bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid State Sintering of SiC-Ceramics
Authors: Biswas Koushik
Published: August 2009

The most interesting feature in silicon carbide is the structure-property relation where the formation of different types of microstructure due to different structural modifications (polytypism) and grain-boundary/interfacial phase chemistry dictate the final properties of the monoliths. Since synthesis of SiC in last century, several methods such as hot pressing with a sintering aid (B, C), pressureless sintering with a sintering aid (B, C, Al) and reaction bonded (Si-SiC) were used to fabricate dense SiC. A newer method of fast sintering (spark plasma sintering) using pulsed current is also employed to consolidate nano/submicron size SiC with or without additives. The solid state sintered SiC materials have fine-grained equiaxed microstructure (grain size 1 to 4 µm) with thin layer of intergranular phases (amorphous film), exhibit moderate high-temperature creep and oxidation resistance, fracture toughness (3 to 4 MPam1/2) and have highly flaw-sensitive strength at room temperature. The high temperature mechanical properties are highly influenced by the presence of free C, Al and B + C containing grain-boundary phases. Moreover, during prolong processing, abnormal grain growth occurs resulting in anisotropic -SiC phase formation. The Si-SiC materials are poor candidates for high-temperature applications due to the limit set by the melting point of silicon, and the limitations of hot pressing (HPSiC) as a densification technique are well known. SPSed SiC without sintering additive revealed inferior mechanical properties attributed to poor bonding between adjacent grains. In the present survey, an overview of the new developments in silicon carbide processing and properties will be presented together with the information on structure-properties correlationship. Information on the structure of the grain-boundary/secondary phases and interfaces until now was not comprehensively analyzed.
Liquid Phase Sintering of SiC-Ceramics
Authors: Biswas Koushik
Published: August 2009

In view of considerable attention in the development of liquid phase sintered SiC, a comprehensive study of the data on processing, structure and properties seems highly relevant. This article provides a detailed and critical overview of liquid phase sintered silicon carbide ceramics with primary emphasis of grain-boundary/secondary phase evolution, their structure, distribution on the final properties of the sintered materials. The roles of individual additives in developing boundary microstructures will be identified and demonstrated to be critical in optimizing the mechanical properties, including fracture toughness, flexural strength and creep resistance. Numerous methods of structure-properties modification, like in-situ-toughening, -SiC phase transformation, volume of liquid phase, partial/full crystallization of grain-boundary and/or secondary phases are conclusively discussed. Apart from conventional pressureless sintering of SiC, enhanced spark plasma sintering with different oxide and non-oxide sintering additives are also discussed in terms of phase evolution, microstructure and their structure mechanical properties are correlated.
Teaching Strategy in Numerical Modelling of Metal Forming Processes
Authors: Miguélez H. , Marín N.C. , Muñoz A. , Cantero J.L.
Published: August 2009

Teaching metal forming processes in Mechanical Engineering Undergraduate program is very important because these technologies are widely used to manufacture a great number of parts to industries like automotive, machine tools, aeronautical and many others. High tooling costs and low numbers of parts produced are typical characteristics of forming processes of metal parts. The development of accurate numerical models capable of predicting parameters process combining time and cost reduction, could help to achieve design objectives, thus avoiding the practice of the empirical “trial and error” method that has been traditionally applied to metal forming design. The main objective of this paper is to show a perspective of the new Mechanical Engineering Graduate Undergraduate curricula in the current context of Engineering Education in Spain, focusing on the solid mechanics and manufacturing fundamentals needed to success in teaching simulation of metal forming processes. A new course dealing with modelling of metal forming processes is proposed, discussing curricula context, contents and methodology.
Computer-Aided System for Teaching Machining with Numerical Control
Authors: Piquero Calleja J.M. , Rubio Alvir E.M. , Sebastián M.A.
Published: August 2009

This paper presents SimUned-CN, software to learn the programming for Computer Numerical Control Machine Tools. This software is able to interpret any code of numerical control and simulates both lathes as milling machines. In addition, it has developed a help system for users less experts. Finally, the application takes up a small size, requires few resources and is able to run on most computers.
Implantation of Virtual Practices about Materials Processing in the Manufacturing Engineering Department of the University of Malaga
Authors: Sevilla L. , Martín M.J. , Martín F. , Cano M.J.
Published: August 2009

In this work the results obtained with the virtualisation of manufacturing processes engineering practices at Malaga University are analyzed. This educative innovation tool allows to increase the efficiency of students learning because they can have available previously, by means of the computer, the different practise classes that they will do later. The results show this improvement obtained with the preliminary realization in virtual way in relation to make only an attended practise being present at the laboratory.
Manufacturing Process Definition as a Basic Teaching Tool in the EHEA
Authors: Cantero J.L. , Canteli J.A. , González I. , Miguélez H.
Published: August 2009

