基于SolidWorks图形系统的数控加工过程模拟

介绍了基于SolidWorks三维建模软件,通过OLE接口技术开发数控加工过程仿真系统的方法.通过开发实例,说明了软件系统的组织框架及SolidWorks API在VB中的调用方法,所开发的仿真系统经实际使用,取得了满意的效果.     

铣削过程中刀具破损的在线检测

本文详细介绍了一种可用于铣削过程在线检测刀具破损的系统,该系统通过时频处理,并利用幅值与脉宽的逻辑“与”来判断刀具破损是否发生。铣刀的磨损过程对该系统没有任何影响。本系统可以用于断续车削加工过程中车刀破损的检测,并可以方便地用于工业生产。     

实体法铣削仿真效率改善及应用算法

轴向切削深度和径向切削宽度是铣削仿真模型求解的几何边界条件,也称为啮合几何参数。根据对啮合参数提取的三类途径的比较,针对直接布尔操作途径仿真效率低的问题,运用集合论描述了实体法铣削仿真中模拟材料去除的布尔运算过程,从时间复杂性角度分析影响实体法铣削仿真效率的因素,提出改善仿真运行效率的4种途径;在此基础上,从几何造型和切削过程两方面给出在仿真计算位置处布尔运算次数由4次减少为1次的可行性分析,提出在简化布尔运算次数情况下的切削几何边界条件的识别和判断算法,对判断算法的有效性和减少布尔运算的时间复杂性进行分析、给出在铣削力仿真中的应用示例,并说明应用范围,从而在保证切削几何边界条件准确提取的同时提高仿真效率,为铣削力等仿真模型的求解奠定基础,推动相关物理仿真研究成果在工程实际中得到切实应用。     

薄壁件铣削过程仿真与分析

针对薄壁件加工过程中易产生变形等问题，提出了利用有限元法对铣削过程进行三维仿真的方法，重点研究了LS-DYNA的动态接触算法，建立了薄壁件铣削加工的有限元模型，对工件变形及切削力的变化规律进行了分析。最后，利用分析结果对铣削参数进行调整与优化，可以减小工件变形，保证加工精度。     

铣削加工过程的智能多目标优化方法

采用神经网络和专家系统的方法,实现带宽容分层约束的铣削加工过程多目标优化,利用Ｂｏｌｔｚ－ｍａｎｎ机神经网络求妥各层次的多目标优化问题,利用专家系统控制进程。通过实例证明了系统优化求解的有效性。     

General geometric modelling approach for machining process simulation

Machining process simulation systems can be used to verify NC (numerically controlled) programs as well as to optimise the machining phase of the production. These systems contribute towards improving the reliability and efficiency of the process as well as the quality of the final product. Such systems are particularly needed by industries dealing with complex cutting operations, where the generation of NC code represents a very complex and error-prone task. A major impediment to implementing these systems is the lack of a general and accurate geometric method for extracting the required geometric information. In this paper, a novel approach to performing this task is presented. It uses a general and accurate representation of the part shape, removed material, and cutting edges, and can be used for any machining process. Solid models are used to represent the part and removed material volume. Bezier curves (in 3D space) are used to represent cutting edges. It is shown that by intersecting the removed material volume with the Bezier curves, in-cut segments of the tool cutting edges can be extracted. Using these segments, instantaneous cutting forces as well as any other process parameters can be evaluated. It is also shown that by using B-rep (Boundary representation) polyhedral models for representing solids, and cubic Bezier curves for representing cutting edges, efficient, generic procedures for geometric simulation can be implemented. The procedure is demonstrated and verified experimentally for the case of ball end-milling. A very good agreement was found between simulated cutting forces and their experimental counterparts. This proves the validity of the new approach.Notation cx ₃,cx ₂,cx ₁,cx ₀ parameters of cubic polynomialx(t) - cy ₃,cy ₂,cy ₁,cy ₀ parameters of cubic polynomialy(t) - cz ₃,cz ₂,cz ₁,cz ₀ parameters of cubic polynomialz(t) - bx _i ,by _i ,bz _i x-,y-, andz-coordinates of ith control point, respectively - b _i ith control point - R tool radius (m) - angular position of point on cutting edge measured from positivex-axis in case of flat end mill (°) - helix angle of cutting edge on flat end mill (°) - A, B, C, D parameters of the equation of a plane - td _i ,tu _i lower end and upper end of theith in-cut segment (before updating) - n number of in-cut segments (before updating) - td _j ,tu _j lower end and upper end of theith in-cut segment (after updating) - m number of in-cut segments (after updating) - dF _t , dF _r tangential and radial components of the infinitesimal cutting force (N) - K _t ,K _r empirical constants in tangential force and radial force equations (N/m²) - b thickness of axial infinitesimal element of cutting edge (m) - h instantaneous chip thickness of axial infinitesimal element of cutting edge (m) - _s shear strength of workpiece (N/m²) - dA _c cross-section area of undeformed chip on the infinitesimal element of cutting edge (m²) - shear angle (°) - _e effective rake angle (°) - friction angle (°) - or (t) angular position of point on cutting edge of ball nose of ball end mill (rad) - u _j , d _j lower end and upper end ofjth in-cut segment (rad) - t parameter     

