bluuebunny/crossref_metadata_2025 huggingface dataset:
Post Welding Heat Treatment Simulation in Welded Stainless Steel Pipe and Comparison with Experiment
Authors: Sedighi Mohammad , Davoodi B.
Published: December 2009

Due to the intense concentration of heat in the welding process, residual stresses are produced in the specimen. One of the most effective ways to relief welding stress is Post Welding Heat Treatment (PWHT). In this paper, finite element method is employed to model and analyze PWHT for two pass butt-welded SUS304 stainless steel pipe. In this simulation, firstly, the welding process has been modeled. Then the stress distribution of the specimen has been transferred to a second analysis for stress relaxation modeling. Norton law is used to investigate creep in stress relief process. Experimental tests are also carried out to verify the effectiveness of the proposed numerical models. The hole drilling method is used to measure the stress distribution in the specimen. The residual stress distribution data before and after PWHT are compared to investigate the effect of heat treatment on residual stress. Based on the modeling and experimental results, the tensile and compressive stresses distributions have been reduced. They are in a reasonable agreement with each other and prove the capability of the proposed modeling technique to simulate PWHT.
Development of a Starch-Based Binder in Metal Injection Molding
Authors: Muhamad Norhamidi , Abolhasani Hooman
Published: December 2009

A new starch-based binder as a natural polymer has been developed for metal injection molding (MIM). In this study tapioca starch which is cheap and readily available in Malaysia has been used as a binder which composed of starch, glycerol, linear low density polyethylene (LLDPE), citric acid and stearic acid. This developed binder system was mixed with 316 L stainless steel powder to prepare the feedstock at three different of powder loadings of 56, 57 and 58% vol. The rheological behavior of the binder and feedstock were evaluated at different temperatures using a capillary rheometer. The rheological behavior of binder shows less than 10 Pa s and the flow behavior index of the feedstocks were determined to less than 1, which indicates the flow characteristic is pseudo-plastic which is suitable for MIM process. Finally, among these three feedstocks, the feedstock of 57% vol. powder loading was selected and its viscosity values within expected shear rate range are less than 1000 Pa s.
Validation of the Method for Generation of Rheological Model to Characterize Non-Conventional Injection Molding by Means of Spiral Mold
Authors: Javierre Carlos , Ponz L. , Clavería Isabel , Fernández A.
Published: December 2009

This paper presents the results derived from the research, whose first results were
presented at AMPT 2005. At this conference, a new method for generation of rheological model to
characterize non-conventional injection moulding by means of spiral mould was presented.
The continuity of this research line has consisted of the development of several tests for
validation of the rheological model obtained with the new method.
Viscosity of a PEHD with different percentages of recycled has been tested, by means of
several kinds of rheometers, like capillary rheometer and rotational rheometer, and the results has
been compared to those obtained with the spiral mould. Conclusions of this research show the
suitable parameters range, at which the results are comparable for the new method.
On the other hand, another work line for the validation of the rheological models has begun, by
applying the models to CAE injection moulding software, and checking the results by experimental
trials with a industrial mould. This mould has been adapted to register pressure results during
injection cycle. These trials take into account the influence of most of the injection process
parameters, as well as different percentages of recycled.
Evaluation and Validation of the Shape Accuracy of FDM Fabricated Medical Models
Authors: Katatny Ihab E. , Masood Syed H. , Morsi Yos S.
Published: December 2009

In the recent years the rapid prototyping technology has become increasingly important as a manufacturing method for many medical devices. Although the advantage of such technology is evident, a precise presentation of the actual anatomical parts as well as shape accuracy and surface quality is a major indicator for choosing the best technique. In this paper, evaluation and validation of the shape accuracy of fabricated models using Fused Deposition Modelling technique is presented. The surface deviation between anatomical models (a mandible) derived from Computed Tomography and their virtual presentation was investigated. A high level of conformity with regard to the surface feature of the anatomical part was observed. Furthermore, surface deviations in the range of ±0.5 mm with an absolute mean deviation of 0.159 mm for the model were reported. The surface accuracies suggest that the reproduction of complex anatomical structures by FDM could potentially be used for surgical planning, custom-made implants and for surgical anatomy teaching.
Magnetostrictive Actuator Modeling and Placement
Authors: Sunar M. , Keles O.
Published: December 2009

Quasi-static equations are presented for a magnetostrictive medium where mechanical and magnetic fields interact with each other. Finite element method is used in conjunction with the Hamilton's principle to deduce equations for the dynamic behavior of the magnetostrictive material. These equations form the basis for the magnetostrictive material to be utilized as a sensor or as an actuator. When used as an actuator, the material can provide enough power to actuate mechanical systems for vibration control. In this work, a cantilever beam with a magnetostrictive actuator is taken to demonstrate the modeling and use of the magnetostrictive actuator in attenuating structural vibrations. The position of the actuator is changed to observe its effect on the response of the system. This is important because it is a well-known fact that the actuator location has impact, sometimes big, on its performance.
Anisotropic Elastic Distortions of a Buried Dissociated Hexagonal Network of Dislocations in a Nickel Based Super Alloys
Authors: Derardja Akila
Published: December 2009

