共查询到20条相似文献,搜索用时 15 毫秒
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在数控机床上加工螺旋面多采用平面啮合理论,但实际在工件表面的切削轨迹为空间曲线,针对平面编程方法存在不可消除的理论误差,对截面包络法数控加工螺旋面时刀触点和刀具运动轨迹进行研究,提出一种新的计算刀触点"最小有向距离算法"的理论并进行论证. 相似文献
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Effect of tool tilt angle on machining strip width in five-axis flat-end milling of free-form surfaces 总被引:3,自引:3,他引:0
M. Javad Barakchi Fard Hsi-Yung Feng 《The International Journal of Advanced Manufacturing Technology》2009,44(3-4):211-222
This paper examines the effect of tool tilt angle on machining strip width in the determination of optimal tool orientation and feed direction in five-axis flat-end milling. The machining strip width is evaluated using the swept profile of the flat-end mill, avoiding both local and global gouging of the tool. An optimization problem is formulated to maximize the machining strip width over feasible gouge-free tool orientations for a constant-feed direction. By solving the optimization problem and analyzing the geometry of the machining strip width, it is shown that identifying the optimal tool tilt angle, instead of following the common practice of setting the tool tilt angle as zero, can significantly increase the machining strip width, especially for 3D free-form surface machining. The optimization has also been extended to identify the optimal feed direction that maximizes the machining strip width at a given cutter contact (CC) point. The minimum curvature direction has been considered as the optimal feed direction at a CC point by researchers. Our results indicate that although the minimum curvature direction is mostly not the optimal feed direction in free-form surface machining, the minimum curvature direction does represent a good approximation of the optimal feed direction at a CC point, in particular for a free-form surface with low-curvature relative to the tool size. 相似文献
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Abbas Vafaeesefat 《International Journal of Precision Engineering and Manufacturing》2010,11(2):327-333
An algorithm for three-axis NC tool path generation on sculptured surfaces is introduced when the free-form surface is modeled
parametrically by free-form surface Kriging. The flexibility of dual Kriging that easily defines the intersection of the surfaces
with a set of parallel planes and Cartesian method are combined to generate the tool-paths automatically. The presented algorithm
can simultaneously generate the tool path with a predefined machining accuracy and remove gougings along the tool path. The
algorithms are validated by three experiments in rough and finish machining and the results prove its reliability. Since Kriging
is based on the interpolation of data points, the proposed algorithm can be used for reverse engineering applications. The
system was executed on a standard micro-computer and the software was structured to offer a library of machining functions
for endusers. 相似文献
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Adaptive tool-path generation on point-sampled surfaces 总被引:1,自引:0,他引:1
In this paper, we present a new approach to generate tool paths for machining point sampled surfaces using a direct projection algorithm, which is based on generating tool paths along planar intersection curves. In our implementation, a guide surface, with simple geometry like planes or cylinder surfaces, is first created according to the bound volume of the point cloud and initial tool paths are planned on it in terms of the motion pattern of the cutters. For each point of the initial tool paths, then, the corresponding cutter contact point (CC) of the point set surface is located by projecting the point onto the point cloud using the direct projection algorithm. In order to obtain adaptive cutter location points (CL), a least squares-based curve fitting method is applied to approximate the CC points using piecewise cubic Bezier, and a numerical method derived to estimate the length of the curve is used to adjust the position of the points along the curve, and make them evenly spaced on the curve with equal arc lengths. In addition, considering that offset curves or surfaces are necessary for locating CL points in many applications, such as machining using ball end milling cutter, torus ended milling cutters, an offset strategy for cubic Bezier curves is also studied. By testing the proposed method on several point clouds, it has been demonstrated to be promising. 相似文献
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S. Ding M.A. Mannan A.N. Poo D.C.H. Yang Z. Han 《The International Journal of Advanced Manufacturing Technology》2005,26(7-8):852-860
Machining of steep regions is an important research topic in the machining of free-form surfaces. A new tool path generation
algorithm to adaptively machine free-form surfaces has been recently developed. However, similarly to many newly emerged methods,
so far it has not been used in industry because no commercial platform is currently available and the user-developed system
is not robust enough for industrial applications. To solve this problem, this paper presents a new implementation method by
integrating it in a commercial CAD/CAM system (Pro/Engineer). With this strategy, other than conducts detailed computations
for parameters, such as scallop heights and forward steps, or designing the non-cutting functions such as engaging and retracting
methods, which are routines in every tool path generation process, the implementation utilizes existing tool path generation
templates in Pro/E to generate the required tool paths. This makes the tool path generation process easier and the tool paths
generated more practicable because the integration is relieved of the time-consuming routine calculation and the entire cutting
and non-cutting functions in the commercial system are transparent to users. Based on the API of Pro/E, the new tool path
generation method was successfully implemented and cutting tests were conducted. Not losing generality, the implementation
could also be conducted in other commercial systems as similar templates are available in these systems as well. 相似文献
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《Computer Integrated Manufacturing Systems》1998,11(4):337-350
