数控车床中刀具循环起点问题初探

众所周知,在数控加工中,实际用于加工的时间并不多,主要是工艺的规划及编制程序占用了大量时间.为了提高编程的效率,系统设计人员设计了许多循环加工指令,如外圆切削循环指令G71、单一形状固定循环G90等.     

螺纹切削循环指令分析及应用

在FANUC数控系统中,数控车床螺纹切削循环加工有两种加工指令:G92直进式切削和G76斜进式切削.由于切削刀具进刀方式的不同,使这两种加工方法有所区别,各自的编程方法也不同,工件加工后螺纹段的加工精度也有所不同.     

G72指令在数控车床加工复杂沟槽的研究

对G72指令在数控车床加工编程方法的研究,分析了数控车床各种沟槽的不同加工方法,比较了G72、G73和G75指令加工沟槽的特性,分析了编程加工时的注意事项。结合加工实例,阐明了G72指令在数控车削复杂沟槽零件时的编程方法和技巧。G72加工复杂沟槽的独特效能证明,熟练掌握和灵活运用编程指令,是提高加工效率的重要途径。     

曲面直接插补和组合曲面的自适应加工

为了提高组合曲面的加工精度和效率，本文论述了曲面直接插补算法和组合自由曲面的混合数控加方法，提出了曲面自适应三角化方法和沿曲面／曲线交线自适应步长加工，这些自适应策略可大大强混合数控加工方法加工组合曲面的能力。     

复杂曲面笔式加工的直接插补算法

复杂曲面笔式加工时的工具轨迹是位于曲面上的自由曲线轨迹．针对此类形式的轨迹，给出一种复杂曲面笔式加工时的自由曲线型刀轨的直接插补算法，即对位于曲面上以投影方式形成的任意自由曲线形式的刀轨进行插补计算，生成控制机床运动的指令．该方法的实现扩充了CNC系统的轨迹控制功能，提高了复杂曲面的加工效率．仿真和试切的结果证明算法可行而且有效．该算法也可以应用到整体曲面加工中．     

FANUC复合固定循环的正确应用

为简化计算、简化编程,FAN UC系统提供了循环加工功能.数控车中G90、G92和G94是单一固定循环,它将"切入→切削→退刀→返回"四个动作、四个程序段简化为一个程序段.它是将典型而固定的连续动作编制成固定循环的子程序,存储在子程序存储器中,需要时,用G指令调出即可进行加工,但有时应用G90、G92和G94这些固定循环还不能有效简化加工程序.FANUC数控系统还在加工软件中设置了多重复合循环,在编制加工程序时,根据零件图样、材质等要求,只需指定精加工路线(即按零件轮廓编程)和粗加工的背吃刀量,数控系统就会自动计算出粗加工路线和加工次数,进一步简化计算,简化加工程序和编程工作.     

深孔切削循环指令在UG中的应用技巧

一、深孔加工编程指令 1.深孔加工指令格式 大多数的数控系统都提供了深孔加工指令,以FANUC系统为例,提供了G73和G83两个指令:G73为高速深孔往复排屑钻指令,G83为深孔往复排屑钻指令.其指令格式为:     

G70指令的运用技巧

在数控车加工过程中,G70是精加工循环指令,它不但与G71\G72\G73配合使用完成零件的精加工,还可以单独使用完成多槽的编程加工。     

FANUC系统中车削循环指令比较与应用研究

数控车削是当今应用最广的加工技术,该文对FANUC数控车床系统中车削循环复合指令G70、G71、G72和G73的功能加以比较和研究,阐明了各自的特点,通过实例对他们各自的应用进行了分析,所以该文有一定的实用价值.     

基于MasterCAM的曲面多轴加工实例分析

在三轴数控机床加工中,规划斜面和曲面可以插补的方法来加工,但精度和效率不高,对于一些特殊的曲面,通常需要多轴联动加工.     

