难加工材料切削参数试验的可靠性评估

针对难加工材料干式切削的加工质量问题,将正交试验法和可靠性评估理论相结合,提出了难加工材料干式切削参数的优化及其加工质量可靠性的评估方法,初步探讨了加工表面原始粗糙度和加工后表面粗糙度的关系。试验证明:该方法能够保证特殊难加工材料的切削质量和切削参数优选值的可靠性,与加工表面原始粗糙度有交互作用的因素对工件表面粗糙度的影响较小,对加工具有指导意义。     

拉杆转子轮盘结合面法向接触刚度试验

用功率谱法分析了拉杆转子轮盘接触面表面粗糙度与分形参数之间的关系,结合分形接触理论,建立了轮盘结合面法向接触刚度模型,通过轮盘表面材料参数、法向载荷及轮盘表面的分形参数来计算轮盘结合面的法向接触刚度,并通过试验进行验证。研究表明:轮盘结合面理论计算刚度与试验测试刚度趋势一致;分形接触理论在定性上是正确的,但分形理论适用范围有限,仅适用于粗糙度较小、法向接触载荷较大的场合,与试验刚度测试结果存在一定的偏差。     

铣削20CrMnTi钢已加工表面粗糙度的试验研究

采用正交试验法研究CBN直柄平底立铣刀高速铣削20CrMnTi淬硬钢时切削参数对已加工表面粗糙度的影响。通过极差分析方法研究了切削参数对表面粗糙度的影响程度,通过单因素试验法得到了切削参数对表面粗糙度的影响规律,建立了基于指数函数的切削参数与表面粗糙度的关系模型。利用预测模型得出的表面粗糙度与试验的结果进行误差分析,说明所建立的模型能比较准确地对表面粗糙度进行预测。试验结果表明：各因素的影响程度从大到小依次为铣削深度、每齿进给量和切削速度,表面粗糙度随每齿进给量和铣削深度的增大而增大,随切削速度的增大而减小。     

微细精密铣削表面粗糙度DRSM研究

DRSM方法具有序贯性、可旋转性、模型的稳健性以及试验次数少等优点,近年来逐渐运用在微细精密车铣加工运用中,笔者着重对微细精密铣削表面粗糙度进行DRSM分析,得出了微细精密铣削条件下工艺参数对表面粗糙度的影响规律,并进行了表面粗糙度的预测,有较强的理论实践和现实意义。     

GB／T3505—2000与GB／T3505—1983的主要区别

GB/T 3505-1983<表面粗糙度术语表面及其参数>(以下简称旧标准)只是对粗糙度而言,即只将表面粗糙度轮廓及其参数定义为表面结构特性的唯一组成部分,给出了相关的术语及其定义.GB/T 3502-2000<产品几何技术规范(GPS)表面结构轮廓法表面结构的术语、定义及参数>(以下简称新标准)是等效ISO 4287:1997对GB/T 3505-1983的修订.新标准是对粗糙度、波纹度和原始轮廓三种特性都给出了定义和评定参数,即规定了用轮廓法确定表面结构(粗糙度、波纹度和原始轮廓)的术语、定义及参数.     

基于响应曲面法的表面粗糙度预测模型的建立与切削参数的优选

文中通过试验设计的方法研究了高速精加工中切削参数的选择对表面粗糙度的影响.采用响应曲面法建立表面粗糙度的响应模型,分析了切削速度、进给量、背吃刀量对表面粗糙度的影响以及切削参数的优选.结果显示背吃刀量对表面粗糙度的影响最为显著,进给量次之,切削速度影响最小.在表面粗糙度选定的情况下,优先选择背吃刀量可以提高加工效率.     

圆柱体表面特征尺度系数的测定试验

特征尺度系数是M-B分形接触模型中的一个重要参数,为了获得该参数的准确数值,以机加工圆柱体为研究对象,在表面形貌仪上测试其表面形貌,并应用结构函数法求解出该参数的大小。结果表明:该参数与表面粗糙度呈指数关系;随着表面粗糙度的减小,该参数增大。最后通过曲线拟合,得到该参数与表面粗糙度之间的近似关系式,大大简化了其求解过程。为后续应用分形理论进行齿轮接触力学特性分析提供了前期参数。     

无心车床车削钛合金棒材工艺参数与表面粗糙度关系研究

采用无心车床对钛合金棒料进行表面处理,以去除其表面缺陷,降低表面粗糙度,研究车削工艺参数主轴转速V、进给速度F、吃刀量a_p对表面粗糙度的影响规律。利用响应曲面法来设计实验,通过对实验数据的回归分析,建立基于加工工艺参数(主轴转速、切削深度、进给速度)表面粗糙度预测模型;分析车削工艺参数及其交互作用对表面粗糙度的影响规律,获得了车削最优工艺参数区间。研究结果表明:车削工艺参数对工艺指标表面粗糙度的影响次序为:a_pfV。在工艺参数交互作用中,f-a_p的交互作用对表面粗糙度影响最大;在最优车削工艺参数区间确定的工艺参数组合可满足表面粗糙度R_a小于0.8μm的生产要求。     

砂带磨削加工表面粗糙度预测与验证

为了研究砂带磨削过程中主要工艺参数对磨削表面粗糙度的影响规律,建立了砂带磨削工件的表面轮廓模型,通过对砂带磨粒运动轨迹的研究分析,由单个磨粒的运动方程建立多个磨粒的运动方程。采用单因素试验法,由仿真软件合成磨削加工表面的三维形貌与粗糙度值的变化趋势,通过建立表面粗糙度回归数学模型与叶片磨削试验进行理论分析验证。结果表明,不同工艺参数磨削后工件表面粗糙度的仿真值与试验结果吻合度较好,为实际砂带磨削工艺参数的选择和优化提供理论依据与参考。     

