共查询到20条相似文献,搜索用时 15 毫秒
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Wei He Ming Lei Hongzan Bin 《The International Journal of Advanced Manufacturing Technology》2009,41(5-6):538-548
The iso-parametric tool path is broadly used in CAM systems to machine sculptured surfaces. To satisfy tolerance constraints CAM systems usually adopt the smallest intervals across discrete tool paths, leading often to overlap and inefficient tool path. This paper presents a novel optimization scheme based on adaptive grid that can produce the optimal tool path on the basis of iso-parametric tool path and introduces the numerical method of generating the adaptive grid. When the generated optimal tool path has the same number of discrete tool path as the iso-parametric tool path, the optimal tool path will produce smaller machining errors. Or when the generated optimal tool path produces the same errors as the iso-parametric tool path, the optimal tool path will have fewer discrete tool paths and higher efficiency. This optimization scheme is robust, concise, and easy to be integrated into CAM systems to produce the optimal tool path automatically. 相似文献
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Pan Ri Zhu Xiangxiang Wang Zhenzhong Chen Dongju Ji Shuting Fan Jinwei Wang Rui 《Journal of Mechanical Science and Technology》2022,36(6):2825-2836
Journal of Mechanical Science and Technology - The polishing mechanism of bonnet polishing (BP) and the tool influence function (TIF) of bonnet tool have been widely studied. However, most of... 相似文献
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The research on the parameters optimization for gasbag polishing machine tools, mainly aims at a better kinematics performance and a design scheme. Serial structural arm is mostly employed in gasbag polishing machine tools at present, but it is disadvantaged by its complexity, big inertia, and so on. In the multi-objective parameters optimization, it is very difficult to select good parameters to achieve excellent performance of the mechanism. In this paper, a statistics parameters optimization method based on index atlases is presented for a novel 5-DOF gasbag polishing machine tool. In the position analyses, the structure and workspace for a novel 5-DOF gasbag polishing machine tool is developed, where the gasbag polishing machine tool is advantaged by its simple structure, lower inertia and bigger workspace. In the kinematics analyses, several kinematics performance evaluation indices of the machine tool are proposed and discussed, and the global kinematics performance evaluation atlases are given. In the parameters optimization process, considering the assembly technique, a design scheme of the 5-DOF gasbag polishing machine tool is given to own better kinematics performance based on the proposed statistics parameters optimization method, and the global linear isotropic performance index is 0.5, the global rotational isotropic performance index is 0.5, the global linear velocity transmission performance index is 1.012 3 m/s in the case of unit input matrix, the global rotational velocity transmission performance index is 0.102 7 rad/s in the case of unit input matrix, and the workspace volume is 1. The proposed research provides the basis for applications of the novel 5-DOF gasbag polishing machine tool, which can be applied to the modern industrial fields requiring machines with lower inertia, better kinematics transmission performance and better technological efficiency. 相似文献
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C. Wang Z. Wang X. Yang Z. Sun Y. Peng Y. Guo Q. Xu 《The International Journal of Advanced Manufacturing Technology》2014,74(1-4):341-349
The purpose of this paper is to investigate the model of the static tool influence function (sTIF) of bonnet polishing (BP). Three kinds of sTIF are mathematically modeled, which are static tool influence function of tilted polishing (sTIFt), static tool influence function of discrete precession polishing (sTIFd), and static tool influence function of continuous precession (sTIFc), respectively. Pressure distribution in the contact area is confirmed based on finite element analysis (FEA) technology. A group of experiments to extract the polishing spots have been conducted to verify the accuracy of the sTIF model. Meanwhile, the difference between sTIFd and sTIFc is studied. It turns out that the removal depths of sTIFd and sTIFc are almost the same, and the continuous precession polishing can be replaced by discrete precession polishing to ease control in practical polishing process especially for the aspheric surfaces polishing. 相似文献
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J.-L. Shih S.-H. Frank Chuang 《The International Journal of Advanced Manufacturing Technology》2006,29(7-8):714-721
A robust method is proposed to generate tool paths for NURBS-based machining of arbitrarily shaped freeform pockets with islands.
