轮对表面几何参量检测

文中介绍设计系统的要求与总体构思.从图像获取和图像处理的角度上,详述车轮表面质量各项参数的获取和处理.最后简要说明过程中出现的误差和问题及应该注意的问题.     

The factors affecting surface roughness measurements of the machined flat and spherical surface structures – The geometry and the precision of the surface

The quantitative determination of surface roughness is of vital importance in the field of precision engineering. This paper presents an experimental study of the roughness analyses for the flat and spherical surfaces of machined metal in order to compare the roughness data taken from the cloud data produced by the stylus type profilometer and two optical-based measurement instruments, namely the infinite focus microscope and the confocal laser scanning microscope.In this experimental study, the roughness measurements for fifteen flat and six spherical surfaces were repeated six times using three different measurement instruments. Great care was paid to measure the same location for each measurement. For the comparison of the measurement techniques, the same measurement process was applied to the flat and spherical surfaces individually, and the configurations of the measurement instruments (filter type, cut-off, resolution etc.) were synchronized. R_a, two-dimensional (2D) roughness parameter and S_a, three-dimensional (3D) roughness parameter were also compared. The measurement results for the samples having spherical surfaces indicated a considerably high difference in values taken from the stylus profilometer and two optical-based measurement instruments in contrast to those for flat surfaces.     

On the calibration of surface plates

Calibration of large surface plates could be performed using different measuring systems. In this investigation an autocollimator system, a laser system and a coordinate measuring machine have been investigated. A comparison among these methods of calibration has been carried out. An Elcomat 3000 autocollimator of resolution 0.05 arcsecond, an Agilent 5529A laser interferometer system of resolution 0.05 arcsecond and a Prismo/Zeiss Computerized Numerically Controlled Coordinate Measuring Machine (CNC–CMM) respectively are used. Large reflecting mirror, angular retro reflector and sensitive probe are used with autocollimator, laser systems and CNC–CMM respectively to identify heights at each position on the tested surface plate. Repeated results from the different methods are carried out and presented in the paper. Uncertainties associated with the measurement results of each method have been estimated using the GUM procedures and given in the paper. The paper discusses the difficults and ease as well as accuracies associated with each method.     

支持机械CAD的表面贴图识别及加工实现

在一均匀的纹理图像中，沿任一方向象素的灰度变化都服从一定规律，据此提出一种新的基于纹理分析识别机加工表面贴图表面粗糙度和机加工类型的方法，同时给出了一个实际例子，试用表明，该方法精确可靠。最后结合该实例，利用优化方法给出了其加工工艺参数。     

Effect of hardness difference on the surface durability and surface failure of steel rollers

Experiments with pairs of rollers of different hardnesses designed to assess the effect of hardness difference on surface durability and surface failure are described. Sliding-rolling contact fatigue tests were performed with combinations of thermally refined, through-hardened and induction-hardened 0.45% C steel rollers. The mode of failure is discussed in relation to the hardness difference between the rollers and the presence of residual stresses. The effect of hardness on the modulus of elasticity was also examined. An empirical equation was devised to describe the relationship between the rolling contact fatigue limit under hertzian stress and the surface hardness.     

Generating surface of a tool for shaping the internal surface of the shaft in a low-pressure turbine

Continuous shaping of the internal surfaces of a shaft in a low-pressure turbine by a single contacting working roller is considered, on the basis of semifree strip grinding with constant radial force, in the absence of a servo system. Formulas for semifree grinding that permit the determination of the basic parameters corresponding to the product specifications are established.     

表面粗糙度标准的应用

表面粗糙度标准是六项互换性基础标准之一。近年来,随着标准的修订,表面粗糙度标准在内容上发生了不同程度的变化,有的甚至变化很大。为了更好地贯彻执行这些标准,笔者根据实际贯标情况,有针对性地提出了应用表面粗糙度标准应注意的问题,以供参考。 1 标准的现行版本 众所周知,标准在应用中所产生的问题,很多都是由于标准使用已被代替的旧版本所致。到目前为止,表面粗糙度国家标准和机械行业标准有如下14项(见表1)。其中,GB/T 131—1993、GB/T 1035—1995、GB/T 3505—2000以及GB/T 10610—1998等是常用的标准,也是在应用时最易产生…     

论表面分析

表面分析不同于传统的体相分析,简述我国表面分析发展概况,说明表面分析技术的特点和应用。并对XIS和AES进行了综述。     

可展曲面展开图的参数表示法

画法几何中通常采用手工绘制展开图,作图结果不精确。这里介绍了参数法绘制可展曲面的推导过程,并在AutoCAD2004软件上编程验证了参数展开的有效性。该方法可用于扩展计算机图形软件的曲面展开算法。     

基于Matlab软件对曲面方程已知的曲面面形误差求解与分析

利用Matlab软件结合Excel软件解决磨削工件曲面面形加工误差问题的一个过程.整个过程描述了测头半径误差补偿方法,坐标的旋转变换,平移坐标系对齐,最后对误差原因进行了必要的分析.因为理论曲面为二次曲面,所以利用截面近点补偿法,方便快捷地对误差进行了补偿.     

