Control of plastic transfer molding process parameters is critical to ensure high yield and part reliability in advanced semiconductor packaging. This paper investigates the parameters influencing air bubble formation and shear stress in the 3D Dual In-Line Package (DIP) encapsulation. To separate out these effects, Mold-flow® simulation was conducted at different processing parameters, namely mold temperature, melt temperature, curing time and injection pressure. The experiment also differentiated the material formula between un-filled and 80% silica-filled epoxy molding compound (EMC). ANOVA-based response surface methodology (RSM) was used to assess the significance and interactions of these parameters. The results indicate that process sensitivity is tightly dependent on the silica filler content (F > 900, p < 0.0001). The unfilled EMC exhibited steady performance, with minimal variation of defects regardless of processing modifications. However, the trend in highly filled EMC is triply diphasic, with the dip as its highest is driven by high viscosity. Among the factors that could be controlled the most, there is the melt temperature that is the most effective way to reduce the air traps and shear stresses (p < 0.0001). The contribution of a mold temperature to a predictable, synergistic, secondary effect was noted. Based on this analysis, a process window was designed for the processing of high filler EMC with high melt and mold temperature and sufficient injection pressure. The developed statistical models have been shown to be highly predictive (R² > 0.96, adequate precision > 37). By elucidating these material–process–defect relationships, this work presents a clear-cut dual-defect mitigation technique for enhanced yield, reduced rework and reliable high-density electronic system outcomes.

This study examines the influence of drilling parameters and techniques on the machining performance of polytetrafluoroethylene (PTFE), a polymer known for its low friction, high chemical resistance, and thermal sensitivity. PTFE’s low thermal conductivity and high deformability often lead to dimensional inaccuracy, burr formation, and heat-induced defects during drilling. To address these challenges, the effects of spindle speed, feed rate, and drilling methods (straight, peck, and dwell) were investigated using an 8 mm HSS drill bit under controlled dry-machining conditions. Temperature distribution along the drilling path was monitored using dual K-type thermocouples positioned at entry and exit points, while an optical microscope was used to evaluate hole roundness. This study presents an analysis and strategic optimization of drilling parameters for PTFE to resolve conflicting performance objectives between geometric accuracy and thermal stability. Using Signal-to-Noise ratio analysis, the most critical quality characteristic, hole roundness, was found to demand a high spindle speed to ensure stable cutting conditions. This requirement imposes a significant thermal penalty, as high spindle speed is simultaneously the least optimal setting for minimizing both Entry and Exit temperatures. The final process configuration addresses this trade-off by selecting parameters that maximize thermal mitigation: a high feed rate is chosen to reduce the time-in-cut and dissipate heat efficiently, and the Dwell technique is implemented. The Dwell technique is identified as the optimal thermal moderator, as it provides robust hole roundness while simultaneously maximizing the SN ratio to minimize the critical Exit Temperature. This strategic compromise effectively achieves the primary objective of superior geometric tolerance while preventing catastrophic material failure caused by thermal degradation at the hole exit.

Inconel 718, a precipitation-hardened nickel-based superalloy, is widely utilised in aerospace applications due to its excellent mechanical strength, corrosion resistance, and high-temperature stability. However, its toughness and work-hardening behaviour pose substantial machining challenges, resulting in rapid tool wear, elevated cutting forces, and increased energy consumption. This study investigates the performance of a bio-based hybrid nanolubricant composed of aluminium oxide (Al2O3) and zinc oxide (ZnO) nanoparticles dispersed in coconut oil, applied under minimum quantity lubrication (MQL) conditions during turning operations. Machining trials were conducted at cutting speeds of 25, 50, and 100 m/min using two nanoparticle concentrations (1 wt

