超精密车削表面微观形貌的几何建模与仿真研究

在综合考虑刀具几何参数，刀具振动和最小切削厚度等因素对已加工表面形貌影响的前提下编写了表面微观形貌的仿真程序，在仿真时把一个随机振动信号成功地叠加在理论表面粗糙度中。提出一种建立圆弧刃金刚石车刀超精密车削表面粗糙度模型的新方法。结果表明，仿真得到的表面微观形貌，能够比较正确地反映出超精密加工将要获得的表面轮廓。     

一种基于AFM的金刚石刀具刃口锋利度的检测方法

金刚石刀具刃口纳米级别的锋利度是影响超精密加工表面质量特别是表面微观几何形貌的重要因素.针对目前测量中存在的问题,介绍了一种新的使用原子力显微镜(Atomic Force Microscope,AFM)进行金刚石刀具刃口锋利度检测的方法,该方法首先利用仿射变换进行截面数据提取,然后利用一种基于曲率的算法求出圆弧拟合点,...     

光学自由曲面反射镜模芯的镜面成型磨削

采用精密修锐修整的圆弧形粗金刚石砂轮在CNC精密磨床上进行了数控成型磨削加工,实现了高效镜面磨削。分析金刚石砂轮圆弧形轮廓的成型修整原理,建立了圆弧形修整的数控模式。通过建立曲面数控成型磨削的行走轨迹算法,实现了自由曲面的圆弧包络成型磨削加工。分析了磨削工艺参数和砂轮出刃形貌参数与超光滑表面形成的作用机制,进行了镜面磨削试验并检测表面微观形貌和粗糙度,分析实现镜面磨削的脆/塑性磨削转换机理。理论分析表明,降低砂轮行走速度,提高砂轮转速以及改善出刃形貌可以获得纳米级粗糙度的超光滑磨削表面。试验结果显示,先将砂轮修锐修整再控制砂轮行走速度小至15 mm/min时,表面粗糙度小于10 nm以下,且微观加工表面没有发生脆性破坏,形成镜面。加工高速钢自由曲面时,面形误差(PV值)可以达到10 μm以下,表面粗糙度R_a可以达到约16 nm。实验结果表明:利用数控技术和粗金刚石砂轮可以实现自由曲面模芯的高效镜面磨削加工,保证了高精度的光学自由曲面反射镜注塑模芯。     

超精密车削时切屑形成及表面微观形貌形成机理的研究

在亚微米级CNC超精密车床上进行了单晶金刚石刀具切削试验 ,根据试验结果分析了切屑形成机理和最小切削厚度与表面粗糙度之间的关系 ,建立了加工表面微观形貌的几何模型。研究结果表明 :通过计算最小切削厚度值可预测金刚石车削加工可获得的表面粗糙度值。     

用于超精表面分析的宽范围扫描隧道显微镜

本文描述了一种能检测超精密度表面纳米级超微观形貌的扫描隧道显微镜，该装置可测到高定向石墨表面原子图象和精密光栅，金刚石切削表面和精密磨削表面的纳米级形貌。     

正弦波微结构的超精密加工技术研究

阐述了同轴调制正弦波微结构的加工原理。结合试验分析讨论了刀具刀尖圆弧半径、被加工材料、切削液等切削条件与主轴转速和刀具进给速度等切削用量对金刚石超精密切削加工后的微结构功能表面的影响。为复杂微结构的金刚石超精密加X-技术研究积累了一定经验。     

表面微观V形槽的超精密加工技术研究

表面微观V形槽是一种常见的微结构形式,应用广泛,加工精度要求高。对表面微观V形槽的超精密加工技术进行了研究,应用单点金刚石切削,分析刀具角度、切削参数、装夹方式、冷却润滑条件、进刀轨迹等影响加工质量的因素,并通过切削试验进行验证。通过试验,在平面和曲面上分别加工出了高精度表面微观V形槽,实现了微结构的超精密加工。     

超精密加工表面微观形貌的光学测量方法

介绍了几种典型的超精密加工表面微观形貌光学测量方法的测量原理及优缺点,评述了表面微观形貌光学测量技术的发展动态。     

圆弧刃金刚石刀具刃磨中的关键技术

天然圆弧刃金刚石刀具是加工球曲面、非球曲面零件的重要工具 ,由于金刚石各向异性 ,使圆弧刃刃磨技术成为金刚石刀具制造中的难点和关键。本文针对圆弧金刚石刀具刃磨机理 ,设计了相应的刃磨机 ,并对刃磨结果进行了检测 ,表明这种刃磨机完全可以满足超精密球面和非球面曲面零件的加工要求     

