自由曲面三轴联动数控加工刀位轨迹生成的研究

自由曲面数控加工刀位轨迹的自动生成，是相关ＣＡＭ技术的关键问题。本文利用点涉法原理推导出刀位点的计算公式，在此基础上，考虑存在干涉的刀具与被加工曲面接触点具有区间连续的特性，以非均匀走刀方式，介绍空间自由曲面三轴联动数控加工刀位轨迹的生成方法。     

整体叶轮数控加工CAD／CAM软件开发

根据软件工程的要求及整体叶轮的结构特点,开发了整体叶轮数控加工CAD／CAM软件,并对开发过程中的关键问题,无干涉刀位轨迹生成算法进行了讨论,最后给出了计算机仿真实例验证了所开发软件和所提算法的可行性。     

数控加工刀具轨迹显示系统

用显示刀具中心运动轨迹的方法来检验数控加工程序（亦称ＮＣ代码）的正确性，无疑是一种又省的办法，多年的使用证明，它对于保证加工程序的质量，提高编程效率，有着很好的实用性。本文概述了必具轨迹显示软件的研制方法，并结合其功能特性，介绍了屏幕绘图软件开发的技术要点。     

铣削二元叶轮数控加工编程方法

介绍了用Pro/E2000i软件编制二元叶轮程序的方法,探讨了编制过程中出现的误差问题,提出了修正误差的措施.     

二维轮廓加工刀具轨迹生成的一种新方法

本文分析了二维轮廓等距环的生成过程，研究了等距环的自交处理方法，揭示了自交后所生成的子环的相邻关系与子环的有效性之间的内在联系。从而提出一和安子环的相邻关系对子环进行分类的方法，使得所有子环被分为两类，有效子环属一类，无效子环属另一类，然后，仅仅只需判断一个子环的有效性就可以得出所有的有效子环。从而筒化了自交处理，减少许多计算量，提高了等距处理的速度。该算法简便，直观，计算量小，运算速度快，具有工     

空间凸轮刀位补偿加工方式中理论加工误差的研究

开展空间凸轮廓面的非等价加工研究是实际生产的需要,刀位补偿加工方式因其加工效率高,成本低而受到研究者的重视。运用等距曲面理论对“刀位补偿加工必然存在理论徊工误差”的命题进行了理论证明,探讨了刀位补偿加工的基本思想,推导出了刀位补偿加工中的凸轮廓面综合的数学模型,给出了相应的计算机实现算法。     

整体叶轮数控加工的干涉检查和刀位修正

为实现自主开发叶轮数控加工CAD/CAM软件,提出了干涉检验及刀位修正算法。通过分析刀具与叶轮曲面的相对位置关系,将干涉分为三种类型,针对不同的干涉类型提出了相应的检查及修正方法,最后给出仿真实例以验证该算法的有效性。     

实体造型生成曲面的数控加工进退刀方法探讨

随着数控技术的发展,CAD/CAM软件的发展也越来越快,其发展不仅使工件的曲面造型越来越方便,而且从根本上改变了工件造型的方法,即利用实体造型方法。很多CAD或CAD/CAM软件如:Pro/E、UG、CAXA等都具有实体造型功能,都有可通用的接口进行数据转换,工件在某一软件中进行的实体造型,可以在其他CAD/CAM软件中读取,进行数控程序的生成。由于实体造型极大的方便性、灵活性、快捷性,因此得到了广泛的应用。然而,工件由实体造型方法生成的曲面,是已经修整好了的曲面(即“裁剪曲面”),没有多余的覆盖面(曲面边界外的延伸面)。在数控加工中往     

离心式压缩机三元叶轮加工工艺

通过对加工三元叶轮的工艺方法的研究，提出有效提高三元叶轮的加工质量和加工效率的一系列方法和措施。     

一种用于多面体加工的圆弧刀轨生成算法

为提高多面体模型的加工效率,提出了一种用于多面体加工的圆弧刀轨生成算法。采用截平面和多面体模型的等距模型求交来计算初始直线刀轨;由等距模型的顶点曲率估算刀位点处沿刀轨方向和刀轨间隔方向的曲率半径,并根据残留高度确定刀轨行距。提出了基于刀位点曲率半径调节的圆弧拟合算法,算法引入拟合约束条件和曲率半径调节系数;在拟合精度范围内,迭代确定曲率半径调节系数,从而确定拟合圆弧。实验结果表明文中方法生成的刀轨保持G1连续且包含的圆弧段数量较少,有利于提高加工效率。     

Grind-free tool path generation for five-axis surface machining

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.     