Although the input and output are all of higher-degree NURBS curves, only one simple category of geometric entities, i.e.,
line segments, is required for initial offsetting and for detecting and removing self-intersecting loops. Furthermore, using
those linear non-self-intersecting offsets as the legs of NURBS control polygons, NURBS-format tool paths can be smoothly
reconstructed with G1-continuity, no overcutting, no cusps, and global error control. Since all operations involved in computing tool path curves
are linear geometric calculations, the method is robust and simple. Examples with integrated rough and finish cutting tool
paths of pockets demonstrate the usefulness and effectiveness of this method. 相似文献
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G. Kiswanto B. Lauwers J.-P. Kruth 《The International Journal of Advanced Manufacturing Technology》2007,32(3-4):293-309
Five-axis milling may be performed with a constant tool-orientation or varying optimal tool-orientation. When applying a constant
tool orientation, the inclination angle, the angle between the tool axis and the normal vector of a contact point (cc-point),
is kept constant along the tool path. On the other hand, when applying a varying optimal tool orientation, the tool inclination
angle is dynamically optimized along the tool path in order to maintain the tool to be as close as possible to the surface
without gouging. In both tool orientation methods, tool lifting is one of the crucial components and involved in tool path
generation, especially when it is used for gouging elimination. For the constant tool orientation, the tool is lifted immediately
when the specified inclination angle causes gouging with the part surface. In the case of varying optimal tool orientation,
the minimum rotation angle (inclination angle) has to be found first to avoid gouging. If the gouging still occurs (e.g. due
to limited rotational axes of the milling machine), then the tool is lifted. In this paper, gouging elimination through tool
lifting for five-axis milling based on a faceted model is presented. The tool is lifted based on the types of gouging. These
types of gouging are described and the tool lifting procedure has been developed and implemented for gouging elimination in
both tool orientation methods. 相似文献
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阐述了基于细分曲面数控加工刀具轨迹的生成方法,主要包括求交点的算法和对交点进行优化处理的算法,该方法具有一定的可行性和实用性。 相似文献
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利用平面Hilbert填充曲线生成方法简单、易于控制填充疏密的优点,将其用于了自由曲面数控加工刀具路径的生成.对平面Hilbert填充曲线的生成原理进行了研究,用矩阵运算的方法生成该曲线.结合自由曲面的形成过程,提出将平面Hilbert曲线通过与曲面参数域相对应的方法映射到曲面上,进而生成加工刀具路径的思想.最后用一个具体应用实例验证了生成平面Hilbert曲线方法的正确性,和用此曲线作为数控加工刀具路径的可行性.通过与经典刀具路径生成方法比较可见该方法具有算法简单,加工余量均匀,加工效率与表面质量高的优点. 相似文献
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熔融沉积成型(fused deposition molding, FDM)的填充路径不连续,电机频繁停止极易导致翘曲变形。结合轮廓偏置法和空间填充曲线中的Hilbert曲线填充,提出了一种基于轮廓偏置与拟合Hilbert曲线的路径优化算法。该算法将Hilbert曲线进行三次B样条曲线拟合,降低了打印过程中电机变化率,减少了电机停止次数,进而减少打印件的翘曲变形,提高打印件精度。通过实验验证,模型平均最大翘曲量减少了60.70%,总平均翘曲量减少了62.26%。 相似文献
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由于现有评价与测试方法不能满足3~4m地基光电探测系统在不同仰角下对光学系统波前检测的需求,本文提出了基于子孔径斜率离散采样,再重构全口径波面轮廓的波像差测试方法。采用光学模拟与数学分析协同仿真的方法,研究了波面重构算法的不确定度以及扫描运动引起的子孔径倾斜误差、子孔径扫描位置误差、像点坐标测量误差与波前复原精度间的作用规律。仿真结果显示,迭代算法的相对误差ΔPV为0.002 8λ(λ=632.8nm),模式算法的相对误差ΔPV为0.002 7λ。当子孔径倾斜误差小于0.2″,波面重构误差ΔPV约为0.02λ。当子孔径采样位置精度优于0.2mm,其引入的波面重构误差小于0.04nm(PV);当子孔径像点坐标提取精度优于5μm,波面重构误差ΔPV约为0.03λ。研究结果表明,当考虑波面重构过程中的实际测量误差时,模式算法的误差容限较高,收敛性更好。此外,构建实际测试装置时,需引入角度监测与算法误差补偿机制,子孔径倾斜角度监测系统的测角精度需优于0.2″。 相似文献
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基于NURBS曲线拟合的刀具路径优化方法 总被引:1,自引:0,他引:1
为解决复杂曲面高速、高精度加工中由于微小直线段链逼近自由曲线产生的刀具路径不连续问题,提出一种基于非均匀有理B样条曲线拟合的刀具路径优化方法.在该方法中,通过分析刀具路径的几何特征鉴别需要平滑的连续直线段链,对其分段进行基于最小二乘法的非均匀有理B样条曲线拟合优化,并设置相邻段连接点处的边界平滑条件,还原刀具路径应有的连续性.拟合算法采用特征点搜索法设定曲线参数,通过误差控制的曲线节点向量和控制顶点调整保证拟合曲线精度.实验表明,经过该算法拟合优化后的刀具路径具有良好的平滑性,显著提高了曲面加工的精度和效率. 相似文献
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