Advanced Materials Research Vol. 576

Abstract: Electroplating is a process of depositing a layer of metal onto another base metal using the electrodeposition technique, where an acid is used as a medium of transferring the desired metal onto the base metal. During electroplating some amount of anodes are wasted and burnt and ended up not being used on the end product. A series of experiments with various input parameters were carried out in order to identify the best possible setting which would result in minimum anode usage. The experiments were designed using two level full factorial design. It was observed from factorial analysis that all the input variables like the porosity of anodes in anode basket, concentration of electrolyte and applied voltage have pronounced effect on the anode usage; however, the most significant influence was from porosity. The usage of the anodes was much less as the porosity due to the arrangement of anode in anode basket decreased. The interactive affects of the input variables such as the porosity and the voltage, and the porosity and the concentration were also prominent. The optimum operating conditions were identified by response optimizer plot and were verified experimentally. Both the analytical and experimental results indicated that anode usage could be reduced by 6.12% from that of the current practice. Hence it can be concluded that the operating variables in electroplating industry have significant effect on anode usage.

Abstract: Accuracy and characteristics of the die and punch plays a significant role in the forming process. The perfectness of the die and punch will not guarantee that the part form as desired. Therefore, the die or punch needs to be modified. In practice, the modifications will be carried by trial and error based on the experience of the fabricator and the amount or removed section is unknown. In this study, the contribution of die modification to the geometric defect will be quantified by comparing the blade profile obtained from the nominal geometry of the blade and the profile constructed by commercial optical method namely Alicona system. For validation, Coordinate Measurement Machine was used

Abstract: For about 70 years, cold roll forming machine has been used to make products whose cross section are uniform in the longitudinal direction. Products formed by this machine are used as construction materials, aircraft structural parts, automotive body parts, oil pipelines and so on. Research and development on production technology to make products with higher quality and higher dimensional accuracy has been carried out. Furthermore, analytical research using FEM method has been vigorously done. On the other hand, in accordance with the development of computer control system combined with CPU technology in recent years, research on development of the flexible cold roll forming machine that can form products with varying width in the longitudinal direction has been carried out in Japan and Europe ^(1)〜(4). The new cold roll forming machine combines the normal cold roll forming technology with computer-control technology, making it possible to form the long sized products whose cross sections vary in width. In 2011, we presented a paper that described the design method of flexible cold roll forming machine and the shape defects caused by this machine. In this paper, the behaviors of surface strains occurred in forming flexible section, which are measured by using resistance wire type strain gauges, are described from the view point of making clear the cause of occurrence of shape defect.

Abstract: This paper investigates the capabilities of Direct Metal Deposition (DMD) process, which is a novel additive manufacturing technique, for creating structures that can be used as bone implants. Emphasis is on the use of bio-compatible metals, because metals are the most suitable materials in terms of mechanical strength when the requirement arises for supporting and replacing the load bearing bones and joints such as hip and knee. Specimens using two different metal powders, 41C stainless steel and Ti6Al4V titanium alloy, are generated by DMD process on mild steel and titanium plates as substrates respectively. Metallographic samples were made from the cladding, and tested for surface roughness and micro-hardness. The results indicate that at low laser power, hard and strong structures with good porosity can be successfully created using the DMD system.

Abstract: This research is aimed to analysis the effect of holding time, grain size and compacting pressure parameter against compressive strength of Aluminum-5% fly ash using powder metallurgy method. The irregular form and homogeneous particles of aluminum powder used in this research is produced by Merck German, while fly ash is taken from residual combustion coal in forging process in mechanical engineering workshop of Politeknik Negeri Sriwijaya (Polsri) which is mashed up to grains size 140 and 270 mesh, pressed with holding time 60 and 120 seconds, with compacting pressure 139 N/mm² and 275 N/mm² by cold iso-static pressing. The green body resulted from these processes then sintered up to 550°C. Taguchi Method is used to determine factors which affect optimum condition of compressive strength of Aluminum-5% fly ash. The research result using ANOVA show that the holding time, grains size, , and compacting pressure parameters has significantly affect the compressive strength of Aluminum-5% fly ash.

Abstract: Metal injection molding (MIM) is a near net-shape manufacturing technology that is capable of mass production of complex parts cost-effectively. The unique features of the process make it an attractive route for the fabrication of the new binder system since the success of MIM process is dependent on the outward appearance of the resultant feedstock. Thermoplastic natural rubbers (TPNR) blends consist of thermoplastics, such as polyethylene (PE), alloyed with natural rubber (NR) with different thermoplastic to NR ratios. The soft grade TPNR is produced by blends with compositions richer in rubber while the harder grades can contain up to about 30 % NR. This study investigates the influence of new binder system consisting of TPNR on injection parameter, density of injected molded specimen and changes during solvent extraction. Results show that TPNR plays an important role as a good binder system and shortens the solvent extraction process.

Abstract: In recent times, impellers have been designed and modified to combine unique hydrodynamic features to overcome redundancy during mixing. One of such impeller is the mixed-flow impeller which displays a unique combination of radial and axial flow. In this paper, the flow characteristic of a mixed-flow impeller is reported. The main focus is to compare the axial and radial characteristic of the velocity component using experimental and numerical study. The continuity and momentum equation were solved using the Reynold’s stress model (RSM). The field of view away from and below the impeller compared better with the numerical solution for the mean, radial and axial velocity component. Although the RSM was used at a higher computational cost, associated power number and energy of the impeller was also observed to be better predicted.

Abstract: Silica free binder was developed from cassava starch to correspond common ceramic mould binder for reactive metal casting application. Ceramic slurry rheology behavior and stability depends on both binder and refractory materials properties. Starch processing started from granule expansion or swelling, gelatinization, depolymerization via prolong heating and by adding plasticizer, citric acid is to improve viscosity. Pseudoplastic or shear thinning behavior for both binder and slurry were observed starting at 0.13 Pa.s and 2.5 Pa.s respectively. Calcium carbonate (aragonite) slurry from starch binder however, exhibited viscoelastic behavior compare to colloidal silica sol. Ceramic slurry aged as both cationic starch and CaCO₃ flocculate and not exfoliate as indicated by increased in the pH of the slurry.

Abstract: The purpose of this study is to investigate the effect of the stearic acid as binder in sintering pure iron using a microwave furnace. The study was focused in mechanical properties such as porosity, density and micro-hardness of sintered product. The experiment was done by varying weight percentages of stearic acid and controlling the sintering parameters such as sintering temperature and sintering time. Increasing the percentage of stearic acid resulted in higher porosity and lower bulk density. Hardness has increased by increasing sintering temperature and sintering time. The optimum material properties were found at 1300 °C sintering temperature with addition 2 % stearic acid within 30 minutes sintering time.

Abstract: Resistance Seam Welding (RSEW) is an ideal welding method to produce airtight joints where welding input parameters play a very significant role in determining the quality of weld nugget and heat affected zone (HAZ) formation. This research is aimed to study the nugget and HAZ development of 1 mm low carbon steel using RSEW. Welding parameters such as weld current, weld time, weld speed and pressure were identified and investigated to study their effect on the formation of weld nugget by using 2⁴ factorial designs. The objective of this work is to find the optimum parameter to optimize the width of weld nugget and HAZ in order to obtain a good quality of RSEW. Furthermore the mathematical models were developed to predict the weld zone development. Experimental confirmation test was conducted at an optimal condition for observing accuracy of the developed model. Based on the confirmation test, the proposed method can be effectively used to predict the size of weld zone which can improve the welding quality and performance in RSEW.