The adaptation of the Spanish university system to the European Higher Education Area (EHEA) requires a thorough review of the teaching methodologies. The student must be able to apply the knowledge acquired in the seeking of optimal solutions to real complex problems that involve multiple interrelated variables. Problem-Based Learning (PBL) is a successful and innovative method to meet this objective.
This paper aims to describe experiences of PBL within manufacturing subjects. The paper shows the great potential of this learning method as well as its main difficulties, especially for monitoring and evaluation of large groups of students. Suggestions, based on the teaching experience of the authors, are made to improve the use of such learning activities.
Methodology for Teaching the Material Removal Processes by Using CAD/CAM Software: Turning Processes
Authors: Luis-Pérez C.J. , Puertas Ignacio , Remirez C. , León Javier , Luri Rodrigo
Published: August 2009

As is well-known, teaching of the computer-aided technologies is gaining more and more importance in the field of Manufacturing Processes Engineering. One such example is the growing tendency to employ computers in the simulation of material removal processes (CAM). In this study, a methodology proposed by the Manufacturing Processes Engineering Section in order to teach material removal processes is shown. This methodology is put into practice by employing one CAM software such as Surfcam® and is applied to the teaching subjects given by the previously-mentioned Section belonging to the Public University of Navarre. Due to the length of the practice manual developed for this purpose, which covers turning, milling and EDM processes, the present work has only been focused on the use of Surfcam® in the first case.
Methodology for the Practical Learning of Pelletizing Processes of Biomass Waste
Authors: Miranda G-Cuevas T. , Montero Puertas I. , Arranz Barriga J.I. , López León M. , Rojas Rodríguez S.
Published: August 2009

In view of the need for practical training and for a high quality standard in the field of Renewable Energies, the University of Extremadura offers postgraduate studies called “Master of Energetic Engineering and Renewable Energy Resources”. One component of this programme is the densification practice which forms part of the subject of Biomass Energy. This laboratory practice involves students in the manufacturing process and the quality analysis of densified solid biofuels (pellets), providing them with the experimental knowledge necessary for a thorough assimilation of the theory. By carrying out this laboratory practice as well as participating in dynamism, which is one of the basics of technical studies, students will get a complete training within this discipline.
Design Optimization of Cutting Parameters Using Taguchi Method and ANOVA during High-Speed Machining Hardened H13 Steel
Authors: Zhang Song , Guo Y.B.
Published: August 2009

High-speed machining thoroughly hardened tool steels has emerged as a competitive finishing technology for making dies and molds. The objective of this paper is to develop an optimization method for the better (i. e., lower value) surface roughness in terms of cutting parameters when high-speed milling hardened H13 steel. The cutting parameters to be considered were cutting speed, feed per tooth, radial depth of cut, and axial depth of cut, respectively. A series of high-speed milling experiments of hardened H13 steel using PVD coated carbide inserts without any cutting fluids were performed to measure the surface roughness data. Taguchi orthogonal arrays, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA) were used to evaluate the effects of cutting parameters on surface roughness and to find the optimal factor/level combination for the better surface roughness. The investigations of this study would be used for design optimization of cutting parameters to obtain the better surface roughness.
Study on the AE Signal Based Grinding Contact Detection Method for Thin-Walled Ceramic Materials
Authors: Liu Gui Jie , Zhang Q.L. , Zhu S.F. , Zhang K.S.
Published: August 2009

Engineering ceramics are hard and brittle materials, that is very easy to crack when grinding, and processing mechanism is rather complex than that of metallic materials. One kind of AE signal based grinding contact detection and feeding control method for ceramic material processing is presented in this paper based on ceramic grinding mechanism study. Through a large number of experimental data analyzing, the relationship between grinding touch and the feature of AE signals is obtained, and the automatic and intelligent grinding process can be realized by grinding contact signal driving grinding numeral program. Application results indicate this method can prove grinding efficiency and process quality.
Analysis and Measurement of Effective Flow-Rate in Flood Grinding
Authors: Li Chang He , Hou Ya Li , Ding Yu Cheng , Lu Bing Heng
Published: August 2009

In the grinding process, grinding fluid is delivered for the purposes of chip flushing, cooling, lubrication and chemical protection of work surface. Due to high speed rotating grinding wheel, the boundary layer of air around the grinding wheel restricts most of the grinding fluid away from the grinding zone. Hence, conventional method of delivering grinding fluid that flood delivery is not believed to fully penetrate this boundary layer and, thus, the majority of the grinding fluid is deflected away from the grinding zone. The flood grinding typically delivers large volumes of grinding fluid was ineffective, especially under high speed grinding conditions. In the paper, a theoretical model is presented for flow of grinding fluid through the grinding zone. The model shows that the flow rate through the contact zone between the wheel and the work surface depends on wheel porosity and wheel speed as well as depends on nozzle volumetric flow rate and fluid jet velocity. Furthermore, the model was tested by a surface grinding machine in order to correlate between experiment and theory. Consequently, the effective flow-rate model was found to give a good description of the experimental results and the model can well forecast the effective flow-rate in flood delivery grinding.
Surface Residual Stress Gradient Distribution in High Speed Milling of H13 Die Steel
Authors: Li Yue En , Zhao Jun , Yan Cao Qing , Wang W. , Han Shi Guo
Published: August 2009