超精密加工表面微观形貌非接触在线检测系统

介绍了专门应用于超精密车档在线检测加工表面微观形貌的检测系统。一种新式高分辨率同轴式激光逻辑设计仪与超精密车床的有机结合,突破了传统的必须卸下工件才能对其进行检测的限制,实现了加工与检测的一体化,达到了检测真正服务于加工的工作原理。实验结果表明,在利用超精密精密气浮导轨作为激光轮廓仪工作台的条件下,测量车削加工表面微观形貌时,在高度方向上的分辩率按国际惯用的均方值表示已倨于０．１ｎｍ。     

Modeling and controlling of surface micro-topography feature in micro-ball-end milling

The machined surface micro-topography has a great influence on the surface quality and the surface function. A simulation algorithm of machined surface topography is present in this paper, in which the influence of the tool vibration is considered. From the overall surface texture formation, surface texture interval, surface texture height, and surface texture direction, the geometric characteristics of surface micro-topography in micro-milling was defined and investigated. The influence of process parameters, especially the initial phase angle of cutter and the tool vibration, on the geometric characteristics of surface micro-topography is investigated, and the method to control the process parameter is proposed. Especially, this paper presents a novel method, through the planning of noncutting tool path, to control the initial phase angle of cutter which has significant effect on surface topography. The experiments shows that the control deviation of the surface texture direction is less than 2°, and the machined surface topography consistent with the simulation result, which means that the modeling and controlling of surface topography is feasible and effective.     

Study on cutting force and surface micro-topography of hard turning of GCr15 steel

This work investigates the cutting force and surface micro-topography in hard turning of GCr15 bearing steel. A series of experiments on hard turning of GCr15 steel with polycrystalline cubic boron nitride (PCBN) tools are performed on a CNC machining center. Experimental measurements of cutting force, 3D surface micro-topography, and surface roughness of the workpiece are performed. The 3D surface micro-topography of the workpiece is discussed, and the formation mechanism of the 3D surface is analyzed. The influence of cutting speed and feed rate on cutting force and surface roughness are discussed. The 2D and 3D surface roughness parameters are compared and discussed. It is found that feed rate has greater influence on cutting force and surface roughness than cutting speed and there exists the most appropriate cutting speed under which the minimum surface roughness can be generated while a relatively small cutting force can be found. Recommendations on selecting cutting parameters of hard turning of GCr15 steel are also proposed.     

高速铣削SiC_p/Al复合材料表面形貌功率谱密度研究

为了研究切削参数对高速铣削SiCp/Al复合材料表面微观形貌的影响,本文采用不同切削参数进行了高速铣削实验,利用Talyscan150型表面粗糙度测试仪对加工表面进行测量,对获得的表面数据进行功率谱密度(PSD)分析。结果表明:高速铣削SiC颗粒增强铝基复合材料时,进给量与铣削深度对功率谱密度影响不大,切削速度是主要影响因素,并且随着切削速度的增大,功率谱密度值降低,表面质量提高。加工表面的主要空间波长成分能够反映加工工艺条件对加工表面形貌的影响。     

研磨表面微观形貌的三维检测及Areal表征

介绍了三维表面微观形貌的检测方法,分析了采用高斯滤波提取基准中面的原理,针对研磨表面形貌的表征选取了一组Areal表征参数。运用原子力显微镜(AFM)扫描研磨工件的表面,采用高斯滤波提取基准中面进而分离出表面微观形貌的三维信息,在此基础上计算出表征参数值。试验表明研磨表面微观形貌呈现高斯分布规律,采用高斯滤波方法及所选的Areal表征参数能够有效地表征研磨表面的三维微观形貌。     

精密干式硬态车削淬硬工具钢加工表面温度参数优化

使用PCBN刀具对不同淬硬状态工具钢Cr12MoV进行精密干式硬态车削试验,运用极差法分析切削速度、走刀量、切削深度、试件硬度、刀尖圆弧半径五个因素对工件表面温度影响的显著性,并得到了最优车削参数。试验表明：影响工件表面温度最显著的因素是工件淬火硬度,切削深度与走刀量的影响相当,刀尖圆弧半径的影响最小。     

PCD刀具几何参数对铝合金加工表面粗糙度的影响

文中研究了PCD刀具在不同的刀具几何参数下车削铝合金的加工表面粗糙度.分别改变刀具的前角、后角和刀尖圆弧半径3个几何参数做单因素切削试验,试验后利用表面轮廓仪测量工件的表面粗糙度,最后分析刀具几何参数对加工表面粗糙度的影响.     

