基于步距规的数控机床误差测量和补偿技术

提出一种在工业现场进行单轴高精度位置误差的测量系统.使用步距规,可以用来代替激光干涉仪进行轴线位置的高精度标定;安装简单,操作容易.对轴线位置误差的补偿结果表明,通过该方法,可以使机床实现"软"升级.     

用Renishaw检查规进行三坐标测量机几何误差检测的研究

本文研究了三坐标测量机几何误差的快速检测方法。根据三坐标测量机空间误差与几何误差关系,提出了使用Ｒｅｎ－ｉｓｈａｗ检查规测量几何误差的方法。该方法通过测量ＸＹ,ＹＺ,ＸＺ平面内特定圆周上各点的空间误差,可获得所有２１项几何误差。这种方法精度高,操作方便,仅用２个小时即可完成全部２１项误差的测量。     

三坐标测量机动态误差补偿的研究

本文研究了三坐标测量机在高速测量过程中的动态误差。针对一移动桥式三坐标测量机,分析了其动态误差的产生原因,建立了动态误差的数学模型,对动态误差进行了全面的测量和补偿。实验证明动态误差具有一定的重复性,可用软件补偿,从而提高三坐标测量机快速测量的精度。     

基于有限元分析的三坐标测量机误差补偿建模的研究

三坐标测量机在高速测量时,由于附加惯性力的影响,引起机体变形,从而导致动态误差.对三坐标测量机动态误差进行了理论分析,在加速、匀速、减速三种状态下,利用有限元方法对横梁沿Z方向进行了受力变形分析,推导出此三种载荷下动态误差补偿模型,并由此得出了任意载荷作用下的误差补偿模型,提高了三坐标测量机的测量精度.     

三坐标测量机动态误差研究分析

现代制造业的发展对三坐标测量机提出了更高的速度和精度要求.高速三坐标测量机已成为测量机发展的一个重要趋势,但测量机速度的提高使动态误差成为了影响测量机精度的主要因素.阐明了三坐标测量机动态误差的概念,分析了测量机的主要动态误差源,并对国内外各种减小动态误差影响的技术进行了较全面的分析.     

三坐标测量机动态误差与测球半径补偿误差的研究

分析了影响给定的三坐标测量机动态误差的因素,对动态偏转角误差进行了测量,并推导出由动态偏转误差得到测头处的动态位移误差的方法,同时分析了测球半径补偿误差的成因及解决措施。     

基于Quindos系统的三坐标测量机几何精度误差补偿技术

三坐标测量机作为一种高精度测量仪器,在生产、制造等众多领域得到了广泛的应用,三坐标测量机的重要性越发显现出来。然而三坐标测量机也是一种机床,在不断的应用过程中也会有精度的衰减,这样就需要对其精度进行必要的补偿,才能保证测量设备的稳定可靠才能为生产、制造提供有效保障。实验证明经过误差补偿的测量机检测精度会显著提高。本文总结了基于Quindos系统的三坐标测量机几何精度误差补偿技术,详细描述了三坐标测量机线性误差的补偿方法。     

坐标测量机形位误差评定方法的研究动态

本文主要对坐标测量机上形位误差的检测方法进行了介绍。指出了只有最小条件法才是符合ＩＳＯ标准的形位误差评定方法。     

步距规使用方法改进

2010年7月工信部首次发布了步距规的国家标准《JB/T10977-2010》。2010年9月国家质监局又发布了步距规校准规范《JJF1258-2010》。本文针对这一新产品的结构材料与使用中存在的测量范围小、受温度限制等缺陷进行了深入分析与研究,总结出克服缺点的方法,开拓了步距规的使用范围,并通过温度补偿值提高了检测精度。对机床检测机构与数控机床制造和使用单位均有很大的应用价值。     

三坐标测量机非刚性误差的分析与补偿

根据移动桥式三坐标测量机非刚性效应测量误差的分布特征 ,通过对坐标测量机构件进行受力变形分析与建模 ,对坐标测量机的非刚性效应测量误差进行了分析 ,为高精度坐标测量机的误差补偿技术提供了新的思路     

Geometric error measurement and compensation for the rotary table of five-axis machine tool with double ballbar

This paper proposes a novel measuring method for geometric error identification of the rotary table on five-axis machine tools by using double ballbar (DBB) as the measuring instrument. This measuring method greatly simplifies the measurement setup, for only a DBB system and a height-adjustable fixture are needed to evaluate simultaneously five errors including one axial error, two radial errors, and two tilt errors caused by the rotary table. Two DBB-measuring paths are designed in different horizontal planes so as to decouple the linear and angular errors. The theoretical measuring patterns caused by different errors are simulated on the basis of the error model. Finally, the proposed method is applied to a vertical five-axis machining center for error measurement and compensation. The experimental results show that this measuring method is quite convenient and effective to identify geometric errors caused by the rotary table on five-axis machine tools.     

Geometric error modeling and compensation for large-scale grinding machine tools with multi-axes

Synthesis modeling of a geometric error-based traditional method for large-scale grinding machine tools with six axes is too complicated to perform in a real-time compensator with a built-in position control system, and it is difficult to obtain all of the error elements corresponding to the model. This paper proposed a novel strategy in which a machine may be considered as translation axes and rotary axes, and geometric errors of the translation axes and rotary axis are modeled and the geometric error models of the machine are very simple for real-time error compensation. The volumetric errors of the translation axes are measured using spatial circular curve ball bar test, and every element of the rotary axis is also obtained by a series of considerate ball bar tests. According to the characteristics of a position controller used in the machine, a synthesis error compensation system based on the NUM numerical control system was developed. Error compensation experiments were carried out, and the results show that the accuracy of the machine is improved significantly.     

