精密超精密加工及现代精密测量技术

论述精密超精密加工的技术内涵和范畴，分析影响精密超精密加工的主要因索．并指出当前国内外精密超精密加工技术研究中的一些关键技术和重点．此外对精密超精密加工中的微／纳米级精密测量技术、误差建模和补偿技术进行介绍。     

精密机床几何误差补偿技术及应用

误差补偿技术是提高精密机床精度的有效途径,本文研究了影响精密机床精度的主要因素,重点分析了几何运动误差及热误差源的检测、建模和实时补偿技术。     

超精密车床主轴偏角检测、分离与补偿技术研究

几何误差对超精密车床加工精度具有较大的影响, 主轴偏角误差就是其中较为主要的一种。超精密车床安装、调试及定期检修都需要进行主轴偏角的检测与调整, 以提高车床加工精度。本文提出了一种基于计算机控制的主轴偏角误差自动检测、分离与补偿技术。详细阐述了其系统组成和工作原理, 最后进行实验研究。应用该技术可将主轴偏角误差控制在0. 5角秒内。     

《精密加工技术实用手册》王先逵 主编／2001

精密加工和超精密加工技术是先进制造技术的基础和关键，是一个国家制造工业水平的重要标志之一。本书分4篇共14章，内容包括总论、精密加工常用材料、超精密车削、精密和超精密磨削、光整加工、超精密加工机床、精密特种加工及微细加工、微型机械与微型机电系统、精密测量及微尺寸测量技术、微位移技术、误差的在线检测与补偿技术、精密和超精密加工的支持环境及精密基础件加工等。     

微结构光学功能元件模具的超精密磨削加工技术

微结构光学功能元件在航空航天、机械电子、光学以及光电子领域都具有非常重要的应用价值和极其广阔的应用前景,针对其大批量复制用模具的超精密磨削加工技术也越来越受到重视。微结构光学功能元件模具的超精密磨削加工技术不同于传统的磨削加工技术,是在模具表面加工制造出各种不同形貌、不同尺度、不同维数并具有不同光学功能的微小几何结构。结合目前国内外微结构表面超精密制造技术的研究和发展,对微结构光学功能元件模具的超精密磨削加工技术进行综述。介绍超精密磨削加工技术在微结构表面制造中的应用,分析目前微结构光学功能元件模具超精密磨削加工中存在的关键技术问题,并对微结构光学功能元件模具的超精密磨削加工发展趋势进行预测。     

重型数控落地铣镗床误差建模及补偿技术研究

正随着科技的不断发展,各行各业对产品精度的要求越来越高。重型数控机床因其结构尺寸空间大、运动范围大,各零部件制造安装精度受限,因而会产生较大的几何误差,同时重型数控机床因其质量和惯量大,驱动系统所需功率较大,零部件发热较为严重,产生较为明显的热变形,因而形成较大的热误差,严重制约数控机床精度的提高。误差补偿技术是提高数控机床精度的一项重要技术手段,本文在对现有误差补偿技术进行分析和研究的基础上,结合"高档数控机床与基础制造装备"科技重大专项以及生产企业急需解决的滑枕热伸长误差较大等实际问题,针对重型数控机床在实施误差补偿技术时存在的技术难点,以重型数控落地铣镗床为研究对象,重点研究了综合误差建模、误差测量与辨识以及误差补偿实施等关键技术难题。误差建模是误差补偿的关键技术之一,本文尝试采用共形几何代数原理建立数控机床的综合误差模型。首先借助共形几     

机床几何误差和运动误差及其误差补偿技术

文中对机床的几何和运动误差状况和误差补偿技术进行了讨论。对几何和运动误差补偿技术的研究和应用现状、关键技术、应用过程中存在的问题以及将来的发展趋势作了详细的分析和介绍。指出采用误差补偿技术是提高机床加工精度的一个重要发展趋势。     

TTTRR型五轴数控机床通用几何误差补偿关键技术的研究

基于多体系统运动学理论,针对TTTRR型五轴数控机床几何误差补偿的关键技术进行研究,建立误差模型,并推导出其精密加工方程和逆变数控指令的求解方法。在此基础上基于OpenGL开发了五轴数控机床刀具加工轨迹仿真模块,以便真实展现空间自由曲面加工路径,并加以对比,验证误差补偿效果。     