The typical distribution of stress in the femoral bone undergoes substantial changes following total hip arthroplasty (THA). With the introduction of a hip prosthesis, it bears a share of the load, resulting in reduced stress in certain areas of the bone and this will lead to stress shielding. Several factors influence stress shielding, including the geometry and cross-section of the hip prosthesis. Additionally, the displacement of the implant is also studied to identify the effects of additional features on displacement. This is because displacement measures the movements of the implant under physiological load. Therefore, in this study, three prostheses were constructed. The dimension of the prosthesis was based on the size of the patients' bone. Two of them had additional fin and hole features in the proximal part of the prosthesis. Finite element analysis was implemented to examine stress distribution under normal walking conditions. Based on simulations, it was found that the addition of features to the basic design increased stress values in the fin and hole regions at the proximal part of the prosthesis. Additions of fins and holes features have caused increments of stress of almost 170% and 85%, respectively as compared to conventional implant. However, for the displacement, it was found that the addition of holes features at the proximal area decreases the displacement by approximates 62%. As conclusion, this demonstrated that the cross-section and geometry of the prosthesis significantly affected stress and displacement distribution. At the same time, it showed that the finite element method could predict the performance of hip implants.

The mechanism of chip formation plays a crucial role in the determination of cutting stability and the machinability of a material. Currently, the predominant emphasis of studies in the field of chip formation mechanism lies in conventional machining, with very less attention given to investigations pertaining to the influence of internal cooling conditions. This study aims to explore the serrated chip formation process of internal cooling machining known as submerged convective cooling (SCC) in the turning process using cutting simulation techniques. The research focuses on the use of AZ31 magnesium alloy as the subject of investigation. This study investigates the effects of varying cutting speeds and different cutting conditions (dry and SCC) on chip serration during turning. Subsequently, the simulation modelling technique was used to determine and analyse the relation between temperature and strain rate throughout the process of chip formation. The modelling of the serrated chip formation under SCC conditions and dry cutting was ultimately conducted. Results demonstrated that chip segmentation ratio increases with the increase of cutting speed in both SCC and dry conditions. The extent of chip serration exhibits an upward trend when subjected to SCC condition, which is attributed to the strain hardening of AZ31 magnesium alloy in SCC and the dominant thermal softening of dry cutting. Combination of strain rate and temperature affects the chip segmentation ratio. SCC has a lower adiabatic shear banding temperature for all cutting speeds; hence, it has a greater chip segmentation ratio than dry cutting.

This study investigates the effect of the endmill flute number and cutting conditions on the milling of PTFE (polytetrafluoroethylene). High-speed steel (HSS) tools with 2 flutes and 4 flutes were evaluated by varying spindle speeds, feed rates, and cutting conditions (dry and wet). Surface roughness and chip formation were the major criteria used to assess the performance of different cutting conditions. The study found that the 2-flute end mill decreased PTFE milling surface roughness better than the 4-flute tool. Due to PTFE’s self-lubrication, dry cutting produces smoother surfaces than wet cutting. The self-lubricating feature of PTFE caused short, discontinuous chips during dry cutting and tangled, needle-like chips in wet conditions owing to coolant interference. These findings contribute to improving the machining of PTFE, bringing insights into selecting the correct cutting tools and cutting conditions.

Crash box is a vital component for a vehicle in absorbing kinetic energy in the event of a road collision. The thin-walled structure is emerging as a favorable geometry in designing the crash box. This article investigates the energy absorption performance of the corrugated nautilus shell bio-inspired thin-walled structure made of AA6061-T6 aluminum alloy. This structure's performance was evaluated using finite element analysis (FEA) under quasi-static and dynamic loading conditions in an axial direction, then validated by a quasi-static compression experimental test, which showed satisfactory agreement. The results show that the corrugated nautilus shell bio-inspired thin-walled structure integrated with corrugated grooves reduced peak crushing force (PCF) by 17.9 % and increased specific energy absorption (SEA) by 1.3 % and crush force efficiency (CFE) by 17.6 % compared to non-corrugated design. It can be concluded that the proposed nautilus shell bio-inspired thin-walled structure integrated with corrugated grooves has the potential to replace conventional hollow square designs in vehicle crash box applications.