Nickel based super alloys are promising materials for high temperature structural applications because of their low density. The single grain super alloys are extremely creep resistant at high temperature, due to the fraction of Ni3Al based ' precipitates coherent with a Ni based  matrix [1, 3]. The cuboids group together and form semi-coherent interfaces after a long annealing at high temperature. The ' precipitate growths in nickel base super alloys often favor the parallelism of (111) planes between cubic dissimilar crystals [4]. In consequences, a hexagonal network of dislocations, that covers the hetero-interphase, is arranged by accommodation of the angular misfit between two semi coherent crystals ( ). In this work, the magnitude of the distortions is simulated as arising from a trigonal network of subsurface misfit dislocations partly dissociated in Shockley dislocations limiting intrinsic and /or extrinsic stacking faults.
The results derived from a previous explicit formulation using double Fourier series [5]. Each harmonic term of the series depends on the anisotropic elastic constants and the thickness of each phase. The program built is in a double precision Fortran language and it shows the magnitude and the aspect of the distortions of the free surfaces when the dissociation change in the hetero-interphase. Also, the program has the advantage to fully apply to hetero-epitaxial systems, whatever is the thickness of the free surfaces.
Statistical Analysis of Hard Turning of AISI 4340 Steel on Surface Finish and Cutting Region Temperature
Authors: Mohammadi Aminollah , Zarepour Hamid
Published: December 2009

The focus of this study is to investigate the effects of cutting speed, feed rate, hardness and cutting tool material on cutting region temperature and surface finish in hard turning process. A L36 Taguchi's standard orthogonal array was applied as experimental design. Machining tests were conducted under controlled conditions. AISI 4340 alloy steel which has numerous industrial applications was used to perform machining experiments. CBN, ceramic and cermet tools were employed to accomplish 36 tests with three random repetitions, resulting in 108 experiments. Main effects of the factors and their interactions are considered in this study using ANOVA (Analysis of variance) method. Also predictive models are derived by regression. Furthermore, optimal factor levels are obtained through S/N (signal to noise) ratio analysis in order to increase the machining efficiency. Finally, the results of confirmation tests are presented to verify the adequacy of the predictive models.
An Investigation on Continuous Steel Slabs Casting Line and Mechanical Design of a 3R Robot for Sampling from Melting Arc Furnaces
Authors: Soltani Esmaeil
Published: December 2009

Automation of industrial activities is one of the most essential needs in recent years since the operator has smaller role in the process. Creation of the various robotic systems in the different industries causes relaxing the operators from working in hard positions, increases the accuracy, efficiency and velocity in the process and decreases the wastage and price of product. In this paper, the study on melting station and continuous casting line in Mobarakeh Steel Complex
is provided. The needs for elimination of difficulties and increasing the automation level of steel slabs casting line with checking the all stations from robotic and automation point of view for stations with the capability of automation system necessitates a suitable robotic system. In this case, selected robot should be able to support the velocity, accuracy, load capacity and other characteristics. Considering the sensitive conditions around the electric arc furnace (E.A.F), a suitable sampling robot with 3-degree freedom in which all three joints moves in revolute form (RRR) has been designed.
Three Dimensional Printing for Casting Applications: A State of Art Review and Future Perspectives
Authors: Singh Rupinder
Published: December 2009

Rapid prototyping (RP) is being widely used in diverse areas, from the building of aesthetic and functional prototypes to the production of tools and moulds for prototypes. Many RP techniques like stereo lithography, laminated object manufacturing, three dimensional printing etc. are commercially available. The implication of these technologies revealed that the time and cost of developing new foundry tools could be greatly reduced. The purpose of the present research paper is to review three dimensional printing for generation of prototype for casting applications.
Production of Nano Leaded Brass Alloy by Oxide Materials
Authors: Farahbakhsh Iman , Tabaian S. Hadi , Vahdati J.
Published: December 2009

Mechanochemical process was applied for brass alloy production using chemical grade oxide powders. Alpha brass was produced when CuO, ZnO and PbO were milled under argon atmosphere in the presence of graphite (as reducing agent). Concurrent reduction of zinc, copper and lead oxides took place in the argon atmosphere, whereas the reactions of the reduction did not proceed well in the closed chamber that filled with air. These reactions were promoted by milling time up to 100 hours. The amount of reduction tends to decrease for longer times.
The Microstructural Study of Nd:YAG Pulsed Laser Beam Weld of Copper Beryllium Alloy
Authors: Akbari Mousavi Seyed Ali Asghar , Niknejad S.T.
Published: December 2009

