ISO5436-2的表面形貌评定基准

为了评价仪器的软件和整体性能,根据ISO软件测量标准(SoftGauge)5436-2,应用过程仿真、以及实测电加工表面和实测珩磨表面得到的标准数据,研究了采用不同方法获得的表面形貌即粗糙度轮廓的评定基准,分别为高斯滤波基准、最小二乘中线基准和最小二乘曲线基准.给出了不同基准下ISO 4287定义的表面粗糙度轮廓典型参数的评定结果,包括Ra、Rq、Rp、Rv、Rsk、Rku等,分析了几种基准下各参数相对于标准结果的计算偏差.计算结果表明:对于仿真数据,3种方法的计算精度都比较好,仅仅参数Rsk在两个最小二乘基准下偏差较大,达50%左右;对于电加工表面数据,高斯基准下的各个参数偏差最小,其它两种基准下偏差稍大,而相对偏差较大的是Rsk和Rp,其中Rsk分别为3.55%和-7.45%,Rp分别为-3.45%和3.95%;对于含有跳跃点的珩磨表面,3种基准下的评定结果都有较大偏差,其中求均值运算的Ra、Rq的偏差稍小,其它较大,经过剔除处理后,Ra、Rq偏差仍然相对稍小,Rsk和Rp由较大偏差明显减小为稍小偏差,而Rku、Rp偏差没有明显改进,仍约为40%.总之,3种方法对奇异点较敏感,对无奇异点的粗糙度轮廓的常用参数评定结果基本一致.在评定一般精度、表面无明显周期波纹度成分和较大奇异特征时,对于常用表面功能评定参数,如Ra、Rq,选用原理简单、实现方便的最小二乘拟合基准即可满足要求.     

基于形貌参数表征系统的表面粗糙度评定实验平台开发

随着对机械零部件表面质量要求的不断提高,需要更准确有效地表征表面形貌参数。本文采用VC++软件,研制了一套适用于表面形貌粗糙度参数表征及研究的系统,可以用于互换性与测量技术基础等课程中表面粗糙度监测与评定实验,也可以用于表面形貌参数表征及其表面性能等方面的研究。本系统主要包括了表面形貌轮廓曲线的绘制、各种表面粗糙度参数的计算和比较等。     

基于多尺度理论的三维表面形貌表征研究

首次将多尺度理论应用于三维表面形貌表征,采用不同的观察尺度对原始表面进行最小二乘、Motif法过滤,得到多尺度基面和多尺度表面,并基于WM函数进行图形、粗糙度参数表征研究。研究发现:多尺度理论的应用可以将形状偏差和波纹度视为某相对较大观测尺度下的粗糙度,并成功定量过滤,从而有效地解决传统粗糙度表征中形状偏差和波纹度的影响,提供一种契实可行的用于表征表面形貌和评定表面功能的理论或方法,更加准确地表达三维表面特性与其表面形貌参数的基本关系。     

微铣削表面BEMD基准面的三维粗糙度参数研究

针对二维粗糙度评价微铣削表面不够合理、全面等问题,根据微铣削表面三维微观形貌结构特征,提出了一种基于二维经验模态分解算法(BEMD)的三维粗糙度参数体系。该体系采用BEMD算法获取三维粗糙度计算的评定基准面,通过数值模拟的微铣削表面选取适用于评价微铣削表面的三维粗糙度参数。研究结果表明,BEMD基准面能够作为三维粗糙度计算的基准面;与二维粗糙度相比,所选取的9个三维粗糙度参数能够更全面准确地反映微铣削表面的微观形貌特征。     

石墨加工表面粗糙度图像评定方法

针对接触式测量脆性石墨材料表面粗糙度时存在探针和工件易损伤等问题,提出基于MATLAB进行表面粗糙度测量数据采集和处理的一种新方法。应用GUI(Graphical User Interface)图形界面回调函数(Callback)编写控件,设计易于用户交互的可脱离MATLAB环境独立运行图形界面粗糙度计算软件。通过MATLAB编写的程序对工件的表面形貌图像进行数字化预处理(灰度化,降噪,滤波等),进行轮廓边缘提取、轮廓边缘曲线数字化和最小二乘法拟合等计算,最终计算出图像灰度对应表面粗糙度,实现表面粗糙度计算和输出,通过试验验证了图像评定机械加工表面粗糙度系统准确性。     

