Manufacturing Engineering
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Item Parameter Optimization of Single Point Incremental Forming on Al6063A Sheet(Addis Ababa University, 2024-06) Bayissa Bedada; Mesfin Gizaw (PhD)The incremental sheet forming (ISF) method is regarded as a practical solution for forming a variety of sophisticated and small-batch sheet components. Surface finish is an important aspect of incremental sheet forming (ISF), and it is influenced by a number of process variables such as tool diameter, step depth (vertical depth increment), spindle speed, and feed rate. As a result, for incremental sheet forming, process parameter optimization is chosen to produce products with an excellent surface finish and with no defects. Hence, the optimization's goal is to produce a good surface-finish product using a single point incremental forming process without fracture. In order to achieve this, aluminum alloy (Al6063A) is studied using ABAQUS simulation technique and experimental analysis. Due to its moderate strength to weight ratio and easy of formability, the aluminum alloy Al6063A is widely used in automotive and part profiles for architectural applications. The Taguchi technique of DOE with ANOVA and L9 orthogonal array is designed to identify the rank, Percentage contribution and optimum values of process parameters in ISF (incremental sheet forming) to reduce the surface roughness. The results of ANOVA revealed that Tool diameter has greater contributions (88.94%) followed by feed rate (7.44 %), Spindle Speed (3.4%), Step depth 0.22% respectively. The stress value of experiment 7 (1216 MPA) which is a good surface finish product of all. The predicted optimum value for the surface roughness is 0.43μm and the confirmation experiments was conducted thrice and the value of surface roughness found to be 0.37μm which is at 95% confidence level. The confirmation result shows the recommended forming process parameter values to surface roughness based on Taguchi analysis were precise and fitted to the optimum values.Item Enhancing Abrasive Grinding Performance of Al -7075 Alloy Through Carburizing(Addis Ababa University, 2024-06) Bersisa Tufa; Desalegn Wogasso(PhD)As compared to other metals aluminums are difficult to work on grinding operation because of its ductility and low melting point. This thesis paper deals with the validation and optimization of enhancement of grinding machinability of aluminum alloy by one of precipitation hardening process called carburization, which is mainly about the ingression of carbon molecules to the aluminum alloy for formation of aluminum carbide surface layer. The machinability is measured and characterized by the material removal rate and roughness by considering the influence of machining parameters and material properties such as wheel speed (1800, 2000RPM), work hardness (88, 109, 171VHN), cutting depth (0.02, 0.04,0.06mm) and surface depth (0mm, 1mm, 2mm). The roughness measurement was carried out on digital roughness tester SURFTEST SJ-310 and the material removal rate is calculated. The roughness and material removal rate results are then gathered and analyzed using Minitab 19 commercial software to determine the rank and percentage of the effects and interaction of machining parameters and material properties with the roughness and material removal rate were analyzed. According to the analysis using the signal-to-noise ratio (S/N ratio) to identify the control factor settings that minimize the variability caused by the noise factors on the material removal rate are surface depth, work hardness, wheel speed and cutting depth ranked respectively with highest delta value difference and for surface roughness work hardness, wheel speed and cutting depth and surface depth, ranked respectively. By using grey relational analysis, the optimum machining parameters also set on cutting speed at 2,000RPM, material hardness at 171 VHN, Surface Depth 2mm from surface and depth of cut at 0.04mm to have higher material removal rate and minimum roughness measurement 26.092 mm3/sec and 1.208μm Ra achieved respectively. The experimental and analysis result shows that the properties improved by the solution heat treatment or carburization have a high positive impact on the grindability of aluminum, by recommending identification research of associated mechanical property changes it is evaluated in this research as a better manufacturing process for reduction of clogging on the wheel and frequent dressing requirements.Item Investigation of Physical, Mechanical, and Thermal Properties on Hybrid Carbon Nanotubes with Flax Fibers and Eggshell Composites for Disk Brake Pad Application(Addis Ababa University, 2024-06) Iliyas Ketsela; Mesfin Gizaw (PhD)Friaction materials are used to make brake pads, and these materials are forced up against the braking rotor, to