bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Propofol and Isoflurane Long-Term Anesthesia on Rabbit’s Heart Size as Consideration for Biomaterial Implant Placement
Authors: Siallagan Sitaria Fransiska , Tan Kevin Timotius , Fakhrul Ulum Mokhammad , Gunanti Gunanti , Noviana Deni
Published: July 2015

The heart function suppression during a long-term anestesia should be considered in implant placement surgery. The aim of this study is to determine the effect of propofol and isoflurane combination as a long-term anesthesia on the heart size using radiography vertebrae heart size (VHS) method. Rabbits were injected by propofol 12.5 mg/kg body weight intravenously as an induction and inhaled by 1.0 ml/minutes rate ofisoflurane in facemasked for next 12 hours. Thorax cardiogram in right lateral (RL) and dorsoventral (DV) view were obtained and compared according to duration of anesthesia at 0 hr, 4 hrs, 8 hrs, and 12 hrs. The result showed that heart size on RL view are 7.67±0.50v, 6.67±0.16v, 7±0.00v, and 7.53±0.23v, respectively, while the values on DV view are 7.33±0.23v, 7.06±0.30v, 7±0.2v, and 7.33±0.35v, respectively. The heart size on RL view was decreased after 4 hrs and increased after at 8 to 12hrs significantly (P<0.05) compared to DV view. As the conclusion, propofol and isoflurane combination as a long-term anesthesia had minimal effect on heart size and is a good candidate for long-term biomaterial implant placement procedures.
Radiography Study of Iron-Based Foreign Body Material Degradation at Different Implantation Site in Mice
Authors: Paramitha Devi , Noviana Deni , Estuningsih Sri , Fakhrul Ulum Mokhamad , Hermawan Hendra
Published: July 2015

Foreign body materials enter human body through ingestion, insertion, or deposited by injury and may migrate from the entry site causing inflammation, abscess formation or undergo distant embolization. The aim of this study was to observe the degradation process of iron-based foreign body materials in different site of implantation through radiography approach. Forty two adult male ddy mice were used and iron-based implants were inserted into nape area, subcutaneously and into right femoral muscle using trocar, aseptically. The implants consisted of iron, chromium(Cr)-coated iron and stainless steel surgical wire (SS316L). Serial radiography was performed at day-1, 4 and 14 after implantation. The gray value of material density were then measured at 4 points : 2 points on both end and 2 points on the middle of the implants by using plot profile module in ImageJ® software. Results showed that the radiodensity of the implants from each group in both implantation site was increased at day-4 and materials’ radiodensity implanted subcutaneously showed higher gray value especially at peri-implant site along the side of the implant than those which implanted intramuscularly. Discussion on the degradation process and radiographic measurement is detailed in the manuscript.
A Simple Dissolved Metals Mixing Route to Prepare Nanostructured Mg0.8Zn0.2TiO3 Solid Solution
Authors: Ermawati Frida Ulfah , Suasmoro Suasmoro , Suminar Pratapa
Published: July 2015

A study of liquid mixing route to synthesize high purity Mg0.8Zn0.2TiO3 nanopowder, a candidate dielectric ceramics, has been successfully performed. Formation of the phases on the dried powder was studied using TG/DTA, XRD and FT-IR data. Rietveld analysis on the collected XRD patterns confirmed the formation of solid solution in the system. Such solid solution can be obtained from the powder calcined at 500 °C, but calcination at 550 °C gave rise to the most optimum molar purity up to 98.5% without intermediate phases. The role of Zn ions on the formation of solid solution was also discussed. Homogeneity of particle size distribution and nano-crystallinity of the system was verified from the particle size analyzer data, TEM image and the Rietveld analysis output.
Radiodensity Study of Hydroxyapatite Coated Porous Tantalum Implant Material of Rat Animal Model
Authors: Panjaitan Budianto , Noviana Deni , Gunanti Gunanti , Sukmana Irza , Fakhrul Ulum Mokhamad
Published: July 2015

The aim of this study was to find out the in-vivo radiography density changes of hydroxyapatite coated porous tantalum biomaterial implant after surgical implantation in rats. Ten adult male Sprague Dawley rats were divided into two groups: hydroxyapatite-coated porous tantalum (pTa-HAp) and uncoated porous tantalum (pTa). The implants with dimension of 5 x 2 x 0.5 mm3 was inserted into flatten bone defects drilled at the femur bone on latero-medial region. The implant density from right lateral view radiogram was analyzed at day 0, 7, 14 and 30 post-implantation. The results showed that the radiodensity of both pTa and pTa-HAp groups decreased in time of implantation. The radiodensity changes of pTa-HAp showed higher decrease compared to pTa.
Sintering of Mg-Ca-Zn Alloy Metallic Foam Based on Mg-Zn-CaH2 System
Authors: Annur Dhyah , Amal M.I. , Sutowo Cahya , Sukaryo Sulistioso G. , Kartika Ika
Published: July 2015