Ti-6Al-4V Titanium alloy is well known as a material that is difficult to cut. Its unique properties made major industries, especially engineering fields, become attracted to it. Its resistance to corrosion and ability to withstand high temperatures without deformation made it applicable in making aerospace parts. This study is focused on investigating the effect of cutting parameters on characteristics of machinability performance. The turning process of titanium alloy was conducted in dry machining, and the cutting insert used is uncoated cemented carbide. Taguchi method is used to find the optimum cutting parameters for turning Ti-6Al-4V titanium alloy with an orthogonal array of L9. Cutting speed (v), feed rate (f) and depth of cut (d) were selected as the cutting parameters, whereas cutting forces as the performance characteristics. The degree of influence of each process parameter on individual performance characteristics was analyzed from experimental results. The optimization parameter level was chosen by using the quality characteristic the-smaller-the-better. From the validation results, the values obtained for the three forces are significantly lower than those achieved in previous experiments. Analyzing cutting forces is important to prolong the tool life as well as minimising machining time and costs.

The internal-cooling approach emerged as an alternative in sustainable machining practices due to its multiple benefits. Cooling channels have been applied to cutting inserts to remove heat concentrated in a small area during machining. As a result, these cooling channels are critical in lowering tool temperatures and wear rates. The design of the cooling channel influences the effectiveness of heat management. In the present study, three types of cooling channel designs have been developed to investigate the cooling effect on the insert from the variety of cooling channel profiles. Computational Fluid Dynamics (CFD) is utilized to simulate the cooling effect for all profiles. A temperature reduction has been observed for the internally cooled cutting insert compared to the conventional tool without a cooling channel. The temperature difference is observed when the profile of the channel is varied. In addition, the coolant profile has been observed to be more effective in heat removal when the inlet pressure of the cutting fluid is increased. Through the velocity vector results, it has been determined that the heat transfer rate increases as the flow velocity of coolant within the channel increases. The Turbulence Kinetic Energy (TKE) simulation's value shows that a heat transfer rate enhancement is attained by elevating the TKE value, which depends on the configuration of the coolant flow channel.

Evaluating heat sink design parameters is vital to ensure the capability and suitability for various applications. Heat sinks can malfunction when experiencing high temperatures for a long period of time due to their poor thermal management. This study aims to analyze the performance of radial heat sinks for high-temperature applications in terms of heat transfer coefficient by using computational fluid dynamic (CFD) optimization analysis. This study focused on optimizing heat sink design parameters (i.e., thickness, height, and the number of fins) to the heat transfer coefficient (h) and Nusselt number (Nu) using Response Surface Methodology (RSM). In the optimization, the optimum height, thickness and number of fins are 41 mm, 3 mm, and 10-fins, respectively, generating maximum values of 9.10 W/m2℃ heat transfer coefficient and 375.97 Nusselt number. The error percentage from both validation ways was considered acceptable since it was less than 10

In recent years, the research and development in conductive polymer composites (CPCs) had gained considerable interests in both industry and academia as potential materials for electronic interconnects. These composites require to have the ability to conduct electric while maintaining sufficient flexibility while withstanding the bending, twisting, or stretching during service. To achieve the desired composite properties, the processing method and the parameters involved plays important role and ought to be investigated. In this study, the effect compounding parameters on the preparation of linear-low density polyethylene/carbon black (LLDPE/CB) polymer composite were carried out. Factors namely filler loadings, screw speed and maximum barrel temperatures were selected and their effects on the tensile properties and conductivity were analyzed in this research. It was observed that the increasing of filler loadings from 5 wt.% to 10 wt.% has increased the electrical conductivity from 1.11×10–2 S/m to 1.46×10–2 S/m. The pareto chart shows that the filler loading was important factors to the result of composite conductivity. Moreover, the main effect plot shows that the filler loading has the highest mean effect on conductivity as it is important for the formation of conducting path in composite. It was also established that the pareto chart also shows that filler loading and barrel temperature have the highest significant effect on LLDPE/CB polymer composite tensile properties. The changes in the combinations of factors affect the tensile properties as revealed by the main effect plots for LLDPE/CB CPCs.