High speed milling experiments are performed for hardened H13 die steel by using coated ball end milling cutter, the residual stress of the work-piece surface on the feed and cross feed direction are measured, and the distribution characteristics of residual stress is analyzed. The result shows that the residual stress presents gradient distribution on feed direction, and furthermore, the three-dimensional surface micro topography has no close relation with the residual stress. In addition, the cumulative effect is discussed for explaining the phenomena.
Tool Wear and Surface Integrity in High Speed Milling of Forging and Cast TA15 Alloys with Coated Carbide Tools
Authors: Liu P. , Xu Jiu Hua , Fu Yu Can
Published: August 2009

TA15 (Ti-6.5Al-2Zr-1Mo-1V) is a close alpha titanium alloy strengthened by solid solution with Al and other component. A series of experiments were carried out on normal and high speed milling of TA15. The recommended tools for many years had been the uncoated tungsten carbide grade K. In this work, the tool life of coated carbide tools used in high speed milling of forging and cast titanium alloy was studied. Additionally, the wear mechanism of cutting tools was also discussed. Finally, surface integrity, including surface roughness, metallograph and work hardening, were examined and analyzed. The result shows that the surface quality of forging and cast machined by carbide cutter is similar, but the tool life of carbide in high speed milling of forging TA15 is longer than that in high speed milling of cast TA15.
Fuzzy Diagnosis of Tapping Process Fault
Authors: Xue H.L. , Wang Le , Chen Xue Yong , Wang Gui Cheng
Published: August 2009

Based on analyzing the problem of tap worn and broken in the tapping process, the faults in tapping process are classified into four types: tap worn, chips jamming, uneven hardness of material and the tapping process failure; According to the fuzzy theory, this paper describes the torque characteristic of the four types of faults, ascertains the characteristic vector of fault, presents the weight matrix among faults, puts forward the judgment method of system faults and establishes the fuzzy fault diagnosis system in tapping process. The experimental study shows that the fuzzy diagnosis method can effectively identify the four types of faults in tapping process and guard against tap broken.
Analysis on Finish Hard Turning of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy
Authors: Ming Wei Wei , Chen Ming , Rong Bin
Published: August 2009

Titanium alloys are extensively applied in aerospace, automotive, biomedical, and chemical industries owing to their excellent performance combining high strength-to-density ratio, good corrosion resistance, and high strength at elevated temperature. Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloys are used to replace the most common Ti-6Al-4V in some important applications such as some parts in aerospace engine. The purpose of this paper is to evaluate the machinability of TC11 alloys in the finish hard turning conditions. The paper presents the machinability results of TC11 alloys compared with Ti-6Al-4V, and analyzes the variables such as cutting force, surface integrity, and tool wear mechanism in the experiments.
Simulation Investigation of Tangential-Feed Centerless Grinding Process Performed on Surface Grinder
Authors: Xu Wei Xing , Wu Yong Bo , Sato Takashi , Lin Wei Min
Published: August 2009

In our previous study, a new centerless grinding method using surface grinder was proposed. This paper describes a simulation method for investigating the workpiece rounding process in which a model taking the elastic deformation of the machine into consideration is created, and revealing how the process parameters affect the machining accuracy in the new grinding technique. In addition, a practice way to determine the machining-elasticity parameter showing the elastic deformation is developed. The simulation results are compared to show the effect of process parameters on the machining accuracy.
Experimental Study of Kerf Machined by Micro-WEDM
Authors: Di Shi Chun , Chu Xu Yang , Wei Dong Bo , Zhang Hong
Published: August 2009

In Micro Wire Electrical Discharge Machining (Micro-WEDM), the kerf width varies with different machining parameters, which will greatly influence the machining precision. In order to study the kerf variations in Micro-WEDM, the influence of kerf variation is analyzed and the experiment considering the kerf width and machining speed are performed on self-developed micro-WEDM under different machining parameters. With the reference of the experiment results, 32μm wide slot is machined with Φ30μm wire-tool on stainless steel workpiece.
Simulation of Debris Movement in Micro Electrical Discharge Machining of Deep Holes
Authors: Wang Jin , Wang Yuan Gang , Zhao Fu Ling
Published: August 2009

In micro electrical discharge machining (micro-EDM) of deep holes, the debris dispersed in gap may increase the possibility of secondary discharge, resulting in electrode shape changing and low accuracy of machined hole. In this paper, the debris movement caused by flow fluid in the machining gap is analyzed to understand the mechanism of debris transport by using software, FLUENT. Comparison of debris movement calculated by the modified N-S equation and N-S equation is conducted. Debris movement calculated by the modified N-S equation is demonstrated to be correct by experiment. The simulation results can explain the phenomena such as subulate electrode and hole, unstable machining process and low machining speed in micro-EDM of deep holes. It is helpful to improve the process of micro-EDM.
Principle and Simulation Study on Multi Point-Single Point Incremental Combined Forming for Sheet Metal
Authors: Li X.J. , Li Ming Zhe , Liu C.G. , Cai Zhong Yr
Published: August 2009

