基于VERICUT的零件虚拟仿真加工研究

在将UG软件的CAM功能与VERICUT的仿真优化功能相结合的基础上,首先建立了配备FANUC系统的虚拟三轴数控加工中心及其刀具库;其次应用UG软件建立了支座零件、虎钳工装的参数模型,并生成了刀具加工路径及数控程序;然后应用VERICUT软件真实模拟零件的加工状态,并对零件的刀具路径及加工参数进行优化;最后通过零件实际加工情况与仿真结果的比较,验证了数控仿真加工可以有效提高零件加工效率,且数控程序经优化后零件可获得更好的表面光洁度和尺寸精度。     

2×3次NURBS旋转曲面造型与数控加工仿真

基于NURBS曲面造型理论,利用CAD软件建立了NURBS曲面模型和2×3次NURBS旋转曲面模型。将曲面模型成功导入CAM软件中,进行数控加工过程仿真,生成刀具路径和NC代码。提出了根据理论刀具路径和曲率图来合理选择刀具尺寸的方法;探究了刀具路径对加工曲面精度的影响。结果表明,融入加工曲面几何信息的刀具路径,能够获得更优的加工效果。     

基于CATIA V5的泵体数控加工仿真

利用CATIA V5软件的加工模块对泵体零件进行数控加工仿真。首先进行泵体零件的三维实体建模,并根据零件的特点进行加工工艺分析和设置加工参数,然后利用加工模块实现实体的仿真刀具路径及快速虚拟数控加工,同时检验数控刀具路径是否有过切和干涉现象,最后将达到要求加工程序以数控机床能识别的格式输出。一方面可以方便地实现零件的数控编程,生成高效、高精度的NC程序;另一方面,可以通过实体仿真刀具路径,检验是否有明显的过切或者干涉现象,及时做出相应的修改,从而大大提高了实际加工效率,进而缩短了生产周期。     

基于空间填充法的刀具路径生成算法及其仿真

针对空间填充曲线法的网格只具有正则矩形,生成的刀具路径存在频繁转向、长度冗长、生成时间长等缺点,提出一种基于空间填充法的刀具路径生成算法。选用T样条曲面为造型曲面,生成具有非正则矩形的网格并进行回路的规划;用改进的Hamiltonian算法初步生成刀具路径;用改进的倒圆角算法进行拐角优化,获得最终的刀具路径。开发出了基于该算法的仿真系统,对算法进行了仿真验证和实际的加工实验,结果表明所提出算法有效可行,生成的刀具路径长度及生成时间都得到缩短。     

基于填充曲线刀具路径的数控铣削过程物理仿真

研究了采用一类填充曲线刀具路径进行数控铣削加工时,铣削过程的动态特性,推导了带有一般意义的瞬时名义铣削厚度算式,并通过数字物理仿真,探讨了填充曲线刀具路径对铣削过程颤振的抑制作用,结果表明,提出的截法线法能有效地解决数控铣削过程瞬时名义铣削厚度的计算问题,同时对不同刀具路径的铣削过程动态特性仿真结果表明,Hilbert填充曲线刀具路径能有效地抑制铣削过程再生颤振的发生与发展,对提高机械零部件加工效率和加工表面质量有重要作用。     

复杂曲面环形刀五轴端铣加工的刀具轨迹规划方法

为了降低复杂曲面类零部件加工的刀具路径,减小刀具路径条数,提高加工效率,提出了一种新的复杂曲面环形刀五轴端铣加工刀具轨迹优化方法。在局部可铣性基础上对刀轴矢量角进行自适应优化,采用新型加工带宽计算方法——等残留高度算法,给出了等残留高度算法的刀具轨迹生成具体步骤。仿真结果表明:与传统等残留高速算法相比,刀具轨迹优化算法的刀具路径更短、条数更少,能够有效提高复杂曲面加工效率。     

Hilbert填充曲线用于刀具路径生成的算法及改进研究

对Hibert填充曲线的生成方法进行了研究,建立了平面Hilbert填充曲线与Bezier参数平面之间的映射关系,得到了平面Hilbert填充曲线到空间曲面的映射规则和相应算法。针对该方法用于刀具路径生成时存在转向过于频繁等缺点,为了减小加工过程中对刀具和工件的冲击,提出了用倒角或圆弧进行过渡来代替原来的直角过渡的方法生成加工刀具路径。针对改进后的生成刀具路径的方法编制了仿真程序,对改进前后的刀具路径的长度和生成时间进行对比分析。通过一具体曲面加工路径生成仿真,验证了该方法的有效性。     

慢走丝电火花线切割加工钨钢刀具实验研究

在慢走丝机床加工平台上搭建了由伺服控制系统控制的主轴系统,进行了刀具的制作研究.通过实验研究了三种不同加工路径、加工路径不同分段进给速度对刀具制作效率的影响,研究不同平移距离对刀具球头形状的影响,通过实验研究刀具削边加工路径对球头直径的影响并分析了原因.分析了加工过程中效率和精度优化的原因.通过本文的研究所搭建的加工平台和加工策略为加工微小型刀具提供了一种方法,加工效率和加工精度的改善为此类刀具制造提供了方法借鉴.     

