Selective Laser Melting (SLM) of Ti6Al4V titanium alloy offers enhanced mechanical properties and design flexibility, making it attractive for biomedical and aerospace applications. However, its poor machinability, especially during milling, presents a significant challenge. Despite previous efforts, limited studies have addressed process optimization for improved surface quality in SLM- manufactured Ti6Al4V. This study aims to enhance machinability by optimizing surface roughness using the Taguchi method. An L9 orthogonal array was implemented to assess the effects of spindle speed, feed rate, and depth of cut. Analysis using Signal-to-Noise (S/N) ratios and ANOVA identified spindle speed as the most influential factor, accounting for 83.67% of the surface roughness variation. The optimized parameters led to a significant reduction in surface roughness. This research provides a systematic approach for improving the milling of additively manufactured Ti6Al4V and contributes novel insights into machining strategies for SLM components.

Modern machining techniques like wire electrical discharge machining (WEDM) enable the cutting of complicated shapes. Parameter optimization is necessary during the machining process of titanium alloy. This optimization may help in cost reduction in machining. The objective of this study is to determine the best parameters for machining processes based on single and multi-objective optimization. The study focused on three machining responses: material removal rate (MRR), gap size (GS), and surface roughness (Ra) in the EDM machining process. To achieve the most optimal outcome, teaching–learning-based optimization (TLBO) was employed by comparing the results obtained from optimized data with experimental data based on WEDM parameters. The optimization using TLBO demonstrated that the optimized data produced better results than the existing experimental data for MRR, GS, and Ra. This method is superior and more efficient than the traditional approach used for parameter optimization in machining processes. It is specifically designed to optimize the parameters of the EDM machine learning process.

Metal injection moulding (MIM) is manufacturing method of intricate, high-quality, and high-density parts at feasible costs and capability. In MIM, each phase is crucial the final part outcome beginning with feedstock making, followed by injection moulding, debinding, and lastly, sintering. In sintering, the powder particles are consolidated which induces part shrinkage and robustness. In this study, pulverised aluminium alloy swarf (PAAS) is binded with palm stearin as a standalone binder which is technically unorthodox since binders usually function with at least two components, if not more. Fortuitously, aluminium properties are continuously desired by almost any field or industry and MIM for aluminium is still being pursued and worked on for commercialisation. In this case, with the use of the standalone binder, the debinding and sintering phase are combined and the work and energy required to produce parts are reduced. Both thermal debinding and sintering are conducted within a controlled atmosphere of a constant flow nitrogen gas. The effects of different heating rate and soaking parameters for both thermal debinding and sintering are presented. Thermal debinding soaking temperature should be at 550 °C and below while the sintering soaking temperature should only be caught between 575 and 580 °C. Conclusively, the working samples for further research work or testing can be produced as the plausibility of particulate consolidation is clear.

A plate construction with holes is frequently used in lightweight (aeroplane) structures. Potential applications for a Polylactic Acid (PLA) plate that has been 3D printed with a hole include lightweight (aeroplane) structures. This study focuses on the surface roughness analysis of eight (3D printed) PLA specimens intended for a notched curved shell. In this case, the Creality 3D printer was used to print the PLA specimens, and specific printing parameters were chosen using the Taguchi method. These procedures involved choosing eight (8) 3D printing procedures from thirty-two (32) printing procedures for a full factorial analysis. The Mitutoyo surface measuring machine, model SV600 (1997), performed the surface roughness analyses. The surface roughness was analyzed on the sample's top and bottom portions. Three (3) values were obtained from the study of the contact surface roughness; Ra, Ry and Rz. The average surface roughness, or Ra values, were utilized. In the areas where surface roughness is not smooth and the machine's diamond tip was unable to analyze the values, estimated values were used. Standard deviation (SD) values were presented to show how far they varied from the mean values.

The Minimum quantity lubricant (MQL) in mist form is supplied towards the cutting zone to reduce friction and heat that are inherently generated. Hence, analysing the mist flow behaviour is important in enhancing its lubrication advantages. Thus, in this study, an established 2D-symmetrical multiphase MQL delivery model was replicated and analysed by using the Computational Fluid Dynamics (CFD) of ANSYS. The main aim is to validate whether the present simulation model accurately represents the MQL mist behaviour based on its intended purposes. For that, Reynolds numbers (Re) at different flow distances from the nozzle were measured based on their velocity values. The obtained results showed approximately similar mist velocity and Re progress pattern with the presence of lubricating effect in the model. Only at a flow distance of 0.1125 mm, a significant difference of Re was identified due to different MQL model designs and parameters applied. Thus, it can be concluded that this validated model is feasible and acceptable to be applied as a reference in developing a new simulation model with an improved MQL delivery system in the future.