Based on Multi-Point (MP) forming technology and Single-Point Incremental (SPI) forming technology, MP-SPI combined forming method for sheet metal is proposed, the principle and two different forming techniques are illustrated firstly. Then the paper is focused on numerical analysis for the novel forming technique with explicit Finite Element (FE) algorithm. During simulation of spherical work-piece, dimpling occurs as a main forming defect in MP-SPI combined forming process. Simulation results show that the dimpling defect can be suppressed effectively by using elastic cushion. An appropriate thickness of elastic cushion is necessary to prevent dimpling. And also the deformation of the work-piece is sensitive to the shape of elastic cushion. The combined forming test shows that the numerical simulation result is closed to the experimental result.
Damaged Layer Analysis for AFM-Based Mechanical Modifications on (100) Si Surface
Authors: Park Jeong Woo , Kim Nam Hun
Published: August 2009

Micro/Nanofabrication of silicon substrate based on the atomic force microscope (AFM) followed by wet chemical etching was demonstrated. A specially designed cantilever with a diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional Si or Si3N4-based micro cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip, which was found to be a low crystallized amorphous silicon layer. Hence these sequential processes, called tribo nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool. According to our results, it has been clearly known that the damaged layer withstands against aqueous potassium hydroxide solution, while it dissolves in diluted hydro fluoric (DHF) solution.
Numerical and Experimental Research on Water-Jet Guided Laser Micromachining
Authors: Yang Li Jun , Wang Mao Lu , Wang Yang , Tang J. , Chen Yan Bin
Published: August 2009

Water-jet guided laser micromachining is the new development of laser machining. This paper analysis the action mechanism of the plasma shock wave and hollow erode effects in water-jet guided laser machining processing, on the base of the thermal effects of the laser and water-jet. And the numerical model on the action effects between the water-jet guided laser and the material was founded. Using the software ANSYS, the processing of the water-jet guided laser micromachining was simulated. This paper gave the investigation on the distributing of temperature field in processing of water-jet guided laser micromachining. And the results of the correlative experiment correspond with the simulation results.
Research on Experimentation of Diamond Wire Saw Cutting Compound Pipes Underwater
Authors: Wang Zhuo , Zhang B. , Wang Li Quan , Xu D.
Published: August 2009

Using diamond saw wire could cut the seabed oil compound pipes. There are different advancing velocities according to the material of pipes; it makes the cutting and advancing velocities under the condition of harmony at the time of cutting the compound pipes underwater. First of all, the experiment system of diamond saw wire was set up by test cistern, equipment of diamond wire saw underwater, hydraulic pressure system, measuring and controlling system, diamond saw wire and single layer seabed oil compound pipes so on. Next, the cutting parameters, which include pipe sizing, working pressure, tensioning force of diamond saw wire, cutting velocity and advancing velocity were initialized and the first experimentation was done. Then, after adjusting the cutting parameters according to the analysis of cutting test, the next cutting experimentation underwater was done. In the end, the wearing capacity of diamond beads was measured and got the optimal advancing velocity which can minish the wearing capacity and prolong the cutting time of diamond beads. So, using these cutting parameters to cut the seabed oil compound pipes validated the feasibility of engineering application.
Surface Topography Characteristic and Statistical Characteristic of 1Cr18Ni9Ti Polished by Electrochemical Polishing
Authors: Pang Gui Bing , Chen D. , Teng Fei , Wei Ze Fei , Xu Wen Ji
Published: August 2009

The surface quality of components has the important influence on the components’ operational performance, characteristic of the geometry topography and statistical Characteristic is the important aspect of the surface quality. This study takes the arithmetic mean deviation of the assessed profile (Ra) to reflect the altitude characteristic of the surface profile, takes the mean width of the profile elements (Sm) to reflect the width characteristic of the surface profile, takes the material ratio of the profile (tp) to reflect the shape characteristic of the surface profile and takes the altitude density function φ(z) and autocorrelation function R(l) to reflect the statistical characteristic. Four groups of experiments are carried out in which 1Cr18Ni9Ti is taken as the material object of the test piece and test pieces with different initial surface roughness are polished. By experiment, the changing rules of the value of Ra, Sm, tp, φ(z) and R(l) after different polishing time are obtained. By analyzing the changing rules of Ra, Sm, tp, φ(z) and R(l), the influence of the Electrochemical Polishing (ECP) process on the surface geometry and statistical characteristic is obtained.
Investigation of the Transient Deformation in the Flexible Forming of Laminated Composite Metal Sheets Using Plasma Arc
Authors: Song Wen Qing , Xu Wen Ji , Wang Xu Yue , Meng J.B. , Jiang Ji Shang
Published: August 2009