Magnesium alloys have broad applications, including medical implants and the aerospace sector owing to their great density and high strength-to-weight ratio. Dry cutting is a frequent technique for machining this material. However, it always leads to an excessive rise in temperature due to the absence of cooling at the cutting zone, which affects the machined surface integrity and chip morphology. In this study, chip morphology and surface integrity of the AZ31 magnesium alloy were investigated in the turning process using an internal cooling method called submerged convective cooling (SCC) to overcome the absence of cooling in dry cutting. This method can exploit the advantage of the high specific heat capacity of water as a cooling fluid without any reaction between water and magnesium to create a cooling element in the cutting zone. The chip morphologies and surface integrity were analyzed experimentally with varying cutting speeds under SCC and dry cutting. The experimental results revealed that SCC and dry cutting produced saw-tooth or serrated chip formation. The chips produced in dry cutting were continuous, while SCC was short and discontinuous as a result of a severe crack on the back surface of the chip. It was discovered that the grain refinement layer on the machined samples was thinner under SCC turning. SCC machining increased the microhardness of the AZ31 magnesium alloy by 60.5% from 55 HV to 88.3 HV, while dry turning exhibited a 49% increase in microhardness. The result revealed that surface roughness improved by 10.8%, 9.4% and 4.7% for cutting speeds (V) of 120, 180, and 240 m/min, respectively, under the SCC internal cooling. Based on the result obtained, SCC cutting outperformed dry cutting in terms of chip breakability, grain refinement, microhardness, and surface roughness.

This task involved numerical analysis study to investigate the air flow distribution affected by blade distributor arrangement of Multi-Stage Swirling Fluidized Bed (SFB). The current systems is in difference with conventional fluidization systems where the current systems will impart swirling motion to the particle. This study focused on the velocity distribution on blade distributor whereby the influence of blades number (30, 45, and 60) via horizontal inclination angle (10°, 12°, and 15) through multi-stage distributor arrangements, therefore a separate velocity component would be obtained. The numerical simulation, was utilised to compute and analyse the performance outcomes of three velocity components: tangential, axial and radial velocity in an Multi-Stage SFB. From the results of the study, the fluidization systems with high blades number of 60 and blades angle of 15° has shown a significant air flow distribution at both stages. Thus, the major velocity component such as velocity magnitude and tangential velocity in the Multi-Stage SFB have shown a retention uniformity along the radius blade distributor and the air flow inside the system rise more than 40 m/s.

Abstract Machining metal alloys such as AZ31 magnesium alloy involve thermomechanical behavior between workmaterial and cutting tools. The interaction between workmaterial and cutting tools has affected the chip formation in metal cutting and cutting performance. This paper developed a finite element model (FEM) by using Abaqus software to simulate the chip formation in cutting AZ31 magnesium alloy under dry condition. The study revealed that serrated chips were formed in dry condition. Chip segmentation increased proportionally with cutting speed as generated heat concentrated in a narrow zone, promoting the formation of an adiabatic shear band.

Machining airtime or non-productive time or airtime is a process of movement of the tool before shaping the workpiece. One of the methods to decrease the total machining time is by reducing airtime. Thus, in this study, an optimization of the sequence operation in machining was conducted using an Artificial Intelligence method, which is the Ant Colony algorithm. This algorithm was employed to decrease the machining airtime to enhance the effectiveness of the machining process. A three-dimensional model consisting of the drilling process and pocket milling process was developed using Solidworks software. Matlab software was used to develop the algorithm based on Ant Colony, which was then used to optimize the process sequence. Hence, the results of the optimization were implemented in MasterCAM software to run the machining simulation. Then, the results of machining time that used the tool path generated by the Ant Colony algorithm method was compared with the machining time that used tool paths generated by conventional methods. Based on the simulation, the Ant Colony algorithm method is, on average, 10.8% better than conventional methods in reducing machining time. It can be concluded that the Ant Colony algorithm is capable of reducing airtime machining and enhancing the machining process's performance.

A simple solvent casting method was proposed to prepare a superhydrophobic expanded polystyrene (EPS)/stearic acid modified palm slag (SA-PS)/titanium dioxide (TiO2) coating with excellent water contact angle. The influence of components, such as mass ratio of palm slag to TiO2 as well as the influence of TiO2 on the morphology and wettability of coating, was evaluated. The morphology, tear behavior, surface roughness, and water contact angle were observed by scanning electron microscopy (SEM), scratch tester, 3D profilometer, and ImageJ software, respectively. The results displayed that the superhydrophobic coating exhibited highest WCA of 151.93° under the optimum condition formula. Additionally, the superhydrophobic EPS/SA-PS/TiO2 showed non-wetting ability. Thus, the existence of a micro/nano-hierarchical structure of superhydrophobic EPS/SA-PS/TiO2 may provide potential practical applications that are useful in many industries such as automotive or shipping.