In this study, the microstructure of Nd:YAG pulsed laser weld of C17200 copper beryllium alloy is investigated by optical microscopy, scanning electron microscopy and X-ray diffraction. The SEM images reveals three distinct solidified structures due to various thermal gradients occurred in the fusion zone. The XRD patterns show that the preferred solidification directions are the same as those of FCC materials. The effects of pulsed laser parameters on the weld pool dimensions were also studied. According to metallographic results, pulsed energy should be kept as low as possible to obtain the weld pool with the highest values of penetration and the least width. In addition, the laser beam diameter should be kept as low as possible. Moreover, polarization was carried out to investigate the effect of passive layer on the reflectivity of surface by incident laser beam. It was found that weld pool increases when the Fresnel absorption phenomenon activated at high pulsed energy.
Strain Rate Sensitivity and Cavitation in Superplastic Deformation of a Commercial AL-5083 Alloy
Authors: Hosseinipour S.J.
Published: December 2009

In this paper the superplastic properties of a commercial 5083 aluminum alloy is studied. The aims are to achieve a proper temperature and strain rate to obtain maximum elongation and to investigate the strain rate sensitivity and cavitation in this alloy. The material is thermo-mechanically processed to produce fine recrystallized grain size. Then hot tensile test is carried out at various temperatures and strain rates. Velocity jump tests are performed to determine stress-strain rate relation and strain rate sensitivity coefficient (m) at various temperatures and strains. The microstructures are studied by optical and electron microscopy (SEM). The area fraction of cavities is determined by analyzing the micrographs from the surface of tensile specimens at various strains. It is found that maximum elongation about 300% is obtained at 520 oC and strain rate of 10-3 s-1. Maximum strain rate sensitivity coefficient (m) about 0.6 is achieved at strain 0.5. With increasing strain the peak m value decreases and shifts to lower strain rates. The failure surface is wide and failure occurs by cavitation.
Effect of Heat Treatment Conditions on the High Temperature Deformation of 6082-Al Alloy
Authors: Soliman Mahmoud S. , El-Danaf Ehab , Almajid Abdulhakim A.
Published: December 2009

High-temperature deformation of an artificially aged 6082-Al alloy was conducted in the present investigation. Tensile tests were carried out at temperatures of 623, 673 and 723 K at various strain rates ranging from 5x10-5 to 2x10-2 s-1. The behavior of the alloy is characterized by high stress exponent, n and high apparent activation energy, Qa that are higher than what is usually observed in Al and Al solid-solution alloys under similar experimental conditions, which implies the presence of threshold stress; this behavior results from dislocation interaction with second phase particles. The threshold stress, σo values were seen to decrease exponentially with temperature. By incorporating the threshold stress in the analysis, the true activation energy, Qt was calculated to be close to that of dislocation pipe diffusion in Al. Analysis of the experimental data of the alloy in terms of the Zener- Hollomon parameter vs. normalized effective stress, revealed a single type of deformation behavior with an n value of ~7. Measurements showed that the values of elongation percent at failure increase with strain rate and temperature.
Different Stress States Deformation of AA6082 Subjected to Different Artificially Aged Conditions
Authors: El-Danaf Ehab , El-Hossainy Tarek M.
Published: December 2009

The artificial aging response of Al-Mg-Si 6082 aluminum alloy is investigated over a wide temperature range. Samples aged to under aged, peak aged and over aged conditions are further subjected to plastic deformation by simple compression, plane strain compression and simple shear. The flow behavior and the corresponding hardening rates are documented. Equivalent stress – strain curves are generated for the three stress states for an aging temperature of 160oC. Strain reversal experiments in simple shear were carried out in order to characterize the Bauschinger effect. Strain path change experiments were also conducted, in which the gage section that was first deformed by simple shear was further deformed by simple compression.
Characterization of the Corrosion Behavior of Hot Pressed Nanocomposites Al-SiC Powder
Authors: Rostamzadeh Taha , Shahverdi H. , Shanaghi A. , Shahrabi T.
Published: December 2009

The object of the present work is the characterization of the corrosion behavior of Al-5%SiC nanocomposites prepared by mechanical alloying and the hot pressing method. Al/SiC metal matrix composite (MMCp) powder with volume fraction of 5% SiC was synthesized by high-energy milling of the blended micro component powder. The mechanically mixed nanocomposite powder was consolidated into bulk compacts using hot pressing at 1 GPa pressure for thirty seconds at three different temperatures of 440, 480 and 520°C. The microstructure was investigated by Secondary electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The corrosion behavior of the coating was evaluated using electrochemical techniques such as potansiodynamic polarization and EIS. It was found that the corrosion resistance of Al-5%SiC nanocomposite when hot pressed at 480°C, in 3.5% NaCl solution was higher than pure Al and Al-SiC nanocomposite that had been hot pressed at other temperatures.
Crude Oil and Outdoor Temperature Effects on the Tensile and Creep Properties of Glass Fiber Reinforced Vinylester Composite Pipes
Authors: Nizamuddin S. , Merah Necar , Khan Z. , Al-Sulaiman F. , Mehdi Mauyed S.
Published: December 2009

