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自由曲面数控加工刀具的研究 总被引:5,自引:0,他引:5
对自由曲面数控加工中的刀具进行了较深入的研究。从刀具有效半径和切削速度的角度,对平头立铣刀在五坐标自由曲面加工中的加工效率与切削性能进行了分析。提出了球头刀和平头刀的刀位计算方法,并对叶片曲面的刀具轨迹进行了仿真模拟。 相似文献
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提出了一种沿参数线加工的无干涉刀位轨迹实时的生成算法,据进给速度和CNC插补周期确定轨迹逼近步长,简化了计算,减少了实时轨迹生成的计算量,采用双重干涉判别准则,成功地消除了干涉。 相似文献
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复杂曲面加工中,如何快速、有效地筛选出特殊曲面点以进行刀具干涉判断是实现无干涉刀具路径生成的关键。通过推导有理Bezier曲面的参数离散算法并结合NURBS曲面可转化为有理Bezier曲面的性质,实现了NURBS曲面基于参数的离散。该离散结果保留了离散曲面点与曲面参数域的一一对应关系,通过切削点的参数信息可快速筛选出少量需进行干涉校验的离散曲面点,从而有效简化了刀具干涉检测计算。实例分析表明,该算法能在保证曲面离散精度的前提下提高无干涉刀具路径规划的效率。 相似文献
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本文详细介绍了在UG中进行数控编程时采用的装配加工技术,通过将夹具定义成检查几何体,使得产生的刀位轨迹能够自动避让夹具,最后给出了一个装配加工实例。 相似文献
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圆柱凸轮的参数化设计及数控加工 总被引:6,自引:0,他引:6
通过圆柱凸轮的轮廓特征分析,运用AutoLisp语言,按等间隔直线逼近方式,参数化编程绘制圆柱凸累主轮廓展开图,将图形数据转换文件格式后送到MasterCAM中生成平面轮廓的NC代码,再将代码中的Y坐标参数为旋转轴参数,可加工出高精度的圆柱凸轮。 相似文献
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对双圆弧齿轮的参数化建模以及加工进行了研究,利用UG软件的表达式等功能实现对双圆弧齿轮的参数化造型,提高设计效率与精度,再利用UG软件的加工模块对其进行加工仿真,并生成可用于四轴联动加工中心的数控代码。 相似文献
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NURBS曲线、曲面造型过程的可视化设计 总被引:10,自引:2,他引:8
由于NURBS曲面、曲线构造的复杂性,描述NURBS曲线、曲面必然采用复杂的数据结构,这样给人—机交互带来很大的困难。本文利用VC++编写的NURBS曲线、曲面造型系统可以实时观察曲线、曲面的控制点、节点信息,可以实时对控制点、节点进行诸如添加、修改、删除等操作,这对NURBS曲线曲面造型无疑会带来极大的方便。 相似文献
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在分析弧面凸轮轮廓曲面上加工刀痕产生的原因,以及对分度机构性能影响的基础上,提出了用NURBS样条插补凸轮从动件运动规律曲线的思想方法.通过对NURBS样条插补改进算法的深入分析,得出了进一步校正满足加工步长条件的NURBS样条参数增量的算式.同时对插补前弧面凸轮从动件运动规律曲线的修正、NURBS插补误差和插补过程的实现进行了计算与分析.结果表明,采用文中给出的方法,能显著提高弧面凸轮轮廓面的加工精度. 相似文献
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Increasing demand on precision machining using computerized numerical control (CNC) machines have necessitated that the tool
move not only with the smallest possible position error but also with smoothly varying feedrates in 3-dimensional (3D) space.
This paper presents the simultaneous 3D machining process investigated using a retrofitted PC-NC milling machine. To achieve
the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non-Uniform Rational B-Spline (NURBS) curve
is proposed. With this accurate and efficient algorithm for the generation of complex 3D shapes, a real-time NURBS interpolator
was developed using a PC and the simultaneous 3D machining was accomplished satisfactorily. 相似文献
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汽车轮辋的NURBS曲面造型设计 总被引:1,自引:0,他引:1
讨论工业设计理论及其在汽车轮辋造型上的应用,讨论NURBS曲面的数学表达并用NURBS曲面造型对轮辋进行大圆弧过渡造型设计,从而获得了产品的三维模型及其效果,为产品的设计制造打下了坚实的基础。 相似文献
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NURBS curve and surface fitting for reverse engineering 总被引:17,自引:4,他引:13
Dr W. Ma J. -P. Kruth 《The International Journal of Advanced Manufacturing Technology》1998,14(12):918-927
Reverse engineering is an approach for constructing a computer-aided design (CAD) model from a physical part through dimensional measurement and surface modelling. This paper presents alternatives for reverse engineering of free-form parts using Non-Uniform Rational B-Spline (NURBS) surfaces. A two-step linear approach is employed for fitting NURBS curves and surfaces using the measured points. During the first step, the weights of the control points are identified from a homogeneous system using symmetric eigenvalue decomposition. The control points are further processed in a way similar to B-spline curve and surface fitting. Some examples are presented to illustrate both the steps of reverse engineering and the process of NURBS curve and surface fitting. 相似文献
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Chung-Wei Cheng Wen-Peng Tseng 《The International Journal of Advanced Manufacturing Technology》2006,30(1-2):98-104
In recent years, various parametric curve interpolators have been proposed for high-speed and high-accuracy machining. However, these methods are based on a constant cutter location (CL) velocity. Hence, the cutter contact (CC) velocity along the surface tends to vary, resulting in a nonuniform machining performance. Furthermore, machining complex surfaces requires the provision of a large number of tool paths and therefore the associated NC data files are generally very large. To overcome these limitations, the current study presents a novel real-time NURBS surface interpolator which ensures a constant CC velocity along the CC paths and its intervals. A PC-based real-time motion control network utilizing SSCNET is developed to achieve the goal of multi-axis synchronous motion. In this study, both the NURBS surface interpolator algorithms and the SSCNET communication protocols are realized by Embedded XP with the RTX real-time kernel. The experimental results confirm that the proposed real-time NURBS surface interpolator is capable of achieving a satisfactory performance. 相似文献
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Five-axis machining plays an important role in manufacturing by dint of its high efficiency and accuracy. While two rotation axes benefit the flexibility of machining, it also brings limitations and challenges. In order to further balance machining precision and efficiency, an improved feedrate scheduling method is presented considering geometric error and kinematic constraints for the Non Uniform Rational B-Spline (NURBS) interpolation in five-axis machining. A simplification method is proposed to calculate the geometric error which describes the deviation between the ideal tool path and the real tool path induced by the non-linear movement. A linear relation between geometric error and feedrate is built to limit the feedrate. The constraints determined by single axis kinematic performance and tangential kinematic performance are also considered. Under these constraints, a constrained feedrate profile is determined. Aiming to get more constant feedrate in the difficult-to-machine areas, this work proposes a scheduling method which combines morphological filtering and S-shape acceleration/deceleration (acc/dec) mode. Simulations and experiments are performed to compare the proposed feedrate scheduling method with two previous feedrate scheduling method and the results prove that the proposed feedrate scheduling method is reliable and effective. 相似文献
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本文通过对圆弧曲面数控雕刻加工的实例表述,给出了圆弧曲面数控雕刻的编程加工应用步骤,在圆弧曲面数控雕刻加工中,针对于编程软件的特点和数控铣床的特点,采用了灵活实用编程方案和可靠有效的数控加工工艺,从而保证零件加工质量和加工效率,也使企业经济效益和生产水平得以提高。 相似文献