This paper discusses automatic tool path generation for five-axis filleted end mill finish-surface machining. A new method of automatic five-axis tool path generation is introduced called Grind-Free (GF) tool path generation. GF surfaces result from tool paths that avoid gouging and have scallops that are within the surface profile or waviness tolerances. New algorithms are presented for determining tool forward step and tool path step-over that produce a GF surface. Gouge-free tool paths can be generated directly from CAD data based solely on local and global machining constraints. The proposed methodology for GF tool path generation has been implemented in the C language using the CODE/Robline system. Surfaces were machined on a Boston Digital 505 five-axis milling machine to confirm this method. 相似文献
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Complex pockets with one or more islands have been widely used in industrial and manufacturing production. In this paper, a new double spiral tool-path generation and linking method are proposed for complex pockets with islands which can be used for high-speed machining (HSM) is used. Taking into account the path interval, step length and other processing parameters, precise milling can be achieved without cutter lifting and retraction motions to guarantee machining accuracy and reduce processing time. The method has been implemented in several simulations and validated successfully through the actual machining of a complicated pocket. The results indicate that this method is superior to other existing machining methods, and it can achieve HSM of complicated shaped pockets based on parametric surface. 相似文献
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Dr Chun-Fong You Chih-Hsing Chu 《The International Journal of Advanced Manufacturing Technology》1997,13(4):248-255
This paper presents a systematic scheme for the verification of tool paths in five-axis machining of sculptured surfaces. The criterion of interference detection is developed for a general APT cutter. Tool interference problems which occur across multiple surfaces can be dealt with. In this work, sculptured surfaces are subdivided into discrete sample points for interference detection. The undetected interference error introduced in the surface subdivision process is ensured within a user-specified tolerance. Simulation results of test examples are included to demonstrate the feasibility of the proposed scheme. 相似文献
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Zhiwei Lin Jianzhong Fu Hongyao Shen Wenfeng Gan 《The International Journal of Advanced Manufacturing Technology》2014,71(5-8):1175-1185
This paper presents an accurate surface error interpolation algorithm for five-axis machining of freeform surfaces. One of the most important steps in the interpolation process is to calculate the next cutter contact (CC) point according to the present one. In this paper, the next CC point is calculated by an accurate chord evaluation method. This method is developed based on the cutting simulation process, which can be vividly described as firstly planting dense grasses on the tool path curve and then cutting them when the tool moves by. The left lengths of the grasses either positive or negative are considered to be the machining error. The method is accurate also because the tool geometry and the tool orientation changes during five-axis machining are taken into consideration. With this method, the chord errors between CC points are controlled uniform along the tool path. The proposed interpolation algorithm is compared with the commercial CAM systems like PowerMILL and UG. The results show that the proposed algorithm can significantly reduce the number of cutter locations meanwhile confine the chord error. A real cutting experiment is implemented, and the result indicates its promising value in industrial applications. 相似文献
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将圆环面刀等效为变直径平底刀,推导切削行距与进给方向和刀具姿态之间的函数关系式,分析进给方向、刀具前倾角和侧偏角对切削行距大小的影响,给出一种新的检查和消除环形刀瓶颈干涉的方法.在无干涉的前提下,选取较小的前倾角,沿最小主曲率方向进给,切削区域宽度最大,加工效率最高. 相似文献
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Combined reparameterization-based spiral toolpath generation for five-axis sculptured surface machining 总被引:1,自引:0,他引:1
Fei Ren Yuwen Sun Dongming Guo 《The International Journal of Advanced Manufacturing Technology》2009,40(7-8):760-768
Reparameterization-based toolpath generation methods are usually adopted for machining triangular meshes, trimmed surfaces and compound surfaces. The quality of the reparameterization has an important effect on that of the surface. In this paper, a combined reparameterization procedure is introduced to generate an optimal mapping between the designed surface and a specified planar circular region with relatively less distortion both in length and in angle. Then, for five-axis sculptured surface machining the mathematical model of spiral guide path with maximum path interval is constructed in the circular region. Cutter contact paths are obtained by inversely mapping the guide path onto the designed surface. Under constraints of gouging and collision, continuous and optimal cutter orientations are subsequently calculated. Finally, the results of simulation and experiment of the machining process are given to illustrate the feasibility and applicability of the proposed method. 相似文献
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J. Jeong Dr K. Kim 《The International Journal of Advanced Manufacturing Technology》1998,14(12):876-881
Voronoi diagrams for closed shapes have many practical applications, ranging from numerical control machining to mesh generation. Curve offsetting based on Voronoi diagrams avoids the topological problems encountered in the traditional offsetting algorithms. In this paper, we propose a procedure using Voronoi diagram-based tool-path generation for machining pockets with free-form boundaries. A pocket can be bounded by 2D free-form curve elements that are differentiable twice. The procedure consists of three steps:
相似文献
1. | Segmentation of a free-form pocket boundary. |
2. | Construction of the Voronoi diagram for the pocket boundary. |
3. | Generation of the tool path for machining the pocket using the Voronoi diagram. |