基于多体系统理论的数控内外圆磨床的综合误差分析及数学模型的建立

为了提高磨削精度,需要对数控机床的几何误差和热误差进行分析和研究。采用多体系统理论坐标变换的方法,在工件运动链和刀具运动链对切削点进行误差矩阵描述,分析热误差与几何误差之间的相互耦合关系,推导出数控内外圆磨床的几何误差与热误差的综合数学模型,建立磨床的精密加工约束方程,为后续的误差补偿奠定理论基础。     

小口径玻璃透镜热压成形模具的超精密微细磨削加工

对小口径玻璃透镜热压成形模具的超精密平行磨削进行了试验研究,并对加工过程中的形状误差补偿技术进行了探讨。结合超精密平行磨削技术和形状误差补偿技术,选用经精密整形和修锐的微小砂轮,对直径和曲率半径均为10mm的小口径透镜模具样品进行了加工试验。试验获得的加工表面的表面粗糙度Ra=5.98nm、Rz=34.95nm,形状精度峰谷值为113nm、均方根值为23nm,其形状精度峰谷值及均方根值均较误差补偿之前有明显减小,加工过程中的残余形状误差得到了有效的修正和补偿,加工精度得到提高。     

Prioritization analysis and compensation of geometric errors for ultra-precision lathe based on the random forest methodology

Geometric errors remarkably affect the dimensional accuracy of parts manufactured by ultra-precision machining. It is vital to consider the workpiece shape for the identification of crucial error types. This research investigates the prioritization analysis of geometric errors for arbitrary curved surfaces by using random forest. By utilizing multi-body system (MBS) theory, a volumetric error model is initially established to calculate tool position errors. An error dataset, which contains information of 21 geometric errors, workpiece shape, and dimensional errors, is then constructed by discretizing the workpiece surface along the tool path. The problem of identifying crucial geometric errors is translated into another problem of feature selection by applying random forest on the error dataset. Moreover, the influence extent of each geometric error on the dimensional accuracy of four typical curved surfaces is analyzed through numerical simulation, and crucial geometric errors are identified based on the proposed method. Then, an iterative method of error compensation is proposed to verify the reasonability of the determined crucial geometric errors by specifically compensating them. Finally, under compensated and uncompensated conditions, two sinusoidal grid surfaces are machined on an ultra-precision lathe to validate the prioritization analysis method. Findings show that the machining accuracy of the sinusoidal grid surface with crucial geometric error compensation is better than that without compensation.     

非球面镜超精密加工系统控制软件的研究

针对非球面镜超精密加工的需要,设计了基于工控PC机和Windows2000操作系统、选用VB作为开发工具及远程传输技术,实现非球面镜超精密加工、加工误差补偿及远程数据传输等多项功能的软件控制系统.系统采用模块化设计技术,可实现初加工,补偿加工和精密测量之间数据的自动转化,满足了超精密非球面镜加工精度的要求.     

Simultaneous geometric error identification of rotary axis and tool setting in an ultra-precision 5-axis machine tool using on-machine measurement

This paper presents a method to identify the position independent geometric errors of rotary axis and tool setting simultaneously using on-machine measurement. Reducing geometric errors of an ultra-precision five-axis machine tool is a key to improve machining accuracy. Five-axis machines are more complicated and less rigid than three axis machine tools, which leads to inevitable geometric errors of the rotary axis. Position deviation in the process of installing a tool on the rotary axis magnifies the machining error. Moreover, an ultra-precision machine tool, which is capable of machining part within sub-micrometer accuracy, is relatively more sensitive to the errors than a conventional machine tool. To improve machining performance, the error components must be identified and compensated. While previous approaches have only measured and identified the geometric errors on the rotary axis without considering errors induced in tool setting, this study identifies the geometric errors of the rotary axis and tool setting. The error components are calculated from a geometric error model. The model presents the error components in a function of tool position and angle of the rotary axis. An approach using on-machine measurement is proposed to measure the tool position in the range of 10 s nm. Simulation is conducted to check the sensitivity of the method to noise. The model is validated through experiments. Uncertainty analysis is also presented to validate the confidence of the error identification.     