Composites are overtaking their traditional counterpart materials by prooving themselves to be superior alternatives even for their application in harsh environmental conditions. The technological innovations and developments in manufacturing processes, which lead to a wide range of new composite products, have made them attractive candidates for applications in oil & gas industry, with their application ranging from oil production to transportation. Lack of enough data regarding their long-term environmental and mechanical durability has been a major hinderance in their full-fledge application. This paper investigates the effect on the tensile and creep strength of filament wounded E-glass/vinylester composite pipes (GFRV) exposed to a combination of crude oil and outdoor temperature conditions of Dhahran. The variation in the tensile and creep properties is considered for exposure periods of 6, 12 and 24 months. The combined crude oil filled GFRV pipes exposed to outdoor environmental conditions for a periods of 6, 12 and 24 months have shown a constant increase in the tensile and creep strengths respectively, when compared with the as-received GFRV samples. This increase in the tensile and creep strengths may be attributed to the dual curing of the GFRV pipes i.e both the outer side and inner side of the pipes due to outdoor temperature and crude oil respectively. Microscopic analysis of fractured surfaces using optical microscope and SEM is used to characterize the failure mechanisms responsible.
Optimization for Secondary Cooling Parameters in Continuous Casting of High Carbon Chromium Bearing Steel
Authors: Chen Wei , Zhang Yu Zhu , Zhu Li Guang , Zhang C.J. , Wang Bao Xiang
Published: December 2009

The high carbon chromium bearing steel, as a kind of special steel, entails high quality. The work aims to simulate the solidification process of continuous casting of high carbon chromium bearing steel, to find the cause for defect, and to optimize the secondary cooling parameters steel. A finite element model is developed to compute heat transfer and solidification in bearing continuous casting. By comparing the calculated data with the metallurgical constraints, the key factor caused the cracks on the strand can be found out. Then based on the subproblem approximation method, an optimization program is developed to search out the optimum cooling parameters. Those optimum parameters can meet all specified requirements but with a minimum expense of the operational and the design constraints and can make it possible to run the caster at its maximum productivity, minimum cost and to reduce the defects. Now, online verifying has been obtained with the cracks decreasing and the water consumption of secondary cooling zone saving.
Effect of Fiber Diameter Waviness and Wavelength Ratio on the Effective Tensile Elastic Modulus of Carbon Nanotube-Based Polymer Composites
Authors: Khaled A.A. , Masud A.K.M. , Chowdhury S.C. , Jannat S. , Obayedullah M.
Published: December 2009

In this paper, the effects of nanotube diameter, waviness ratio and wavelength ratio on the tensile elastic modulus (TEM) of the carbon nanotube (CNT) reinforced polymer composites is investigated using a 3-D nanoscale representative volume element (RVE) based on continuum mechanics and using the finite element method (FEM). Formula to extract the effective material constant from solutions for the RVE under axial loading is derived based on the elasticity theory. Both long and short CNT embedded in the matrix are considered for investigating the effect of fiber diameter variation whereas only long wavy CNT is considered for investigating the effect of waviness and wavelength ratio variation, all at a volume fraction of 5%. First, the effects of CNT diameter on the TEM of the composite are investigated. Numerical results show that TEM of the polymer composite is influenced by tube diameter variation for both long and short CNT. Then the effects of waviness ratio and wavelength ratio on the TEM of polymer composite are investigated. Results show that both the waviness and wavelength ratio variation of CNT significantly influence the TEM of the polymer composite.
Effect of Residual Gradient Stress of Cantilever Plate Structure Deposited Metal Layers with Different Constraints on Deformation
Authors: Lin Meng Ju , Hwan Chung Li , Chou Yun Ju
Published: December 2009

Cantilever plate structure deposited metal layer is widely used MEMS. Due to mismatch of thermal expansion coefficients between structure and metal layers, residual gradient stress would be induced and deform structure as devices cooling down from process high temperature to room temperature. In this work, constraints effect is investigated. There are three constraints discussed and could be fabricated by back etching, isotropic wet etching, and anisotropic dry etching. For detail analysis, finite element method is used to analyze. Different width and length of structure sizes are used to discuss constraint effect. From the results, it is found different constraint would affect deformation. Under the same structure sizes, flat surface constraint has the largest deformation. And ICP etching constraint has the smallest deformation. Due to mechanics behavior of plate being much different comparing to beam, deformation of plate is no long parabolic shape in length direction. There are complex deformations in width direction. It is also found the deformation is determined by mechanics behavior on constraints. Width and constraint types have no significant on deformation when length is large at free end and middle section. And length has no significant effect on deformation for ICP and backside etching at clamped end. Temperature would induce increasing deformation linearly at free end and middle section.
Effect of Gamma Irradiation on the Microstructure and Morphology of Polyethylene Oxide and Polyvinyl Alcohol Blends
Authors: Al-Ma'adeed Mariam , Al-Thani N.J.
Published: December 2009

