Applied Mechanics and Materials Vols. 541-542

Abstract: This research deals with the multi-response optimization of CNC WEDM process parameters for machining titanium alloy Ti 6AI-4V using Response Surface Methodology (RSM) to achieve higher Material Removal Rate (MRR) and lower surface roughness (Ra). The process parameters of CNC WEDM namely pulse-on time (T_ON), pulse-off time (T_OFF) and wire feed rate (WF) were optimized to study the responses in terms of material removal rate and surface roughness. The surface plot and the contour plots were generated between the process parameters and the responses using MINITAB software. The results show that the Response surface methodology (RSM) is a powerful tool for providing experimental diagrams and statistical-mathematical models to perform the experiments appropriately and economically.

Abstract: This Paper Presents the Optimization of Injection Molding Conditions to Minimize the Warpage and Volumetric Shrinkage Using Design of Experiments and Taguchi Optimization Method. Considering the Process Parameters such as Injection Time, Packing Pressure, Packing Pressure Time, and Cooling Time, a Series of Mold Analysis are Performed. Orthogonal Arrays of Taguchi, the Signal-to-Noise(S/N) and Analysis of Variance (ANOVA) are Utilized to Determine the Optimization Parameter Levels and to Find out Principal Processing Parameters on Warpage and Volumetric Shrinkage. from the Results it is Clear that Warpage and Volumetric Shrinkage are Reduced. also, the Dominant Parameters were Cooling Time and Packing Time for Warpage, on the other Hand, the most Important Factor for Shrinkage was Injection Time. from this, it can be Concluded that Taguchi Method is very Suitable to Solve the Warpage and Volumetric Shrinkage Problems in Injection Molding Parts.

Abstract: Titanium alloys are attractive materials for aerospace industry due to their exceptional strength to weight ratio that is maintained at elevated temperatures and their good corrosion resistance. Major applications of Titanium alloys were military aerospace industry, but since last decade the trend has now shifted towards commercial industry. On the other hand Titanium alloys are notorious for being poor thermal conductor that leads to them being difficult materials for machining. In this experimental study brazed carbide end mill of grade 5 is used for rough down milling of Ti6Al4V for large depth of cut under different combinations of parameters and application of high pressure coolant. The machining performance was evaluated in terms of tool wear, tool life, thermal crack and tool breaking. The tool wear was mostly observed at the tool tip and at bottom part of tool thermal cracks were observed which propagated with respect to time. Flank wear due to scratching of the cutting chips and diffusion wear because of high thermal stresses were observed specially at the bottom of the cutting tool. At cutting speed of 38m/min tool wear couldnt be observed due to tool failure because of fracture under high thermal stresses. It was found that maximum tool life is obtained at the speed of 25m/min, feed rate of 150mm/min and depth of cut of 10mm. In the end it was concluded that machining of Ti6Al4V is a thermally dominant process which leads to high thermal stresses in machining zone that results in increasing tool wear rate and fracture propagation.

Abstract: Application of petroleum based cutting fluids in machining operation may cause many problems such as eye burn and skin inflation etc. Vegetables oils are good alternative to overcome such issues. In this work, experiments were carried out to study the influence of coconut oil on the performance of single point cutting tool insert in turning operation. Three cutting conditions viz. dry, wet and coconut oil were considered to evaluate the tool wear. Results obtained from the experiments highlighted the advantages of coconut oil, a considerable reduction in flank wear, crater wear and auxiliary wear was observed in the turning operation.

Abstract: Equilibrium moisture contents (EMC) of air dried sheet (ADS) rubber were determined by commonly gravimetric-static method with saturated salt solution among surrounding temperatures of 40-70°C correlated to water activity (a_w) ranges between 0.10 and 0.9. The experimental results was analyzed by 5 commonly EMC model. The results showed that equilibrium moisture content of ADS rubber decreased with increase of surrounding temperature at constant water activity and the simulated data using Chung-Pfost model has a good relation to experimental data with R², RMSE and χ² equal 0.9565, 0.0235 and 0.0006, respectively. However some physical property of ADS rubber sample affects to evaluate EMC modeling. Due to avoid this effect, thus the aim of this research work was to determine EMC value by using Artificial neural network (ANN) method and also evaluate the isosteric heat of sorption by following the Clausius-Clapeyron equation. The results showed that simulated results using ANN approach has relatively high accuracy compared to common EMC model. Finally determination of isosteric heat of sorption and entropy of sorption of ADS rubber were carried on. The results stated that the enthalpy and entropy of heat sorption was power function and polynomial function of moisture content respectively. These two parameters of ADS rubber can be used for prediction suitable storage condition and drying condition for ADS rubber drying in the near future work.

Abstract: Recently work shown that an imperfection interface can be deduced by a fast sintering, which termed as Self-propagating High-temperature Synthesis plus Quick Pressing (SHS/QP). In order to investigate the effect of imperfection interface on the transport properties of function ceramics, the SHS/QP was applied to fabricate permittivity BaTiO₃ in this article. It was found that this ultra-fast sintering method could not only lead to a broaden-amorphous grain boundary but also semi-conductive grain body simultaneously. It is interesting that the new rapid route can result in the giant permittivity of BaTiO₃.

Abstract: A modification of using fly ash grout of different levels was adapted to treat the surface of recycled fine aggregate (RFA).The physical properties of RFA before and after modification and the effect on the mechanical performance of cement mortar was studied.The result indicated that the modification of RFA could strengthen the enhancement effect on mechanical performance when modified by 15wt% fly ash grout. After modification, water absorption of RFA was 6.12% and decreased by 47.5%. The 28d flexural strength was increased by 17.4% and compressive strength was increased by 24.2% of RFA cement mortar compared with the reference samples. The superficial microstructure and sectional morphology of RFA was observed by scanning electron microscopy (SEM). The modification mechanism was carried out.

Abstract: Red mud lightweight baking-free brick was prepared by red mud, fly ash and cement, mixed with a certain amount of activator agent and foaming agent. The influence of foaming agent on properties of red mud lightweight baking-free brick was studied. The micro-structure of red mud lightweight baking-free brick was characterized by scanning electron microscopy (SEM). The results show that when the foaming agent content is 10ml, the sample with better performance obtained and the density is 423kg/m³, flexural strength is 0.49MPa and compressive strength is 1.87MPa.

Abstract: In turning operations a coolant is usually introduced to the cutting zone to reduce the friction developed at the tool-workpiece contact area and remove heat generated because of this rubbing action. Conventionally, a coolant is introduced into the cutting zone in excessive quantities. However, a lot of concern has been raised recently as a result of the uncontrolled using of coolants in the metal cutting industry. Therefore, the concept of minimum quantity lubricant (MQL) has been introduced recently. In this paper, the principle of MQL is utilised in machining of a steel grade. The performance of MQL in terms of surface finish is evaluated against both, the flood coolant and dry cutting modes. The results obtained show that MQL produces acceptable surface finish. Therefore, it is highly recommended to consider the application of MQL instead of flood cooling when turning steel grades.

Abstract: Microbial oil is one of the ideal raw materials for biodiesel production because of its rapid reproduction and less influence by the climate and season variation. However, the high cost is one of the key issues that restricted its production in a large-scale. Lignocellulosic biomass, the cheap and renewable resource, might be the best raw material for microbial oil production by oleaginous microorganisms. Recent development on the microbial oil production from lignocellulosic biomass was summarized in this paper. Furthermore, the challenges and application potential of microbial oil were prospected.