Analysis and Application of Grey Relation and ANOVA in Chemical–Mechanical Polishing Process Parameters

The parameters for chemical–mechanical polishing (CMP) in an ultra-large scale integrated (ULSI) planarisation process are explored. First, an analysis of variance (ANOVA) is conducted on the CMP process parameters derived from the Taguchi method. The objective is to understand the ranking of the effects of CMP parameters such as down force pressure, platen speed, carrier speed, oscillation, and flowrate on the removal rate. Findings are verified by grey relational analysis. The values of the sequencing results allow us to adjust the parameters to the required machining condition during the CMP experiment. This will reduce the number of experiments needed and the length of time required. This study also analyses the effect of data normalisation and data integrity in grey relational analysis on the degree of sensitivity. The results indicate that it is feasible to use grey relational analysis to predict the rank of the parameter effect in the case of insufficient data derived from the Taguchi method. ID="A1"Correspondance and offprint requests to: Professor Z.-C. Lin, Department of Mechanical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 10672, Taiwan. E-mail: zclin@mail.ntust.edu.tw     

Development and Analysis of Foil Electrodes for High Speed Electrolytic In‐Process Wheel Dressing

This paper discusses the development of an effective electrolytic in‐process dressing technique for high speed grinding. An innovative foil electrode has been designed and tested. The performance of a hydrodynamic foil electrode is discussed. Experimental investigations confirm that foil electrodes show significant improvement on electrolytic in‐process dressing even when the electrolyte supply rate is low.     

Process characterization of vibrostrengthening and application to fatigue enhancement of aluminum aerospace components��part I. Experimental study of process parameters

Vibrostrengthening is a fatigue-enhancement process, originally developed by the Russian aviation industry (Rumyantsev et al. 2004). A potential alternative to shot peening, currently a standard industrial surface treatment for fatigue enhancement, vibrostrengthening offers the potential for shorter processing times and uniform treatment of the surface, especially when dealing with fragile parts and complex part geometries. Vibrostrengthening is a modification of a vibratory finishing process in which the parts or workpieces and a medium of hard granular particles are vibrated together in a processing tub causing the particles to mechanically work the surface of the workpiece. In vibrostrengthening, the workpiece is fixed inside a vibratory tub, increasing the relative velocities between the particles in the medium and the workpiece. This gives rise to more aggressive mechanical working of the workpiece surface. The resulting plastic deformation at the surface produces a sub-surface compressive residual stress, which together with a better surface finish, is conjectured to improve the fatigue strength of workpiece. This paper is an experimental study of vibrostrengthening of aluminum components for fatigue life enhancement. The effects of various process parameters on the fatigue strength of a specimen are studied to experimentally characterize the process. These experiments also demonstrate that the vibrostrengthening process produces significant fatigue enhancement on experimental samples produced by machining. Further, these experiments verify that, in fact, fatigue enhancement in the vibrostrengthening process is a result of the combined effect of inducing a compressive residual stress field within the material and improving the material??s surface finish. Fatigue tests indicate that the fatigue enhancement of this process is comparable to, if not better than, shot peening. One important reason for such a favorable comparison, given the lower levels of residual stress that result from this process, is the superior surface finish it produces. A companion paper (Sangid et al. 2010) presents a study involving process visualization to understand and explain the process mechanics; further, a computational model is produced to characterize the fatigue enhancement of the process through the compressive residual stress field and surface topography.     

Real Time Control of pH in Fed‐Batch Process

Abstract

The objective of this work is to implement the linear, non linear model based and linear cascade controllers to control pH in a fed batch neutralisation process in real time and compare the performance with the simulation results. The control objective here is to make the process output pH to follow the given reference trajectory. This work aims at bringing out the best features of model‐based control and linear cascade control, when applied to highly non‐linear systems like pH‐controlled fed‐batch processes. For these processes, control of pH by a conventional Proportional Integral Derivative controller fails to provide satisfactory performance because of the extreme non‐linearity in the pH dynamics. Typical problems in control, e.g., uncertainty in model parameters, are addressed in this work. These controllers are implemented in real time using a lab scale setup and compared with the simulation. The results show the superior performance of the non linear model‐based and linear cascade controller over that of the conventional Proportional Integral controller.     