Thin films of a blend of 90, 75, 50 (wt/wt%) percentage of polyethylene oxide and polyvinyl alcohol were synthesized and irradiated with 5, 25, 50, 100 and 200 kGy. The presence of PVA leads to diffusion controlled mechanism where it decreases the crystallinity of PEO as restricted crystallization occurs.Low doses of 5 kGy cause crosslinking of the blends and increase the thermal stability. Higher doses up to 100 kGy cause the PEO crystallite boundaries to be erased and to blur spherulites structure; it also leads to an increase in the crystallinity. Higher doses of 200 kGy cause an increase in the hydrogen bonding where the material is more crystalline in structure and broken down which made more segments available for the hydrogen bonding. Degradation and oxidation of the blends due to the presence of free radicals in the polymer irradiated in air is noticed for blends with very high doses. Never the less, PVA in these blends protects the PEO composite from the effect of radiation.
Effects of Simulated Pit Distribution Parameters on Tensile Properties of a Structural Steel Plate
Authors: Alipour S. , Farhangi Hassan
Published: December 2009

Degradation of tensile properties resulting from geometrical discontinuities due to localized pitting is usually evaluated in terms of the reduced section thickness associated with pit geometry which lowers the load carrying capacity of the structure. However, the effects of finer parameters associated with pit distributions such as pit area percent (PAP) are not usually taken into account. In this research, the effects of spacing, depth and PAP on tensile properties of a structural steel are investigated. Simulated pit distributions were produced on the gage sections of flat tensile specimens using mechanical drilling. It is found that final elongation is more adversely affected than tensile strength with increasing PAP, pith depth and pith spacing. However, the reduction in final elongation tends to be largely recovered at higher PAP values due to increasing uniformity of strain distribution. It is noted that increasing pit spacing at a constant PAP leads to greater reductions in tensile properties, especially at higher pit depths, due to the increased stress concentration and strain localization. It is further clarifies that the introduction of first few pits and their growth to larger depths could be very detrimental to the mechanical properties of structural alloys.
Tribological Studies of Steels Using the Abrasive Wheel
Authors: Abbasi Majid , Kheirandish S. , Kharrazi Y. , Hejazi J.
Published: December 2009

The abrasive wear behaviors of different types of steels were evaluated using the abrasive wheel as a new technique in the pin on disc method. It is shown that the abrasive studies using this test method is acceptable for high wear resistance metals such as Hadfield steels, while it is not proper for soft materials such as mild steel. The test results on the different materials also show that initial hardness of materials cannot merely determine the wear resistance. However, microstructural changes during the sliding have significant effect on the wear behavior and must be included.
Removal of Toxic Arsenic and Antimony from Groundwater Spiro Tunnel Bulkhead in Park City Utah Using Colloidal Iron Hydroxide: Comparison with Reverse Osmosis
Authors: Pawlak Z. , Cartwright P.S. , Oloyede Adekunle , Bayraktar E.
Published: December 2009

Verification testing of two model technologies in pilot scale to remove arsenic and antimony based on reverse osmosis and chemical coagulation/filtration systems was conducted in Spiro Tunnel Water Filtration Plant located in Park City, Utah, US. The source water was groundwater in abandoned silver mine, naturally contaminated by 60-80 ppb of arsenic and antimony below 10 ppb. This water represents one of the sources of drinking water for Park City and constitutes about 44% of the water supply. The failure to remove antimony efficiently by coagulation/filtration (only 4.4% removal rate) under design conditions is discussed in terms of the chemistry differences between Sb (III, V) and As (III, V). Removal of Sb(V) at pH > 7, using coagulation/filtration technology, requires much higher (50 to 80 times) concentration of iron (III) than As. The stronger adsorption of arsenate over a wider pH range can be explained by the fact that arsenic acid is tri-protic, whereas antimonic acid is monoprotic. This difference in properties of As(V) and Sb(V) makes antimony (V) more difficult to be efficiently removed in low concentrations of iron hydroxide and alkaline pH waters, especially in concentration of Sb < 10 ppb.
The Applicability of GRP and NRP Composites in Rehabilitation of Unpressurized Pipes
Authors: Akinci Akin , Güleç Ahmet , Yilmaz Fevzi
Published: December 2009

Glass fiber reinforced polymer (GRP) and needle reinforced polymer (NRP) composites have been used to produce a new kind of thin cross section liner for rehabilitation of in ground sewer pipes. The liner made from resin impregnated glass fiber woven (or plastic needle felt) is in-placed and cured for the rehabilitation of deteriorated pipe. This technique is entitled as cured in place pipe (CIPP) and penetrating to all over the world. Among the renovation technologies, CIPP appears less expensive and more promising than other techniques. CIPP liners are made up of several reinforcement layers impregnated with various thermosetting resins such as epoxy, vinyl ester and unsaturated polyester. Different woven geometries can be used for the felt and tube. In this study, the experimental results obtained from cured composites are given. The mechanical characteristics of CIPP tubes manufactured with different materials were given. Specifically glass fiber and synthetic felt impregnated in thermosetting unsaturated polyester resin were investigated. Standard three point flexural tests were carried out on specimens cut out from the cured liners. Beside these three point flexural tests, abrasive and erosive wear tests were also performed on these samples.
Failures of Chemical Injection Points in Upstream Facilities
Authors: Al-Omari A.S. , Al-Nabulsi Khalid M. , Al-Mari Ali F.
Published: December 2009