Mg-Ca-Zn alloys are promising candidate metal cellular material for biocompatible and biodegradable implant. This is due to its corrosion behavior which enables well controlled degradation, as well as due to the fact that the corrosion product shows no cytotoxicity at all. In this present work, the characteristics of Mg-Ca-Zn alloy metallic foam prepared by the foaming of a powder compact based on Mg-2Zn-Ca and CaH2 system were investigated. Mg-Zn-CaH2 powders with various compositions of 67-96 wt.% Mg, 1.2-30 wt.% CaH2, 9 wt.% Ca and 2 wt.% Zn constant were studied. The prepared powders were then pressed under a load of 26 MPa at room temperature. Sintering process of green compacts was conducted at 350 °C for 2 h continued to 520 °C for 1 h. The sintered green compacts were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis (EDS). The XRD results showed the sintering process affects the phase formation of Mg, Ca, Mg2Ca, and MgCaZn. Mg2Ca binary phase to be avoided because its leading to reduce mechanical properties of the final product.
Friction Spot Welding of Similar AA5754 to AA5754 Aluminum Alloys and Dissimilar AA5754 Aluminum to AZ31 Magnesium Alloys
Authors: Suhuddin U.F.H. , Piccolo Debora , Fischer Vanessa , dos Santos Jorge F.
Published: July 2015

Friction spot welding is a solid-state spot welding process developed and patented by Helmholtz-Zentrum Geesthacht, Germany. A non-consumable rotating tool consisting of two rotating parts, a pin and a sleeve, and one stationary clamping ring is used to join two or more similar/dissimilar sheets of materials in lap configuration. The result is a spot welded lap connection with minimal material loss and a flat surface without keyhole. The present work presents a summary of results from studies in similar AA5754 to AA5754 Al alloys and dissimilar AA5754 Al to AZ31 Mg alloys.
The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut
Authors: Mufid Ali , Zainuri Mochammad
Published: July 2015

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.
Study of Frangible Cu-Sn Composite by Powder Metallurgy Method
Authors: Widyastuti Widyastuti , Vicko G.A. , Ardhyananta Hosta , Rochman Rochiem
Published: July 2015

The Cu-Sn composite is one of material for frangible bullet application. Frangible bullet are designed to disintegrate on impact against rigid surfaces to avoid ricochet hazards in shooting ranges or law enforcement training facilities. The manufacturing process of CuSn is based on powder metallurgy with variation of weight percent of Sn and compacting pressure. Sintering is performed at temperature of 260°C within 30 minutes period with nitrogen gas atmosphere. The secondary phase (Cu3Sn and Cu6Sn5) was identified. The highest density and hardness are 7,446 g/cm3, 83 HRF for Cu-5 wt% Sn at 500 MPa. The pressure strength and modulus of elasticity are 275,72 MPa and 59,43 GPa.
Modification of Ceramic Mold for Investment Casting with Silica Sand as Stucco and Nylon Addition
Authors: Sofyan Bondan Tiara , Syahid M. , Khairuddin Hafid. A. , Nurdin R.
Published: July 2015

The investment casting process has increasingly been used to produce components because it has the advantage to produce high precision part. One of the obstacles in the investment casting process in Indonesia is imported ceramic mold material. However, Indonesia has the potential silica sand which can be developed as an alternative material mullite . This study aims to develop local silica sand as stucco with the addition of nylon fibers in the slurry. Characterization of the ceramic material is bending test, edge test, and porosity tests that will be compared with the ceramic mold mullite-based. Characterization also conducted on casting product of aluminum impeller turbine by hardness test, microstructure examination by optical microscopy and SEM . The results showed that strength of ceramic molds made ​​from silica sand increase due to the addition of nylon but has not reached a standard ceramic strength. Ceramic mold is able to withstand the load at the time of pouring. There is not misrun in the casting product but some porosity due to low permeability.
SiO2/MgO Ratio Effect on Carbothermic Reaction of Synthetic Nickelliferrous Mixtures
Authors: Harjanto Sri , Ulum Reza M.
Published: July 2015

The objective of this study is to understand the effect of SiO2/MgO ratio on the reducibility of Fe and Ni in the synthetic nickel laterite mixtures of similar composition to Indonesia saprolitic nickel ore. The samples were made with addition (in wt% basis ) of 12% cokes, 2 % NiO, and varied SiO2 of 0 %, 10 %, 20%, 30%, and 40 % . Two types of samples were made, with and withou 14% MgO addition. Fe2O3 was added to both types of samples as balance. The synthetic compounds were mixed homogenously and compacted, before subjected to carbothermic reduction process at temperature of 1250 °C for 120 minutes. The results showed that Ni was strongly influenced by MgO content after reduction processes. Higher content of MgO was more unfavorable for nickel reduction, while a higher content of SiO2 was unfavorable for Fe reduction. According to the characterization results of carbothermic product, nickel oxide had been reduced to form Fe-Ni phase. Nickel recovery tends to increase with increasing of SiO2 addition on sample with MgO addition.
Synthesis of Magnesium Carbonate Using Indonesian Dolomite
Authors: Solihin Solihin , Sulistiyono Eko
Published: July 2015