触针式三维粗糙度仪的设计

由于传统的二维粗糙度仪不能从整体上表示出零件的微观特性,而三维光学粗糙度仪只能在实验室使用,不能适应工业现场的场合。所以,在分析传统二维粗糙度仪的结构基础上,改装设计了机械式的三维粗糙度仪。提出了用最小二乘法来拟合基准面;并且根据总结的三维表征参数体系,用LabVIEW编写了一套上位机软件系统。软件能够自动的计算三维粗糙度值,并且显示出零件的三维表面形貌。最后在试验中验证了三维参数的评定方法,测试表明,这些参数能有效表征表面粗糙度,能够克服原二维参数统计性差,测量存在较大偏差的不足,更加接近真实表面。     

表面形貌评定方法对比分析

表面形貌特征直接影响了零件的使用功能和技术性能,为了能合理地对表面形貌特征参数进行评估,分析了传统的最小二乘拟合法和经典的高斯滤波法对表面轮廓参数的评估,讨论了最小二乘拟合和高斯滤波法在评估中所存在的不足。根据表面形貌的综合成分,建立表面形貌的数学模型,首次运用B样条小波分析实现了表面形貌数学模型的小波构建。通过小波的分解与重构原理,分离出表面形貌评定基准线。通过工程实例对比分析,验证了B样条小波对表面形貌多尺度分析的合理性,其结果与实际值的误差最小。     

2Cr13不锈钢高速铣削表面粗糙度预测模型研究

针对汽轮机叶片常用钢2Cr13不锈钢在切削加工中表面质量存在的问题,对高速铣削条件下2Cr13不锈钢表面粗糙度预测模型进行了研究。将最小二乘支持向量机原理应用到高速铣削2Cr13不锈钢的表面粗糙度预测建模中。得出的模型能方便地预测铣削参数对表面粗糙度的影响,并能利用有限的试验数据得出整个工作范围内的表面粗糙度预测值。经试验验证,应用最小二乘支持向量机原理建立的粗糙度预测模型回归预测精度高。基于最小二乘支持向量机原理建模方法适合于表面粗糙度预测。     

基于白光扫描干涉的振动补偿方法

研制了一种基于白光波长扫描干涉法的表面形貌抗振反馈测量系统,介绍了白光扫描干涉法的相位提取算法和相位去包裹算法,对声光可调滤光器低速率扫频时产生的非线性误差进行了算法修正,设计了用于振动补偿的DSP硬件控制模块,并搭建了抗振反馈测量系统。在不同振动环境下,对研磨12级的标准样块进行了三维表面形貌测量以及粗糙度参数评定。结果表明,施加低频振源后的粗糙度评定参数大小为未施加任何振源的粗糙度评定参数大小的2倍左右,开启系统振动反馈后,粗糙度评定参数接近最大允许值,说明本测量方法能在一定程度上消除振动噪声的影响,保证测量的顺利进行。二维、三维表面评定结果对比表明,三维表面评定能更全面地表现被测表面的形貌特征。     

基于最小二乘支持向量机的铣削加工表面粗糙度预测模型

在分析以往所建立的表面粗糙度预测模型方法不足的基础上，将一种基于最小二乘支持向量机的预测模型引入铣削加工领域，并给出了相应的步骤和算法。该模型能方便地预测铣削加工参数对加工表面粗糙度的影响，并能利用有限的试验数据得出整个工作范围内的表面粗糙度预测值，有助于准确认识已加工表面质量随铣削参数的变化规律。通过具体实例及与其他几种预测方法的对比表明，在相同样本条件下，其模型构造速度比标准支持向量机方法高1～2个数量级，模型预测误差约为支持向量机方法的40％，预测精度比常规BP模型高1个数量级。因此，基于最小二乘支持向量机方法建模速度快、预测精度高、适合加工表面粗糙度预测。     

