Abstract: The purpose of this paper is to present the study of internal structure for investment casting Fused Deposition Modeling (FDM) , and compare it between open and closed ceramic cube . This research aims to introduce a new internal structure for investment casting FDM pattern. With modeling 3D-thermal condition with mechanical finite element analysis on cube ceramic shell open and closed type (during burnout stage) have been computed. As numerical observation the deformation stress for cube square 90° and hollow models with two variants cube open and closed have been evaluated by put the temperature at model. Model was be imposed until 700 °C. Several investigations indicate the probability of better performance for influencing factor drainage ability for each model. However the main scope of the paper is to compare the performance of model during burnout stage ( the deformation on ceramic shell ) . Therefore, a more analytical and practical approach will be good for future research for other mentioned factors. A new generation of internal structure (or a new build style) for investment casting FDM patterns is presented here. The significant reduction of critical loadings on ceramic shell will ensure investment casting foundries for using FDM patterns, which are by square 90° and hollow models.
Abstract: In the past 17st century, revolution of industrial had been started and transited to new manufacturing processes, going from hand production to machining process. In order to reduce the manufacturing cost and protect the environment, several techniques are used. While lubrication play a significance role in variable parameters, such as tool life, cutting temperature, surface finishing, chip formation and cutting force.In this paper, ultrasonic assisted turning (UAT) was introduced for the machining of Aluminium 6061-T6. In this technique, ultrasonic vibration which excess 20kHz is combine with conventional turning process to achieve combined advantages of both techniques in machining process. UAT control system is developed using function generator to generate required frequency and output voltage direct connected to piezo actuator. While piezoelectric actuator PPA10M is the main device used to convert electrical energy to vibration energy,where the vibration transmitted to the cutting tip and perform in mechanical energy to remove unwanted material and produce precise dimension of work material. The characteristic of this machining process in theoretically capable to reduce tool wear, cutting force and based on current experimental analysis had shown significance improvement on surface finishing and reduction in tool wear. In the present work, comparison data had been done based on conventional and advanced machining process in the scope of wet and dry machining on AL6061-T6.
Abstract: An experimental study of GTAW was conducted to determine the optimization of weld parameters on the droplet formation in the surface quality of weld pools. These optimization investigations consisted of welding current, welding speed and feed rate. The strength and surface quality of weld pool were measured for each specimen after the welding parameter optimizations and the effect of these parameters on droplet formation were researched. To consider these quality characteristics together in the selection of welding parameters, the Orthogonal Array of Taguchi method is adopted to analyze the effect of each welding parameter on the weld pool quality, and then to determine the welding parameters with the optimal weld pool quality.
Abstract: Welding is a reliable and effective metal fabrication process which is widely used in industries. Localized heating during welding, followed by rapid cooling generates residual stress and distortion in the weld and base metal. In the last few decades various research efforts have been directed towards the control of welding process parameters aiming at reducing the residual stress and distortion. In the present paper the distortion in fillet welds and the affect of the distortion control techniques on the welded joint are studied. The welding is done with different process parameetrs and under different surrounding conditions. Due to this the distortion level in the T Joint was measured and observed. The study is necessarily aimed at developing the prediction and controlling techniques for distortion in welded T-joints. Key Words: Distortion, preheating, peening, leg length, Shielded metal arc welding (SMAW), Manual metal-arc welding (MMAW)
Abstract: This paper presents the effects of spot welding parameters on multi-response weld quality and optimizes the governing parameters of Resistance Spot Welding (RSW) towards the tensile shear strength and nugget size using Taguchi method. The main affecting welding parameters such as electrode force, weld time and weld current were determined as the basis for quality evaluation. The selected quality features were classified into shear strength and nugget size which were required for application with highly dynamic loading. The optimum welding parameter was obtained using multi signal-to-noise ratio (MSNR) and the significant level of welding parameters was further analysed using analysis of variance (ANOVA). Based on the results, electrode force was found to be most effective parameter affecting shear strength and nugget size. The experiment was conducted at optimum welding parameter and validated the used of multi-objective Taguchi method for enhancing performance and optimizing the welding parameters in RSW process.
Abstract: Woven composite based on natural fiber increasingly used for many applications in industries because of their advantages such as good relative mechanical properties and renewable resources, but there are some issues as cost and protracted development period to perform reliability evaluation by experimental with real scale. Predictive modeling technique is use to minimize the need for physical testing, shorten design timescales and provide optimized designs. Mechanical properties of woven fabrics for technical textile depend on a) type of raw materials b) type and count of warp and weft yarns c) yarn density and d) the type of weave structure. The effect of fabric architecture to the mechanical properties is investigated. Woven kenaf composite is modeled using the modeling software to get the properties of the model. Further, the model is analyzed using finite element analysis to predict the mechanical properties of the woven kenaf composite. In addition, the effect of the combination of yarn size and weave pattern to the woven kenaf composite is stated base on the mechanical properties to predict the optimum structure of woven kenaf composite.