Magnesium carbonate is important material used in certain industries. It is used as raw materials for drug making in pharmacy, as filler in painting industry, as raw material for magnesium metal making, as nutrient element in fertilizer, etc. Natural source of magnesium carbonate in Indonesia is mainly in the form of dolomite mineral. The larger deposit of dolomite in Indonesia is located in East Java. Through a series of unit process that consist of roasting, carbonation, and nucleation, the dolomite from East Java Indonesia has been converted into ultra fine grain magnesium carbonate. Since the process does not utilize harmful compound and does not produce harmful waste, it can be classified as environmental friendly process. Roasting process was operated at temperature range of 600 – 1000 °C. It is found that dolomite can be converted to magnesium and calcium oxide at this range of temperature. The mean particle size of magnesium carbonate obtained through this process is around 1.073 micron.
Sonocrystallization Technique to Optimizing the Crystallization Process of PCM CaCl2.6H2O
Authors: Palittin Ivylentine Datu , Kurniati Nia , Sutjahja I.M. , Kurnia Daniel
Published: July 2015

Salt hydrate CaCl2.6H2O is one of inorganic Phase Change Material (PCM) that have melting temperature (Tm) of about 29 °C and latent heat of fusion (DH) of around 190 kJ/kg that can be used for latent thermal energy storage. This material can be used for conditioning the air-temperature of the room, in order to reduce the electrical energy consumption for air conditioning (AC) system. In order to reduce the subcooling and phase separation effects of CaCl2.6H2O to maintain its performance, we adopt sonocrystallization technique that uses ultrasound radiation for crystallization of CaCl2.6H2O. The data are taken qualitatively for the crystal growth observation and quantitatively based on real-time temperature recording. The results show that sonocrystallization can slightly reduce the phase separation effect and improving the quality of the crystal. Hence, the resulted crystals have large and long size, uniform distribution and dense arrangement.
The Effect of Additives on the Crystallization PCM CaCl2.6H2O for Stabilizing the Air Temperature for Energy Conservation
Authors: Kurniati Nia , Palittin Ivylentine Datu , Sutjahja I.M. , Kurnia Daniel
Published: July 2015

Phase Change Material (PCM) is a material that uses the phase transition properties as latent heat storage for certain application. Salt hydrate CaCl2.6H2O (melting temperature, Tm = 29°C, and melting entalphy, DH = 190 kJ/kg) is a common inorganic PCM that can be used for regulating the air temperature of the room, in order to reduce the electrical energy consumption for energy conservation. General problems of inorganic PCM, in particular during the crystallization or latent heat release, are the subcooling and phase separation effects. It is worth mentioning that understanding the crystallization of PCM is important to keep its performance for application. In this research we choose two types additive materials as nucleator to CaCl2.6H2O to overcome those two negative effects, namely Ba2CO3 and K2CO3. We also study the amount of additives needed for effective reduction of subcooling and its phase stability by performing the cycling process. The average temperature and maximum temperature of the subcooling will be determined from temperature vs time recording.
Synthesis and Characterization of Zero-Valent Iron Nanoparticles
Authors: Yusmartini Eka Sri , Setiabudidaya Dedi , Ridwan Ridwan , Marsi Marsi , Faizal Faizal
Published: July 2015

Nanoparticles, particles of size 10 -9 have a high potential as water, waste water and air pollution treatment. In this research, nanoscale iron particles were synthesized by reduction of Fe2SO47 H2O by NaBH4 at low temperature to avoid oxidation during the process. Characterization of the particles based on particle size, material structure, surface morphology and the composition of forming element was done by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectometry (EDS), respectively. Surface area and magnetic character was measured by BET surface area and vibrating sample magnetometry (VSM), respectively. Morfological observation showed that structured core-shell of size < 44 nm and shell of size ~ 3 nm with saturated magnetization value ~ 132 emu g‾¹ has been formed.
Thevetia peruviana: A Wild Natural Resource for the Green Synthesis of Gold Nanoparticles
Authors: Rupiasih Ni Nyoman , Aher Avinash , Gosavi Suresh , Vidyasagar Pandit Bhalchandra
Published: July 2015

The biosynthesis of nanostructures using plant extract (green chemistry) has emerged as an ecofriendly and evergreen branch of nanoscience and nanotechnology for the development of biomedical applications. In this study we report the use of aqueous extractof the latex of Thevetia peruviana (TP) for the synthesis of gold nanoparticles (AuNPs). The reaction time was optimized for maximum yield of AuNPs. The AuNPs formed were characterized using FTIR, EDS, TEM and XRD. The formation of AuNPs was confirmed using SPR spectra observed at around 589 nm. XRD pattern shows the FCC crystal structure of the nanoparticles, orresponding to (111), (200), (220) and (311) faces of gold. TEM analysis revealed that the particles are spherical with size distributions ranging from 41-50 nm. HRTEM image showed 2.35Å interplaner spacing. FTIR analysis confirmed that the flavonoid and reducing sugar found in the extract were the main reductive and the protein was capping components in the biosynthesis of AuNPs.
Formation of Porous Anodic Alumina from Impure Aluminum Foil in Inorganic Acids
Authors: Nurrudin Ahmad , Yuliarto Brian , Suyatman Suyatman , Sriwongo Agung
Published: July 2015