A sustainable cutting method of Minimum Quantity Lubricant (MQL) was introduced to promote lubrication effect and improve machinability. However, its performances are very dependent on the effectiveness of its mist to penetrate deep into the cutting zone. Optimizing the MQL system requires massive experimental work that increases cost and time. Therefore, this study conducts Computational Fluid Dynamic (CFD) analysis using ANSYS Fluent and focuses on the grid independence study in dispersed-continuous phase of MQL delivery system. The main aim is to identify the best mesh model that influences the accuracy of the CFD model. The analysis proposed two different unstructured grid cell elements of quadrilateral and triangular that were only applicable for 2-dimensional fluid flow in CFD. The unstructured grid was controlled with three different mesh quality factors such as Relevance Center, Smoothing, and Span Angle Center at coarse /low, medium, and fine /high. The results showed that the best mesh quality for quadrilateral was at 60,000 nodes number and coarse mesh, whereas the triangular was at 90,000 nodes number and coarse mesh. Both combinations resulted the most consistent and reliable result when compared with past studies. However, this study decided to choose quadrilateral cell element with 60,000 nodes number and coarse mesh as it is considered to be sufficient to provide accurate and reliable result as well as practical in terms of computational time for the MQL model in CFD analysis.

Volumetric shrinkage and warpage are the most two common defects in plastic injection moulding process that affects the overall quality characteristics of the plastics part. The use of the Taguchi optimization technique to assess and minimized volumetric shrinkage and warpage concerns that impact processing parameters during the production of disposable mouth mirrors made of Polypropylene (PP) plastic is described in this article. The process parameters that have been selected includes melting temperature, flow rate, cooling time and mold temperature during the injection moulding process simulation based on three levels and four factors in L9 orthogonal array. The Taguchi Method was used to further analyze the simulated responses, followed by Grey Relational Analysis (GRA). The signal-to-noise (S/N) ratio graphs are examined to determine the influence of process parameters. Furthered, the Analysis of Variance (ANOVA) has been used to verify the accuracy of the optimization findings. Finally, an optimal combination of operating parameters has been proposed: melting temperature at 180 °C, flow rate at 243.6 cm3/s, cooling time at 12 s and mold temperature at 30 °C was suggest for best optimum combination.

Many factors influenced the final product of an injection molding process. All the factors are needed to be optimized to able to use the most optimum choice and produce a defect-less product. In this study, a series of gate system designs on the syringe’s body was analyzed with a fixed dimensions and parameters values to obtain the most ideal design. The model was developed on CAD software, and the gate system was built in the CAE software. There were three different designs of the gate system; Design 1, Design 2, and Design 3. Then, a series of results were discussed and compared between all three designs. The main focused was how each design influenced the results, the whole process, and hence the final product itself. It was found that Design 2 was the most reliable gate system design. A design that has one injection location on each syringe and it’s located at a discreet point of the body’s surface.

Engine mounting system is an essential component to a vehicle in providing the isolation of vibration and noise which are generated by the engine. While various system designs have been studied for improvements, less attention were given to study the effects of vibrational load to subcomponents of the mounting system – for example: the engine bracket. At high frequency working condition, the engine bracket may experience fatigue failure due to cumulative vibrational loading. Henceforth, any efforts to further reduce the structural weight of the said brackets may degrade its strength and this may lead to catastrophic result. This study aimed to enhance the mechanical property of an engine-mounting bracket with respect to cyclic load by means of weight-reduction topology optimization. An actual enginemounting bracket under vibrational load transmitted was modeled and analyzed using two different computer aided design software. An improved design of engine mounting bracket was modeled by reducing its total weight via the use of HyperWorks. In conclusion, this study has discovered an incremental of stress concentration area across the bracket when predetermined load is applied to the weight-reduced engine bracket.

Austenitic stainless steel of medical grade was subjected to low-temperature thermochemical heat treatment process which forms a distinctive layer on the surface of the material. The distinctive layer is commonly known as `S phase', and resulted due to diffusion of elemental species present in the heat treatment atmosphere. A crosssectional microstructural investigation confirms that the layer thickness increases with the increase of methane (CH4) contents in the carrier gas and the microstructure contain abundance of structural defects like slip bands, stacking faults, twins, and dislocations. Subjected to micro-pillar compression, the ultimate compressive strength of this layer was up to 190% more than that of bulk material which comes in expense of limited strain accommodation of such layer. Consequently, the critically resolved shear stress of the S phase layers were higher than that of the bulk material and microstructural defects contribute up to 83.17 MPa on that. On course of the micro-pillar compression, the S phase layers show catastrophic cleavage type brittle fracture in contract of progressive ductile fracture of the bulk material.