Abstract: Cyclic polarization test was used to determine the breakdown potential of passive film for stainless steel 316L at different temperatures (20°C, 30°C, 40°C, 50 °C) and different salinity (15%, 25%, and 35%). The results show the highest breakdown potential occur at low temperature and low salinity indicate that incresing the temperature and salt content in seawater will increasing the corrosion attack on 316L. Increasing the temperature from 20°C to 50°C was decrease the Eb value for 75%. Before and after testing, visible pits and hardness for each sample were observed by using Scanning Electron Microscopy (SEM) and Vickers hardness testing. It was found that at temperature 20°C, it can be seen that number of pits is more but the pits size is a bit tiny. However, the number of pits reduce as the temperature and salinity increased but the size of the pit become larger and wide which indicate that pitting has propagate during that period. Furthermore, increasing the temperature from 20°C to 50°C also lead to increased the hardness different value which indicate that reducing in hardness properties of 316L at increasing salinity because of corrosion attack.
Abstract: Tungsten carbides (WC) are widely used as wear resistant components such as seal, valves, rings, nozzle and bearings. But in some processing operations, the environment necessarily includes severe corrosion or extremes of temperatures. In paper reveal, the corrosion performance of commercial cobalt tungsten carbide (WC-6%Co) and nickel tungsten carbide (WC-9%Ni) in seawater with 3.5% salinity. The experiment was performed in four different temperatures (20°C, 40°C, 60°C and 80°C) and the surface structure by corrosion attack was reveal under SEM. The Icorr value of WC-9%Ni is lower than WC-6%Co, elucidate that WC-9%Ni is better in corrosion resistance compare to WC-6%Co. As the temperature increased, the corrosion rate for every material increased as expected. Decreasing in hardness value for both materials reveal that, the material’s hardness decrease after corrosion has attacked.
Abstract: Effects of material and process parameters on the electrospun polyacrylonitrile fibers were experimentally investigated. Response surface methodology (RSM) was utilized to design the experiments at the setting of solution concentration, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on pore size, contact angle, modulus young and clean water permeability. Effect of applied voltage in micron-scale fiber diameter was observed to be almost negligible when solution concentration and collector distance were high. However, all three factors were found statistically significant in the production of nano-scale fibers. The response surface predictions revealed the parameter interactions for the resultant fiber diameter, and showed that there is negative correlation between the mean diameter and coefficient of variation for the fiber diameters were in agreement with the experimental results. Response surfaces were constructed to identify the processing window suitable for producing nanoscale fibers. A sub-domain of the parameter space consisting of the solution concentration, applied voltage and collector distance, was suggested for the potential nano scale fiber production.
Abstract: Bottom ash is a solid residue produced through combustion process in a coal-fired power plant. It has been catogarized as a waste and usually disposed in the utility disposed site. With higher demand on the power energy, more coal-power plant are constructed and abundance of bottom ash are produced. Recently, the utilization of bottom ash in the construction industry has gained the interest of researches. Since it has similiar particle size distribution as normal sand, many attempt has been made in studying it potential use in mortar and concrete. In complementary to that, this paper presents the effect of bottom ash on fresh and hardened properties of self-compacting concrete (SCC). Bottom ash is used as fine aggregate replacing sand with replacement ratio range from 0% to 30% by volume. The effects of bottom ash on the SCC were investigated by comparing the test result of SCC mixed bottom ash with control specimens (0% of bottom ash). The test result on fresh properties of the concrete mixture revealed that, as the replacement level of bottom ash increased, the slump flow, L-box passing ratio and segregation resistance ratio (SR) decreased. Nevertheless, the slump flow time (T500) result increased with the increased of bottom ash content. The results show that the porosity and the irregular shape of the bottom ash particle has great influence on workability and viscosity of the fresh concete. The compressive strength and water absorption test are carried out on the sample at curing time of 7 and 28days. In terms of strength, the use of bottom ash in the production of SCC has increased the compressive strength of the concrete up to 15% replacement level. The increase in strength show the presence of the pozzolanic reactivity in a concrete with bottom ash particle. The water absorption rate was observed to be lower with a sample which having 10% and 15% replacement level.