Mesh-based tool path generation for constant scallop-height machining

This paper presents a new approach to mesh-based tool path generation for obtaining constant scallop heights. The mesh surface has recently become the focus of considerable interest, because its geometric computation is simpler and more robust than that of the parametric surface. These advantages make it easy to check and remove interference in the process of tool path generation. The previous tool path generation method based on the mesh surface, however, can generate only one topology of iso-planar type where tool paths have evenly spaced tool path intervals. As constant scallop heights cannot be obtained from evenly spaced tool path intervals, unevenly spaced tool paths based on offset meshes are necessary for reducing the machining time and for easy interference removal. This paper proposes and compares four methods to estimate curvatures from the mesh surface; the curvature is essential for calculating unevenly spaced tool path intervals. This paper also proposes an improved drive surface method to propagate CL-paths unevenly and to generate tool paths with various topologies.     

Tool path generation for machining free-form pockets using Voronoi diagrams

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:

组合曲面叶片的螺旋加工刀位轨迹生成

为提高叶片加工质量和改进现有螺旋加工方法,提出了一种新的针对组合曲面造型叶片的四轴螺旋加工方法.该方法在叶片曲面造型过程中,将叶片曲面分割为叶盆、叶背、前缘和后缘四个区域.根据组合曲面叶片造型,提出了组合曲面叶片螺旋加工刀位轨迹生成方法和切触点的计算公式.最后,基于UG软件平台,以二次开发方式编制了相应的数控编程模块.生成了连续光滑的叶片螺旋加工刀位轨迹.试验结果表明,该方法能够实现叶片的四坐标螺旋加工,并可有效提高叶片的加工质量.     

The implementation of adaptive isoplanar tool path generation for the machining of free-form surfaces

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.     

Iso-parametric tool path generation from triangular meshes for free-form surface machining

The polyhedral model is widely used in the manufacturing industry. However, apart from the iso-planar method, the tool path generation methods for polyhedral machining are very limited. In such a case, the given tool paths are no longer boundary-conformed or efficient. This paper presents a new approach to iso-parametric tool path generation for triangular meshes. The strategy proposed herein first parameterizes the triangular faces via a harmonic map. The cutter-contact (CC) points and the path interval are then calculated based on the machining tolerance requirements and the iso-parametric tool paths are finally generated. The method is implemented on a computer and some illustrative examples are provided to show the effectiveness of the developed algorithm. The main advantage of the proposed method is that the tool paths can be generated naturally along the boundary of a polyhedral model, thus eliminating internal tight-radius corners in conventional paths. This leads to substantial reductions of tool wear and machining time. In addition, the proposed method can also be used in other non-iso-parametric tool path planning methods for triangular meshes and compound surfaces machining.     

Constant scallop-height tool path generation for three-axis discrete data points machining

This paper presents a new approach for the determination of constant scallop-height tool paths in the machining of discrete data points using three-axis ball-end milling. Compared with the existing approaches for surfaces, this approach avoids offsetting data points, which is complex and time consuming. This paper firstly creates the local coordinate system centered at each CL point of the current path to calculate the corresponding scallop point and then the similar local coordinate system is created at each scallop point to calculate the wanted CL point of the next tool path. The tool paths generated by the approach keep the scallop-height constant and meet the step error requirement. The experiment result indicates that the approach is feasible and efficient and the overall tool path length can be reduced significantly compared with the iso-planar method.     

自由曲面数控加工刀具轨迹生成的约束条件分析

在提出自由曲面数控加工过程和刀具轨迹的规划原则情况下,分析无干涉控制、恒表面速度进给、伺服能力控制和相邻加工曲线影响等轨迹控制的约束条件,实时对轨迹的生成进行系统优化控制。通过系统分析刀具轨迹生成的约束条件,为刀具轨迹优化控制提供决策,对提高自由曲面的切削质量和加工效率具有重要意义。