A three-layer FEM model, based on the characteristics along the thickness direction of laminated composite metal sheets (LCMS), was developed to study the variation rules of transient deformation in the flexible forming of LCMS using plasma arc. Besides, the comparisons of the typical LCMS Q235A/1Cr13 and single layer metal sheet (SLMS) Q235A were performed. It indicates that the displacement of end point of SLMS is 0.076 mm larger than that of LCMS with the same process parameters. Moreover, the differences of X-axis plastic strain, Z-axis plastic strain along the thickness direction of LCMS decide the bending direction, the occurrence of the edge effect of LCMS during linear heating, respectively. Furthermore, Y-axis stresses of LCMS different layers undergo three dramatic changes with the maximum stress difference of 1.420×107 Pa, and the possible failure of interface delamination occurs in the bonding interface of Q235A and transition layer.
Electrochemical Micro Drilling of Stainless Steel with Tool Electrode Jump Motion
Authors: Liu Zhuang , Qiu Z.J. , Heng C. , Qu Ning Song
Published: August 2009

ECM micro drilling with tool electrode jump motion in cycles is introduced in this work. A linear motor is employed to carry tool to jump with high acceleration in cycles. Due to the high accelerating motion of tool electrode, the electrolyte within machining gap is able to be refreshed. The Z-axis feeding motor, linear motor and DC supplier are coupled in the experimental setup and a series of micro-holes are drilled on stainless steel (1Cr18Ni9Ti) plate with thickness of 0.5mm to investigate the presented process. Experimental results shows, cycle jump motion of tool electrode, higher jump acceleration, longer jump height and shorter cycle machining time lead to better machining accuracy.
A New Variable Feedrate CNC Interpolator for Abrasive Waterjet System
Authors: Tang Wei Xiao , Zhang X.D. , Wang L.
Published: August 2009

It is becoming general that the contour of part is defined with free-form curves for abrasive waterjet cutting. In this paper, the effect of the traverse speed on cut surface quality is discussed. After that, the free-form Pythagorean Hodographs (PH) curve is defined and its main characteristics are discussed. A new CNC interpolator capable of driving the nozzle along the PH curves at the feedrate adaptable of the curvature of the contour is presented. The taper shape or jet lag can be minimized with it through the variation of the traverse speed. Experimental data indicate that a decrease of about 58 per cent in kerf taper angle can be obtained under a given condition.
A Two-Dimensional Ultrasonically Assisted Grinding Technique for High Efficiency Machining of Sapphire Substrate
Authors: Liang Z. , Wu Yong Bo , Wang Xin Bing , Peng Y. , Xu Wei Xing , Zhao Wen Xiang
Published: August 2009

This paper discusses the feasibility of improving machining efficiency of sapphire substrate by using two-dimensional (2D) ultrasonic vibration assisted grinding. An elliptic ultrasonic vibrator is designed and produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304). The sapphire substrate is fixed onto the top face of the vibrator and ultrasonically vibrates in 2D vibration mode when the PZT is excited by two alternating current voltages with a phase difference. A grinding apparatus mainly composed of the ultrasonic vibrator is constructed, and experiments are performed with lateral modulation of elliptic ultrasonic vibration vertical to the grinding direction. Both the grinding forces and the ground work surface are measured and examined. Experimental results show that the grinding force decreases significantly and the resulted surface is improved in certain degree with the ultrasonic vibration compared to those of conventional grinding without ultrasonication. This indicates that the high efficiency grinding for sapphire substrate can be performed with the two-dimensional vibration grinding technique presented in this paper.
Influence of Beam Polarizations on Evaporative Laser Cutting Nonmetallic Materials within High Absorptance
Authors: Xie Xiao Zhu , Lu J.G. , Wei Xin , Hu W.
Published: August 2009

The three dimensional (3D) coupling model is set up for analyzing the energy reflection and absorption on the kerf using ray tracing method after the laser beam cutting nonmetallic materials with high absorptance through multiple reflections. The laser beam characterized by focused gauss beam and fresnel absorption on the kerf are taken into account. The influences of the polarization on the absorbed intensity both in the front and the two walls are also discussed. Results indicate the differences of absorptive intensity among the three polarized lights are relatively small compared to metal. Thus, the polarization has little effects on the kerf of nonmetallic materials with high absorptance. The experimental results also agree well with the theoretical analysis.
Fabrication of Customized Bio-Electrode for Neural Stimulation Using Rapid Prototyping Technique
Authors: Qin G. , Ding Y.C. , Liu Ya Xiong , Du R.K. , Qi X.P.
Published: August 2009

In the treatment of disorders, bio-electrodes are used to be implanted into the patients’ deep brain for long-term stimulation. This paper presents a custom design and flexible fabrication process of bio-electrode for treating neural disorders using rapid prototyping (RP) technique. A 3D model of the bio-electrode is designed and the photosensitive resin electrode prototype is fabricated on the laser rapid prototyping machine, and then the bio-electrode is fabricated using this electrode prototype and the silicon rubber mold and winding technique. The spatial distribution of the electric field fabricated of the bio-electrode is analyzed, and the optical photomicrograph reveals that the cylindrical surfaces of the polyurethane of the bio-electrode have smooth surface and no visible microcracks, and the spiral lines are arranged densely and have no defects of loose and falling and partly protruding. The electrochemical experiments show that the electrochemical process of the bio-electrode is reversible and the bio-electrode has good functionality and stability property.
Automated Fabrication of Complex Shape Metallic Parts Using Mold Decomposed Injection Sculpturing
Authors: Wang F. , Jiang Kai Yong , Xu Xi Peng
Published: August 2009