slow down or stop a vehicle. Now days Metallic and semi-metallic compounds have replaced asbestos-based in commercial brake pads. Consequently, problems such as; excessive wear rates, noises, and vibration persist. Therefore, this research is required to improve the current performance of the brake pads in terms of wear rate, and coefficient of friction (COF). Naturally extracted fibers and fillers (flax fibers and eggshells) are required as a component for structural strength and polyester resin as a binding material in brake pad applications to overcome such problems. As a result, Hybrid nanomaterial constituents like (MWCNTs) and additional friction modifier (Al2O3) composites can replace asbestos-based ones which can cause lung cancer. Also, to guarantee long-term performance and to reduce environmental pollution, a higher level of care must be taken in the selection of good friction materials, to convert these materials a literature review is conducted on natural fibers and friction modifiers to obstacle this problem Also, the effects of particle size and volume fraction distributions are discussed the methodology section has the design of experiments, material preparation, and testing procedures for formulated materials. Nine samples were created for the comparison of (flax fiber, eggshell, MWCNTs, and Al2O3) reinforced with polyester resin composite in detail with variable fractions using the compression molding technique. The physical, mechanical, and thermal properties of the samples are evaluated and analyzed using the FEM analysis technique. Finally, The well-dispersed Flax fiber, eggshell, alumina particles, and polyester resin of sample SE with a 6wt.%, 21wt.%, 3wt.%, 8wt.%, and 62wt.% respectively created a larger contact surface. Consequently, the composite's surface hardness rose, reducing the specific wear rate of the brake linings and raising the coefficient of friction, also with improved absorption capabilities.Item Assessment, Evaluation and Enhancement of Operational Performance of Metal Fabrication Factory for Cargo Body, Van Body and Trailer Fabrication Through Lean Practice (A Case of KAKI PLC)(Addis Ababa University, 2024-06) Lewutie Edmealem; Desalegn Wogaso (PhD)This study aims at investigating on assessment, evaluation and enhancement of the operational performance of metal fabrication factory for cargo body, van body and trailer fabrication by using lean practice at case company of Kaki PLC which is located at Addis Ababa around Sebeta (alemgena). The factory has a huge capacity but has a low operational performance and a large waste. The assessment and evaluation are performed on selected three major product types of the case company based on their demand volume and product nature. Using value stream mapping assessment of the current fabrication process of each product and identify the major waste of the company which are waiting time, defect, unnecessary movement and inventory and large setup time. During the investigation the data are collected by direct observation and using stop watch and the company document is also referred. Then by using cause and effect diagram, further analysis is conducted to identify the root causes for the bottlenecks which is found the poor layout of the factory. The research work is proceeded to develop the solution standing from the assessment and evaluation result. The developed solution is designing new product lay out for three product mix namely NPR van, FSR cargo and trailer by using systematic layout planning, future value stream mapping as a model. In addition to product layout applying an oven in painting process and using simple press machine is the axle preparation in trailer fabrication process. Finally, the solution bring a significant operational performance improvement of the fabrication process of each product mix. The process efficiency of NPR van is improved by 25.4%, the process efficiency of FSR cargo improved by 31.9% and the process efficiency of trailer if improved by 32.42%. To conclude this research work is conducted the assessment and evaluation process by using value stream mapping and cause and effect diagram and also using questioner. Then design new product layout for the factory using systematic layout planning. That will bring a valuable operational performance improvement.Item Predicting Sand Casting Defects using a Data-Driven Supervised Machine Learning Approach: A Case Study of Akaki Basic Metals Industry(Addis Ababa University, 2024-06) Demewez Demeke; Mesfin Gizaw (PhD); Henok Zewdu (Mr.) Co-AdvisorThis research investigates supervised machine learning to predict sand casting defects and its severity, aiming to enhance product quality and reduce costs in metal casting. Effective quality control is essential for maintaining structural integrity, energy efficiency, and environmental sustainability. Defects