基于超单元方法的铣削加工变形快速仿真计算

介绍了铣削过程的力学建模 ,提出了基于有限单元法中的超单元计算技术快速预测工件铣削加工变形的新方法。结合两个典型零件实例 ,分别对两种铣削方式 (端铣、周铣 )进行数值计算分析 ,算例结果表明了应用超单元技术可以大大提高加工变形的仿真计算效率 ,具有重要的应用价值。     

Development of an Open Parallek Intelligent CNC Milling System. Part 2. Milling Experiment

In this paper, a fuzzy control strategy is developed in the intelligent controller module of an open parallel intelligent CNC milling system and some experiments with the fuzzy control straategy are carried out. The results of the intelligent milling experiments with fuzzy control strategy show that the open parallel intelligent CNC system has high robustness and global stability, and higher machining efficiency.     

数控铣削仿真系统的研究

根据数控铣削加工特点,提出一个基于Z-MAP结构的工件分解表达模型,利用该模型与刀具实体模型做布尔减运算,实时模拟工件材料的去除加工过程,并对仿真结果进行检验。仿真实例证明,该系统运行可靠,可提高数控加工效率。     

优化自适应控制在铣削加工中的应用

通过应用优化自适应控制对铣削加工中加工参数的主要因素进行在线测量，分析计算并修正控制参数使预先给定的评价函数成为最佳，从而大幅度提高生产率和加工精度。人工神经网络在铣削加工优化自适应控制中的成功应用使自适应控制成为智能制造系统的一大突破。     

数控铣削过程动力学仿真技术原理的研究

介绍了铣削过程动力学仿真几个关键技术的原理,并分别给出了详细的分析研究,所得结果较好地反映了铣削动力学的实际情况,为对应仿真系统的开发提供了必要的理论基础.     

An Operation Planning System for Multi-Axis Milling of Sculptured Surfaces

Multi-axis milling of sculptured surfaces with cylindrical or toroidal cutters has many advantages compared to the use of three-axis milling with ball nose cutters. Surfaces to be machined are often of complex shape and characterised by convex, concave and saddle areas. Today, CAM-systems do not support the user in the selection of the different operations in order to finish the workpiece. This paper describes an operation planning system, which facilitates process planning for the multi-axis machining of sculptured surfaces. The core of the system is surface analysis, which divides the surfaces into regions, each characterised by a preferred milling direction and tool diameter. Further, for each region or set of regions, a drive surface is constructed that is used as the basis for the tool-path calculation. The drive surface approximates to the original workpiece as closely as possible, and the isoparametric lines which will be the tool-path feed direction lie in the preferred milling direction.     

铝合金Al2024铣削仿真分析与实验研究

采用有限元分析软件AdvantEdge对铝合金Al2024铣削加工过程进行了仿真研究,重点模拟分析了铣削力变化和切削温度分布情况。采用相同的切削参数在DMU-70V五轴加工中心上进行了铣槽加工实验。结果表明:仿真分析获得切削力变化曲线与实验结果吻合良好。仿真分析可用于铣削加工参数及刀具寿命的优化。     

面向STEP-NC铣削加工的刀轨优选与仿真研究

研究了STEP-NC标准和应用协议,重点分析了STEP-NC数控程序的数据格式,全面了解了STEP-NC程序中制造特征的描述方法,从加工效率(走刀路线长短)方面衡量,应用神经网络建立STEP-NC铣削加工的刀轨优选的数学模型.并将该方法应用到具体零件的加工过程中,基于MATLAB开发一仿真系统,并对加工过程进行仿真.验证了神经网络在刀轨优选中的有效性.     

微细电解加工的过程检测及精度控制

超短脉冲微细电解加工时,极间加工间隙很小,加工过程的稳定性是影响加工精度的重要因素。在所建立的加工控制系统中,采用两步短路对刀法精确定位电极初始间隙,利用霍尔电流传感器实时检测平均加工电流,动态控制电极的进给运动速度,从而保持不同加工条件下稳定加工的最小加工间隙。进行了微细结构的电解加工试验,通过检测加工过程的状态,保证了加工的稳定性,实现了线宽只有25μm的微细结构加工。     

东德FV400V铣床及圆盘的自动控制

基于多年从事中国民航专用钢刹车加工工艺规程,以加工过程中机械顺序和工人加工操作动作为依据,本着成本最低(利用Z80单片机),充分利用现有设备(东德FV400V万能铣床),尽量以减少机械部件改造为原则,论述了单片机在铣床中的应用及硬件和软件分析。     

具有反向响应过程的最优预估控制

本文在最优控制理论和鲁棒控制理论的基础上,提出一种反向响应过程的控制器的解析设计方法,从根本上解决了这类对象的控制问题。所得到的控制器不但可以具有最优的性能,而且可以获得任意好的鲁棒性。     

数控铣削过程仿真技术的研究

讨论了数控铣削过程仿真技术，并以在高速铣削中应用球头铣刀为例，对数控铣削过程几何仿真和物理仿真作了详细的介绍。