FPGA-based hardware CNC interpolator of Bezier,splines, B-splines and NURBS curves for industrial applications

Tool path interpolation is an important part of Computerized Numerical Control (CNC) systems because it is related to the machining accuracy, tool-motion smoothness and overall efficiency. The use of parametric curves to generate tool-motion trajectories on a workpiece for high accuracy machining has become a standard data format that is used for CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) and CNC systems. Splines, Bezier, B-splines, and NURBS (Non-Uniform Rational B-splines) curves are the common parametric technique used for tool path design. However, the reported works bring out the high computational load required for this type of interpolation, and then at best only one interpolation algorithm is implemented. The contribution of this paper is the development of a hardware processing unit based on Field Programmable Gate Arrays (FPGA) for industrial CNC machines, which is capable of implementing the four main interpolation techniques. It allows the selection of the required interpolation technique according the application. Two CAD models are designed for test the CNC interpolations; experimental results show the efficiency of the proposed methodology.     

数控加工工装物流自控系统的设计与实现

数控加工技术以其加工过程人工干预少、加工效率高、产品质量稳定等优点在现代航空制造业中得到了广泛应用。因航空产品更新换代快、新研发项目多等因素的影响,传统的单纯人工物流方式耗时大、速度慢、占据空间大等缺点凸显。构建该物流自动控制系统的主要目的在于对数控加工过程中的工装物流环节进行系统、科学管理,自动地实现存取、调配,进一步提高数控加工的生产效率。     

基于五轴数控机床的激光在线检测方法研究

在制造行业中,零件的质量检测通常采用手工检测和离线检测,随着激光技术的发展,激光在线检测逐渐进入零件的质量检测领域;文中针对传统的零件质量检测方法的不足,分析了目前国内外激光检测技术和数控机床在线检测技术的发展态势,探讨了基于五轴数控机床的激光在线检测方法及其在检测路径设计过程中的一些亟待解决的技术问题;该方法基于光学三角测量原理,将零件加工场所和检测场所统一于数控机床,从而提高了检测活动的效率和检测结果的准确性。     

Automated surface subdivision and tool path generation for -axis CNC machining of sculptured parts

As an innovative and cost-effective method for carrying out multiple-axis CNC machining, -axis CNC machining technique adds an automatic indexing/rotary table with two additional discrete rotations to a regular 3-axis CNC machine, to improve its ability and efficiency for machining complex sculptured parts. In this work, a new tool path generation method to automatically subdivide a complex sculptured surface into a number of easy-to-machine surface patches; identify the favorable machining set-up/orientation for each patch; and generate effective 3-axis CNC tool paths for each patch is introduced. The method and its advantages are illustrated using an example of sculptured surface machining. The work contributes to automated multiple-axis CNC tool path generation for sculptured part machining and forms a foundation for further research.     

一种新颖铣床智能数控系统的体系结构及其硬件实现

提出了一种新颖的开放式铣床智能数控系统的体系结构。该结构具有多层次、面向任务、模拟化的特征。在功能上加入了智能控制模块和刀具状况监视模块，以此提高数控机床的加工效率，并使加工精度得到保证。详细介绍了智能数控系统硬件的实现方法，该系统的硬件配置具有功能强、成本低、软件资源丰富、实用性好等特点。     

基于CRIO的数控机械在线监测诊断系统设计

目前提出的数控机械在线监测诊断系统温度采集准确度较低,导致诊断过程稳定性及准确性较差,为此基于CRIO设计了一种新的数控机械在线监测诊断系统,以期更好地分析数控机械的运行状态;通过数控机床在线监测模块、远程设备管理模块及故障诊断模块组成系统总结构,硬件设备包括NTI CRIO驱动器、新型伺服电动机、采集卡、传感器以及PC上位机,设计多参数在线监测模块、网络控制模块、设备管理模块和故障诊断模块;在采集信号中提取数控机械运行状态数据,通过格拉布斯准则估算标准偏差,去掉误差数据后,输出有效数据,完成数据的采集及存储,实现数控机械在线监测诊断系统设计;实验结果表明,基于CRIO的数控机械在线监测诊断系统的温度采集准确率为99%,振动信号采集准确率为95%,可以有效提高采集精准度,增强数控机械在线监测诊断系统的准确性及稳定性。     