Chemicals play an important role in the enhancement of oil and gas production and processing. They control corrosion, prevent organic and inorganic deposits, aid in phase separation and control microbial problems. Several factors can have significant impact on the safety, maintenance, operation, and service life of the chemical injection point. Failures encountered in the high pressure retrievable chemical injection points are presented. This paper also provides guidelines for materials selection and design of chemical injection points in upstream facilities.
Mixing of Multiphase Silicone for the Production of Breast Prostheses
Authors: Naher Sumsun , Vickery Gerard
Published: December 2009

The quality of breast prostheses dependant on homogeneous mixing of materials during
the manufacturing process. This research endeavoured to investigate the mixing of two silicones
that are widely used in the production of breast prostheses. The effect of impeller design on
obtaining a homogeneous mixture was investigated. Four different types of impellers were used to
investigate the effect of stirrer type, diameter, speed, position and time to obtain a homogeneous
mixture. Stirring speeds of 500 rpm, 800 rpm and 1100 rpm were investigated together with stirring
height and stirring diameter. Percentage of homogeneity of the mixture was investigated ranging
from 10 to 60 minutes with a 10 minutes interval. The effect of stirring time and speed on viscosity
was also examined. It was found that a four blade radial impeller gives the best result for mixing in
all cases.
Determination of the Optimal Ball Grinding Parameters for the Bio-Ceramics ZrO2 on a PC-Based Multi-Axis CNC Engraving Machine
Authors: Shiou Fang Jung , Fang Jian Chi
Published: December 2009

The objective of this study is to determine the optimal ball grinding parameters of the bio-ceramics ZrO2 by executing the Taguchi’s L18 orthogonal array experiment, analysis of variation (ANOVA), and the full factorial experiment on a PC-based multi-axis CNC engraving machine. The manufacture of a ZrO2 coping using the optimal ball grinding parameters has also been studied based on a tooth plaster model via reverse engineering technique. The 3D data points of a tooth plaster model were digitized by the developed on-machine measurement system on a PC-based CNC multi-axis engraving machine by integrating a circular triangulation laser probe with the machine and a PC. A CAD model of a coping could then be constructed by Pro/Engineer software, based on the digitized 3D data points. With the help of the PowerMill CAM software, the machining path of a coping has been simulated, and the correspondent NC codes have been generated to fabricate the ZrO2 coping using the determined optimal ball grinding parameters, on the CNC multi-axis engraving machine. The average surface roughness of Ra=0.49 um for the ground ZrO2 ceramics coping could be obtained by utilizing the optimal flat surface grinding parameters.
Cutting Performance and Predictive Models for End Milling Aluminum Alloy
Authors: Tsao Chung Chen
Published: December 2009

End milling is considered to be one of the most commonly applied for both roughing and finishing operations to make flat surfaces, slots and pockets in precision molds and dies. Predictive models were developed for cutting force, flank wear and surface roughness in end milling aluminum alloy by regression analysis. The correlation coefficients for cutting force, flank wear and surface roughness equations were 91.6 %, 89.8 % and 79.6 %, respectively. The goal of these predictive equations is to become a good assistant to the researcher in understanding the machining process. Through the analysis of variance (ANOVA), however, it can be found that the cutter diameter, the helix angle and the feed rate are the important milling process parameters to obtain the machined quality on cutting force, flank wear and surface roughness. The investigations show that cutting force, flank wear and surface roughness can be improved in end milling aluminum alloy by using the lower cutter diameter, medium helix angle and lower feed rate.
Predictive Modeling and Investigation on the Formation of Stiff Air-Layer around the Grinding Wheel
Authors: Mandal Bijoy , Majumdar Sujit , Das Santanu , Banerjee Simul
Published: December 2009

In grinding process, a stiff air layer is generated around the wheel periphery due to high surface speed of the porous grinding wheel. This stiff air layer restricts grinding fluid to reach deep inside the grinding zone. The formation of stiff air layer has been studied experimentally by obtaining the variation of air pressure around the wheel periphery under different wheel speeds. With the help of the experimental data, a mathematical model has been developed to predict the pressure of the stiff layer of air under different wheel speed. From the model it is found that at close proximity to the wheel, air pressure obtained is very high, and this establishes quantitatively the formation of stiff air layer around the grinding wheel.
A New Cutting Force Model for Micro-Milling and Determination of Optimal Cutting Parameters
Authors: Wang Shih Ming , Chiang Zou Sung , Chen Da Fun , Tsai Yao Yang
Published: December 2009

A new cutting force model of micro-milling was developed based on calculating the
instantaneously projected area of cutting in this study. According to the rotation trajectory of
cutting edge, the instantaneous cutting area projected to xy-plane was first divided into several
portions and determined with rectangular integral. After the cutting coefficients were
experimentally investigated, the cutting force of micro-milling with different cutting conditions
can be determined. Because the developed cutting force was function of cutting parameters,
such as spindle speed, feed rate, depth of cut, with taking the cutter deflection into account it
was further used to the determine of optimal cutting parameters for obtaining better cutting
efficiency and machining accuracy. To verify the proposed cutting force model and the way to
determine the optimal cutting parameters, micro-milling experiments were conducted. The
results have shown the feasibility of the proposed model and method.
The CAM System for Scroll Profile with Three CNC Interpolations
Authors: Lee Jeng Nan , Li Chien Nan
Published: December 2009

