A process planning strategy for removing arbitrary and axially symmetric profile by a polishing process

In this study, a machining strategy for a polishing process to remove an arbitrary and axially symmetric profile is proposed. The strategy is to plan the tool motion so that a desired profile can be accurately machined. From the volume removing analysis of a polishing process, it is suggested that the dwelling time of the tool at a position should be a linear function of the product of the depth to be removed by its corresponding radius. By using this strategy, three types of errors may be induced: the machining time–distribution error, the ripple error and the resolution error. It is shown that these errors are related to the profile, the tool step, the volume removing rate and the size of the machining zone. The qualitative and quantitative properties of these errors are analyzed. This analysis indicates that a dominant factor in deciding these errors is the tool step size. By increasing this size, both the machining time–distribution error and the resolution error are reduced but the ripple error is enhanced. A tactic is proposed to solve the conflict in choosing the tool step. The experimental study conforms that the proposed strategy can accurately remove an arbitrary profile and the error analysis is reasonable.     

Optical fiber polishing automation with on-line force sensing

This study proposes a bare fiber polishing control strategy and force sensing mechanism to improve the performance of fiber polishing in optical communication. By analyzing the force and problems encountered during polishing, this study successfully measured the force with the required precision. Finally, the experimental results demonstrate a yield improvement from 20% to 80%, for a fiber tip offset within 1.5 μm.     

Evaluation of texture distribution during the industrial polishing process of porcelain stoneware tiles

The present work addresses the distribution of texture over the surface of porcelain stoneware tiles due to kinematics imposed by industrial polishing process. The scratching process was simulated using a computational algorithm, which was based on the kinematic equations for the whole myriad of abrasive particles. Different scratching patterns were identified over the polished surface and their corresponding positions were mapped. The experimental results showed that regions in the tile centre present smaller tendencies for exhibiting preferential textures than those of the lateral ones. The final texture was slightly asymmetric and different from those simply left by the last scratches. The definition of three polishing domains was then suggested according to different phenomenological criteria. Results from both experiments and simulations made evident the influence of the kinematic parameters adopted by the industries on the polishing quality of porcelain stoneware tiles.     

螺旋马达转子的抛光研究

提出以数控加工的方式对螺旋马达转子进行抛光,取代传统的人工手动抛光方式;通过有限元分析得到螺旋马达转子的表面在抛光中所选取各节点应力值,分析节点应力变化规律;然后进行抛光实验,得到抛光量大小,验证了有限元分析的合理性,为螺旋马达转子数控抛光提供参考。     

Dependence of pad performance on its texture in polishing mono-crystalline silicon wafers

Mono-crystalline silicon wafers are important materials in the semiconductor industry for fabricating integrated circuits and micro-electro-mechanical systems. To ensure high surface integrity of polished wafers, the effect of pad texture and its variation on the pad performance needs to be understood. This paper studies experimentally the dependence of pad performance on its texture deterioration by investigating its correlation with polishing time, polishing pressure, and material removal rate. The study concludes that material removal rate decreases as the cylindrical cell structure of a pad is gradually deteriorated, that there is a pad life limit beyond which polishing quality can no longer be maintained, and that the workable pad life can be extended to a certain degree by applying higher polishing pressure.     

定偏心锡磨盘超精密平面抛光均匀去除模拟计算(Ⅰ)

定偏心平面抛光中，工件表面各区域材料的均匀去除问题涉及工件加工后的面形。本文从理论上讨论了锡磨盘与工件的转速比、偏心距及转速对工件表面面形的影响，以及工件边缘露出磨盘的情况下，表面的不均匀去除程度。模拟计算结果表明当转速比为１，工件不露出磨盘时，可以实现工件材料的均匀去除。     

自流平无磨料抛光剂

叙述自流平无磨料抛光剂的研究和应用概况，重点介绍以有机硅化合物为主要成分的硬表面抛光剂的组成和制备。     

A Two-stage Clustered Multi-Task Learning method for operational optimization in Chemical Mechanical Polishing

Operational optimization of Chemical Mechanical Polishing, which sets the proper polishing time, is very important for improving the production efficiency of semiconductor manufacturing processes. However, usual operational optimization methods based on Run-to-Run strategies have not been suitable for the mixed-product processing mode of CMP. Also, under the mode, it is very difficult to model the polishing time due to the insufficient number of the corresponding samples. In this paper, a Two-stage Clustered Multi-Task Learning method is proposed for the above modelling problem with small sample size, in which the proposed Probability-based Task Clustering algorithm first groups similar products so that their corresponding samples can be used for modelling simultaneously. After this, in each cluster, the proposed Shared Multi-Task Learning (SMTL) algorithm obtains the corresponding model for each kind of products cooperatively, in which the parameter vector of each model is the sum of two parts – the shared part and the private part. In each cluster, the shared part represents the common characteristics of all products and the private part represents the particular characteristics of each kind of products. Also, in SMTL, the two parts can be obtained after a non-smooth convex optimization problem is constructed and solved through the Accelerated Proximal Method. The results of numerical simulations on a practical industrial data set and the other two data sets demonstrate the effectiveness of the proposed algorithms. The proposed algorithms can also be used in other problems such as the modelling problems of key indexes of urban development and operation.     

Mechanisms and processing limits of surface finish using laser-thermochemical polishing

Laser thermochemical machining allows a controlled material removal of metallic workpieces for an aesthetic or functionalized structuring. This work deals with the question, why does a smoothing effect occurs and what are the mechanisms behind it? The results show, that the surface smoothing is based on the preferred material removal of the roughness peaks compared to the valleys, as well as microstructure related limits of the surface quality. This might be caused not by one single, but a combination of electrical, thermal and physicochemical mechanisms. These effects can be used for the controlled and selective surface polishing.     

车用上光乳化蜡的制备

采用54#石蜡、巴西棕桐蜡、蜂蜡为主要原料,有机硅为成膜改性剂,复合表面活性剂为乳化剂制备了乳化型膏体汽车上光蜡。所研制的膏体上光蜡是通过LEE乳化模式制得的复合表面活性剂,实验得出适宜的乳化剂用量为产品质量比的12％、乳化温度为85℃、乳化时间为20min,可以得到稳定的乳化蜡。