The morphology of porous anodic alumina (PAA) formed by anodizing in inorganic electrolytes is reported. An impure aluminum was anodized in sulfuric acid, phosphoric acid and chromic acidat room temperature with a constant applied potential 2 – 30 V. The formation of porous anodic alumina was carried out by one and two steps anodization. It is clearly noted that anodizing impure aluminum at room temperature provide higher kinetic of oxide dissolution compared to oxide growth. Two steps anodizing aluminum in sulfate electrolyte always resulted in random porous alumina, while phosphate electrolyte provided strong anodization producing irregular porous alumina with average diameter of 61.6 nm. Two steps anodizing aluminum in chromate electrolyte produce better pore ordering with relatively large size pore distributions. The average pore diameter of alumina increases linearly with applied voltage, with proportionality factor lp 0.83 nmV-1. Annealing the sample increased the interpore distance, removed stresses providing lower activation energy for pore formation.
Graphene-Based Flexible Circuit on Cotton Fabric Using Wax Patterning Method
Authors: Lam Chee Leong , Mohd Rafi Muhamad Firdaus , Mohd Fishol Mohamad Fahmi Hazwan , Mohd Yudin Muhamad Bakhtiar , Michi Aldi , Sriprachuabwong Chakrit , Tuantranont Adisorn , Wicaksono Dedy Hermawan Bagus
Published: July 2015

With recent development in the field of wearable devices for biomedical applications, various studies have been conducted on the fabrication of electrically conductive circuit on flexible substrate materials such as paper or textile. In this project, we propose the fabrication of electrically conductive circuit on cotton fabric using simple wax patterning method. Using this method, hydrophilic and hydrophobic regions were patterned on the fabric and graphene-poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid) (graphene-PEDOT:PSS) ink was deposited on the hydrophilic region using pipetting method. Conductive lines with higher conductance were fabricated by multiple deposition of the conductive ink and electronic components were successfully attached on the fabric to develop a simple fully functional flexible circuit.
The Effect of the Initial Stress and Strain State in Sheet Metals on the Roller Levelling Process
Authors: Grüber Markus , Oligschläger Marius , Hirt Gerhard
Published: July 2015

Due to increasing requirements regarding the flatness of sheet metals, the process of roller levelling is of particular importance. The process itself is influenced by a high number of parameters such as machine design, sheet dimension, and material properties. Therefore, it is desirable to provide an online process control to react on changes of those process parameters. One possible approach for the layout of a process control and the identification of reference values is the use of the Finite Element Method (FEM). Considering the alternate bending a sheet metal undergoes when passing through a roller leveller, kinematic hardening of the sheet material must be taken into account. Additionally, the initial stress and strain distribution of the sheet metal – e.g. induced by coiling – has an influence on the material behaviour and consequently on the process parameters. With respect to these effects, a coupled FE model, which accounts for the initial state of the sheet metal, is introduced. An inverse calculation of material parameters describing the behaviour under cyclic load conditions has been done for an aluminium alloy AA5005 and a mild steel DC01. Based on this numerical setup, the influence of the initial stress state in the pre-levelled sheet metal on the roller levelling process has been deduced. Accompanying experiments on a down-sized roller leveller were carried out for a validation of the numerical setup.
Machinability of the EBM Ti6Al4V in Cryogenic Turning
Authors: Sartori Stefano , Bordin Alberto , Bruschi Stefania , Ghiotti Andrea
Published: July 2015

In machining operations, the adoption of a cutting fluid is necessary to mitigate the effects of the high temperatures generated on the cutting zone, and, therefore, to avoid severe detrimental effects on the tool wear and surface integrity. In the biomedical field, the traditional processes to manufacture surgical implants made of Titanium and Cobalt Chromium Molybdenum alloys involve turning and milling operations. To cool the cutting tool with standard oil emulsions leaves contaminants on the machined surfaces, which require further cleaning steps that are expensive in terms of time and costs. Currently, this limitation is marginally overcome by machining without the coolant; however, as a consequence, severe tool wear and poor surface integrity take place. In the last years, many studies have been conducted on the application of Liquid Nitrogen as a coolant in machining difficult-to-cut materials such as Ti6Al4V. Thanks to its properties to evaporate immediately when getting in contact with the cutting zone, thus living the workpiece and chips dry and clean other than its ability to lower the cutting temperature. The adoption of Liquid Nitrogen as a cooling mean in machining surgical implants may represent an optimum solution enhancing the benefits of dry machining. This work is aimed at evaluating the performances of the Liquid Nitrogen as a coolant in semi-finishing turning of Ti6Al4V produced by Electron Beam Melting, a comparison with dry turning is presented. The alloy machinability in such conditions is evaluated in terms of tool wear, machined surface integrity and chip morphology.
Cutting Process of Double Angle Drill
Authors: Tamura Shouichi , Matsumura Takashi
Published: July 2015