Nanoindentation is a technique broadly established and practiced for material characterization, however, the experimental nanoindentation is very complex and is highly susceptible to several factors. If issues such as initial penetration, thermal drift, instrument compliance, etc. have not been correctly handled, the result could be incorrect. The purpose of this study is to employ the nanoindentation technique for measuring the material characteristics such as the elastic and plastic deformation of zirconia ceramic material using the simulation method. The nanoindentation simulation model is developed based on Berkovich indenter using ABAQUS 6.14 software. The study starts with the modelling of the sample and the indenter. Four materials are considered for the sample, copper, iron, ceramic similar to glass and ceramic similar to metal films and finally Y-TZP ceramic. Total indenter displacement of 200 nm, 550 nm or 1000 nm was imposed, and then unloaded and taken back to the initial position. The result on the deformation response of the sample and the load–displacement curve is obtained from the nanoindentation simulated model. Furthermore, the results were compared with published journals for validation purposes. The model successfully obtained the same load–displacement curve as obtained by the researchers. As the sample models are successfully varified, the result obtained for Y-TZP ceramic is valid as well. In conclusion, this study managed to develop the nanoindentation simulation technique using Berkovich indenter to measure and study in-depth the material characterization of Y-TZP ceramic which are used for prosthetic restorations.

Issues in friction stir spot welding focus mainly on the mechanical characteristic affected by its Hardness. This Hardness must be maintained by evenly temperature distribution in weld zones during welding. The process parameters are mainly responsible for the development of the hardness of the friction stir spot weld. This study presented the hardness evaluations on the friction stir spot weld via the Hardness-Vickers test and analysis of the temperature distribution in the weld zones via the finite element method. The workpiece samples used in this study were Aluminium alloy 5052-H112 with a thickness of 2 millimeters in the lap-shear mode based on 3 main parameters at low and high levels of parameters configuration. The results obtained via the Hardness-Vickers tests exhibited a value of 42-HV located in the middle of the spot-weld center using a low-level parameters configuration. This value increased to 64-HV around the vicinity of the keyhole. And then the value decreased to 53-HV outside the keyhole, about 6 millimeters from the spot-weld center. Using high-level parameter configuration, the Hardness-Vickers value increased to 61-HV in the middle of the spot-weld center. The value then increased to 76-HV in the vicinity of the keyhole. Furthermore, the value decreased at 60-HV outside the keyhole, which ca 6 millimeters away from the spot-weld center. The temperature distribution of the weld zones achieved 480 oC in the vicinity of the keyhole using the low-level parameter configuration. Slowly, the temperature declined to 380 oC at 6 mm away from the friction spot-weld center in the HAZ. Using the high-level parameters configuration, the temperature distribution reached 540 oC in SZ, and slowly reduced to 425 oC in HAZ. Based on the results, it was found that by using high-level parameters configuration the hardness of the friction stirs spot weld exhibited better Hardness-Vickers value and evenly temperature distribution in the weld zones.

A low-temperature hybrid gas diffusion of thermochemical heat treatment process at 475 degrees C for 12 h was employed to treat the surface of medical grade 316LVM austenitic stainless steel that formed S phase layer. In this study, cross-sectional nanoscratch tests were performed to evaluate the response and changes in tribological characteristics of such S phase layer for load ranges of 10-50 mN. The nanoscratch of the bulk as well as S phase layer was examined using scanning electron microscopy and surface profilometer after nanoscratch tests. The experimental results demonstrated that there was no delamination across the interface for all applied normal loads. Cracks propagation was observed at the top of a scratch groove near the top surface showing the brittle fracture of the S phase layer. Plastic flow from scratching significantly improved for the heat-treated layer compared to the bulk metal. The amount of CH4 content during surface treatment also influenced the wear resistance coefficient of the S phase layer.