Rapid increase in world population and economic growth, improvements in living standards after the industrialization of the world brought about high demand of energy. In the last two decades, extensive work has been done for alternative and sustainable sources and technologies to meet up current and future energy demand such as solar energy, wind energy, hydro and biofuels energy. One of the viable biomass sources available in Malaysia is Domestic wastewater sludge. Further study on this biomass is required to promote as the biomass fuel. This study focused on the production of volatile and char yield during pyrolysis and combustion with particle size range between 0.4 mm and 2.0 mm and heating rate (5, 10, 15, 20, 30, 50 and 100 K/min) by using thermogravimetric analysis. Based on the finding, the total volatile shows a tendency to decrease when the heating rate increase with the highest value was 84.51%. However, the highest char was produced at the highest heating rate was 23.80%. The lowest heating rate is favourable since produce high volatile matter content and low char content.

Low melting point and material adhesion are associated challenges of magnesium alloy, leading to extreme built-up edge (BUE) and built-up layer (BUL) formations during machining process. Dry machining is favorable for machining magnesium alloy. However, this strategy inflicts excessive adhesive wear on the cutting tool. Therefore, this current work focuses on application of an innovative cooling technique, known as submerged convective cooling (SCC) for the turning of AZ31 magnesium alloy. Prior to cutting experiment, a computational fluid dynamics (CFD) simulation was conducted to evaluate internal structure of cooling module. Based on the CFD simulation, a small inlet/outlet diameter of 3 mm significantly contributed to the reduction of the tool temperature, due to high heat transfer coefficient of cooling fluid in the SCC. From the experimental results obtained, it was evident that SCC at high cooling water flow rate of 130 mL/min effectively reduced the tool temperature, chip temperature, and tool-chip contact length by approximately 50, 8, and 28%, respectively. Consequently, it improved the surface roughness by 37%, when compared with the dry cutting condition. Finally, both BUE and BUL were observed in dry and SCC conditions, but the severity of these wear mechanisms improved or decreased remarkably under SCC conditions.

Polymeric materials are known to have insulating properties in general. Nevertheless, the insulating nature of polymers can be turned into electrically conductive by adding conductive fillers subjected to their critical filler loading or percolation threshold. In this study, the effects of various conductive fillers additions, namely copper, silver, and carbon black, on the percolation threshold of linear low-density polyethylene conductive polymer composites were investigated. The mechanical properties were determined using the tensile test, and the electrical conductivity was determined using the four-point probe. The incorporation of conductive fillers generally had an impact on the tensile strength and elongation at the break of the linear low-density polyethylene conductive polymer composites. Nonetheless, it was found that the electrical conductivity of all composites increases where the percolation threshold is estimated for carbon black at 2 wt% and for Ag and Cu at 6 wt% of filler additions.

Magnesium alloys are lightweight materials which exhibit high specific strength and is broadly used in aerospace, automotive, electronics, and biomedical. Dry cutting is a common practice in machining this material which always results to an excessive rise in temperature due to the absence of cooling at the cutting zone. The low melting point of AZ31 magnesium alloy always puts the process to the inevitable built-up edge (BUE) and built-up layer (BUL) formation. This study implemented a novel work in turning AZ31 magnesium alloy via an internal cooling technique, known as submerged convective cooling (SCC), to compensate for the absence of cooling in dry cutting. The experimental result revealed that SCC outperformed dry cutting in adhesion wear mechanism, cutting force and temperature due to the cooling induced. SCC recorded up to 15% reduction in cutting temperature with 6% and 12% reduction in cutting and feed force, respectively. In addition, SCC significantly reduced BUE and BUL formation, consequently restrained cutting force fluctuation, owing to the cooling effect of SCC. This research provides an insight into the potential of implementing internal cooling in the severe plastic deformation process, especially in cutting ductile materials like magnesium alloy.