一种圆柱度测量基准的误差分离方法

通过对主轴回转误差运动的分析，结合三点法圆度误差分离技术，提出了一种完全分离圆柱度测量基准误差的分离方法，即利用主轴回转轴线平均线、测量传感器及直行导轨之间的空间位置关系，建立相应的坐标系，在分离出被测截面圆度误差、最小二乘圆心初始坐标的基础上，完整地分离出影响圆柱度精密测量的径向回转运动误差和导轨的直行运动误差。该技术不仅可以消除测量基准误差对圆柱度测量精度的影响，还可以实现主轴回转误差、导轨直线度以及导轨对主轴平行度误差的精密测量，对高精度误差补偿加工和机床的精度检验也具有重要意义。     

减少机械加工精度误差的措施

1．机械加工产生误差的主要原因（1）主轴回转误差主轴回转误差是指主轴各瞬间的实际回转轴线相对其平均回转轴线的变动量。产生主轴径向回转误差的主要原因有：主轴几段轴颈的同轴度误差、轴承本身的各种误差、轴承之间的同轴度误差和主轴挠度等。适当提高主轴及箱体的制造精度,选用高精度的轴承,提高主轴部件的装配精度,对高速主轴部件进行平衡,对滚动轴承进行预紧等,均可提高机床主轴的回转精度。     

形位误差测量的误差分析

分析了影响形位误差测量精度的各种误差因素,指出回转精度是测量仪器最重要的精度指标,轴向导轨直线度误差将影响被测工件圆柱度误差和素线直线度误差的测量精度,轴向导轨对回转轴线的平行度误差主要影响圆柱度误差评定结果,工件安装误差对测量结果的影响可以忽略。     

圆柱度的三点法测量技术

本文针对圆柱度误差的精密测量,提出了一种可分离截面圆度误差、截面半径差和截面最小二乘圆心初始位置并重构出被测圆柱形貌的方法,即三点法圆柱度误差分离与重构技术。据此方法,只要拾取3个传感器在各测量截面上的输出信号,就可以获得各截面上的测点在绝对坐标系内的位置,实现圆柱度的精密测量。同时还可以得到回转轴的纯回转运动误差和测量架的直行运动误差。     

球尾检验棒

机床在验收或检修过程中需要反复进行几何精度检验，机床主轴旋转轴线与工作台或车床溜板沿导轨移动的平行度误差是其中的主要检验项目之一。目前国内外普遍采用的检验方法是用标准锥尾检验棒插入主轴锥孔中，然后沿导轨移动固定在工作台上的千分表，测量检验棒母线与导轨的平行度误差。为了消除检验棒的安装误差，需将主轴旋转180°后再重复测量一次，以两次测量结果的平均值来判定平行度误差的大小和方向。这种方法虽然能够满足检验精度要求，但存在以下不足：（1）千分表不能直观、动态地指示平行度误差的大小和方向，必须经过计算，容易…     

多项几何量指标简易三坐标电脑量仪(下)

四、导轨相对工件旋转轴线的平行度和工件轴线径向运动误差的测量及算法对于通过测量工件半径来测量圆度,圆柱度的仪器来说,虽然影响测试精度的因素有很多,例如:测头的安装精度,仪器的分度误差以及工件的安装偏心等。但可以证明这些误差的影响都不大,而影响测试精度的主要因素有两个。一个是导轨相对工件旋转轴线的平行度误差,另一个是工件旋转轴线的径向运动误差。这两项误差都一比一地反映为实测半径的变化,所以是圆度、圆柱度测量中最应该予以消除的误差。然而在实际测量工作中上述两项误差的     

顶尖支承件检测精度的分析

分析了用顶尖支承回转工件的圆度及国跳动的检测精度，着重分析了顶尖支承回转轴线的径向回转误差对圆度及径向圆跳动检测精度不可忽视的影响，指出应控制该回转误差以保证圆度及径向国跳动的检测精度。     

平行三点法圆度误差分离技术的精度分析

阐述了一种能临床测量与分离工件圆度误差和主轴系统回转误差的新方法——平行三点法误差分离技术的测量原理 ,定量分析了测量装置的结构参数、传感器初始调零误差、传感器随机误差和标定误差对圆度测量精度的影响 ,给出了误差传播方程。并讨论了一些消除或减小上述误差的方法。     