Double angle drills have recently been used to improve the surface finish in drilling. The double angle drill consists of lower edges at a large wedge angle and upper edges at a small wedge angle on the lips. The paper discusses the cutting processes of the double angle drill in analysis and experiment. A force model is applied to simulate the cutting force and the chip flow direction. The cutting tests are conducted to verify the force model in drilling of carbon fiber reinforced plastic (CFRP) and aluminum alloy (A7075) with a single and a double angle drills. The double angle drill is effective in control of delamination in drilling of CFRP due to reduction of the thrust force. Meanwhile, in drilling of A7075, the small wedge angle of the upper edges on the double angle drill is not effective in reduction of the thrust forces. The curved edge at the end of the lip, in turn, promotes burr formation in drilling of A7075. The effectiveness of the double angle drill depends on the workpiece material.
Dynamic Recrystallization of Spheroidal Graphite Iron during Hot Cutting Operations
Authors: Le Mercier Kevin , Watremez Michel , Fouilland-Paillé Laurence , Dubar Laurent
Published: July 2015

The objective of the present paper is to analyse the dynamic recrystallization process occurring during the hot cutting of spheroidal graphite iron. In the first instance, hot cutting tests are performed with an orthogonal cutting test bench. The emergence of dynamic recrystallization is highlighted thanks to microstructural observations. Then, a finite element model of the hot cutting operation is introduced. The material behaviour is modelled with a specific constitutive model considering the influence of dynamic recrystallization on the plastic flow stress. Finally, the predictive response of this model is compared to the experimental observations.
A Numerical Procedure for Machining Distortions Simulation on a SAF 2507 Casting Workpiece
Authors: Franchi Rodolfo , Del Prete Antonio , Papadia Gabriele
Published: July 2015

The workpiece distortion that occurs during machining, can lead to a large increase in the number of the scrap parts. Residual stresses are the main cause of these distortions and they are generally present in both forging and casting products. In order to obtain the desired microstructure and mechanical properties, the workpiece is subjected to heat treatment before being worked. Quenching produces residual stresses that exist throughout a large percentage of the casting or forging part. Distortion occurs as a result of removing stressed material from the workpiece. The component will re-equilibrate and distort as each layer of stressed material is machined away. This paper describes a procedure development for distortions numerical analysis on a SAF2507 casting bulk workpiece. A solubilization heat treatment has been simulated, in order to predict the bulk residual stresses distribution. Different metal cutting processes have been considered to measure the numerical distortions induced in the workpiece.
Numerical Modelling of Orthogonal Cutting of Electron Beam Melted Ti6Al4V
Authors: Bordin Alberto , Imbrogno Stano , Bruschi Stefania , Ghiotti Andrea , Umbrello Domenico
Published: July 2015

Finite element analysis of cutting processes of difficult-to-cut alloys is attracting more and more interest among the scientific community thanks to the change of predicting difficult to measure parameters as cutting forces, specific cutting pressures, cutting temperatures and the chip morphology. Aiming at calibrating and validating an FE numerical model, the predicted variables have to be compared with experimental results. Nowadays, Additive Manufactured Titanium alloys are being increasingly employed in the production of surgical implants and aero engine parts, but their peculiar fine acicular microstructure have to be taken into account dealing with their thermo-mechanical behavior as during machining operations. Based on the lack of literature works concerning experimental investigations on the machinability of Additive Manufactured Titanium alloys, this paper is aimed at investigating the cutting forces and temperatures arising during orthogonal cutting of an Electron Beam Melted (EBM) Ti6Al4V alloy.
Studies on the Effect of Tool Wear on the Production Process in Two Stage Shear Cutting
Authors: Gläsner Thorsten , Schaffner Tobias , Sunderkötter Christina , Volk Wolfram , Hoffmann Hartmut , Golle Roland
Published: July 2015

The formability requirements of high-strength steels are increasing as a result of progressive lightweight construction. An innovative two-stage shear cutting process has been developed in order to meet these requirements. It significantly reduces the edge crack sensitivity of the material in the cutting zone. Studying the effect of worn tool elements on process safety is a key focus for the ongoing improvement of this production process. A production-based tool condition was simulated by creating different cutting edge radii on the active tool elements. Collaring tests showed a reduction of residual formability through wear of up to 65% for high-strength heavy plates (plate thickness > 3 mm).
Separated Representations of Incremental Elastoplastic Simulations
Authors: Nasri Mohamed Aziz , Aguado Jose Vicente , Ammar Amine , Cueto Elías , Chinesta Francisco , Morel Franck , Robert Camille , Elarem Saber
Published: July 2015

