共查询到19条相似文献,搜索用时 109 毫秒
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分析了曲面高速加工对刀具轨迹的要求,提出了等残留高度法生成曲面高速精加工刀具轨迹的基本原理。通过微分几何理论计算短程线曲率半径,提出了残留高度刀具轨迹生成算法。 相似文献
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目前关于自由曲面轨迹生成的算法有很多,但加工效率受所生成轨迹的长度影响,提出一种基于等照度线的自由曲面轨迹生成法,在整体生成轨迹的基础上,考虑局部路径间的残留高度,在根据需要进一步细化,使整体残留高度在误差范围内,减少了总体刀具轨迹的长度,提高了加工效率,通过实例相比较,证明可以获得更高的表面质量。 相似文献
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为提高自由曲面数控加工的切削效率和加工精度,对自由曲面三坐标数控加工刀具路径工艺特点进行研究。分析了在MasterCAM软件内可采用的几种刀具路径规划方法及其实现的约束条件。研究了该软件内由参数线法、路径截面法和等残留高度法等三种算法生成各种刀具路径的优缺点,并根据三种算法所生成刀具路径的特点优化加工各种曲面的刀具路径。通过实例对三种算法所生成的刀具路径进行应用比较,结果表明,根据曲面形状特点合理选用及规划刀具路径,可提高刀具路径对曲面形状变化的适应性,减少残留高度,从而提高切削效率和加工质量。 相似文献
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根据微分几何中短程线的原理,在传统的基于等残留高度刀具轨迹生成方法的基础上,通过判断曲面特性,提出基于曲面特性的误差补偿步长计算法.引入NURBS曲线实现相邻刀具轨迹的平稳过渡,实现高速加工下刀具轨迹行间的平滑优化.以上算法利用Visual C+ +实现,通过仿真得到平稳光顺、载荷均匀的曲面高速加工刀具轨迹. 相似文献
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结合空间填充曲线法与等残留高度法的优点,提出了一种新的刀具轨迹铺放算法。对u和v方向的等残留高度路径进行叠加求交,用参数变量代替笛卡尔坐标进行自由曲线求交,速度远高于包络面求交法。将每相邻的四个交点作为一个路径回路,通过综合条件判断回路合并方向,使得合并过程满足哈米尔顿回路要求,最终合并得到的哈密尔顿回路即为刀具路径。该方法能够生成近似最短并且连续的刀具轨迹,缩短了自由曲面加工的时间。通过实例验证了该方法的有效性。 相似文献
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基于正向杜邦指标线的五坐标侧铣加工 总被引:2,自引:0,他引:2
为实现叶轮类零件的多坐标侧铣加工,通过引入正向杜邦指标线,利用鼓锥形刀对自由曲面的五坐标侧铣加工进行研究。针对具有严格凸切削刃的侧铣加工刀具,提出不发生局部干涉的充要条件是切触点处刀具曲面的正向杜邦指标线位于被加工曲面的正向杜邦指标线之内。给出利用鼓锥形刀侧铣加工自由曲面时实施干涉检查的判断准则以及消除干涉的修正方法,推导出具有严格凸切削刃的刀具在给定的残留高度下侧铣加工带宽的计算方法。在此基础上,利用等残留高度法实现鼓锥形刀侧铣加工自由曲面无干涉刀具轨迹的生成。算例表明,在相同残留高度下,鼓锥形刀侧铣较之球头刀加工效率提高37.44%,说明侧铣加工是提高切削效率和加工质量的一种有效途径。 相似文献
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针对环形刀五轴加工自由曲面的残留误差问题,在传统等残留高度算法的基础上,提出了一种基于定向距离理论的等最大残留高度刀具轨迹规划算法。首先根据微分几何理论计算已知刀触点的初始侧向行距,并在侧向行距方向进行偏置得到相邻刀触点;然后以基于定向距离理论的残高误差计算模型对相邻刀触点间的实际残高值进行计算;最后通过迭代计算规划出等最大残留高度的相邻刀具轨迹。如此循环,从而获得整个曲面的刀具轨迹。实验结果表明,相对于商用软件MasterCAM9.0,该算法在充分保证曲面加工质量的同时最大限度地减小了刀具轨迹的总长度,从而提高了加工效率。 相似文献
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Su-Jin Kim Min-Yang Yang 《The International Journal of Advanced Manufacturing Technology》2006,28(3-4):314-320
In this paper, we present a cutter location (CL) surface deformation approach for constant scallop height tool path generation
from triangular mesh. The triangular mesh model of the stereo lithography (STL) format is offset to the CL surface and then
deformed in accordance with the deformation vectors, which are computed by the slope and the curvature of the CL surface.
In addition, the tool path, which is computed by slicing the deformed CL surface, is inversely deformed by those same deformation
vectors to a tool path with a constant scallop height. The proposed method is implemented, and a tool path is generated and
tested by simulation and by numerical control (NC) machining. The scallop height was found to be constant over the entire
machined surface, demonstrating much better quality than that of mesh slicing, under the same constraints for machining time. 相似文献
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A New Tool-Path Generation Method Using a Cylindrical End Mill for 5-Axis Machining of a Spatial Cam with a Conical Meshing Element 总被引:2,自引:2,他引:0
R. S. Lee J. N. Lee 《The International Journal of Advanced Manufacturing Technology》2001,18(9):615-623
The geometry of a spatial cam is normally generated using a form-milling cutter and a special multi-axis machine and software.
