用三坐标测量机进行测量能够保证高精度、目的明确以及灵活的方法,可以使得在测量大部分加工过程中的参数对于误差的表现包括形状以及位置都满足要求.因此,被广泛应用于曲面的测量.本论文对基于CAD的已知曲面和未知曲面的测量分别进行了研究分析. 相似文献
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采用CMM测量系统的智能测量技术 总被引:1,自引:1,他引:0
复杂空间自由曲面测量是实现快速成型(RP)技术的关键,介绍智能测量技术在空间自由曲面测量中的应用.主要通过三坐标测量机(CMM)获取三维测量数据,经过曲面拟合形成CAD模型,从而得到三坐标加工数据. 相似文献
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随着数控技术的发展 ,产品中以自由曲面为主要特征的零部件的数量不断增多 ,对制造质量的要求也在提高。这些工件的CAD模型是已知的 ,并成为加工和事后检查的依据 ,轿车车身就是最有代表性的例子。从图 1可以看出 ,整车有一个确定的坐标系 ,车身上的任何零部件———无论是单一的冲压件、拼合后的焊接总成 ,还是整个车身 ,它们的CAD模型均以这个坐标系为基础。图 1 1 关于曲面测量中的误差表述为了对组成这类工件的自由曲面进行准确的测量和作出评定 ,具有矢量检测功能的现代CNC坐标测量机发挥了重要的作用。那么 ,为什么要强调“矢… 相似文献
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反求工程中实物测量数据补缺及重构技术 总被引:4,自引:0,他引:4
复杂曲面反求工程建模是目前 CAD领域的热门研究课题之一 ,通用 CAD/ CAM软件还不能很好地解决这个问题。尤其是一些带凹边、孔或槽等特征的复杂自由曲面零件的 NURBS曲面重构 ,在实际 CAD建模过程中更是耗时、费力。本文针对这类反求工程 CAD建模问题。提出了对实物零件进行人工局部补缺和通过专门软件对数字模型进行补缺的复合数据预处理方法 ;基于三角曲面模型 ,研究了复杂曲面零件的分区 NURBS曲面重构。利用反求工程软件 RE- SOFT,解决了有关零件的反求工程 CAD建模 ,大大缩短了实物样件的反求设计和建模时间 ,提高了复杂曲面产品的设计效率 相似文献
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结合反求技术、快速成形和快速模具技术,提出了一种新型钛合金/多孔陶瓷复合半膝关节系统的定制化制造方法。基于医学影像技术和反求技术进行半膝关节假体的个性化设计,通过快速成形技术制造人工关节的树脂原型,运用离心铸造和粉末烧结技术成形钛合金关节假体和多孔生物陶瓷活性人工骨。结果显示,半膝关节的重构误差小于0·25mm,能满足医学对假体精度的要求(0·5mm)。将钛合金/多孔陶瓷复合人工关节假体植入动物(狗)体内,与周围组织匹配良好,既具有足够的机械强度,又保证了假体的生物活性。因此,该复合型人工关节假体可用于修复体内大段骨缺损,通过机械重建和生物重建相结合,达到受损关节的功能重建,具有广泛的医学应用前景。 相似文献
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A turbine blade has complex shaped free-form surfaces that can be modelled as surfaces with variable curvature by high-degree polynomials. Industry typically utilizes a turnkey system and special-purpose machine tool to manufacture turbine blades. A turkey system is a closed form design. Users need only input relevant data to this system to manufacture the product directly. However, users are unaware of the internal operation of the system. With rapidly advances in computing technology, commercial CAD/CAM systems can be utilized to design freeform surfaces and generate a tool path for the designed surfaces. This study uses a reverse engineering technology that is used to reconstruct the CAD model for a turbine blade. The prototype is measured by a coordinate measuring machine to obtain the geometrical control data points that are used to generate the CAD model in the UniGraphics (UG) CAD/CAM system. The UG/GRIP (GRaphics interactive Programming) language is used to generate the cutter location data rather than using the default UG CAM module. A five-axis NC code is acquired by the developed postprocessor and verified by the solid cutting simulation software VERICUT®. Real turbine blade machining is performed on a table/spindle tilting five-axis machine tool, demonstrating the effectiveness of the proposed approach. 相似文献
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研究加工中心机床滚珠丝杠动结合面的动态特性,运用机械阻抗凝聚法和子结构综合法,建立了该结合面的力学模型。据此提出动特性设计方法,并在改变两种工况参数的条件下,识别出7种不同外载荷与5种不同预紧载荷时的结合面动态参数数据,供整机CAD系统使用。 相似文献
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Ta-Shi Lai 《The International Journal of Advanced Manufacturing Technology》2006,28(7-8):665-670
This paper presents a mathematical model and design procedures to design the epicycloid planet gear of cycloid drives. It
is based on coordinate transformation, envelope theory, and theories of conjugate surfaces, from which the equation of meshing
is derived, while the path of machining tools is obtained by the equidistant curve principle. In addition, a program is developed
to solve the equations of meshing and conjugate surfaces. Therefore, the epicycloid-profile is obtained. Then, these data
are used to construct the 2D drawing and solid modeling of the epicycloid-planet-gear using AutoCAD and Pro/E (a CAD software
package), respectively. The CAD data is used for machining, in this case by a wire-cutting machine. The manufactured component
is presented to demonstrate that the design procedures and manufacturing are feasible. The design approach and machining method
are suitable for applying CAD and CAM in industrial fields. 相似文献
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A Reverse Engineering Approach to Generating Interference-Free Tool Paths in Three-Axis Machining from Scanned Data of Physical Models 总被引:3,自引:4,他引:3
C.-M. Chuang C.-Y. Chen H.-T. Yau 《The International Journal of Advanced Manufacturing Technology》2002,19(1):23-31
An NC tool path is usually generated by sweeping parametric surfaces of a CAD model. In modern design, freeform or sculptured
surfaces are increasingly popular for representing complex geometry for aesthetic or functional purposes. Traditionally, a
prototype is realised by machining the workpiece using the NC codes generated from a CAD model. The machined part can then
be compared with the CAD model by measurement using a coordinate measuring machine. In this paper, a reverse engineering approach
to generating interference-free tool paths in three-axis machining from the scanned data from physical models is presented.
There are two steps in this procedure. First, a physical model is scanned by a 3D digitiser, and multiple data sets of the
complex model are obtained. A surface registration algorithm is proposed to align and integrate those data to construct a
complete 3D data set. A shortest-distance method is used to determine the connecting sequence of the neighbouring points between
two adjacent scan lines, such that the scanned data are converted into triangular polygons. Tool paths are then generated
from the tessellated surfaces. Using the Z-map method, interference-free cutter-location data are calculated, relative to
the vertex, edges, and planes of the triangles. The algorithms for tool-path generation are usually different for cutters
of different geometries. Some algorithms found in the literature require complex numerical calculations and are time consuming.
In this paper, an efficient algorithm is developed to calculate interference-free cutter-location data by easy geometric reasoning
without complex computation. This robust method is suitable for generally used cutters such as ball, flat, and filleted end
mills, and the time taken to obtain full tool paths of compound surfaces is short. Some real applications are presented to
validate the proposed approach. 相似文献
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机床结合面静态基础特性参数的建模及其应用 总被引:3,自引:0,他引:3
首次提出了机床结合面静态基础特性参数的统一建模方法-人工神经网络建模,并就机床结合面静态基础特性参数的应用技术进行了研究。 相似文献