Forming processes usually involve irreversible plastic transformations. The calculation in that case becomes cumbersome when large parts and processes are considered. Recently Model Order Reduction techniques opened new perspectives for an accurate and fast simulation of mechanical systems, however nonlinear history-dependent behaviors remain still today challenging scenarios for the application of these techniques. In this work we are proposing a quite simple non intrusive strategy able to address such behaviors by coupling a separated representation with a POD-based reduced basis within an incremental elastoplastic formulation.
High-Speed Cropping of Rods and Wire with Superposition of Various Stress Conditions
Authors: Henry Robinson , Liewald Mathias
Published: July 2015

In the manufacturing of mass products, material and energy costs are an important part of the total costs. Competitiveness in the production of raw materials can only be maintained if waste of material is minimized and a high productivity is ensured. An outcome of these efforts is the further development of conventional cropping. High-speed cropping is characterized by the cropping speed as far as tooling is concerned. The cropping tool is accelerated up to a blade speed of 8 to 10 m/sec. This increase in cropping speed influences the surface quality of the specimens.This paper is mainly focused on the experimental investigation into the high-speed cropping in bulk metal forming. The first part of this investigation presents a comparison between conventional and high-speed cropping to demonstrate the difference between both methods. In this case study, materials of different mechanical strength are examined. The produced specimens are analysed with an optical system (GOM ATOS) to determine their geometrical properties, such as end-face flatness, ovality, and the draw-in of the specimens. The second part examines stress superposition. Here stress is superimposed on the specimens during cutting to trigger off an earlier failure of the investigated material. High-speed cropping with stress superposition is aimed at reducing the draw-in of the investigated samples. The results of this will be compared with the results of the first part to show the difference between high-speed cropping with and without stress superposition.
Inverse Identification of Process Variations for Thin Steel Sheet Bending
Authors: Havinga Jos , van den Boogaard Ton
Published: July 2015

The stability of a metal forming production process is influenced by several sources of scatter such as variation of material and lubrication properties. Identification of the sources of variation is needed to optimize the process settings or to design a control strategy for the process. Many engineers point out sources of variation by experience, but in complex cases a computational identification algorithm may be used to investigate the process. When using parameter estimation in a control system, process forces can be used for the estimation. However, many parameters may influence the process forces. Therefore extensive models are needed to be able to identify the process parameters, including parameters such as tooling misalignment. In the current work, a thin steel flap bending process is studied. Measurements from an industrial press are used to identify the process parameters. A metamodel based inverse analysis procedure is used. The procedure is extended with proper orthogonal decomposition (POD) of the force curves to increase its convergence rate.
Sensitivity Analysis for Numerical Sheet Metal Forming Processes
Authors: Maia Ana , Oliveira Marta C. , Andrade-Campos António , Menezes Luís F.
Published: July 2015

Sheet Metal Forming is a widely used process in industry. However, it is also an expensive onedue to the diversity and complexity of methodologies used to obtain the adequate tools combination.In fact, even though there is already finite element based software to compute the final shape of aformed sheet from a given tool, there is no efficient procedure to predict the inverse problem: the toolgeometry from the formed component final shape.The final aim of this work is to improve the current trial-and-error process for the inverse problem.To achieve this objective, an integrated approach for tools geometry manipulation is presented, basedon the parametric NURBS description of the tools surface. This is applied to perform a sensitivityanalysis in order to evaluate the effect of numerical noise and small disturbances on the tools designvariables in the final formed sheet. Furthermore, the robustness of the proposed approach is evaluatedusing two parts with distinct complexity.
Intelligent Advisory System for Support of Production Process Design in the Domain of Metal Forming
Authors: Rojek Gabriel , Regulski Krzysztof , Szeliga Danuta , Kusiak Jan
Published: July 2015

The domain of the presented work is the design of a computer advisory system which should offer support on general design of production cycle. The idea of functioning of the advisory system is related to the reuse of information gathered from previous processes of production design. The information on the design of entire production cycle is suggested to be split into fragments related to specific production phases in the whole manufacturing chain. The advisory system should provide the possibility of making use of diverse piece of information so as to obtain the full production cycle for a new product similar to others manufactured in the past. The idea of information processing is based on the data mining rules induction methods and is visualized with examples of fasteners manufacturing.
Investigation of Cold Pressure Welding: Cohesion Coefficient of Copper
Authors: Schmidt Hans Christian , Ebbert Christoph , Rodman Dmytro , Homberg Werner , Grundmeier Guido , Maier Hans Jürgen
Published: July 2015

Joining materials by forming is an interesting approach to the manufacture of hybrid (multi material) parts. By establishing a cold pressure weld between metallic surfaces, high quality joints with superior properties can be achieved. Reliable cold welding conditions are difficult to set up, however, since the weld initiation requires extraordinary clean, virtually sheer surfaces. Until today such conditions could only be achieved under a high vacuum conditions. Various studies on cold pressure welding reported that under vacuum welds can be established at significantly lower deformation than in a normal atmosphere. Since adverse deformation is currently needed in industrial cold pressure welding processes like the cold roll cladding of metal bands, a new process with in-line electrochemical surface treatment, is investigated. The ECUF process is intended to supply clean and thereby highly activated surfaces to the cold pressure welding process.This paper presents first results on the weld-ability of copper specimens with regard to the influence of the welding environment: air, argon and KCl solution. Butt welds were made by pressure welding of previously fractured specimens.
Physically Based Criterion for Prediction of Instability under Stretch-Bending of Sheet Metal
Authors: Perdahcioglu Emin Semih , Hou Bo , van den Boogaard Ton
Published: July 2015