The scroll profile is complex with involute curve and high precision is required. Owing to the interpolation method has significant effects on the dynamic behaviour and to obtain the flexibility of the machining, this paper focuses on the development of a computer-aided manufacturing methodology for precision scroll by the combination of curve fitting and CNC interpolation. In this paper, the method for design and manufacture of the scroll profile is established based on the differential geometry and the enveloping theory. The cutter location using the cylindrical end mill is derived and the cutting path sequences are planned. Three types curve fitting methods: linear fitting, circular biarcs curve fitting, and NURBS curve fitting are adopted to approximate the toolpath of the scroll profile. The error control is used as the basis for generating appropriate toolpath to ensure the machining accuracy. The circular biarcs fitting and NURBS curve fitting can obtain continuous smooth toolpath. In the identical chordal deviation, the circular biarcs curve fitting provides the best performance. The toolpath generated by the proposed method is verified through the solid cutting simulation and the trial-cut on a three-axis machine tool.
An Investigation on Machining Power of EN-AC 48000 Aluminum Alloy Used in Automotive and Aerospace Industries
Authors: Shahali H. , Zarepour Hamid , Soltani Esmaeil
Published: December 2009

In this paper, the effect of machining parameters including cutting velocity, feed rate, and tool material on machining power of EN-AC 48000 aluminium alloy has been studied. A L27 Taguchi's standard orthogonal array has been applied as experimental design to investigate the effect of the factors and their interaction. Twenty seven machining tests have been accomplished with two random repetitions, resulting in fifty four experiments. EN-AC 48000 is an important alloy in automotive and aerospace industries. Machining of this alloy is of vital importance due to build-up edge and tool wear. Machining power is an essential parameter affecting the tool life, dimensional accuracy, and cutting efficiency. Three types of cutting tools including coated carbide (CD 1810), uncoated carbide (H10), and polycrystalline diamond (CD10) have been used in this study. Statistical analysis has been employed to study the effect of factors and their interactions using ANOVA analysis. Moreover, optimal factor levels have been presented using signal to noise ratio (S/N) analysis. Also, regression model have been provided to predict the machining power. Finally, the results of confirmation tests have been presented to verify and compare the adequacy of the predictive models.
Evaluation of Thrust Forces in Dry Drilling of UNS A97050 Alloy
Authors: Domingo Rosario , Reina José M. Arenas , Marcos Bárcena Mariano , Sebastián Miguel Ángel
Published: December 2009

This paper presents a study of the thrust forces in the aluminium alloy, UNS A97050-T7. The measurement of these forces during the dry drilling in plates is evaluated under cutting different conditions and in through and blind holes. The experiments have been performed in a CNC milling and HSS Co drills have been utilised with unlike diameters (6.3 mm and 4 mm). The thrust forces have been measured by means of a piezoelectric dynamometer. In addition, the results have been compared with theoretical forces, obtained by the Kronenberg equation. The ANOVA study has allowed confirming the similitude between the forces obtained, independently of number of holes drilled, with the exception of through holes of 4 mm, in whose case the Kruskal-Wallis test has corroborated the dissimilitude. Moreover, the comparison with Kronenberg forces is coherent for diameters 6.3 mm, but it is very different for diameter 4 mm. Thus, the results respect to through and blind holes are dependent of diameter of drill, and also the differences found in the theoretical forces. The high variability of the forces for minor drills, in through and blind holes, points to an inadvisable use in this material.
Applications of Nanocomposite Materials in the Oil and Gas Industry
Authors: Savino Vincenzo , Fallatah Gasem M. , Mehdi Mauyed S.
Published: December 2009

Research activities in nanocomposite materials have been carried out for the last decade. Some of the objectives of these activities have been focused in increasing polymer physical properties. This has resulted in products for many fields of application, including: motor vehicle parts, packing, bottles, furniture, protective coatings and flame resistant material. The higher thermal-mechanical properties, better fire resistance characteristics and the low permeability rates present possibilities for the development of nanocomposite materials for components in oil, gas and chemical facilities as pipes, valves and tanks. This paper shows the vision of the authors in some potential uses of nanocomposite materials for manufacturing nonmetallic components and their possible features to reduce the high cost of corrosion.
Design of Synchronous Processes of Rolling-Leveling and Ultrasonic Electrochemical Finishing of Holes
Authors: Pa Pai Shan
Published: December 2009