The general purpose CAD/CAM software can generate the cutter location file of this class of product only by the sculpturing
method. Because of the limited choice of cutting tool when using the generating method, this paper presents a new toolpath
generating method which combines the advantages of the generating and sculpturing methods for machining a spatial cam. In
the machining process, the cutter location is derived for rough and finish machining using a cylindrical end mill. The guidelines
for choosing cutter diameter for the machining process are discussed. To avoid interference, the principal curvatures and
the principal induced normal curvatures are analysed. The mathematical errors including chordal deviation and scallop height
are used as the basis for generating appropriate tool-paths. Cutting simulation of a solid model was performed to verify the
proposed tool-path generation method. 相似文献
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Generating tool-path with smooth posture change for five-axis sculptured surface machining based on cutter’s accessibility map 总被引:4,自引:4,他引:0
L. L. Li Y. F. Zhang H. Y. Li L. Geng 《The International Journal of Advanced Manufacturing Technology》2011,53(5-8):699-709
In five-axis high speed milling, one of the key requirements to ensure the quality of the machined surface is that the tool-path must be smooth, i.e., the cutter posture change from one cutter contact point to the next needs to be minimized. This paper presents a new method for generating five-axis tool-paths with smooth tool motion and high efficiency based on the accessibility map (A-map) of the cutter at a point on the part surface. The cutter’s A-map at a point refers to its posture range in terms of the two rotational angles, within which the cutter does not have any interference with the part and the surrounding objects. By using the A-map at a point, the posture change rates along the possible cutting directions (called the smoothness map or S-map) at the point are estimated. Based on the A-maps and S-maps of all the sampled points of the part surface, the initial tool-path with the smoothest posture change is generated first. Subsequently, the adjacent tool-paths are generated one at a time by considering both path smoothness and machining efficiency. Compared with traditional tool-path generation methods, e.g., iso-planar, the proposed method can generate tool-paths with smaller posture change rate and yet shorter overall path length. The developed techniques can be used to automate five-axis tool-path generation, in particular for high speed machining (finish cut). 相似文献
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鉴于采用等间隔参数法和截面法加工椭球面零件时存在残留量不均匀、表面质量和加工效率不高等缺点,提出采用等残留高度法原理加工椭球面。推导了该方法的加工刀具轨迹算法,并采用VB编程实现了该算法,生成了NC加工程序。加工结果表明,该方法可以满足光学自由曲面的加工精度要求。 相似文献
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A new tool path generation method for sheet metal computer numerically controlled incremental forming was proposed based on the stereolithography model, considering the factors of sheet thickness variation, surface smoothness, and extruding direction. The new cutter contact surface modeling algorithm based on the non-equidistant offset was presented, which can be adapted to the sheet thickness variation so as to guarantee a reasonable gap between the forming tool and support. Moreover, a spiral tool path generation algorithm was introduced by considering the scallop height in both z-axis direction and circumferential rotation direction, so that a smoother surface can be obtained. In addition, the algorithm for keeping the tool direction perpendicular to the wall surface was also presented. Finally, the case study shows that the proposed method can automatically generate smooth and continuous spiral tool path with constant scallop height. The developed software system runs steadily and reliably. 相似文献
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Yun-fei Zhou Bin Li Si-jie Yan 《The International Journal of Advanced Manufacturing Technology》2005,26(4):342-350
Current five-axis machining path planning is based on cutter location points, and only the scallop height of the points are calculated roughly to evaluate the planning precision, but the height of the scallop formed in the whole movement of the cutter can’t be calculated effectively, therefore, the machining precision can’t be controlled reasonably. This paper presents a new method to calculate the scallop height of the whole movement of the cutter and control the machining precision, which derives a five-axis machining cutter movement envelope equation, calculates the intersection of the cutter enveloping surfaces of adjacent paths to acquire the scallop curve and calculates the distance from the curve to the design surface to acquire the maximal height. Based on the method, the precision evaluation can be realized accurately and the machining precision can be controlled effectively by adjusting the cutter pose and optimizing the machining path interval. 相似文献
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提出了一种直接从测量的散乱数据点云用球头刀对自由曲面进行三轴数控加工时生成刀具路径的方法。不同于现有散乱点云基于逆向工程的刀具路径生成方法,本法考虑并估计了曲面加工误差和粗糙度。将散乱数据点云向XY平面投影,以获得的投影边界为刀具路径的主方向,然后根据曲面所需的加工误差和残留高度要求划分该投影数据点云,得到一系列刀位网格单元。通过最小化每个刀位网格单元的加工误差以确定每个刀位网格的节点位置,加权平均相关联刀位网格节点来对齐相邻刀位网格单元的边缘。为了缩短加工时间,裁去刀位路径上多余的线段,最终生成高效合理的数控加工刀具路径。已用实测的数据点云验证了本法直接生成刀具路径的有效性。 相似文献
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C. Tournier E. Duc 《The International Journal of Advanced Manufacturing Technology》2002,19(5):318-324
The machining of sculptured surfaces such as moulds and dies in 3-axis milling relies on the chordal deviation, the scallop
height parameter and the planning strategy. The choice of these parameters must ensure that manufacturing surfaces respect
the geometrical specifications. The current strategies for machining, consist primarily in driving the tool in parallel planes
which generates a tightening of the tool paths. A constant scallop height planning strategy has been developed to avoid this
tightening. In this paper, we present a new method of constant scallop height tool-path generation based on the concept of
the machining surface. The concept of the machining surface is developed and its use to generate constant scallop height tool
paths is described. The approach is compared with existing methods in terms of precision and in particular its aptitude to
treat curvature discontinuities. 相似文献