磨削系统加工过程的计算机仿真分析

为了对磨削系统更有效,更快地辨识,本文采用正试验法进行试验法进行试验研究,分析了磨削工艺参数对表面粗糙度的影响,并对影响的显著性水平进行了比较,提出磨削参数对表面粗糙度的作用链,衰减系数,阻尼比与表面粗糙度之间的关系有待进一步研究。     

新国标表面粗糙度参数的评定程序

介绍了表面粗糙度最新国家标准的评定参数,并据此编制评定程序实现了多项粗糙度参数的计算,通过实例说明了程序的有效性。     

Surface roughness evaluation by using wavelets analysis

Based upon wavelets theory, a novel reference for evaluating surface roughness is proposed here, wherein the surface roughness can be separated from the actual surface profile f(t). Some examples have shown that more precise evaluation results could have been achieved than those found using classical reference lines.     

陶瓷刀具高速干式切削等温淬火球铁的表面粗糙度研究

结合现有等温淬火球墨铸铁(ADI)材料的生产情况,制备三组试样并测定力学性能;采用CC650陶瓷刀具实施高速切削试验,探讨ADI高速切削时加工材料-刀具材料-切削用量-表面粗糙度之间的关系,基于微粒群算法建立了ADI高速切削过程中工件表面糙度与切削参数之间的理论模型,为高速切削加工ADI的最佳生产工艺提供理论指导。     

工件表面粗糙度检测装置的智能化改造

表面粗糙度是一个评定工件表面质量的重要公差指标。基于VB技术设计检测系统,利用MATLAB数字图像处理技术,对表面粗糙度进行计算,并基于光切法的表面粗糙度智能自动化检测技术进行改造与研究。     

电解、磨粒、超声复合加工技术及其加工表面粗糙度的预测方法

介绍了电解、磨粒、超声复合加工的基本原理,分析了各主要加工参数对加工表面粗糙度的影响规律,并在此基础上应用神经网络理论中的遗传ＢＰ算法在线预测复合加工工件的表面粗糙度。     

PROTOTYPE SURFACE MICRO- PRECISION IN FUSED DEPOSITION MODELING PROCESS

To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping (RP) process, the inherent characteristics of FDM process, and some micro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better.     

Surface texture assessment of ultra-precision machined parts based on laser speckle pattern analysis

Surface texture plays an important role in overall product specification, because the surface quality of the product is dominated by the nano-scale surface texture. This paper presents a surface texture assessment method for evaluating roughness and periodicity of surface structure with a laser speckle pattern analysis. By investigating the relation between surface texture and laser speckle pattern, characteristic parameters for describing a laser speckle pattern are proposed. The proposed characteristic parameters can evaluate the surface texture in entire observed area and in limited area in any given direction. Furthermore, the surface texture can be qualitatively assessed with a radar chart of the proposed laser speckle characteristic parameters.     

超声纵扭辅助铣削高强铝合金表面润湿性能研究

针对超声辅助加工在工件表面形成微刻划表面可以提高高强铝合金表面的微结构性能的现象,进行了单激励旋转超声纵扭复合铣削表面微观结构的试验,基于水接触角理论和纵扭铣削运动学理论分析了加工参数对水接触角的影响;搭建了单激励超声纵扭铣削试验平台,采用正交试验法研究了不同加工参数对表面粗糙度、铣削力以及表面润湿性能的影响。结果表明：超声振幅为4μm时表面质量最佳,切削速度和进给量与表面粗糙度和水接触角呈正相关的关系;超声加工方式下的表面水接触角较普通方式更大,而在超声加工时低振幅加工比高振幅加工的表面水接触角大,当转速达到一定值时,高振幅和低振幅所加工的表面水接触角差别不大。合适的加工参数条件下超声纵扭加工方式可以降低加工表面的粗糙度,改变表面的润湿性。     

Fractal characteristics and microstructure evolution of magnetron sputtering Cu thin films

How to describe surface morphology characteristic and microstructure evolution are the hottest researches of current thin film researches.But in traditional characterization of surface morphology,the roughness parameters are scale related.And the microstructure evolution of thin film during post-treatment is usually not considered in detail.To give a better understanding of the roughness of thin films topography,fractal method is carried out.In addition,microstructure evolution of thin films is analyzed based on the crystallography and energy theory.Cu thin films are deposited on Si(100) substrates by magnetron sputtering,and then annealed at different temperatures.Surface topography is characterized by atomic force microscope(AFM).Triangular prism surface area(TPSA) algorithm is used to calculate the fractal dimension of the AFM images.Apparent scale effect exists between the surface morphology roughness and film thickness.Relationship between the fractal dimension and roughness is analyzed by linear regression method and linear relationship exists between fractal dimension and surface roughness root mean square(RMS).Fractal dimension can be characterized as a scale independence parameter to represent the complex degree and roughness level of surface.With the increase of annealing temperature,surface roughness and fractal dimension decrease.But when the annealing temperature exceeds the recrystallization temperature,due to the agglomeration and coalescence of Cu grain,surface roughness and fractal dimension increase.Scale effect and changing regularity of grain growth and shape evolution for different film thickness under different annealing temperatures are analyzed.Based on minimum total free energy,regularity of grain growth and changing is proposed.The proposed research has some theory significance and applicative value of Cu interconnect process and development of MEMS.