such as porosities, inclusions, shrinkages, cracks, and blowholes increase energy consumption and environmental impact. Rework, scrap, and product rejection due to defects gain significant production costs and reduce profitability. The study identifies and mitigates defects in bronze, steel, and cast iron products weighing from 15 kg to 16,800 kg. Using a dataset of 1001 samples with 37 features, it evaluates machine learning algorithms: Decision Tree, K-Nearest Neighbors, Gradient Boosting, Random Forest, XGBoost, SVC, Ensemble methods, and NN. XGBoost is most effective, with 87% accuracy in defect type prediction and 94% in severity classification. Specifically, the ensemble XGBoost model achieves 93.07% accuracy in defect severity and 86.67% in defect types. The Neural Network also performs well but shows signs of overfitting due to the small dataset. Severity is classified into severe, minor, and moderate; defect types include non-defect, porosity, shrinkage, and others (misrun, blowhole inclusion, crack, and metal penetration). User-friendly tools based on these models are accessible via URLs (https://scdp-dt.streamlit.app/ and https://scdp-severity.streamlit.app/), aiding defect assessment and decision-making in sand casting. In conclusion, machine learning enhances operational efficiency and product quality while promoting sustainability. It also reduces energy use, minimizes rework costs, and enhances quality control, aligning with global environmental goals.Item Analysis and minimization of sand- cast defects for casting aluminum A356 alloy through Pro CAST simulation(2024-06) Tibebu Mulatu; Desalegn Wogaso (PhD)In this research analysis of the existing casting process through scientific tools at the case company, Selam Children Village Tsehayi Roschili Industrial and Agricultural Engineering in Addis Ababa Ethiopia is conducted. Inside foundry shop of case company defect becomes the most series problem, which makes the product to reject due to certain quality and bad surface finish. From different products, pulley product are selected using failure mode analysis and further analysis is conducted on it. In this investigation, various casting process parameters such as mold initial temperature, molten metal flow rate, newly designed model with three different scenario and pouring temperature considered. Then simulation are conducted according to Taguchi L18 orthogonal array. 3D model for the product designed on solid work 2022 and imported to Pro-CAST software for simulation. Different real time parameters given as input and various simulation carried out. From meticulous simulation, it is achieved a remarkable 100 percent void-free casting process. This outcome ensures structural integrity and enhances the reliability of the final components. Hotspot occurrences also reduced from an initial 35 points to an impressive 14 points. This optimization mitigates localized stress concentrations and enhances overall part performance. On further investigation, total volumetric of shrinkage porosity is also successful decreased from 5.67% to 4.77%. This improvement has direct impact on material density and mechanical properties of products. Additionally total defect distance on the ISO surface of product was significantly minimized from 55.62 cm to 25.59 cm. Finally, from selected trial according to Taguchi method and grey relational analysis with Minitab 21.2 software 52.22% total defect minimization is achieved. Depending on the simulation result, selected pulley part fabricated inside foundry shop from aluminum A356 metals. Comparison between previous fabricated products with ought casting simulation software and new product that made after simulation result done and result of sample tested under scanning electron microscope machine presented.Item Optimization of Process Parameters of Friction Welding of Brass – Steel Metals(Addis Ababa University, 2024) Mulugeta Mucheye; Mesfin Gizaw (PhD)Brass metal has a high strength, strong corrosion resistance, and high electrical and thermal conductivity, making it popular engineering materials in industry and electromechanical works for building water supply systems. They have a good appearance and are easily formed, but fusion welding of brass with other brass and with metals like black steel is a challenging process. The zinc evaporation during the welding process is the primary issue with these alloys in fusion welding. After the welding process, the metal is permeable after welding. Furthermore, because evaporation reduces the amount of zinc in the alloy, the material made of brass lacks its typical chemical and physical characteristics. These issues are not being sufficiently resolved when it comes to fusion welding brass metals; Investigators were instructed to use novel techniques. These issues appear to be resolved by friction welding, one