A new finishing method of holes that uses an effective electrode and a nonconductive roller to execute the design of synchronous processes of ultrasonic electrochemical finishing and rolling-leveling is investigated. The submitted processes can be used among the traditional techniques of various holes machining. Through simple equipment attachment, ultrasonic electrochemical finishing and rolling-leveling can follow to execute the finishing process on the same machine. Among the factors affecting finishing processes, the performance of rolling-leveling combined with ultrasonic electrochemical finishing is primarily discussed. In the experiment, the electrode is used with continuous and pulsed direct current. The controlled factors include roller material, roller geometry, chemical composition and concentration of the electrolyte, and flow rate of electrolytes. The experimental parameters are frequency and power level of ultrasonics, feed rate of electrode and roller, rotational speed of the finish-tool, die material, electrical current rating, and pulsed period. The design of the synchronous processes through rolling-leveling is the most influential parameter in this study. An adequate finish-tool rotational speed produces better finishing. The average effect of the ultrasonic is better than the pulsed current while the machining time needs not to be prolonged by the off-time. An effective and low-cost finishing process through the ultrasonic electrochemical finishing and using the rolling-leveling assistance after the process of traditional holes machining make the surface of the holes smooth and bright is presented.
The Interaction between Particles and a Plasma Beam in the Thermal Projection Process
Authors: Kriba Ilhem , Djebaili A.
Published: December 2009

Plasma spray processes have been widely used to produce high performance coatings of a wide range of Materials (metallic, non-metallic, ceramics), offering protection from, eg. wear, extreme temperature, chemical attack and environmental corrosion. To obtain good quality coatings, spray parameters must be carefully selected. Due to the large variety in process parameters, it is difficult to optimize the process for each specific coating and substrate combinations. Furthermore modelling the spray process allows a better understanding of the process sequences during thermal spraying. Good agreement of the virtual spraying process with the real coating formation is achieved by modelling the particular process steps. The simulation of coating formation to estimate the process parameters is an important tool to develop new coating structures with defined properties. In this work, the process of plasma sprayed coating has been analyzed by numerical simulation. Commercial code is used to predict the plasma jet characteristics, plasma –particle interaction, and coating formation. Using this model we can obtain coating microstructure and characteristics which form a foundation for further improvement of an advanced ceramic coating build up model.
Laser Polishing Operation for Die and Moulds Finishing
Authors: Ukar Eneko , Lamikiz Aitzol , López de Lacalle Luis Norberto , Liebana F. , Etayo J.M. , del Pozo D.
Published: December 2009

The presented article proposes a laser based polishing operation which consists in the application of a laser beam in a very controlled way. The work presents several polishing tests carried out with CO2 and High Power Diode Lasers, for a DIN 1.2379 tool steel tempered up to 62HRC. This material is commonly used for injection moulds and inserts for stamping dies.
The Laser Polishing tests results have been used as the input data for a design of experiments (DoE), therefore the optimum operation parameters for the process as well as its degree of influence in the melted surface have been defined. Experimental tests have been performed from different initial roughness values obtained by High Speed Milling operations. Reductions of final roughness higher than 80% have been obtained with respect to the initial roughness, with values below 0.8μm Ra.
Engineering Materials and Manufacturing Processes from Qur’anic Perspective
Authors: Haque Mohammad M. , Ismail Ahmad Faris
Published: December 2009

Any useful object is commonly made from selected engineering materials with proper shape and dimension. The selection of materials and manufacturing processes is an important criterion towards the production of useable and affordable objects. The technologies behind this knowledge are needed to acquire through study, proper education, practical training and scientific research related to Materials and Manufacturing Engineering (MME). Allah (swt), the sources of all power and knowledge, has bestowed the Guide Book, the Holy Qur’an through His beloved Messenger Prophet Mohammad (pbuh) to the mankind. Allah (swt) narrated various stories in many Surahs of the noble Qur’an related to applied science and technology. This paper is an attempt to view the integration between the revealed knowledge and the science and technology based knowledge related to engineering materials and manufacturing processes. Finally, stresses have been given to acquire knowledge on science and technology based education and understanding, and disseminate it for the cause of humanity.
Manufacturing of 18 Ni Marage 300 Steel Samples by Selective Laser Melting
Authors: Campanelli Sabina L. , Contuzzi N. , Ludovico Antonio D.
Published: December 2009

Selective Laser Sintering (SLS), has become one of the most popular technique in the layer manufacturing processes because of the ability to build complex geometries models with a wide range of materials. Recently, the interest in SLS is mainly focused into metals because of the possibility of producing models not only for the prototyping step but also as functional parts. Driven by the need to process nearly full dense objects, with mechanical properties comparable to those of bulk materials and by the desire to avoid long post processing cycles, Selective Laser Melting (SLM) has been developed. SLM represents an evolution of the SLS process: in the first one the complete melting of powder occurs rather than sintering or partial melting of the second one. SLM, is mainly suitable to produce tools and inserts with internal undercuts and channels for conformal cooling for injection molding.
A careful control of the parameters which influence the melting and the amount of energy density involved in the process is necessary to get parts with optimized quality. The aim of this paper was to study the effect of the main process parameters (laser power, scan speed, scan spacing, hatch spacing, scanning strategy) and of thermal treatments on the quality of built parts in terms of hardness, density, microstructure, and mechanical properties. The 18 Ni Marage 300 steel, one of the most used materials in the die industry was investigated, using a Nd:YAG laser with a maximum power of 100W.