车床主轴回转误差对工件圆度的影响

1、前言工件的形状误差主要反映机床各部件的几何误差,即主轴的回转误差、移动式工作台等的直线运动误差、轴的位置误差以及基准面误差等。拖板对主轴方向的平行度以工件圆柱度的形式出现,并在工件的形状误差中占有相当大的比例1)。机床主轴的回转误差由组成回转机构的零件、主轴的形状及装配等误差所引起,并影响工件的圆度等圆柱形误差。主轴的回转误差与工件形状的关系可以参阅和工件表面粗糙度关系的报告,但是,研究其和工     

主轴回转精度的评定原理及计算程序

一、概述在理想的情况下,机床主轴回转轴线在空间的位置是固定不变的。但是实际上,由于存在着轴承的轴颈加工误差,存在着回转过程中的静力学和动力学等方面的影响,主轴的回转轴线在空间的位置是不断变化的。这一变化直接反映到加工零件的形状精度和表面光洁度。因此机床主轴的回转精度是评定机床精加工性能的一项极重要的依据。为了测得这一运动误差,我们研制了主轴回转精度测量系统。该系统包括:主轴回转精度测量仪、数据处理装置和记录仪三部分。系统的测量方法见图1。     

Rotation error measurement technology and experimentation research of high-precision hydrostatic spindle

The hydrostatic spindle is widely applied in the field of high-precision machine tools, which has some advantages such as high stiffness, high rotary precision, and the high damping shock absorption. The spindle rotation error is an important index to measure the machining accuracy of machine tools. Due to the installing eccentric error of the test bar, conventional method based on the standard test bar to measure the rotation error indirectly is applied to the precision machine tools and common machine tools whose rotation error is greater than 1 μm only. In order to eliminate the installing eccentric error of the standard test bar, it presents a self-reference approach that takes the online finish turning test bar, rather than that of the standard test bar, as the measuring datum. Using the capacitive micro-displacement sensor and the LMS data acquisition equipment as the test platform, it designs a set of spindle rotation error measurement system. Then it studies the frequency domain three-point method and has the rotation error and roundness error of high-precision hydrostatic spindle separated. Experimental study shows that the rotation error and the roundness error of the spindle are 0.9 and 0.3 μm, respectively, under the circumstance of conventional standard test bar as the measuring datum. However, if it takes the online finish turning test bar as the measuring datum, the rotation error and the roundness error of the spindle are only 0.3 and 0.1 μm, respectively. The self-reference method is able to eliminate the installing eccentric error of standard test bar directly, and the measurement system has realized the accurate measurements of the rotation error and roundness error of the high-precision hydrostatic spindle.     

A comprehensive technique for measuring the three-dimensional positioning accuracy of a rotating object

A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a machine tool which results in increased surface roughness of machined work pieces. Three capacitance-type displacement sensors were used to measure the position of a rotating master ball. The sensors were mounted at the three orthogonal points on the spindle axis. The measurement data were analysed for rotating spindle accuracy, not only for the average roundness error but also for the spindle volumetric positional error during rotation. This method is simple and economical for industrial field use for regular inspection of spindles using portable equipment. The time taken for measurement and analysis using this method is only about two hours. This method can also measure microscopic amplitudes in 3-D directions of vibrating objects.     

Modeling and error analysis for assessing spindle radial error motions

The rotating accuracy of a machine tool spindle directly affects the roundness of machined parts. Commonly, a precision arbor and one or two probes are used to inspect the spindle axis error motion. When the spindle error motion is in the same order of magnitude as the accuracy of the reference arbor, it is desirable to separate the roundness error of the reference arbor from the spindle error. One of the methods used is the three-probe method. This paper presents an exact geometric model and error analysis for the conventional three-probe method. The exact model is used to show that there is an approximation error in the commonly used governing equations of the three-probe method. To reduce inaccuracy in the converted axis motion and arbor contour, the reference arbor accuracy should be at least ten times better than that of the axis motion. It is also shown that the mounting error of the probes should be less than one-fiftieth of the size of the axis motion and the arbor size. The exact geometric model developed in this paper can also be extended to analyze the accuracy of other spindle inspection or roundness measurement methods.     

