Removal Behaviors of Different SiC Ceramics during Polishing

Comparative experiments were conducted to reveal the removal behaviors of three kinds of silicon carbide (SiC) ceramics during polishing and the effects of ceramic microstructure on the surface quality were also reported. Experimental results show that the second phase in SiC ceramics plays an important role in the surface quality when its size is large enough. The surface quality is enslaved to the formation of steps at interfaces between second phase and SiC matrix that results from different elastic modulus and hardness between two phases. Under 3 μm abrasive grains polishing condition, different SiC ceramics show different removal mechanisms. With decreasing abrasive grain size, all of different SiC ceramics exhibit a ductile removal mode, which decreases surface roughness effiently.     

表面粗糙度的光学测量方法

表面粗糙度的光学测量方法，具有非接触、精度高和响应快等优点，致使研究十分引人注目，发展极快。本文简单介绍了几种典型的光学测量原理和方法及一些商品化的仪器。     

Experimental Investigation on Uncontrollable Parameters for Surface Finish during Diamond Turning

Single point diamond turning is one of the ultraprecision methods to generate high quality surfaces with highest possible profile accuracies. However, diamond turning process also introduces some unique errors which affect the surface finish. Some of these errors are controllable, while some are noncontrollable. Controllable parameters need proper selection, whereas uncontrollable parameters require adequate understanding of the process behavior. In this study only the effect of uncontrollable parameters on surface finish is explored. Tool overhang results tool–workpiece vibration whereas dynamic unbalance of vacuum responsible for workpiece wobble and both affect the surface finish considerably. Chipping of tool edge, improper extraction of chips, and slipping of workpiece on vacuum chuck are the main reasons of random scratch marks on surface and are contributing factors for degradation of surface finish.     

花岗石抛光表面的粗糙度、分形维数及其关系研究

对两种典型的不同晶粒度的花岗石抛光表面的分形特性和粗糙度特性进行了研究，分析了花岗石抛光表面的分形维数、粗糙度与金刚石磨盘目数的关系，同时也对组成花岗石的重要成分的分形特性及粗糙度做了分析。研究了花岗石抛光表面粗糙度与分形维数的相互关系，并对两者作为花岗石表面质量评价指标的适用性进行了讨论。     

Roughness Evolution of Previously Milled Samples Along a Polishing Test

In the present work results about roughness evolution along a polishing operation with corundum disks of size Norton 400 are presented. Hardened steel and hardened stainless steel samples were previously subjected to ball-end milling or side milling with cylindrical tool at different cutting conditions. Roughness height parameters Ra and Rt, as well as parameters related to the Abbott-Firestone curve such as Rk, Rpk, and Rvk, and shape parameters such as Rsk and Rku were studied. It is usually considered that a polishing operation is complete when Ra does not decrease significantly with more polishing time. In the present paper, an alternative method for determining the end of a polishing test is presented. Roughness is measured both in the longitudinal and in the transversal direction with respect to cutting marks, and it is assumed that the polishing operation is finished when longitudinal values equal transversal values, provided that from that moment on roughness values do not decrease significantly. Moreover, it is recommended to measure parameter Rvk in addition to or even instead of Ra, in order to obtain information about the presence of valleys from the previous milling operation.     

Experimental Study of Surface Roughness and Tool Flank Wear during Hybrid Milling

Two advanced machining methods such as thermally enhanced machining and ultrasonic-assisted machining are recently considered in many studies. In this article, a new hybrid milling process is presented by gathering the characteristics of these two methods. In order to determine the axial depth of cut and engagement in the process, three-dimensional thermal finite-element analysis is applied to determine the dimensions of softened materials. Finite-element modal analysis is used to determine the dimensions and clamping state of the workpiece while cutting area has the highest vibration amplitude. Full factorial experimental design is applied to investigate the effect of hybrid machining parameters on the surface roughness and tool wear. Tool flank wear was investigated under the condition of constant cutting speed during different period of times. Hybrid milling process with an amplitude of 6 µm and a temperature of 900°C creates a surface with 42% lower roughness in comparison to conventional milling in feed 0.08 mm/tooth. In a study of tool flank wear, the results show that application of TEUAM decreases flank wear at least 16% in comparison to all other processes.     