This research focuses on the prediction of the forming limit of certain Advanced High Strength Steel grades under stretch-bending conditions. For these types of steels it is experimentally observed and shown that when there is a bending component added to the main membrane deformation the formability predicted by the regular FLCs underestimate the material behavior. Due to the added effects of thickness stress due to contact and small radius bending as well as bending stresses, a through-thickness stress gradient forms which gives additional stability to the material beyond the forming limits determined by tests that generate mostly uniform membrane deformation. It is observed experimentally and by the detailed simulations that the cross-sectional stability is not lost instantaneously but gradually. A surface dent forms first on the outer surface and progresses in a stable manner towards the contact side since on the contact side the material has still potential to harden. This process delays the localization of the strains and stabilizes the formation of the local neck. For the prediction of this phenomenon theoretically and using shell elements, a modified incremental form of the maximum tension stability criterion is proposed to be applied at integration points through thickness. It is shown that with this criterion the phenomenon of gradual loss of stability can be captured during stretch-bending with shell elements.
Forming Behavior during Joining by Laser Induced Shock Waves
Authors: Veenaas Stefan , Vollertsen Frank
Published: July 2015

The ongoing trend of miniaturization makes hybrid joint also for the micro range necessary. Existing solutions often have restrictions due to the principle of joining. Therefore a new joining technology, which is realized by a plastic forming process based on TEA-CO2-laser induced shock waves, is used at BIAS. This technology enables the joining of different sheet materials with thicknesses between 20 µm and 300 µm. The manufacturing of the joint is an incremental process where several laser induced shock waves are needed to form the undercut, which presents the joint itself. For the analysis of the incremental forming behavior of this process a 50 µm thick forming sheet of aluminum (Al99.5) is joined with a 100 µm thick stainless steel (1.4301) die sheet. The first ten laser pulses are leading to relative high induced strain while for forming of the undercut 200 laser pulses are needed. The incremental induced strain per laser pulse decreases exponentially with the amount of used laser pulses. This behavior is explained by the acting pressure distribution of the induced shock wave and the contact area.
Thermo-Mechanical Characterization of Friction Stir Spot Welded Sheets: Experimental and FEM Comparison between AA6060 and AA7050 Alloys
Authors: D'Urso Gianluca , Giardini Claudio
Published: July 2015

A study was carried out to evaluate how the Friction Stir Spot Welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. An experimental campaign was performed by means of a CNC machine tool and FSSW lap joints on both AA6060 and AA7050 aluminum alloy plates were obtained. Some thermocouples were inserted into the samples to measure the temperatures during FSSW. A set of tests was carried out by varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the execution of the experiments by means of a piezoelectric load cell. The mechanical properties of the joints were assessed by executing shear tests on the specimens. A comparison between the quality of the joints obtained on the two materials and a correlation between process parameters and joints properties was found. A FEM model for the simulation of the process was set up using the commercial code Deform 2D. The peculiarity of this model is a 2D approach used for the simulation of a 3D problem, in order to guarantee a very simple and practical model able to achieve results in a very short time. This solution was achieved, based on a specific external routine for the calculation of the developed thermal energy due to the friction between tool and workpiece. The collected experimental data were finally used to validate the model.
Influence of Process Induced Damages on Joint Strength when Self-Pierce Riveting Carbon Fiber Reinforced Plastics with Aluminum
Authors: Landgrebe Dirk , Jäckel Mathias , Niegsch Ronald
Published: July 2015

The importance of environment friendly mobility strengthens the need of lightweight design in the automotive industry. New electric car models, like the BMW i3, already have car body with a high amount of carbon fiber reinforced plastics (CFRP) to allow, as a result of the low vehicle weight, appropriate ranges without reloading the battery. Methods for joining materials like CFRP play a key role to implement lightweight designs into car body production. Conventional joining methods like spot welding cannot be used for such material combinations. Due to the good automation and possible combination with adhesive, mechanical joining techniques such as self-pierce riveting (SPR) are very relevant for joining these lightweight materials. While generally self-pierce riveting of CFRP with aluminium is possible, different damages e.g. delaminations, fiber or matrix fractures in the CFRP can occur during the joining process and have to be considered.
This paper shows an analysis of these process induced damages when self-pierce riveting CFRP compound with aluminum sheet metal and investigates their influence on the joint strength. In our research the conventional SPR process of CFRP-aluminium joints is compared to the application of a new die concept for SPR in which a separated die is used to reduce the process induced delaminations in the CFRP. Additionally, these joining results are contrasted to SPR joints with pre-drilled CFRP components. Through the pre-drilling the damages in the CFRP can nearly be avoided completely and so these joints can be used as a reference. The results of the three processes to produce CFRP-aluminum joints are compared by micrographs, computed tomography and strength tests.
Formability of a Magnesium Alloy AZ31B Deformed under Channel Die Compression Tests: Macroscopic Shearing of Specimens
Authors: Francillette Henri , Marco Fabien
Published: July 2015