of the more recent techniques created. These researches describes optimization of process parameters and give result of rotational speed, friction time and material size of Taguchi design experimental investigation by using direct drive friction welding (DDFW) methods for welding of brass with black steel rod on set up of Lathe machine with the help GRA. Finally on this research the optimization process parameter of 1200rpm rotational speed, 30sec of friction time and 15 mm diameter material size with quenching cooling system was attained. In addition of state optimizations from a Taguchi experimental process result it shows as cooling system and material size was more influenced as best performance whereas rotational speed is next to cooling system and material size influenced welding performance but from Taguchi experimental welding time is less effect or almost no effect in welding performance.Item Investigation of Properties of Hybrid Glass-Sisal Fibers Reinforced Polyester with Al2O3 Filler Composite for Wind Turbine Applications(Addis Ababa University, 2024-06) Azeb Teklemariam; Desalegn Wogaso (PhD)The purpose of this study is to examine and characterization of the mechanical and physical characteristics of glass reinforced with sisal fiber that has been filled with Al2O3. Due to their exceptional performance and customized qualities, fiber reinforced materials are extensively utilized in a wide range of engineering applications. These days, particular fillers and additives are added to composite materials to lower material prices, increase and adjust the composites' quality to some extent, and in certain situations, improve the product's performance and capacity to be processed. The creation, characterization, and examination of the mechanical and physical characteristics of a polyester hybrid composite reinforced with glass-sisal fibers and Al2O3 is the goal of this research. It also aims to evaluate the hybrid composite suitability for wind turbine blade material applications. In the present work Aluminum Oxide (Al2O3) with different weight fractions (0, 2, 4, 6, 8 and 10wt %) were studied .The HFRC samples are prepared using the hand lay-up method followed by light compression loading. The experimental results shows that the addition of Al2O3 improved the mechanical properties of the HFRC, with the optimal composition being 6% Al2O3, 22% glass fiber, 12% sisal fiber, and 60% polyester. This composition showed the highest tensile strength (93.66 MPa), flexural strength (176.29 MPa), and impact strength (22.17 kJ/m²). It also had the lowest water absorption (3.26%) and density (1.22 g/cm³).The experimental results were also analyzed using ANSYS software. The ANSYS analysis showed that the optimal HFRC composition could withstand the static loads that wind turbine blades are subjected to. Based on the experimental and ANSYS results, the HFRC with 6% Al2O3, 22% glass fiber, 12% sisal fiber, and 60% polyester has the potential to be used as an alternative material for wind turbine blades material.Item Investigating The Effect of Coating Material, Thickness and Joint Configuration on Mechanical Property of Welded Mild Steel(Addis Ababa University, 2024-05) Samrawit Mehari; Mesfin Gizaw (PhD)The influence of coating material, thickness and joint configuration on mechanical property of SMAW welded joint for SAE1020 mild steel was assessed in this study. The coating material has 2 levels zinc and copper with 4 different coating thickness levels 85-95, 100-110, 115-125 and 130-140 with 2 welding configuration butt and lap joint. The design of experiment (DOE) was done using taguchi orthogonal array then for the mixed level taguchi design array L16 (4^1 2^2) experimental runs were conducted. During welding coated mild steel there is a trapping of zinc and copper in molten pool of steel causing mechanical property reduction and welding defect on microstructural analysis. This work investigates mechanical properties namely hardness, tensile and flexural strength of welded joint under different coating material, thickness and joint configuration. In addition to this the micro structure analysis of welding zone of uncoated and coated with 85-95 and 130-140 coating thickness was analyzed using an optical microscope with 100* magnification. The result of the investigation indicates that significant decrease in hardness with increase in coating thickness. From the experiment with increasing the coating thickness from 85 micro meter to130 micro meter the hardness value decrease with 15.55% and in joint configuration butt joint configuration reduced with 1.605% compared to lap joint. The tensile strength and flexural strength is lower with 9.21% and 8.9% with increasing coating thickness from 85 micro meter to130 micro meter. The optimal parameter set are 85-95 coating thickness, copper coating material and