Evaluation of Surface Roughness of Aluminum Alloy in Burnishing Process Based on Chaos Theory

Burnishing experiments with different burnishing parameters were performed on a computer numerical control milling machine to characterize the surface roughness of an aluminum alloy during burnishing. The chaos theory was employed to investigate the nonlinear features of the burnishing system. The experimental results show that the power spectrum is broadband and continuous, and the Lyapunov exponentλis positive, proving that burnishing has chaotic characteristics. The chaotic characteristic par...     

Ultrasonic Welding of Magnesium–Titanium Dissimilar Metals:A Study on Thermo-mechanical Analyses of Welding Process by Experimentation and Finite Element Method

Ultrasonic welding is an effective ways to achieve a non-reactive/immiscible heterogeneous metal connection, such as the connection of magnesium alloy and titanium alloy. But the thermal mechanism of magnesium alloy/titanium alloy ultrasonic welding has not been defined clearly. In this paper, the experimental and the finite element analysis were adopted to study the thermal mechanism during welding. Through the test, the temperature variation law during the welding process is obtained, and the accuracy of the finite element model is verified. The microscopic analysis indicates that at the welding time of 0.5 s, the magnesium alloy in the center of the solder joint is partially melted and generates the liquid phase. Through the finite element analysis, the friction coefficient of the magnesium–titanium ultrasonic welding interface can be considered as an average constant value of 0.28. The maximum temperature at the interface can exceed 600 ℃ to reach the melting point temperature of the magnesium alloy. The plastic deformation begins after 0.35 s and occurs at the magnesium side at the center of the interface.     

Three-Body Abrasive Wear Behavior of Low Carbon Fe–B Cast Alloy and Its Microstructures Under Different Casting Process

This study investigates the effect of semi-solid processing on the microstructures, mechanical properties of low carbon Fe–B cast alloy. The as-cast microstructure of Fe–B cast alloy consists of the eutectic boride, pearlite, and ferrite. Compared with the coarse eutectic borides in the ordinary alloy, the eutectic boride structures in the semi-solid alloy are greatly refined. Moreover, the boride area fraction, Rockwell hardness, impact toughness, etc., before and after heat treatment under different casting methods are also investigated systemically. The wear behaviors of low carbon Fe–B cast alloy are studied by three-body abrasive wear tester. The wear weight loss of semi-solid Fe–B cast alloy is lower than that of the ordinary Fe–B cast alloy because of the lower average boride area for semi-solid specimen. Meanwhile, the wear mechanism of the low carbon Fe–B cast alloy under different casting process is depicted and analyzed by using the physical models.     

回顾与展望International Trade Fair for Intralogistics Solutions and Process Management

正LogiMAT国际内部物流解决方案及流程管理展览会,始终专注内部物流领域——通过汇聚行业领军企业,为行业及客户推荐创新产品,并打造出具有国际影响力的商业平台。2018年3月13日在德国巴登-符腾堡州斯图加特市的新斯图加特会展中心举办的第十六届LogiMAT国际内部物流解决方案及流程管理展览会(以下简称LogiMAT)刷新了先前几届的相关记录。1564个国际参展商占用新斯图加特会展中心117000平米的展览面     

Scuffing as a Desorption Process—An Explanation of the Borsoff Effect

The hypothesis that scuffing of surfaces lubricated by a plain mineral oil results from desorption is tested for high speed cases using two types of apparatus. One uses a medium speed, 1-inch steel ball, 4-ball machine, and a simulated oil consisting of hexadecanoic acid in hexadecane. This lubricant is shown to behave in the same fashion at medium speeds as it does at very slow speeds. Thus, a graph of logarithmic concentration of acid against reciprocal absolute scuffing temperature gives a good straight line, just as at slow speeds. In the second high speed gear tester, the rise in scuff load of gears at very high speeds, the Borsoff effect, can be explained semiquantitatively by considering the residence time of molecules. These two types of results suggest that the desorption-failure mechanism may be valid over the whole rubbing speed range, and not merely at the very low speeds normally tested.     