Mold Decomposed Injection Sculpturing (Mold DIS) is a rapid prototyping technique for producing complex shaped fugitive wax molds. Metallic materials have been used to make parts from these molds. This paper describes the Mold DIS method and an automated mold building machine based on the integration of a CNC sculpture machine and a wax injection device. Material selection, process parameters determination and equipment issues are explained. A 316L stainless steel turbine part with feature sizes ranging from 2 to 50 mm will be shown.
Effect of Cutting Parameters on Minimum Quantity Lubrication Machining of High Strength Steel
Authors: Yan L.T. , Yuan Song Mei , Liu Qiang
Published: August 2009

The cutting performance (tool wear, surface roughness of machined work-piece and chip formation)of wet, dry and Minimum Quantity Lubrication (MQL) machining when milling of high strength steel (PCrNi2Mo) using cemented carbide tools under different (cutting speed, depth of cut, feed rate) was analyzed. The experimental results showed that as the cutting speed, depth of cut and feed rate changed, MQL conditions provided the lowest flank wear and the highest surface quality. Chip formation produced under MQL conditions become more favorable in terms of color and shape. The results obtained prove the potential of using MQL technique in the milling process of high strength steel (PCrNi2Mo) for high cutting speed, feed rate and depth of cut.
Analysis of Factors Effecting Profile Accuracy of Metal-Bonded Ball-Headed Diamond Wheel in Electrical Discharge Dressing Process
Authors: Chen M.J. , Li Ziang , Liang Ying Chun , Fang Z.
Published: August 2009

Metal-bonded ball-headed diamond wheel with small diameter has been widely used in the ultra-precision grinding of optical parts, especially in the parts with complex surface. In-position precise dressing technique of ball-headed diamond wheel is the key technology to improve grinding precision. The effect of mechanical errors on the profile accuracy of wheel dressing were theoretically analyzed firstly. Afterwards a ball-headed diamond wheel dressing equipment based on electrical discharge principle has been designed and built. Orthogonal experiments have been carried out on the dressing equipment, and the dressing quality of wheels under different dressing electrical parameters were analyzed in terms of wheel profile accuracy and wheel surface micro-topography. The influence of dressing electrical parameters on the dressing quality were investigated and the best electrical parameter combination was obtained. Experimental result showed that the wheel profile accuracy can reach upward 0.8μm after dressing, and the protrusion heights of diamond grain were uniformity and the protrusion effect was better than without dressing.
Study on Thermal Errors of High Speed Motorized Spindle on 5-Axis CNC Machine Tools
Authors: Wang Z.C. , Hu X.L. , Zhang C.H.
Published: August 2009

A simplified one-dimensional model, accounting for thermal errors related to high speed spindle of 5-axis CNC machine tools, is developed, and the relationship between heat sources of rotating spindle and thermal deformation in axial direction is found with the help of Fourier’s law for heat transfer under two different boundary conditions. Based on the theory of homogeneous coordinate transformation in robotic, the transformation matrixes between the coordinate system of kinematic pairs and the relationship between errors and compensations are obtained, through which the compensation of thermal errors in high speed motorized spindle is obtainable.
Research on Modeling Flow of Volumetric Error for Five-Axis NC Machine Tools
Authors: Sun Wei , Ma Hui , Li Chao Feng , Wen Bang Chun
Published: August 2009

Based on the achievements of early works, a volumetric error modeling flow which is based on multi-body system theory is put forward. The flow includes 4 key steps mainly: describing structure, setting up coordinate system, creating characteristic matrix and generating volumetric error model are respectively. The operating method of every step is discussed in detail and the solving formula is given. At last, taking the VMC650 machining center of milling and boring which is developed by a machine tool factory as example, the validity of modeling flow is verified. This study can be used as a reference for opening automatic modeling system.
On the Modeling and Analysis of an Improved CNC Interpolation Algorithm
Authors: Luo Lei , Wang L. , Hu Jun
Published: August 2009

An improved interpolation method is presented based on B-spline curve back calculation which regards data points as control points. First, a B-spline surface reconstruction is done, and a favorable condition for real-time interpolation can be provided for NC machining. Then, by prejudging the trajectory feedrate, the tangent vectors of spline curve junction can be calculated, which can be used to establish the spline curve equations based on time. At last, with the equations mentioned above, the trajectory and feedrate profile can be generated simultaneously by the improved interpolation algorithm. An error analysis is also discussed and the feasibility of the improved algorithm is verified by the simulation results.
Sliding Mode Variable Structure Control of a Redundantly Actuated Parallel Robot
Authors: Li Y. , Wang Yong
Published: August 2009