基于VB的数控铣削图形仿真系统研究

介绍了数控铣削仿真系统的设计背景以及实现系统的整体技术路线,采用VisualBasic语言在Windows操作系统环境下,设计了针对具体类型机床的仿真系统。该系统界面简单、操作方便。实现了对数控铣削程序的仿真,并以图形方式输出刀具的路径,以此来验证加工程序。     

带角圆柱铣刀对自由曲面3轴NC加工的刀具干涉检测

对自由曲面用带角圆柱铣刀3轴NC加工提出了系统的刀具干涉检测方法。加工自由曲面时,刀具干涉可以出现在包括刀具驱动面的刀具周围的任何地方。本文提出先检测自由曲面上可能产生刀具干涉的区域,然后再生成刀具路径,这样不但可极大地简化安排刀具路径的过程,改善加工的精度和可靠性,而且有利于产品的几何设计和影响加工效率的刀具选择。研究表明所提方法和算法是合理有效的。     

Experimental investigation on various tool path strategies influencing surface quality and form accuracy of CNC milled complex freeform surface

Four tool path strategies such as equal-interval tool paths, parallel tool paths, parallel–tangency tool paths, and freeform tool paths are proposed in computer numerical control milling of a complex freeform surface. The objective is to understand how 3D tool paths influence their machining efficiency, surface quality, and form accuracy. In this study, their scallop heights were less than or equal to 15 μm. First, their scallop heights distributions and 3D tool path distances were theoretically analyzed; then, four tool path strategies were investigated with reference to machining efficiency, surface texture height, surface roughness, and form errors. It is shown that scallop heights distribution can be used to display the surface texture state and predict tool path distance. Experimental results indicate that the surface texture height, the surface roughness, and the form errors were nearly identical on the machined flat location and surface for various tool path strategies, whereas their surface quality and form accuracy are easily destroyed on the abrupt ones except for the parallel tool paths. Although the freeform tool paths produce the shortest tool path distance through 3-axes driving mode, the parallel tool paths offer the best surface quality and form accuracy through 2-axes driving mode. This is because the 3-axes driving and its vector changes on abrupt location easily lead to large machine vibration and movement errors. It is confirmed that the parallel tool path strategy with 2-axes driving mode can improve the surface quality and form accuracy in actual milling of a complex freeform surface.     

Development of an analysis system for geometric contour error evaluation in ultra-precision machining for microlens arrays

A basic principle for acquiring precisely shaped machined parts is to create dense tool path data. However, as the density of tool paths increases, the volume of data increases. The significant increase in data consumes more memory and machining time. Therefore, the creation of tool path data of unlimited density is impractical. This paper proposes a contour error evaluation system. The system makes correct decisions based on the expected quality of a workpiece. Specifically, the user creates tool path data by calculating deviations in the contour in relation to variations in the intervals of the tool path. The user can create tool paths by adjusting the amount of tool path data within the desired quality level. Accordingly, before the start of the machining process, the user can predict any machining loss likely to result from the excessive amount of data created in the creation phase. In addition, the tool path data of the proposed system are experimentally compared with the actual shape of a part machined with a microlens array machining system.     

数控玻璃雕刻图形自动编程系统研究

介绍数控玻璃雕刻图形自动编程系统的结构和功能，该系统在研究玻璃图案加工轮廓的基础上，通过对轮廓图形进行刀具信息，加工信息的处理，形成加工路线，自动生成NC代码和走刀模拟，实现玻璃图案磨削，抛光自动循环加工。     

Direct tool path regeneration for physical object modification from digitized points in reverse engineering

To reuse the tool paths in tool path regeneration for physical object modification in reverse engineering, this paper presented a novel CL tool path regeneration algorithm based on the CL tool path generated from the measured data points. When a physical part captured is modified, the new tool paths for the modified part can be regenerated efficiently by only calculating the affected CL tool paths on the modified region. With this strategy, if a measured physical part has been modified and the CL tool paths were generated directly from its corresponding digitized points, the affected CL tool paths are identified first; then, new CL tool paths are regenerated and used to replace the affected CL tool paths for a given machining accuracy δ. The tool paths not affected are maintained in the new NC-codes. For the method, only the tool paths for the modified regions need to be regenerated; thus, the tool path, which combines the original and modified tool paths, can be regenerated efficiently.     

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.     

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.     

刀具路径对单点渐进成形的影响

在单点渐进成形技术中,刀具路径是加工时刀具在空间中的运动轨迹。本文使用有限元分析软件ANSYS／LS—DYNA模拟了刀具路径对渐进成形过程的影响。模拟结果表明：当刀具四点压下时,模拟的轮廓曲线对称性最好,底面上凸的幅度较小;同时,板材的最大等效应变和主要变形区节点的塑性应变较小,板材连续逐层变形能力较好。     

Dynamic evaluation of spatial CNC contouring accuracy

An instrument capable of measuring arbitrary, dynamic CNC tool paths through three-dimensional space with micrometer-level accuracy is developed and tested. The instrument uses three Laser Ball Bars simultaneously (i.e., simultaneous trilateration) to allow for dynamic path measurements. The design of the instrument is described. The performance is verified by static repeatability testing, comparison with an independent measurement system, and comparison with the dimensions of machined parts. The instrument is demonstrated to be capable of measurement of arbitrary three dimensional tool paths with near micron level accuracy.     

Master CAM刀具路径对偏心工件的加工效果

为解决运用Master CAM软件的外形铣削刀具路径对偏心工件加工时,存在浪费刀具路径的现象,需要作做辅助线纠正的问题,尝试不作辅助线,使用Master CAM挖槽刀具路径对偏心工件加工;通过对挖槽各种类型的刀具路径及外形铣削刀具路径,对偏心工件的加工效果进行比较,得出了边界再加工挖槽刀具路径适合对偏心工件加工的结论。