中达PUTNC—H6数控系统在凸轮轴高速磨床上的应用

本文介绍了中达电通最新推出的PUTNC—H6系列通用数控系统在数控凸轮轴高速磨床上的应用。通过选择H6数控系统,该磨床在提高凸轮轴磨削质量,提高加工精度和效率以及安全防护等方面均得到很大的提升。     

Bicriteria robotic operation allocation in a flexible manufacturing cell

Consider a manufacturing cell of two identical CNC machines and a material handling robot. Identical parts requesting the completion of a number of operations are to be produced in a cyclic scheduling environment through a flow shop type setting. The existing studies in the literature overlook the flexibility of the CNC machines by assuming that both the allocation of the operations to the machines as well as their respective processing times are fixed. Consequently, the provided results may be either suboptimal or valid under unnecessarily limiting assumptions for a flexible manufacturing cell. The allocations of the operations to the two machines and the processing time of an operation on a machine can be changed by altering the machining conditions of that machine such as the speed and the feed rate in a CNC turning machine. Such flexibilities constitute the point of origin of the current study. The allocation of the operations to the machines and the machining conditions of the machines affect the processing times which, in turn, affect the cycle time. On the other hand, the machining conditions also affect the manufacturing cost. This study is the first to consider a bicriteria model which determines the allocation of the operations to the machines, the processing times of the operations on the machines, and the robot move sequence that jointly minimize the cycle time and the total manufacturing cost. We provide algorithms for the two 1-unit cycles and test their efficiency in terms of the solution quality and the computation time by a wide range of experiments on varying design parameters.     

A comprehensive adaptive approach to calculating the envelope surface of the digital models in CNC machining

The digital models are the fundamental elements used in the virtual simulation of CNC machining for process planning, result prediction, analysis, etc. The essential work to build the digital models of machined parts is the calculation of the envelope surface generated by moving a cutter surface relative to workpieces. This calculation is usually complicated, and the requirements in different cases are also varied. Hence, it is very beneficial to develop an effective approach for different requirements. In this work, a comprehensive envelope approach is established, and it adaptively choose 1) the elimination parameter among two cutter surface parameters, 2) the representation form of envelope surface, and 3) the discretization way, so it is robust to satisfy different requirements. The elimination parameter and representation form are adaptively chosen to improve the calculation efficiency by obtaining the closed-form representation of the envelope surface prior to the implicit one. The discretization way is further adaptively chosen to obtain approximately even point distribution to the applications of 3D and FEA modeling. Finally, comprehensive algorithms are proposed to effectively implement this adaptive envelope approach for different applications. The examples are given to the manufacturing of spiral bevel gears and five-axis CNC milling.     

数控系统连续微段重构与插补算法研究

针对目前微段加工研究中采用的非重构微段加工方法存在的加工轨迹与设计曲线轮廓误差较大,轮廓加工精度较低,及微段节点处速度方向不连续,因此加工表面质量不高,加工过程机床振动较大的问题。在计算机数控（Computerized Numerical Control,CNC）中采用实时曲线重构与插补算法进行连续微段加工以实现对曲面的高速高精度加工。微段插补技术包括样条曲线的实时重构及递推插补算法,及建立满足加减速要求的可以直接递推的插补样条曲线的重构条件。应用微段曲线重构技术进行的样件数控加工实验中,在保证曲线轮廓加工精度达到um级精度的同时,加工速度提高了2~2.4倍。实验结果表明,实时曲线重构微段加工不仅可以实现在重构曲线的范围内进行整体加减速速度规划,提高加工效率,而且加工轨迹的进给速度的衔接平滑,轨迹光滑,表面质量好,并且利用重构的可以直接递推插补的样条曲线,有效解决了平衡了复杂算法加工过程中精度与运算速度的矛盾,提高了加工精度。