Redundant actuation has good performance in eliminating singularities and optimizing force distribution, a 2-DOF redundantly actuated parallel robot is taken as the object of study. The dynamic model of the parallel robot is derived. Because the parallel robot is an uncertain nonlinear system, the sliding mode variable structure controller is designed considering its fast response and robustness. Then the stability of the proposed controller is analyzed. The saturation function is used instead of the sign function to eliminate the chattering of the sliding mode control. The simulation results show that the torque of each servo motor changes smoothly when using the quasi-sliding mode control. So the damage of the servo motors and robot arms is decreased. The results of the trajectory tracking demonstrate the effectiveness of the quasi-sliding mode control.
Study on the Machinability of Glass Soda-Lime in Diamond Cutting Process
Authors: Zhou Ming , Jia P. , Li M.
Published: August 2009

Glass possesses poor machinability in diamond cutting due to its high hardness and high brittleness. In order to investigate the effect of cutting fluids on the machinability of glass, this paper first conducted soda-lime indentation experiment, and then examined the resulting indentation by optical microscope. Based on this, turning tests were carried out to evaluate the influence of the cutting fluid properties on the machinability of glass. Boric acid solutions were selected as cutting fluids in the tests. The surface processing quality of soda-lime was assessed based on the observations of the micro- morphology of the turned surfaces utilizing AFM. Experimental results indicated that compared with the process without cutting fluid action, the machinability of glass soda-lime can be improved by using boric acid solution as the cutting fluid.
Tangent Following Control Method of Arc with CNC Cutting Machine Tool
Authors: Zhao Yan Wei , Tian X.B. , Xu X.W. , Chu Xu Ming
Published: August 2009

In order to resolve the problem of cutter rotation controlling in the process of cutting using in CNC cutting machine tool, the principle of cutting of CNC cutting machine-tool is analyzed and the coordinate of the machine tool’s motion is built. Tangent Following interpolation of arc based on data sampling algorithm is researched. Interpolation formula is educed and its arithmetic flow chart is given. Two kinds of inaccuracy are analyzed and their comparison graph is studied. PC and Controller motion control system is used in this paper and close-loop speed control system is selected. Dynamic simulation of this interpolation is realized by testing the program written by VC++6.0 under the Googol motion control platform. The result shows that the Tangent Following interpolation can satisfy the need of cutting control process well.
Application of Wavelet Packet Transform for Detection of Ball Bearing Race Fault
Authors: Wang Dong Yun , Zhang Wen Zhi , Lu Wei Ping , Du J.W.
Published: August 2009

In this study, a fault diagnosis system is proposed for rolling ball bearing race using wavelet packet transform(WPT) and artificial neural network(ANN)technique. Vibration signal from ball bearings having defects on inner race and outer race is considered and the extraction method of feature vector based on wavelet packet transform with frequency band energy is used. The vibration signal is decomposed into the individual frequency bands. The variations of the signal energy in these bands reflect the different fault locations. Further, the artificial neural network is proposed to develop the diagnostic rules of the data base in the present fault identification system. The experimental work is performed to evaluate the effect of fault diagnosis in a rolling ball bearing platform under different fault conditions. The experimental results indicate the effectiveness of the proposed method in fault bearing identification.
Fault Diagnosis Model for Hydraulic Punching Machine
Authors: Chen J.P.
Published: August 2009

A modeling method termed as the discrete time hybrid Diagnosis (DTHD) is presented to constructure models for a hydraulic punching machine. The DTHD method is an extension of the works on FDD (the fault detection and diagnosis) which are based on FSM-based modeling. FDD of DTHD models are suited for real time systems because of their capability of detecting faults leading to failures in terms of erroneous delays and deadlines. The occurrences of faults or failures are represented for individual system components by categorizing the set of states of each individual system component model into normal or failed conditions of various types. The condition corresponding to the states (of a component model) are represented by an unmeasurable variable. The components are then composed to produce the overall representation of failures on the whole system model with a single unmeasurable variable.
Fault Diagnosis of Rolling Bearings Based on LLE_KFDA
Authors: Wang Guang Bin , Liu Y.I. , Zhao X.Q.
Published: August 2009

Locally linear embedding (LLE) algorithm is an unsupervised technique recently proposed for nonlinear dimension reduction. In this paper,LLE manifold learning algorithm is introduced into the field of equipment fault diagnosis firstly, a method of the fault diagnosis based on LLE_KFDA is proposed. By LLE algorithm, original sample data is directly mapped to its’ intrinsical dimension space,which data still keep primary nonlinear form. then via kernel fisher discriminant analysis(KFDA), the characteristics data in intrinsical dimension space are mapped into knernel high-dimensional linear space,and then different fault data are discriminated based on a criterion of between-class and insid-class deviatione ratio maximum. LLE_KFDA algorithm is based on original data, avoided from fall of pattern recognition ability which caused by inappropriate or blind choice of the feature parameters in the traditional fault diagnosis method.The experiment to fault diagnosis of rolling bearing shows this method can effectively identify the equipment fault pattern, diagnostic result is good.
Research on Deliquescent Polishing Fluid for KDP Crystals
Authors: Guo Shao Long , Zhang Fei Hu , Zhang Yong , Luan Dian Rong
Published: August 2009

