在线测量技术在前端盖加工中的应用

在数控机床上对被加工工件进行在线自动测量是提高数控机床自动化加工水平和保证工件加工精度的有效方法,因此,数控机床工件在线自动测量系统是衡量数控机床技术水平的     

数控机床在线测量系统的分析

对使用在线工件测量系统的数控加工机床进行了介绍,从工件定位、加工余量自动分配、加工过程监控和加工结果检测等方面对在线测量系统的应用进行了论述,并对数控机床在线测量系统的前景进行了展望。     

RENISHAW测头在NTC数控加工中心机床上的应用

现代柔性加工系统、柔性加工单元、加工中心和某些数控机床均需配置先进的自动测量系统。在加工设备上对被加工工件进行自动测量是提高自动化加工水平和保证工件加工精度的有效方法之一。介绍了FANUC数控系统的加工中心普遍使用的Renishaw测量系统,阐述了Renishaw OMP60的组成部分以及工作原理,Renishaw测头在NTC数控加工中心机床上的应用,以及如何通过在线测量对工件坐标系的修正。     

巧用加工中心在线测量系统

许多加工中心都配有在线测量系统,其典型用途是:①对加工后的工件进行在线检测。②自动校正刀具或工件的坐标位置。③加工前检测工件参考点(面)的安装位置等。在某种程度上起着约束适应控制的功能,构成数控机床质量保证系统中的一     

非球面形状在线测定系统的开发

为通过在线校正法加工出高精度非球面表面，其中最重要的是准确测出工件偏差。另外，在线测量可提高各种机加效率。本文讲述的是一种在线非球面高精度系统。并已用于镜面，透镜以及二者模具的加工。该系统的特点是：（１０设置在研磨的探头，其对轴对称非球面工件表面的扫描由ＮＣ（数控）程序控制，（２）接触式蓝宝石探头由空气静压轴支撑，其对工件表面的测量偏差量由ＬＶＤＴ测定。在测量试验中，所用被测物是曲率半径为２２ｍｍ     

机器人自动研抛系统平台搭建及重力补偿研究

为进行复杂曲面工件的柔顺研抛加工,自行搭建了机器人自动研抛系统平台,系统的关键技术之一是实现ATI六维力/力矩传感器和PC机的在线研抛力控制。通过对传感器测量值进行受力分析,提出研抛工具和连接件的重力补偿算法,用于消除加工过程中重力产生的干扰。采取基于位置内环的力外环柔顺控制策略,以45钢曲面工件作为加工对象进行研抛实验。实验结果表明,研抛力在一定范围内保持相对恒定,研抛曲面加工质量稳定,证明了该机器人自动研抛系统平台的可行性,良好地实现了机器人的自动化研抛加工。     

基于Microstation图形平台的双刀架数控车床图形自动编程系统

以SINUMERIK-810T数控系统作为控制系统的数控车床车削加工火车车轮为研究对象,分析毛坯制造精度低的工件的数控加工特点,提出毛坯加工余量在线测量后进行数控加工的自动图形编程方法。研究利用数控系统的刀具监控功能对加工余量进行测量的CAPP及NCP途径,并介绍了图形自动编程系统的系统总体构成。     

用于数控车床的工件自动测量系统

介绍了用于数控车床工件在线测量的触发式测头自动测量系统的组成、工作原理以及测量软件的编制方法。     

测量加工一体化技术

“测量加工一体化”是指将测量技术与加工技术有机地结合,即对工件的模型进行测量,将测量所得到的数据由计算机进行分析、修正,自动产生三维图形及刀具加工轨迹的程序,再经后处理系统就可送到CNC机床对工件进行加工,加工出理想的或经CAD修正过的工件。简言之就是将模型的测量与工件的加工有机地结合,从根本上解决精度高、形状复杂工件的加工问题。     

FMC在航空大型结构件加工中的应用研究

基于航空大型结构件的加工设备,对于柔性制造单元(FMC)系统进行了研究和设计,使该系统具备了自动找正工件,自动调用程序,自动调用并测量刀具,自动更换已装载工件并加工,达到了加工区域人工零干预.     

Design,manufacture, and development of a novel automatic scraping machine

Scraping is a basic and key technique for high-precision machine tools. The accumulated tolerance from a machine tool can be eliminated by scraping. In general, the traditional scraping process is a time-consuming and tedious manual labor. To overcome these shortcomings, a novel automatic scraping machine with efficiency higher than manual scraping that comprise an automatic scraping mechanism, a three-dimensional (3-D) measurement system, a computer program, and a three-axis CNC machine tool has been developed in this study. The self-developed computer program is utilized to automatically determine the scraping location, depth, and pattern of the 3-D surface of a workpiece before scraping and then generate a set of NC codes which is sent to the machine tool to process the scraping motion. Three types of scraping pattern, namely, quadrate, triangular, and plover-shaped pattern, can be produced by the automatic scraping machine. The proposed 3-D measurement system and scraping mechanism can be utilized by the user to easily and precisely obtain, evaluate, and even control the scraping parameters of the workpiece to meet the demanded specifications for maintaining prolonged accuracy life of machine tools.     