Realising the potential of duplex surface engineering

We are now close to the new millennium and on the threshold of an era of rapid change. Limitations to the further advance of manufacturing industry in the 21st century are most likely to be surface-related. Many mechanical systems will operate under ever more severe application conditions, such as intensive loads, high speeds and harsh environments, in order to achieve high productivity, high power efficiency and low energy consumption. Consequently, many challenging complex design situations have emerged where the combination of several properties (such as wear resistance, load bearing capacity, and fatigue performance) are required. These new challenges can be met only through realising the potential of duplex surface engineering. Indeed, there are thought to be great technical and economic benefits available through the application of duplex surface engineering technologies in many new market sectors. The present paper is a synthesis of several strands of recent surface engineering research at the University of Birmingham, including the duplex ceramic coating-nitrided steel system and the duplex DLC coating–oxygen diffusion treated titanium system. The prediction of the performance of duplex systems based on advanced contact mechanics modelling is also discussed.     

啮合副空间曲面的检测

利用三坐标测量仪检测啮合副空间曲面的加工误差。     

机器人化月表采样器的研制

首先介绍了月表采样的新特点与存在的困难;根据月表环境、月表样品的特点以及嫦娥三期工程中对月表采样的要求,合理地选择了采样方式,研制出了一台六自由度机器人化月表采样器,并且对采样器的采样原理,机械系统和运动原理做了详细的分析;最后在石灰粉上做了采样实验,验证了多功能的机器人化月表采样器的基本功能与可行性.     

机械加工的表面品质探讨

介绍了机械加工表面品质对零件使用性能的影响,分析了影响切削加工表面品质的因素,并阐述了提高零件加工表面品质的措施。     

Image processing of the grinding wheel surface

Identifying the situation of grinding wheel wear and loading is a very important issue for high-efficiency grinding operations. This paper presents a new method that detects and identifies the chip loading and cutting edge wear of a grinding wheel using the image processing toolbox of the MATLAB package. The different optical characters of the metal chips and the abrasive grains are analysed. The Sobel operator is adopted to make the edge detections. A sensitivity threshold based on the global condition is used to lower the noise. Image dilation and erosion processes are used to ensure that the edge of each loaded chip is covered by a continuous section. The ratios of chips are calculated and displayed to monitor the wheel surface working status.     

轴承端面缺陷自动检测研究

针对微小轴承端面字符与缺陷两者的灰度值相差无几,对缺陷的直接检测造成干扰,提出了基于缺陷周围高亮度特征的检测方法通过对图像的迭代法阈值分割,定义检测目标的像素数作为缺陷识别的主要依据.结合PLC控制系统,开发的缺陷自动检测程序系统,可实现不合格轴承的在线分拣处理.实验结果表明,系统检测误检率不超过1‰,满足了高精度、高效率检测轴承端面缺陷的要求.     

Effect of surface roughness and surface texture on scuffing

This paper discusses the results of disk tests designed to examine the effect of surface roughness and surface texture on scuffing and related behavior. AISI 9310 steel disk of varying surface roughness and surface texture, along with a MIL-L-7808G lubricant, were used. It is shown that, under otherwise comparable situations, (a) an increase in the composite surface roughness increases the coefficient of friction at scuffing, decreases the scuff failure load, and decreases the critical temperature, (b) the cross-ground disks give a lower coefficient of friction at scuffing and a higher scuff failure load than the circumferentially-ground disks, but nearly the same critical temperature, and (c) an increase in the sliding velocity or sum velocity, at a constant sliding-to-sum velocity ratio, decreases the coefficient of friction at scuffing, decreases the scuff failure load, and decreases the critical temperature.The superior performance of the cross-ground disks compared with the circumferentially-ground disks is attributed to the effect of surface texture on microelastohydrodynamic action. The variations of the oil film thickness ratio at scuffing, the coefficient of friction at scuffing, and the critical temperature with respect to surface roughness, surface texture, and operating variables have been shown to correlate well with a dimensionless parameter $\text{ξ}{}_{\mathrm{?}}$.     

具有复杂型面机架的快速曲面重构技术

零件的曲面模型是获得其逆向设计数据等后续处理的关键环节。为了快速获得具有复杂型面机架的设计数据,研究了该机架点云曲面重构的获取方法。鉴于机架不同部位对逆向设计精度要求不同,采用Imageware和Geomagic Studio软件对机架的销孔和外形点云分别进行曲面重构之后,再实施整个模型的曲面整合策略。介绍了应用两种软件完成机架曲面模型的主要处理过程及关键环节。该方法能快速获得符合精度要求的机架曲面模型,可行且高效,为机架曲面模型的实体化及其后续处理提供了可靠依据。     

Prediction of surface reconstruction uncertainties for freeform surface inspection

A method is introduced to predict uncertainties of the B-spline freeform surfaces that are reconstructed from the measurement points for inspection of freeform surfaces. The uncertainties of a reconstructed B-spline surface are modeled by variances of coordinates of points on this freeform surface. Prediction of the uncertainty at any location on the reconstructed B-spline surface is carried out in two steps: (1) estimation of variances of the B-spline surface’s control points introduced by the surface reconstruction process, and (2) propagation of the variances from the control points to the points on the B-spline freeform surface. In this research, the variances of the control points of the reconstructed B-spline surface in all three directions are considered to improve the accuracy of uncertainty prediction in the regions with significant changes of geometric shapes. Both the errors and uncertainties at different locations on the reconstructed surface are considered in freeform surface inspection to compare the manufactured surface against the design surface and its tolerance. The developed method has been applied to two case studies to demonstrate its effectiveness.     

磨合表面形貌的分形模拟研究

采用分形插值法模拟磨合期的45钢表面轮廓,并计算相关的模拟参量,得出模拟出的表面轮廓与实测的表面轮廓有统计相似性,因而可用模拟出的轮廓预测实际磨合匹配表面可能有的形貌。