数控电熔爆机床的应用与发展

数控电熔爆机床是为轧辊加工、蜂窝密封材料加工、大型轧辊切割等加工而研制的专用加工设备，并已成功应用。电熔爆机床专用数控系统研制过程中，应将对机械运动的控制与对电源的监测控制相结合。数控电熔爆机床可在某些加工场合取代金刚石砂轮磨削、碳弧气刨加工。几乎没有切削力、工件基体保持常温、污染低等加工特点，可适应一些特殊加工要求。     

试论机械数控加工过程中刀具的合理使用控制

机床在加工精度、生产效率和加工产品的稳定性等方面具有普通机床无法比拟的生产加工优势。数控加工具有越来越广泛的应用前景。然而,在机床数控加工中,刀具的使用直接影响产品生产的质量,也在一定程度上影响机床运行的稳定性。因此,在机械数控机床的加工中,有必要对刀具的使用进行科学合理的控制。本文研究了数控加工过程中刀具的合理使用控制。分析了钻井原理、工具的特点和工具的控制技术在加工中的应用,并讨论了数控加工过程中刀具的控制技术和措施,从而大大提高数控加工的工作效率。     

电火花成形机的模糊控制

一 随着电子计算机技术的迅速发展,机床自动控制技术也已不但从数控发展到自适应控制,而且已发展成约束性自适应控制和最佳自适应控制。这些控制技术在提高加工速度、改善加工质量以及减轻劳动强度等方面都发挥了重大作用。然而对电火花成形加工等时变的、非常复杂的加工过程来说,即使是具有最佳自适应控制功能的机床的加工效果,有时还不如熟练操作人员单凭经验操纵(没有计算机控制装置)机床加工的效果。从而出现了要求供应“不管任何人都能达到熟练操作人员加工水平的电火花成形机”的呼声。最佳自适应控制系统的控制效果为何不如熟练操作…     

基于HNC-818数控系统的加工区域气氛控制集成

以DM4800立式加工中心为载体,通过对华中数控系统的定制开发和机床再制造,实现机床硬件主体与国产数控系统的深度融合。根据产品加工环境的要求,对加工区域与内部气氛进行独立处理,达到在不同气氛状态参数、不同流体介质等条件下的环境控制,并在NC系统中集成定制化的功能模块,深度挖掘国产数控系统的内置性能,实现数控加工与气氛控制的一体式控制,极大地提高了原有机床对特殊材料加工的适应性。     

机床加工状态的电量参数监控技术

机床电量参数监控技术,是用机床电机的电流或功率因数(即相位差角)、转差率、功率等作控制信号来对机床加工状态进行监     

国外机械简讯

电化学电火花組合机床日本Japax公司1963年制造ECDM-30A型电化学电火花組合加工机床,能进行电化学(电解)加工,也能进行电火花加工。它除具有电化学加工和电火花加工的单独电源系統和加工液(电解液和介电质)循环系統外,其他如控制台、电极定位装置、主軸头工具、夹具等都是机床本体共有的。     

GC1080A淬火机床改造

通过使用直线导轨、滚珠丝杠等新型功能元件,完成对老式液压控制机床的改造,恢复了机床加工性能,取得了一定的效益.     

机床控制线路设计上的几个问题

机床的控制电路,是根据机床的加工性能和传动特点而设计的,它通常反映机床自动化程度的高低。就普通机床来说,控制线路基本上是由各种手动和自动的交、直流电器以及其它传动器件(如液压、气动等元件)通过连接导线组合而成。由于JZ、JL、JS等系列的继电器和CJ、CZ系列的接触器具有结构简单、体积较小、重复频率高、过载能力强等优点,所以目前仍被广泛应用于机床和其它生产机械的控制线路。但如何合理地设计继电——接触控制线路,使之既满足机床加工工艺要求,又达到经济可靠运行,仍值得讨论。本文拟就一些机床控制线路在设计上的几个问题…     

海德汉系统运用循环功能编程在多轴加工中心的应用

多轴加工是指3轴以上的控制加工,其中具有代表性的是5轴控制加工中心,这种加工中心可以加工用3轴控制机床无法加工的复杂形状工件。如果用它来加工3轴控制机床能加工的工件,那可以提高加工精度和效率。对刀具和工件的相对位置来说,     

基于模糊PD控制理论的电解加工机床控制系统研究

介绍了一种用于等壁厚螺杆钻具定子内侧螺旋曲面加工的电解加工专用机床,并详细阐述了该机床的控制要求,对机床的控制系统进行了初步设计;然后结合模糊PD控制理论,针对电解加工这一复杂的多输入非线性时变系统,设计了基于模糊PD控制器的电解加工间隙控制系统,使其能够对螺杆钻具定子这类细长零件内侧螺旋曲面的电解加工过程进行同步控制,以保证电解加工的速度和成形精度。     

七轴并联机床数控加工后置处理技术研究

七轴并联机床是在六轴并联机床的基础上，在工作台上串联一个数控转台，实现七轴联动，从而提高了并联机床的加工能力。为了利用七轴并联机床进行数控加工，必须对刀位文件进行后置处理，生成六根驱动杆的杆长和数控转台的转角等数据来驱动并联机床。本文研究了七轴并联机床数控加工的后置处理技术，提出了后置处理的过程以及相关的算法。     

新型并串联机床加工叶片程序的后置处理与仿真

用并联机床加工汽轮机叶片时 ,往往受其工作空间的限制而不能在最佳的切削姿态下进行加工。因此我们在并联机床六轴联动的基础上 ,再串联一个数控转台 ,实现七轴联动 ,即可在一次装夹过程中 ,以最佳的切削姿态完成叶片汽道型面、叶顶、叶根圆角、进、出汽边圆角的加工。本文给出了七轴联动并串联机床加工叶片时的坐标变换公式及数控加工程序的计算机仿真验证方法     