基于G代码修改的数控机床几何误差补偿方法

为减小数控机床的空间运动定位误差,研究了一种基于G代码修改的几何误差补偿方法。以多体系统理论为基础,构建起多轴数控机床的通用误差模型,并据此建立了三轴数控机床空间误差模型。提出三维空间内任意直线轨迹的直线插补补偿算法和可提高圆心位置精度的平面内圆弧插补补偿算法,且这2种补偿算法都可分别设定不同的插补精度。采用修改G代码方式实现补偿方法的通用性,在XZOY型三轴数控机床上开展了误差补偿实验,验证了其有效性。     

3920型齿轮测量中心几何结构建模分析

针对如何减小齿轮测量中心的几何结构误差从而提高测量精度,以多体系统拓扑结构分析理论为基础,计及测量中心自身的27项几何结构误差参数和运动误差参数,推导出齿轮精密测量方程式和理想测量方程式,为齿轮测量结果的误差补偿和仿真分析作了必要准备．     

Geometric error compensation software system for CNC machine tools based on NC program reconstructing

It has been proved that error compensation is an effective approach to improve machining accuracy of a machine tool cost efficiently. In this paper, the framework of an error compensation software system, which can realize software error compensation via numerical control (NC) programs reconstructing, is investigated. And the algorithms relating to error prediction are discussed in detail, such as positioning movement error compensation, linear interpolation movement, and circular interpolation movement error compensation. To realize the error compensation, NC program is reconstructed according to the predicted errors during virtual machining before it is fed to the actual machining. Two controlled machining experiments were carried out. The results show that error compensation methods via reconstructing NC programs can improve the movement accuracy of a computer numerical control CNC machine tool obviously.     

Automated measurement and compensation of thermally induced error maps in machine tools

In this paper, a direct method of machine tool calibration is adopted to model and predict thermally induced errors in machine tools. This method uses a laser ball bar (LBB) as the calibration instrument and is implemented on a two-axis computerized numerical control turning center (CNC). Rather than individually measuring the parametric errors to build the error model of the machine, the total positioning errors at the cutting tool and spindle thermal drifts are rapidly measured using the LBB within the same experimental setup. Unlike conventional approaches, the spindle thermal drifts are derived from the true spindle position and orientation measured by the LBB. A neural network is used to build a machine model in an incremental fashion by correlating the measured errors with temperature gradients of the various heat sources during a regular thermal duty cycle. The machine model developed by the neural network is further tested using random thermal duty cycles. The performance of the system is also evaluated through cutting tests under various thermal conditions. A substantial improvement in the overall accuracy was obtained.     

一种利用坐标测量机实现圆度误差评价的方法

针对直角坐标系下圆周截面形状误差评价,介绍了一种圆柱体截面圆度误差的测量与评定方法.在研究了圆度误差定义及测量方法的基础上,建立了基于三坐标测量机的最小外接圆圆度误差三维评测模型.利用双截面最小二乘拟合轴线调整坐标系位置,减少了位姿误差对测量结果的影响.对模型进行坐标系统一转换,使得变换后的模型能更适用于计算机数据处理.然后在坐标变换的前提下,提出了一种利用几何关系搜索最小外接圆圆心的方法,开发了相应的数据分析软件.实验和数据证明,此算法优于传统最小外接圆算法,实现了在直角坐标系下三坐标测量机对圆度误差的最小外接圆法评价.     

Thermal error compensation method for machine center

High-speed machining (HSM) technology has become the most important application in metal cutting industries. However, overcome the positioning error is one of a great concern. The position error happens due to poor machine structure design and thermal expansion comes from cutting, especially when HSM is applied. In this paper, a new technique is developed to compensate for these errors. The thermal images are used to confirm dispersion of all the affect positions. PT-100 thermo-measuring sensors are applied to detect the thermal expansion. And a mathematical model is built by multi-variable regression analysis, which is based on the sensed temperature variation and the thermal expansion. Finally, these errors are reduced significantly by sending a feedback to the microprocessor. Meanwhile, the thermal deformation can be compensated by the mathematical model, under the condition when the machine is equipped with linear encoder. Moreover, based on the simulation, it is possible to reduce the number of sensors from ten to six, which save the memory capacity and great benefit for calculating and speeding the process of algorithm. The model improves the accuracy of machining which meets the precision requirement of HSM technology. As the result of various machining tests, the axial positioning error can be reduced from 20 μm to be 3 μm, which is a significantly improvement than existing methods.     

Five-axis automated measurement by coordinate measuring machine

This research paper presents an analysis of the undercut interference and inclination interference caused by complicated 3D workpiece during measurement. The objective of this research is to propose a solution to the collision between measuring probe and workpiece for the purpose of automation and interference-free measurement. The fundamental procedure is based on the 3D CAD model of workpiece and five-axis coordinate measuring machine (CMM) measuring facility to generate an interference-free stylus orientation through three phases—adjustment of inclination angle under linear contour, adjustment of inclination angle under non-linear contour, and definition of rotation-free angle. Such manner not only solves the interference problems but also incorporates the minimization of counts of measuring probe rotation. In terms of methodology, the research adopts projection of cutting plane to determine the interference status of the measuring point, and based on the measuring inclination angle on the proposition of self-intersected contour and cross-intersected contour concepts, the range of safe rotation range can be determined by sweeping operation. Following the presented methods and procedures, the five-axis CMM simulation system for automated measurement is finally developed to validate the feasibility of proposed solution.