An identification method for spindle rotation error of a diamond turning machine based on the wavelet transform

This paper presents an identification method for the spindle rotation error from the flatness error in the workpiece surface. The spindle rotation error is identified by the wavelet transform, Weierstrass function, and power spectral density (PSD). The flatness error comprises various errors of the machine tool, such as spindle rotation error, guideway error, motor error, and ball screw error, therefore, wavelet transform is used to process the measured result of the workpiece and the signal is decomposed into high-frequency and low-frequency signal. Weierstrass function is used to fit the spindle rotation error. According to the PSD analysis of the processed signal in the frequency domain, the spindle rotation error is identified from the measured flatness error, this method provides a basis for the identification of machine tool errors.     

测试设备位姿失调对自准直仪法测量圆分度误差的影响

为了提高圆分度仪器分度误差的测量精度,介绍了用多面棱体自准直仪测量分度误差的原理和方法,对影响测量结果的误差源进行了分析。根据测量原理建立了多面棱体和自准直仪坐标系,利用坐标变换分别建立了多面棱体工作面与受检仪器轴线的平行差、自准直仪光轴与多面棱体工作面不垂直度误差、自准直仪电十字竖线与受检仪器轴线的平行差对分度误差影响的精确模型。在实验室内,以单轴位置转台的定位精度为测试对象,设计了以上三种位姿失调误差模型的验证实验,实验结果与理论模型仿真结果具有很好的一致性,三种位姿失调引入的误差实测值与理论值的最大偏差小于0.9″,验证了位姿失调量引入测量误差模型的正确性,该模型及仿真结果可以准确指导圆分度误差测试。     

基于激光干涉仪的旋转轴误差快速检定方法

为了提升五轴数控机床各旋转轴精度,解决旋转轴几何误差难以测量的问题,提出了一种基于激光干涉仪的旋转轴几何精度快速测量方法。该方法针对AC双转台和BC摆头转台的结构特性,采用旋转轴与直线轴联动的测量技术,可以避免传统测量方法对旋转轴中心的依赖性,推导了测量中直线轴转角误差与直线度对旋转轴几何误差约束关系,在保证精度的同时减少了测量过程中的设备安装调试时间,实现了五轴机床旋转轴转角误差、重复转角误差以及反向间隙的快速测量和补偿。对实际五轴机床AC双转台几何精度进行检定,提高了旋转轴的几何精度,实验证明该测量方法具有很强的工程应用价值。     

<Emphasis Type="Bold">Roundness Error Prediction with a Volumetric Error Model Including Spindle Error Motions of a Machine Tool</Emphasis>

This paper proposes a modified volumetric error model that includes spindle error motions as well as geometric errors. The model is constructed using rigid-body kinematics and homogeneous transformation matrices and an additional error matrix describing spindle error motions is included. The suggested model predicts the positioning errors at a given axis position as a function of both the axis position and the engaged spindle rotation angle. Two circular interpolation tests (inner and outer circle of the same radius) are simulated and the machined part profiles are predicted. To verify the simulation results, machining tests are performed according to the ISO 10791-7 standard. The error model with spindle errors shows a better agreement, between the simulated and measured roundness errors, than the simple geometric model. It can be seen that the geometric errors determine the basic part profiles and the spindle errors change the basic profiles according to the magnitude of the errors and the spindle rotation angle.     

转台误差对数字天顶仪轴系误差的影响

针对数字天顶仪在定位过程中存在的的轴系偏差,研究了如何对光轴与旋转轴、旋转轴与垂直轴之间的角度偏差进行补偿的方法。为了高精度地解算出测站点位置垂直轴的天文坐标,采用对称位置的两幅星图直接解算旋转轴的坐标,从而避免了光轴与旋转轴之间的补偿。采用双轴倾角仪测量倾角,并对旋转轴进行倾角补偿得出垂直轴的位置坐标。考虑进行轴系补偿时,转台误差会对旋转轴坐标和倾角补偿造成影响,分别研究了转台误差对于旋转轴以及倾角补偿的影响,并得出了转台误差的范围。实验结果表明:当测站点纬度的绝对值小于或等于88.3°时,转台误差必须小于或等于35″;当测站点纬度的绝对值大于88.3°时,转台误差值要小于|1 166.8cosδ|″。在对称位置解算测站点位置坐标时,必须提高转台的精度,以减小转台误差对于定位精度的影响。