The characteristics and principle of deliquescent polishing technology for potassium dihydrogen phosphate (KDP) crystals are introduced, and the performance requirements of deliquescent polishing fluid for KDP crystals are proposed. The main components of the deliquescent polishing fluid for KDP crystals were selected according to these performance requirements. Through uniformity experiment, stability experiment and fluidity experiment, uniformity, stability and fluidity of deliquescent polishing fluid for KDP crystals prepared using the selected components were tested. Through deliquescent polishing experiment of KDP crystal, polishing performance of deliquescent polishing fluid compounded using the selected components was tested. The material removal rate of the KDP crystal in the deliquescent polishing experiment was 6.03μm/min, and the surface roughness of the KDP crystal after deliquescent polishing was 4.857nm. The experimental results show that the compounded deliquescent polishing fluid for KDP crystals has good polishing performance and can reach the requirements.
Using ASTFT Spectrum to Suppress Cross Terms in WVD and its Application in Fault Diagnosis
Authors: Tang B.P. , Li F. , Liu W.Y.
Published: August 2009

A new fault diagnosis method to suppress cross terms of Wigner-Ville distribution (WVD) using Adaptive Short-time Fourier Transform (ASTFT) spectrum is put forward. The relationships of correlation between auto terms and cross terms of WVD are obtained theoretically by analyzing the WVD. Firstly, the signal ASTFT spectrum which can determine the signal component positions in the time-frequency plane is obtained. Then, the ASTFT spectrum as a window function is selected to process the signal WVD. Thus the cross terms can be effectively restrained. The simulation results show that a better resolution and more effective suppression of cross terms can be obtained. At last, the proposed method is applied to the fault diagnosis of bearing. The simulation and the experiment results indicate that the proposed method is effective in feature extraction.
Study on Realization of Minimally Invasive Dental Implant Based on Techniques of Digital Design and Manufacturing
Authors: Liu Yun Feng , Shao X.H. , Dong X.T. , Peng Wei
Published: August 2009

Advanced engineering techniques have been used in medical area wildly, but experience of surgeon is still relied heavily in dental implant in China. Aiming at this problem, a methodology of minimally invasive dental implant based on techniques of digital design and manufacturing is proposed, the procedure and some key problems of design and manufacturing are studied deeply. With designed implant plan based on 3D computer model reconstructed from CT images of oral and point cloud of oral plaster model, a surgical guide on the mucosa and teeth surface can be designed and fabricated. In clinical operation, the surgical guide is fixed on oral inner surface directly to guarantee the implant plan implemented accurately. Contrast to traditional dental implant, the minimally invasive surgery can be realized without soft tissue flap, and the temporary denture can be fabricated and fixed in the oral to recover the tooth function immediately. Clinical applications illustrate that, with proposed methodology, the efficiency and quality of implant operation can be improved effectively.
Experimental Study on Modeling of Milling Force of 1Cr18Ni9Ti Stainless Steel
Authors: Li Yan Cong , Xu Yan Shen , Zhang Lian Hong
Published: August 2009

Based on characteristic of stainless steel material, its milling performance is analyzed. Milling force of 1Cr18Ni9Ti stainless steel was obtained with single-factor test of milling depth, line spacing, and feed per tooth on a CNC Milling Machine. An empirical model for the milling force of stainless steel was established by regression. The validity of the model is verified by comparing the model data with the experimental data. The impact of milling parameters on milling force is sorted in order of milling depth, feed per tooth and line space according to the exponents in the model. The conclusions have great help for the milling cutting tool’s design of stainless steel and the selection of milling parameters .
Finite Element Analysis on the Cutting Deformation in Drilling
Authors: Han Rong Di , Wu Jian
Published: August 2009

Drilling is one of the complex machining ways. The object of this investigation was to study cutting deformation in drilling by finite element method. A finite element model was developed to study the cutting deformation in drilling with various feed rates and various drilling velocities based on equivalent model. Experimental study on the cutting deformation in drilling was also carried out by a drilling quick-stop device. It is indicated that cutting deformation decreases when the drilling velocity and the feed rate increase; the closer the distance to the web is, the smaller the cutting deformation is; the laws of cutting deformation obtained from finite element method are according to that obtained from experiment.
Application ANSYS CFX in Modeling Turbine Blade
Authors: Yang Li Feng , Zhang Shu Ren , Liu W.N. , Yang Yu , Zhang Y.J.
Published: August 2009

The main component of turbine is made up of stator and rotor, w hose function is to transform liquid energy in to mechanical energy on the main shaft. ANSYS CFX－BladeGen is applied to model turbine , ANSYS CFX－TurboGrid is applied to create a mesh for an turbine blade and then numerical simulation calculation on the obtained model is conducted. In the fact, the result of the above calculation indicates that ANSYS CFX BladeGen is more convenient and swift to fulfill the modeling request of turbine blade. When the performance of the turbine blade is achieved, these blades’ geometric data can be directly exported to Pro/ENGINEER or AutoCAD so as to further CAD and CAM.