Journal of Measurement Science and Instrumentation

Journal of Measurement Science and Instrumentation(CN14-1357/TH,ISSN 1674-8042)is published by North University of China.It is a comprehensive academic journal,aiming to present scientific research papers in the fields of measurement science and instrumentation,including general principles,technologies and instrumentation of measurement and control applied to such academic and industrial fields as mechanics,electric and electronic engineering,magnetics,optics,chemistry,biology,and so on.     

Fabrication and characterization of rugate structures composed of SiO_2 and Nb_2O_5

1Introduction Opticalcoatingdesignsbasedonlayers,whichareinhomogeneousalongthestackaxis,haveopticalandmechanicalpropertiesthatdiffer fromthoseofconventionalhigh low index stacks.Particularly,thewideaccessibleangular rangeandthelowopticalscatterlevelmake themsuperiortotraditionalstackswithrespect toselectedpurposessuchasomni directionalde vicesornotchfilters[14].Manufacturingsuch systemsinpracticerequiresthecalculation,dep osition,monitoringandcharacterizationofopti calcoatingswithawelldefinedc…     

Journal of Measurement Science and Instrumentation

Journal of Measurement Science and Instrumentation(CN14-1357/TH,ISSN 1674-8042)is published by North University of China.It is a comprehensive academic journal,aiming to present scientific research papers in the fields of measurement science and instrumentation,including general principles,technologies and instrumentation of measurement and control applied to such academic and industrial fields as mechanics,electric and electronic engineering,magnetics,optics,chemistry,biology,and so on.     

Machine,Manufacture 和 Process 的辨析

在英语中,Machine,Manufacture和Process三词都可作动词,表示“加工”,但含义有些不同。 1.Machine指“机(械)加工”,主要指“切削加工”。如: The five basic techniques of machining me-tal inclued drilling and boring,turning,planing,milling,and grinding.金属机械加工的五种基本方法是钻和镗、车、刨、铣及磨。在某种意义上,tomachine与to cut相通。machinability(可加工性)就是指cutability(可切削性)。下句中的to machine可以改用to cut: ECM excels in machining difficult-to-mach-ine metals.当加工难以切削的金属时,电化学加工特别优越。     

Open Process在热电系统中的应用

热电企业的生产一般是以供热为主．发电为辅。热电联产具有节约能源．改善环境．提高供热质量．补充电力供应等综合效益。本文介绍了美国通用电气公司Open Process开放型DCS系统在热电自动控制系统中的应用。     

Role of Third Bodies in Friction and Wear of Cold-Sprayed Ti and Ti–TiC Composite Coatings

Titanium (Ti) and Ti-based alloy wear performance is often poor unless coating or lubricants are used. An alternative is to use hard phase reinforcement. Cold spray is a relatively new method to deposit composite coatings, where here we report the deposition of a Ti–TiC coating and its sliding wear behavior. Mixtures of mechanically blended Ti–TiC with various TiC content were injected into a de Laval nozzle and sprayed onto substrates. Two composite coatings and a pure Ti coating are reported here, where the as-sprayed compositions of the composites were 13.8 and 33.4 vol% TiC. Reciprocating dry sliding wear was performed using a custom-built in situ tribometer. All tests were conducted with a sliding speed of 3 mm/s and at a normal load of 0.5 N. Using a transparent sapphire hemisphere of 6.25 mm as counterface, dynamic behavior of third bodies was directly observed. It was found that adhesive transfer of Ti was the primary wear mechanism for the Ti coating, with oxidative and abrasive wear also occurring for longer sliding cycles. The superior wear resistance of the composite coatings compared to Ti was related to dual function of TiC particles, where they reinforced the Ti matrix and facilitated the formation of a stable and protective tribofilms. The tribofilms contained carbonaceous material that provided easier shear and lower friction. The formation of these tribofilms was highly dependent on the TiC particles, which contained excess carbon compared to the equilibrium composition. Higher TiC content was more effective in quickly developing and sustaining the tribofilms.