Repetitive Measurement and Compensation to Improve Workpiece Machining Accuracy

Achieving workpiece high accuracy at low cost is one of the greatest challenges in the manufacturing industry. A repetitive error measurement and compensation scheme to improve the workpiece diameter accuracy for machining centres is des-cribed. The scheme entails an on-machine measurement and error compensation technology between machining processes. The workpiece diameters are measured along the workpiece length by using a fine touch sensor. The workpiece diameters in the compensation program are modified for implementation of next pass error correction. The technology is realised on a CNC turning centre. This method works well in hard machining and turned workpieces with large length–diameter ratios where the machining process induced errors are significantly greater than errors from other sources. It demonstrates that the work-piece can obtain maximum possible machining accuracy by this repetitive measurement and compensation technique.     

Neural network-based modelling and error compensation of thermally-induced spindle errors

This research is concerned with enhancing the accuracy of a machining centre by compensating for thermally induced spindle errors in real-time. A neural network model was developed for on-line thermal error monitoring. A PC-based error compensation scheme was also developed to upgrade a commercial CNC controller for real-time thermal error compensation without any hardware modifications to the machine. The spindle thermal errors of a vertical machining centre were reduced by 70% after compensation.     

A new approach to thermally induced volumetric error compensation

A traditional model for thermally induced volumetric error of a three-axis machine tool requires measurement of 21 geometric error components and their variation data at different temperatures. Collecting these data is difficult and time consuming. This paper describes the development of a new model for calculating thermally induced volumetric error based on the variation of three error components only. The considered error components are the three axial positioning errors of a machine tool. They are modelled as functions of ball-screw nut temperature and travel distance to predict positioning errors when the thermal condition of the machine tool has changed due to continuous usage. It is assumed that the other 18 error components remain identical to the pre-calibrated cold start values. This assumption is justified by the fact that the machine tool’s thermal status significantly affects three axial positioning errors that dominate machining errors for a machine tool after its continuous use. To demonstrate the effectiveness of the proposed model two types of machining jobs, milling and drilling, on a three-axis horizontal CNC machining centre are simulated and the machined part profiles are predicted. The results show that the thermally induced volumetric error was reduced from 115.40 to 45.37?μm for the milled surface, and the maximum distance error between drilled holes for the drilling operation was reduced from 38.69 to ?0.14?μm after compensation.     

机械制造业数控机床几何误差自动控制

为了降低数控机床几何误差,提升加工精度,提出机械制造业数控机床几何误差自动控制方法。通过激光跟踪仪辨识机械制造业数控机床的几何误差,采用快速定位补偿算法与圆弧插补补偿算法相结合的方法补偿数控机床几何误差。利用计算机辅助制造软件生成刀位文件,依据刀位文件生成数控机床加工程序,通过补偿控制器生成数控机床各轴运动的控制指令,数控机床伺服系统接收控制指令后,自动控制数控机床各轴运动,以达到数控机床几何误差自动控制的目的。实验结果表明,采用该方法自动控制数控机床几何误差后,方向与角度的几何误差分别低于0.03 mm与0.1°,实际应用效果较好。     

基于误差补偿的加工中心在线检测软件的开发

对加工中心在线检测软件误差补偿技术进行研究，基于Windows平台开发了在线检测误差补偿软件。并对软件开发中的关键技术检测系统的几何误差模型的建立、测头误差处理技术进行了研究。可以同时对测头误差、机床几何误差进行补偿，有效地提高了在线检测精度。软件系统在MAKINO立式加工中心上进行了实验验证。     

工件分特征下的五轴数控机床关键几何误差分析与补偿方法

提出了工件分特征下的五轴数控机床关键几何误差分析与补偿方法,将复杂工件进行特征分解,通过灵敏度分析辨识工件分特征下的关键几何误差并补偿,从而提高工件整体加工精度。以某一复杂工件为例,首先,将其分解为平面、斜面、圆柱和圆锥台四个典型特征;然后,基于灵敏度分析分别辨识出各典型特征对应的关键几何误差;最后,分特征地进行误差补偿。在AC双转台五轴数控机床上进行了实验验证,实验结果表明,辨识得到的关键几何误差灵敏度系数之和占比均大于90%,补偿后工件四个典型特征的加工精度提高了20%~30%。研究结果表明,所提方法能有效辨识不同工件分特征下的关键几何误差,从而提高复杂工件的加工精度。     

数控机床在线测量技术与误差分析

对数控机床在线测量技术和系统误差分析进行了研究,认为随着制造技术的不断发展,对于超精密加工,相应的测量设备必须跟上,才能保证精度达到设计要求;要开发出具有在线测量功能的数控机床,才能够适应机械加工的需求.