Channel die compression tests were performed at 175 °C on polycrystalline magnesium specimens AZ31B which present specific initial textures. Deformation stages up to 90% plastic deformation are considered. The specimens were defined initially by a specific angle characterizing the starting position of the majority of the  axes of the hexagonal phase in the experimental device. Stress-strain curves and the evolution of crystallographic textures (using X-ray diffraction measurements) are determined. A macroscopic shearing is observed for most of the investigated specimens. A phenomenological law is applied in order to describe the experimental true stress-strain curves. The identification of the parameters of the law indicates its good ability to reproduce the experimental curves.
Fabrication of Ingot with Lotus Type Through-Holes in Semisolid Condition
Authors: Haga Toshio , Fuse Hiroshi
Published: July 2015

In this paper, an easy casting method of an ingot with through holes is shown. The Core-Bar-Pulling Method is proposed to improve the disadvantages of lotus type porous metal. The through holes were formed by pulling core-bars from a semisolid ingot. Holes with diameters ranging from 0.5 mm to 5 mm and length 50 mm were made in Al-Si alloy ingots. The relationship between temperature and formability of the holes was investigated by using eutectic Al-Si alloys. The pulling of core-bars and the forming of holes were easy, under the condition that the Si content was less than 6 mass%. This means that the forming of holes in Al-Si alloys is easy under the condition that flow ability at semisolid condition decreases.
Microstructural Characterization of Indirectly Extruded EN AW-6060 Square Tubes with Axial Variable Wall Thickness
Authors: Negendank Maik , Taparli Ugur Alp , Müller Sören , Reimers Walter
Published: July 2015

Today, innovative lightweight constructions increasingly demand for profiles with higher strength and stiffness. In this investigation an axially moveable stepped mandrel allowed the manufacturing of load adapted (tailored) aluminum tubes with axial variable wall thicknesses by the extrusion process. Thus, on the one hand it is possible to produce thick-walled sections for highly stressed areas and on the other hand save profile weight by applying reduced wall thicknesses in areas with lower loads. Varying the extrusion ratio along tube direction affects the product velocity as well as the profile exit temperature und thus the microstructure in different tube sections. At high temperatures and high strain rates the microstructures revealed very large grains due to static recrystallization. However at low temperatures and low strain rates dynamic recovery lead to a microstructure dominated by fibrous grains. Small equiaxed grains were also found indicating geometric dynamic recrystallization.
Deformation Characteristics of Advanced High Strength Steel under Cyclic Bending and Reversed Bending
Authors: Chen Fuh Kuo , Lin Sin Liang , Tsai Heng Kuang , Lin Yi Wei , Lin I Kai
Published: July 2015

In the present study, the Bauschinger effect exhibited in the advanced high strength steel under cyclic bending and reversed bending deformation was examined by both the experimental approach and the finite element analysis. The cyclic tension-compression tests were first conducted for the DP590 steel sheet to determine the material constants required in the Yoshida-Uemori model used in the finite element simulations. Since the deformation mode occurred in the reversed bending tests is similar to that presented in the sheet metal passing across the draw bead or die corner, a three-point reversed bending test apparatus was also developed and the experiments were conducted in the present study. The reversed bending test results clearly demonstrate that the Bauschinger effect presents in the reversed bending process. It confirms that the cyclic reversed bending tests can be applied to examine the Bauschinger effect exhibited in the sheet metal forming process. The finite element analysis was also performed to simulate both the U-hat bending and cyclic reversed bending processes. The comparison of the simulation results with the experimental data reveals that the finite element predictions in both springback and reversed bending load are more accurate if the Yoshida-Uemori model is adopted. It implies that consideration of the Bauschinger effect is necessary in the sheet metal forming if a reversed loading path is present during the forming process.
Alternative Temperature Control of Closed Forging Dies Using Heat Pipes
Authors: Behrens Bernd-Arno , Prüß Tobias
Published: July 2015

The temperature of forging dies has a high influence on the wear development of the tool surface. To reduce the thermal impact on tool life cooling lubricants are used in many manufacturing processes. They perform two functions: tool cooling and reduction of friction. Cooling lubricants must always meet these two requirements. Within this article the separation and the particular optimization of both functions is presented.As an alternative to a graphite-water-mixture, boron nitride is the medium of choice for lubrication purposes, since it features excellent lubricant properties. For a high wettability it is applied by electrostatic coating.As an alternative approach to removing heat from a forging die, the usage of heat pipes is for the first time investigated in this paper. These passive elements are able to transport heat without using external energy. They will be varied in form and volume. This cooling method will be qualified for the use in forging dies.