基于地貌学的零件表面三维形貌评定

Motif方法作为轮廓法的一种,用7个参数可以完成2维粗糙度和波纹度的评定.近年来,国际上加大了对零件三维形貌评定方法的研究,基于地貌学的理论和Motif方法,对零件三维表面结构要素进行了定义,采用变化树和图形分割等方法,用特殊的点和线表述零件表面山峰和谷地的特性,用谷地的概念描述3维Motif.为了避免过分割现象,需要将无意义的谷地合并为有意义的较大的谷地.峰顶密度、封闭的谷周面积、封闭的谷体体积等评定参数可用于零件三维表面形貌的评定.     

Novel method for evaluating surface roughness by grey dynamic filtering

The evaluation of surface roughness is of great importance for manufacturing industries as the roughness of a surface has a considerable influence on its quality and the function of products. For surface roughness evaluation, to find an appropriate reference line is of the utmost importance. A smooth grey reference line obtained by grey dynamic filtering is proposed to evaluate surface roughness. The primary sampling data of the measured surface need not obey the typical distributions and the surface profile with less data can also be evaluated without losing primary data. Through sample analysis, the grey reference line is well consistent with ISO Gaussian reference line and their evaluation results for surface roughness are in agreement. The grey reference line can be used as one of complements for Gaussian reference line.     

Edge effect elimination in the recursive implementation of Gaussian filters

The paper discusses a general methodology to the design of recursive Gaussian filters to be used for separating the form, waviness and roughness components of the surface texture. By selecting appropriate initial values for the filter difference equations, it is possible to eliminate the so-called edge effect and evaluate the whole registered profile. Two ways of filter implementation were considered: series and parallel. The incremental difference operator is applied in place of the usual shift operator z to describe the filter transfer function. This increases the accuracy of the representation of filter parameters and decreases the number of rounding errors. The results of the analysis were illustrated using 2D and 3D roughness profiles of a ball bearing race. The data show that the mean line and the mean surface were correctly determined for the whole area of the measured profile.     

Dynamics of contact line motion during the wetting of rough surfaces and correlation with topographical surface parameters

Dynamics of contact line motion and wettability is essential in many industrial applications such as liquid coating, lubrication, printing, painting, condensation, etc. However, the wettability of surfaces depends not only on liquid-solid chemical properties but also can be strongly affected by surface roughness. As a practical application of controlled wettability, we can mention the self-cleaning surfaces, protective clothing, microfluidics devices, electro wetting, etc. In this article, we experimentally investigate the spreading of droplets deposited onto rough surfaces. Anisotropic surfaces were prepared by abrasive polishing on the following materials: aluminium alloy AA7064, titanium alloy Ti-6Al-4V, steel AISI 8630, copper alloy UNS C17000, machinable glass ceramic, and poly-methylmethacrylate. Topographical 2D parameters were calculated according to the following standards, defining Geometrical Product Specifications (GPS): ISO 4287, ISO 12085, ISO 13565, ISO 12780, and ISO 12181. The influence of topographical parameters on wettability and spreading phenomenon has been evaluated by statistical covariance analysis. The following parameters have strong influence on fluid spreading on rough surfaces: R(mr) is the relative material ratio of the roughness profile, T(rc) is the microgeometric material ratio, P(mr) is the relative material ratio of the raw profile, K(r) is the mean slope of the roughness motifs, RON(t) is the peak to valley roundness deviation, and P(sk) is the Skewness of the raw profile. The physical meaning of selected parameters is discussed, and K(r) (the mean slope of the roughness motifs) is selected as the most important and physically meaningful parameter. It has been found that for all tested materials, fluid spreading shows increasing tendency when mean slope of the roughness motifs (K(r) ) increases.     