钢板微观表面质量控制理论与技术研究进展

分析给出钢板表面质量缺陷的分类及描述,重点阐释与表面微观形貌相关的钢板微观表面质量缺陷;结合钢板微观表面质量控制的工艺原理,综述国内外针对钢板微观表面质量生成与控制的关键——钢板表面微观形貌的表征与轧制转印生成、轧辊表面微观形貌的磨损演变、钢板表面的视觉美观性和涂镀黏附性与冲压储油性的描述与建模等方面的重要研究进展及成果;分析总结目前钢板微观表面质量的理论研究与生产实践中存在的主要问题,提出进一步开展钢板微观表面质量控制理论与技术研究的若干建议,展望当前在我国着力开展钢板微观表面质量研究的科学意义和应用前景。     

Performance investigation of fitting algorithms in surface micro-topography grinding processes based on multi-dimensional fuzzy relation set

For the purpose of improving the resultant performance processes of microsurface precise grinding in different machining conditions, the obtained grinded surface should be quality-evaluated and influence-assessed under the instructions of topography modeling. Since microsurface fitting algorithms exerts a considerable influence on those constructed topography mathematical features in geometric domain, which results to different grinding micro-topography processes caused by one specific influence mechanism, and makes the performance investigation of fitting algorithms in surface micro-topography grinding processes indispensable. Through extracting the coordinate positions of those selected physical control points in one objective surface topography sample to be grinded by using a series of precise spatial coordinate measurement apparatuses, several typical algorithms of surface fitting in geometric domain were used for constructing the micro-topography models of those sample section surface with complicated point cloud. On the base of computing the newly proposed mathematical features caused from those micro-topography models, fuzzy evaluation data sequences were established and one new multi-dimensional mathematical quantitative evaluation method derived from fuzzy relation set was proposed and employed to deal with their inherent mutual-relationships. As the performance comparisons of resultant grinded topography between using surface modeling operations and not using surface modeling operations were clearly quantified, it is obvious that the multi-dimensional fuzzy influence relation set between surface fitting algorithms, topography geometric features, and practical grinding processes in different experimental conditions will be quantitatively analyzed in detail, which contributes to the acquirement of final conclusions concerned with the inherent influence mechanism and mutual mathematical relation set emerged from the performance results of different surface fitting algorithms, together with the topography spatial features and practical surface grinding process characteristics in one specific experimental conditions as well. Through realizing grinding processes evaluation based on multi-dimensional fuzzy relation set and making performance comparisons with several other typical statistical evaluation methods in index analysis, an in-depth performance inspection of surface precise grinding with objective micro-topography will be facilitated and optimized; simultaneously, a new research idea for improving microsurface modeling and its subsequent grinding processes in a practical experimental operation can also be demonstrated in the long run.     

Some aspects in the surface integrity associated with turning of powder metallurgy compacts

The shape of the tool insert geometry, particularly the size of the tool nose radius, plays a significant role in influencing a variety of surface integrity characteristics such as surface finish, roundness, tool life, edge frittering etc. It has been found in previous work that a large tool nose radius is beneficial in improving the component quality. This paper substantiates these facts and shows that increasing the feed rate generally debilitates the surface integrity but, probably due to some elasticity in the porous compact's surface, this does not cause residual hardening to the machined surface. Abrasion during secondary machining suggests that flank, rather than crater, wear determines the end point during cutting operations. Tool nose geometry plays a significant role in improving surface topography, by reducing the cusp height—when the nose radius is large. The manufacturing envelopes defined by skewness and kurtosis for the machined surfaces suggest that there is a general drift either from a bearing to a locking surface or vice versa. Furthermore, the dispersion of these envelopes reduces with increasing feed rate. These conditions can be attributed to the tool nose geometry, feed rate and depth of cut which modifies the machined surface topography.