测量表面粗糙度的新型光纤传感器

介绍了一种测量表面粗糙度的准直型光纤传感器。该传感器成功地消除了光纤测头到被测表面距离变动和环境的杂散光线对输出的影响,传感器光通量的计算方法可用于位移及其它反射型光纤传感器的特性分析和结构设计。     

Optimization of Removal Rate and Weibull Modulus in Polishing of Ceramic Blocks Using the Fuzzy-Based Taguchi Method

This paper not only analyzed the Weibull modulus through reliability engineering but also obtained the optimal parameters with multiple performance characteristics using the fuzzy-based Taguchi method for polishing ceramic blocks. Optimization with the multiple performance characteristics is found to be the highest speed and greatest load, and diamond particle of 3 μm and 30% concentration. The analysis of variance shows that the most significant polishing parameters are load (57.75%) and speed (24.43%), followed by concentration (12.52%) and diamond particle size (5.30%). Experimental results have shown that the multiple performance characteristics can be improved effectively through this approach.     

Delamination and Surface Roughness Analyses in Drilling Hybrid Carbon/Glass Composite

Previous attempts at drilling of fibrous composites have been challenging due to the limited mechanical properties and presence of severe delamination damage at the top and bottom surfaces of the drilled hole. With the recent introduction of hybrid carbon/glass fiber reinforced polymer (HFRP) composites in both research literature and industrial applications, the need for evaluating their drillability is inevitable prior to their final usage. This is mainly because of the unique properties of HFRP composites as compared to the single-type FRP composites. Therefore, this paper aims to present a research initiative that will elucidate the high-range parametric effects of drilling control factors on delamination damage and surface quality. Taguchi methodology and statistical analysis of variance were applied to determine the performance of the drilling process. Experimental results revealed that delamination damage and surface quality values were strongly influenced by the feed and special tool geometries rather than the spindle rotational speed. Changes in the feed are likely to contribute to increase in the thrust force and strain rate on the workpiece. Confirmation tests have shown the closeness of the calculated values via a regression model and additive rule with the experimental values. This indicates that the regression model from the response surface can be employed to estimate delamination damage and surface roughness during drilling of HFRP composite.     

高精度光学表面的OFHC铜反射镜抛光技术

已研制出用于红外波段光辐射的特殊光样品－高精度光学表质量的无氧高导铜平面板射镜。本文描述了此种铜镜基底的抛光技术。讨论了材料的选择，基底成形精度及抛光工艺研究，给出了最终光学表面的测量结果。     

不锈钢表面处理:酸洗、钝化与抛光

介绍了近年来开发的部分不锈钢产品的酸洗、钝化及机械抛光、化学抛光、电化学抛光工艺,针对不同的不锈钢牌号及零件规格,给出了相应的表面处理配方及工艺方案。     

高斯滤波在花岗石表面粗糙度研究中的应用

阐述了花岗石表面轮廓的特点,提出先对原始轮廓曲线进行高斯滤波,然后再进行粗糙度计算的方法;并对用高斯滤波和最小二乘中线两种方法计算的粗糙度进行了比较,认为高斯滤波方法更适合花岗石表面轮廓的粗糙度研究.其计算方法较为可靠和简捷.     