The incorporation of carbon and nitrogen elements concurrently during low-temperature gas diffusion process on the austenitic stainless steel surface leads to the formation of S phase layer. However, findings on the characterization studies of gas diffusion hybrid S phase layer are still unprecedented. This study examines the effect of treatment time on the S phase layer forming behavior of AISI 316LVM (ASTM F138) stainless steel through low-temperature hybrid gas diffusion process. The hybrid heat treatment process performed at 475 °C, with the gas composition of N2, CH4 and NH3 at 10%, 10% and 80% respectively. The variation of treatment time tested from 3 to 18 h. The outcome demonstrates the treatment time proportionally influence the expanded layer thickness. However, when the duration of treatment exceeds 15 h, the surface quality of the S phase layer decreases due to the possible high residual stress that causes the layer to crack. There are no traces of chromium precipitates at 18 h of treatment time which indicates the duration of heat treatment does not influence the formation of the precipitate. Thus, the treatment time plays significant roles in the development of the hybrid S phase layer other than heat treatment temperature and gas composition for the hybrid gas diffusion process.

This paper presents the performance of three-dimensional Puck failure criteria emphasising on the gradual degradation law to predict the structural responses, as well as the onset and propagation of failure due to different interface modelling technique. The proposed damage model is performed using Abaqus explicit analysis. Four different cohesive models are analysed using three-dimensional finite element model based on low-velocity impact loading. The structural responses are compared with experimental data taken from literature to measure the performance of such damage model. It is found out that the model adopted here responses well with test curves and demonstrates the high capability of predicting the damage in the direction of in-plane as well as out-of-plane in a composite laminate. The simplified model using combination of tie-cohesive layer technique demonstrated the balance performance between the quality of the result as well as calculation time.

Turning is one of the conventional material removal processes and it is essential in today’s manufacturing industry. Nowadays, titanium alloys are favorable and widely used material due to its superior material properties. However, despite having superior material properties, titanium alloys are hard to machine and will result in shortened tool life. Hence it is important to determine the suitable turning parameter to prolong tool life with best surface roughness. This work focused on investigating the influence of machining parameters in machining titanium alloy under dry cutting condition. The influence of three machining parameters namely feeds rate, cutting speed and depth of cut are investigated using a full factorial design. Surface roughness and tool wear were the responses variables. Analysis of variance was utilized in the analysis to determine their contribution ratio and interaction on each response. The experimental results showed that the feed rate was identified as the most influential factor on surface roughness and tool wear at 54% and 33% contribution ratio respectively. Further multi-response objective optimization was adopted through the desirability function analysis method. For the titanium turning operation, the minimal surface roughness and tool wear were significantly obtained through the specified machining parameters at cutting speed of 44 m/min, feed rate of 0.05 mm/rev and depth of cut of 0.5 mm. The results showed that the single objective response successfully converted into multi-objective optimization through the desirability function analysis method.

This study investigates the characteristics of flame propagation in a gasoline S.I engine through a combined thermodynamic and optical approach. Two high-speed CMOS camera were used together with an endoscopic system to visualize the early flame in a spark-ignited engine. An unintensified high-speed (20 kHz) imaging of early flame kernel formation and turbulent flame propagation for hundreds of consecutive combustion cycles has been analysed and compared to pressure-derived heat release rates and mass fraction burn (MFB) profiles. At very low light levels, the patterned read-out noise on the detector becomes significant. Filtering in the Fourier domain was effective in suppressing this noise component to acceptable levels. In this paper, a previously-developed algorithm with automatic dynamic thresholding was used to separately detect spark ignition and flame kernel in the image sequences. The detected flame boundary was post-processed to compute basic flame characteristics such as flame area and turbulent flame speed based on spherical flame propagation assumption. Ignition and flame propagation are compared for fast combustion cycles and slow combustion cycles based on the optical flame speed and crank angle resolved mass fraction burned profile. The good burn (fast) cycles show higher spark stretch caused by local tumble flow-field, greater early flame growth rate, and nearly spherical flame propagation at the center of combustion chamber. In contrast, the poor (slow) cycles show slower flame kernel growth rate, and mostly asymmetric flame propagation near the spark-plug and pent-roof of the combustion chamber. The analysis shows a good correlation between thermodynamics and optical data.

Composites suffer a degradation of structural stiffness due to various types of impact loading resulting in damage which is difficult to observe from the surface of the structure. The paper deals with the finite element model (FEM) to study the possible modelling procedures in low-velocity impact (LVI) and failure mechanism of carbon fiber reinforced polymer (CFRP) composite laminate of CCF300/epoxy and its structural responses. In finite element calculation, a proposed three-dimensional progressive damage model is used to determine the intralaminar damage, whereas the cohesive contact formulation is employed to analyse the interlaminar damage. The failure model performances are validated and verified based on different boundary conditions while maintaining the impact energy. Through simulation, the variation in boundary conditions significantly changes the structural responses and energy absorption of the laminates. It is hoped this study will be a great tool in determining the different composite impact scenarios.