并联机床数控系统软件开发

根据并联机床的特点，开发了一套具有自主知识产权的开放式并联机床系统，该系统是基于工业PC机和Windows98操作系统的单CPU数控系统，所有数控功能均由软件实现，对并联机床数控系统进行了软件模块划分，重点介绍了程序设计模块，加工及仿真模块，手动测量模块的主要功能，该数控系统提供了多种数据接口，参数化编程模块实现了代码自动生成；工件定位模块通过在工件基准平面内采集6点即可自动计算工件在机床坐标系的位置和姿态，实现了工件在机床坐标系任意位置的定位与加工。     

On-line Estimation of Workpiece Height by Using Neural Networks and Hierarchical Adaptive Control of WEDM

Wire breakage and unstable machining drastically reduce the machining efficiency and accuracy in wire electrical discharge machining (WEDM). When a stair-shaped workpiece is machined, poor electrolyte flow around the steps leads to wire rupture or unstable machining. This paper presents a WEDM adaptive control system that maintains optimal machining and improves the stability of machining at the stair section where workpiece thickness changes. A three-layer back propagation neural network is used to estimate the thickness of a workpiece. The developed adaptive control system is executed in the hierarchical structure of three control loops, using fuzzy control strategy. In the first control loop, the total sparking frequency is controlled within a safe level for wire rupture suppression. In the second control loop, the proportion of abnormal sparks is maintained at a pre-determined level for process control purposes. Based on the estimated thickness of a workpiece, adaptive parameter optimisation is carried out to determine the optimal machining settings and to provide the reference targets for the other two control loops. Experimental results demonstrate that the workpiece height can be estimated by using a feed-forward neural network. The developed adaptive control system results in faster machining and better machining stability than does the commonly used gap voltage control system.     

新型5自由度并联机床运动控制算法研究

在分析 5 UPS/PRPU 5自由度并联机床机构的基础上 ,介绍了并联机床运动控制的基本原理 ,确定了具体的运动控制算法 ,将输入控制系统的数控刀位数据转化为驱动轴的控制指令 ,从而实现对机床加工过程中刀具位姿的控制。根据该算法编制的数控软件已成功地应用于实际的并联机床控制 ,取得了较好的效果。     

卧式加工中心工件坐标系自动补偿的研究

通过分析卧式加工中心机床坐标系与工件坐标系、工作台旋转中心之间的关系,并利用FANUC系统中的宏指令及参变量,开发数控系统功能。实现卧式加工中心机床在零件加工过程中,工作台任意角度旋转后,工件坐标系原点得到自动补偿与设定。     

Workpiece locating error prediction and compensation in fixtures

In machining process, fixture is used to keep the position and orientation of a workpiece with respect to machine tool frame. However, the workpiece always cannot be at its ideal position because of the setup error and geometric inaccuracy of the locators, clamping force, cutting force, and so on. It is necessary to predict and control the workpiece locating error which will result in machining error of parts. This paper presents a prediction model of a workpiece locating error caused by the setup error and geometric inaccuracy of locaters for the fixtures with one locating surface and two locating pins. Error parameters along 6 degrees of freedom can be calculated by the proposed model and then compensated by either using the “frame transformation” function of a numerical control (NC) system or modifying NC codes in post-processing. In addition, machining error caused by the workpiece locating error can be predicted based on a multi-body system and homogeneous transfer matrix. This is meaningful to fixture design and machining process planning. Finally, a cutting test has shown that the proposed method is practicable and effective.     

In-process measurement and a workpiece-referred form accuracy control system (WORFAC): concept of the method and preliminary experiment

Precision machining can achieve high levels of accuracy through the use of a highly accurate spindle, straight feed mechanisms, a rigid base and a single-point diamond tool. Research is underway aimed at achieving even higher levels of accuracy by adding computers, interferometers or encoders for practical control. In this report, a control system (workpiece-referred form accuracy control system) is proposed in which the control is based on the workpiece, instead of the conventional approach which achieves the accuracy by increasing that of each mechanical element. This system performs inprocess measurement of the workpiece and uses this information to execute direct control over the machining.     

用触发式测头实现牙掌在线检测

在SSK—U6035五轴加工中心上，利用触发式测头（英国雷尼绍的MP10工件测头）系统和相应的检测自动编程系统实现牙掌在线定位、测量、数据处理、误差校正控制和加工一体化，大大提高了加工中心利用率和工件加工精度，降低了废品率。同时增加了该机床的功能，提高了检测自动化的程度，并且为其他类型的工件检测提供了新的方法。     

Study on the influence of geometric errors in rotary axes on cubic-machining test considering the workpiece coordinate system

Evaluating the influence of geometric errors in rotary axes is a common method used by a five-axis machine tool for improving the machining accuracy. In conventional geometric error models, the table coordinate system is considered as the final workpiece coordinate system. In this study, an additional workpiece coordinate transformation was proposed to identify the influence of geometric error. First, a cubic machining test was conducted. Second, the necessity of workpiece coordinate transformation was analyzed, and a method for coordinate transformation was proposed. In addition, both machining simulation and an actual machining experiment of the cubic machining test were conducted to verify the efficiency of the proposed method. The results indicate that the workpiece coordinate transformation is an essential part of the geometric error model for accurately simulating the geometric error influence. The method for identifying the geometric error influence considering the workpiece coordinate transformation is applicable in manufacturing.