Experimental Investigation to Optimize Tool Life and Surface Roughness in Inconel 718 Machining

In addition to the cutting conditions, the surface quality is also affected significantly by a worn tool in machining processes. Identification of the desirable tool life so that the surface quality is maintained within a desirable level is an essential task, especially in the machining of hard materials. In this paper, an optimal tool life and surface quality were identified in the turning operation of Inconel 718 Superalloy by means of experimental investigations and intelligent methods. First, the effect of machining time (MT) at the different cutting parameters was widely investigated on the surface roughness using the neural network model. Then, the modified Non-dominated Sorting Genetic Algorithm (NSGA) was implemented to optimize tool life and surface roughness. For this purpose, a new approach was implemented and the MT was taken into account as the input and output parameters during the optimization. Finally, the results of optimization were classified and the suitable states of the machining outputs were found. The results indicate that the implemented strategy in this paper provides an efficient approach to determine a desirable criterion for tool life estimation in machining processes.     

单晶硅镜面超光滑表面工艺技术研究

用古典的沥青盘抛光技术,通过对超光滑抛光时所使用磨料的选取、沥青抛光盘的软硬和 厚度的合理应用、抛光温度的控制等工艺参数的优化,以f220mm内的单晶硅进行了超光滑表面抛光工艺试验。试验结果,单晶硅表面粗糙度RMS值达0.37nm,平面面形误差PV小于l/15,且加工工艺技术稳定可靠。     

Development of a Precision Surface Polishing System for Parts Fabricated by Fused Deposition Modeling

Additive manufacturing (AM) is the process of fabricating 3D physical models by layered manufacturing without the need of molds or dies. The surface finish of AM physical models is not satisfactory for most general engineering purposes. The aim of this study is to develop an acetone-vapor polishing system to smooth acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM). Acetone vapor dissolved the outer surface of ABS parts, and the surface roughness of ABS parts with complex geometries can be significantly reduced. The advantages of this system include the flexibility to maintain dimensional accuracy, high polishing efficiency, low equipment costs, and no waste chemicals compared with conventional approaches.     

用ARS法分析光纤面板表面粗糙分布

使用光散射空间分布自动测量系统对液晶光阀大屏幕投影系统中使用的光纤面板的表面在入射平面内的微分散射分布进行了测量，该系统的测量灵灵敏度优于１０，线性动态范围达６０ｄＢ，使用角负分布散射方法分析了光纤面板的表面粗糙分布特性及其对象质可能造成的影响。     

Investigation into Influence of Feed Speed on Surface Roughness in Wire Sawing

Aimed at obtaining the minimum machined surface roughness at an appropriate feed speed during the wire-sawing process, the theoretical mathematical model of material removal rate of the non-rigid cutting tool-wire saw is presented, which is based on the Preston equation. According to this theoretical model, this diamond wire-sawing experiment is designed to study the effects of feed speed on machined surface roughness. The experimental results indicate that the minimum machined surface roughness can be acquired by setting the process parameters as the setting curve of spindle speed and feed speed. The investigation provides the theoretical basis and research methods for study of this kind of wire-sawing machine and optimizing process parameters, in order to obtain a low-roughness machined surface.     

Surface Roughness Investigation in the Hard Turning of Steel Using Ceramic Tools

The present work evaluates the use of conventional and multi-radii ceramic tools in the turning of AISI H13 in terms of surface quality. The selected design factors are the cutting speed, feed rate, and type of tool. To carry out this research, a design of experiments was used. The obtained results were analyzed using the analysis of variance (ANOVA), which allowed recognition of the influence of the feed rate and type of tool on the surface quality. By contrast, the cutting speed was found to be a factor that had no statistical significance. When comparing the experimental with the theoretical values, the results of the conventional and multi-radii tools were found to differ. In addition, it was highlighted that the feed rate has an important influence on the difference between the experimental and theoretical results.     

陈列冷柜玻璃门表面结露问题的试验研究

透明的玻璃陈列冷柜为顾客挑选食品提供了方便,但现有的陈列冷柜玻璃门表面容易凝结水雾,失去透明展示效果。本课题在对玻璃陈列冷柜玻璃表面结露条件与影响因数进行分析的基层上,试验研究了采用双层发热导热膜玻璃冷柜玻璃门表面结露有关问题,并与普通双层充氩气涂层玻璃门冷柜进行了性能比较,为玻璃展示冷柜玻璃表面防露设计提供参考。