Correlating motif analysis and morphological filters for surface texture analysis

In contrast to the mean-line based evaluation system, motif analysis and morphological filters are two techniques oriented to the characterization of functional properties of surfaces. The motif combination procedure is consistent with the functionality of the morphological closing filter that insignificant peaks on the profile are suppressed. By linking the functionality of the structuring elements with motif combination criterions, morphological envelopes are computed efficiently. Reversely the morphological closing filter coupled with horizontal line-segment structuring elements with lengths equivalent to the motif limits for roughness and waviness provides an alternative for motif analysis. The proposed morphological method has a sound mathematical basis and is stable. An example of applying the empirical motif method (ISO 12085) and the morphological method is demonstrated. The motif parameters resulted from two methods reveal that they coincide with each other. Thus two distinct function oriented methods for surface texture evaluation are technically correlated by mutual exploitation.     

一种新型稳健样条轮廓滤波器

在表面计量学中,通常利用轮廓滤波器提取轮廓中线作为表面评定的基准线。由于传统轮廓滤波器极易受到划痕和深谷等奇异信号影响而产生失真甚至错误的中线,为了增强其稳健性并保证评定精度,国际标准中给出了两种替代滤波器,即稳健型样条滤波器和高斯回归滤波器。然而,这两种滤波器的构造原理和实现算法迥异,其滤波特性差异较大,从而导致对同一表面具有不同的评定结果。为解决这一问题,提出将M估计权函数与样条滤波器相结合构造了一种新型稳健样条滤波器。该滤波器不但具有更强的抗差能力,其计算效率也远高于国际标准推荐的稳健滤波器。更重要的是,大量实验表明,其滤波特性与高斯回归滤波器接近,该滤波器的应用有助于表面评定标准的传递和测量结果比对。     

利用功率谱密度函数表征光学薄膜基底表面粗糙度

光学表面的表面粗糙度通常利用两个传统参数方根粗糙度σ和相关长度l来进行表征。主要就如何引入功率谱密度函数(PSD)表征表面微观形貌进行了初步研究。说明了一维和二维功率谱密度(PSD)函数的数学计算方法、PSD函数的物理意义,同时给出了PSD函数与传统的表面评价指标σ和l之间的关系。利用不同仪器对多种样品进行测试,在分析比较测试结果的基础上,总结了利用PSD函数评价光学表面粗糙度的优点。功率谱密度函数作为一个全面的光学表面评价参数,正得到越来越广泛的重视和应用。     

Influence of surface texture and roughness parameters on friction and transfer layer formation during sliding of aluminium pin on steel plate

Surface texture of harder mating surfaces plays an important role during sliding against softer materials and hence the importance of characterizing the surfaces in terms of roughness parameters. In the present investigation, basic studies were conducted using inclined pin-on-plate sliding tester to understand the surface texture effect of hard surfaces on coefficient of friction and transfer layer formation. A tribological couple made of a super purity aluminium pin against steel plate was used in the tests. Two surface parameters of steel plates, namely roughness and texture, were varied in the tests. It was observed that the transfer layer formation and the coefficient of friction along with its two components, namely, the adhesion and plowing, are controlled by the surface texture and are independent of surface roughness (R_a). Among the various surface roughness parameters, the average or the mean slope of the profile was found to explain the variations best. Under lubricated conditions, stick–slip phenomena was observed, the amplitude of which depends on the plowing component of friction. The presence of stick–slip motion under lubricated conditions could be attributed to the molecular deformation of the lubricant component confined between asperities.     

磨削表面形貌及其加工工艺参数的关系

采用平面磨床在20钢、45钢、40Cr钢试件表面进行磨削加工,通过粗糙度测试仪测量加工试件表面形貌,采用表面形貌统计参数中的轮廓高度算术平均值Ra、微观不平度十点高度Rz、轮廓微观不平度的平均间距Sm、轮廓支承长度率tp对表面形貌进行评价,分析了表面形貌参数与磨削加工工艺参数、试件材料的关系。结果表明,磨削表面形貌与加工过程中的工艺参数密切相关。