butt joint configuration this was analyzed using grey relation analysis. The signal-to-noise ratio rank conclude that Varying the coating thickness found to cause more significant changes on mechanical properties than varying coating material and joint configuration. The micro structural investigation of uncoated and coated mild steel was done using an optical microscope. The result of the investigation indicates that a weld ing defect was seen in microstructure of zinc coated mild steel as coating thickness increase. in addition to this in the fusion zone of the welding there is a small increase in grain size then this will reduce the strength of material. Finally uncoated mild steel shows better mechanical property than the coated one but for some critical reasons if coated mild steel is used this work recommend to use a mild steel with coating thickness of 85-95 for safe and quality structural construction.Item Analysis and Optimization of Process Parameters for Friction Stir Welding of Dissimilar Aluminum 6061 and Commercial Pure Titanium Metal(Addis Ababa University, 2024-06) Dawit Gebeyehu; Henok Zewdu (Mr.)Friction stir welding (FSW) is a solid-state weld process were invented in 1991 that broadly used by industries and preferred rather than other weld process due to its capability to weld similar and dissimilar materials under high quality. FSW offers a number of advantages over other weld methods, including being automatic, suitable for most materials, able to be performed in any position, having minimal distortion, and not requiring filler or shielding gas., can be employed under water, and environmentally friendly. In this research, a joint between 6061 aluminium alloy and commercially pure titanium Gr-1 was butt welded by using friction stir welding. at a speed of rotation (1100, 1400, 1600) rpm , a transfer (welding) speed at (50, 60, 80) mm×min-1, a tool pin profile (cylindrical, square, conical), and a dwell time of (5, 10, 15) sec. welded material microstructure and mechanical properties were assessed using the tensile test, the hardness test, and optical microscopy (OM), respectively. Tensile testing, hardness testing, and optical microscopy (OM) were used, respectively; to assess the mechanical characteristics and interfacial microstructure. The numbers of welding experiments were determined using both of the Taguchi and Grey relation analysis approaches. The strength of friction welded dissimilar joints and effect of parameters were analysed using ANOVA (analysis of variance) on Minitab 20 software. After the materials are welded successfully, their tensile strength and hardness were evaluated at room temperature. According to the results, the cylindrical pin profile, 1100-rpm rotational speed, 80 mm/min transverse speed and 15 sec dwell time are the optimal conditions for combining these different joints. In the stir zone, strengthening precipitates were distributed finely and uniformly.Item Development and Analysis of Composite Material using Honey comb Orientation of Bamboo Fiber and Epoxy Composite for Prosthetic Socket Application(Addis Ababa University, 2023-06) Yelshaday Regasa; Henok Zewdu (Mr.)This thesis focuses on utilizing honeycomb fiber orientation techniques to develop a prosthetic socket with enhanced mechanical properties at a lower cost. The current challenges in prosthesis production include the high cost of fibers and the inadequate strength of the composite fiber. To address these issues, this research explores the tensile characteristics, water absorption and impact strength of bamboo fiber reinforced epoxy composites with an optimized material mix ratio design. The Finite Element Method for Numerical Analysis is employed to predict the desired properties of the composite material. Using numerical analysis software solutions, the stacking sequence is determined based on established standards. The newly designed prosthetic socket is evaluated for improved qualities, such as stance stability, speed control, multiple speed adoption, shock absorption, and reduced weight throughout the entire cycle. By closely emulating nature, the study investigated the relationship between woven fiber orientations and honeycomb pattern fiber orientations. It examines the optimal material mix ratio design, as well as the best fiber orientation pattern and angle of fiber orientations. The obtained results include a tensile strength of 53.4 MPa, compressive strength of 57.6 MPa, flexural strength of 64.55 MPa, impact strength of 13.02 J/cm2, and water absorption rate of 2.31%. The findings of this research aim to contribute to the development of low-cost, high-strength composite materials for prosthetic sockets. Prosthetic socket designers can utilize these recommendations to improve the overall performance and durability of prostheses.Item Integration of Rice-Husk Filler on Physico-Mechanical Characteristics of Hybrid Sisal and Glass Fiber Reinforced Epoxy Composites for Neck Brace.