新型的复杂曲面磁粒光整加工机床

介绍了一种复杂曲面光整加工机械--三坐标数字化磁粒光整加工机床.该机床通过对复杂曲面的数字化测量和自动编程,得到磁极与工件保持一定间隙沿工件表面运行的加工轨迹,利用吸附在工具磁极上面的磁性磨料为工具,通过磁极带动磁粒沿工件表面作高速旋转,从而实施对工件表面的光整加工.该机床的研制成功实现了复杂曲面光整加工的自动化.     

多轴数控机床的在机测量方案创成及优化方法

多轴数控机床的在机测量会存在冗余运动自由度,由此导致一个测量任务会有多个与之对应的伺服运动方案,而确定最优的伺服运动方案,是保证在机测量性能的前提。针对这一问题,提出一种基于机床功能且面向测量任务的在机测量运动方案创成方法：采用多体系统理论及齐次坐标变换方法对被测对象的几何特征及数控机床的运动形式进行数学解析;建立以被测几何特征为自变量、以机床伺服运动为因变量的函数方程;求解该方程获得所有可能的测量运动方案。在此基础上,通过分析方程解的取值范围,验证所有测量运动方案的功能;考虑到数控机床的结构及伺服特性对测量精度的影响,提出了测量方案性能评价准则,并据此确定最优的测量方案。在某数控成形砂轮磨齿机上进行了齿形偏差的在机测量,试验结果验证了该方法的有效性和可行性。利用该方法确定的最优在机测量方案测量精度高、重复性好。     

基于PLC的数控机床电气控制系统研究

数控机床在解决复杂、精密零件的加工方面起到了重要的作用,是具有典型机电一体化系统的数控机床。基于PLC的数控机床电气控制系统是数控技术发展的必然结果。PLC数控机床在应用中有很多优点,例如,电气控制系统通过采用工件自动夹紧、断刀检测和机械手自动换刀等实现了数控机床的自动化。本文探讨了加工中心的电气控制技术和设计方法,对确保机床的安全可靠,提高加工精度和生产率具有重要意义。     

Real-Time Prediction of Workpiece Errors for a CNC Turning Centre, Part 1. Measurement and Identification

This paper analyses the error sources of the workpiece in bar turning, which mainly derive from the geometric error of machine tools, i.e. the thermally induced error, the error arising from machine–workpiece–tool system deflection induced by the cutting forces. A simple and low-cost compact measuring system combining a fine touch sensor and Q-setter of machine tools (FTS FQ) is developed, and applied to measure the workpiece dimensions. An identification method for workpiece errors is also presented. The workpiece errors which are composed of the geometric error, thermal error, and cutting force error can be identified according to the measurement results of each step. The model of the geometric error of a two-axis CNC turning centre is established rapidly based on the measurement results by using an FTSFQ setter and coordinate measuring machine (CMM). Experimental results show that the geometric error can be compensated by modified NC commands in bar turning.     

Integration of cutting force control and chatter suppression control into automatic cutting feed adjustment system design

Abstract

This study designed an automatic cutting feed adjustment system for computer numerical control (CNC) turning machine tools, which integrate the operational characteristics of cutting force control and chatter suppression control to shorten the machining time and maintain the quality of workpieces. The setting of appropriate machining conditions (such as cutting feed, spindle speed and depth of cut) to consider both machining quality and efficiency often causes difficulties for machine tool operators. Therefore, this study uses cutting force control to design an automatic cutting feed adjustment method for cutting tools, and then, the chatter suppression control design is used to modify the cutting force command to suppress cutting chatter. The experimental results of the CNC turning machine tool show that the use of the cutting force control to adjust the cutting feed can shorten the machining time; however, the cutting chatter results in larger surface waviness on the workpiece surface. When the cutting force command is properly modified by actuating the chatter suppression control, the workpiece shows better surface roughness with prolonged machining time. Therefore, the cutting tests demonstrate that the proposed system is feasible for satisfying the machining requirements of the manufacturing processes of mechanical parts for high speed and high accuracy.     

数控车床实用对刀方法及刀具补偿的应用

对刀的实质是确定随编程而变化的工件坐标系的程序原点在机床坐标系中的位置。对刀问题处理的好坏,直接影响到加工零件的精度和数控机床的操作。因此本文在研究数控车床坐标系统的基础上,重点探讨了几种实用的对刀方法和刀具补偿在对刀过程中的应用。     

利用配方功能实现通用淬火机床数控系统工件管理和编程

在由PLC和HMI组成通用淬火机床数控系统中,由于PLC存储容量限制,难以实现淬火工件管理.文章介绍了Digital公司GP477R的配方功能,并利用其配方功能实现了工件管理和淬火程序编写,使数控系统可以存储70个工件淬火程序.     

Elimination of Settling Error Due to Clamping Forces in On-Machine Measurement

When using OMM (on machine measurement), accuracy in the measurement of finished, machined parts is important; these parts are commonly measured by CMMs (coordinate measuring machines). This paper reports on new OMM hardware (and its operating software) developed to enhance accuracy in measurement. In assessing the value of the system, measurement accuracy was evaluated by comparing results of both CMM and OMM. Factors that can affect accuracy (sensor installation error, repeatability of the CNC machine tool, and settling error in the set-up of the workpiece) were then analysed quantitatively. The results show that the major source of error in OMM accuracy is settling error due to clamping forces, specifically in the workpiece clamping system (for example, a pallet). Therefore, the greatest improvement in measurement accuracy can be achieved by estimating and compensating for settling error beforehand.