(Addis Ababa University, 2023-10) Kiros Gebreegziabher; Kiros Gebreegziabher (PhD)Despite the fact that composites have better corrosion resistance, light weight, good consolidation, and are available in large sheet sizes and wide range of thicknesses, physical and mechanical properties still need to be examined and improved to meet the needs of a wide range of applications. At the time of operation of composites some mechanical properties are significantly influenced by the presence of voids. The voids are the locations where stress is concentrated which accelerates the failure process leading to early and catastrophic failure of the composite. Different investigation also described important properties, including water resistance, weathering, surface smoothness, stiffness, dimensional stability, machinability, shrinkage, voids and temperature resistance, can all be improved through the proper use of fillers. The objective of this research work is to develop and characterize the physico- mechanical properties of hybrid sisal and glass fiber with rice husk filler epoxy composite. Hand lay-up fabrication technique will be used to prepare the specimen with 20% fiber and 0%, 2%, 4%, 6% and 8% rice husk filler which are then compressed using a compression molding machine. compressive strength (ASTM D3039), flexural strength (ASTM D790), impact energy tests (ASTM D256) and physical properties such as density (ASTM D792) and water absorption (ASTM D570) was conducted using ASTM standard. From the experiment executed, it is observed the flexural strength, water absorption and void content improved with addition of filler. However, compression and impact strengths slightly reduced. The design of composite structures was then evaluated using Ansys ACP analysis in order to utilize it for the required application. In compared to the others, the hybrid sisal and glass fiber reinforced epoxy composites with 2% and 4% rice husk filler exhibit outstanding performance.Item Fabrication, Characterization and Simulation of Flax-Sisal Fiber Reinforced Epoxy Hybrid Composite for Prosthetic Socket(Addis Ababa University, 2021-07) Luna Geo; Desalegn Wogaso (PhD)Prosthetic limb socket is the major part of a prosthetic leg and arm. It provides comfortable connection, transfers the load, ensures stability between the residual limb and the device. This study aims to investigate tensile, flexural, compression, impact and water absorption properties of Flax-Sisal Fiber Reinforced Epoxy Hybrid Composite. The research also targets to explore its application for prosthetic socket. Hand-layup method was utilized to fabricate thirteen composite specimens having 30mm fiber length and fiber-matrix volume percentages of 40-60, 30-70, and 35-65 according to ASTM standards. Eight composite specimens were treated with 5% NaOH. Comparing the thirteen composites, the result showed the treated composite with F25%-S15%-E60% had superior mechanical and physical properties with tensile strength of 68.40MPa, flexural strength of 145.7MPa, compression strength of 45.64MPa, impact energy of 10.83J and water absorption percentage of 3.66%. In addition, using ANSYS 2020, Prosthetic socket was modeled and loading conditions were applied on composition F25%-S15%-E60% from this, maximum von missed stress of 2.214MPa and deformation of 0.0064mm was obtained. Based on the results and analysis, the selected Flax-Sisal-Epoxy hybrid composite has the potential to be further developed as an alternative material of prosthetic socket.Item Optimization of Machining Parameters in Drilling Hybrid Sisal – Cotton Fiber Reinforced Polyester Composite(Addis Ababa University, 2021-07) Nurhusien Hassen; Desalegn Wogaso (PhD)As compared to metals, composite materials machining is a challenge because the cutting tool needs to move through the matrix and fiber alternately, which have various properties. The objective of this work is to optimize the machining parameters in drilling hybrid sisal-cotton fiber reinforced polyester composite (HSCFRPC) to reduce the hole roundness error and surface roughness using Taguchi's method. The influence of machining parameters such as spindle speed, drill diameter, and feed rate on the surface roughness and roundness error of HSCFRPC during the drilling process on the vertical CNC milling machine have been analyzed using the methods of Taguchi’s design of experiment. A series of experiments based on 𝐿16 orthogonal arrays were established with different feed rates (10, 15, 20, 25 mm/min), spindle speeds (600, 900, 1200, 1600rpm), and drill diameter (6, 7, 8, 10mm). The measurement of roundness error and surface roughness have been carried out using ABC digital caliper and Zeta 20 profilometer respectively. The experimental values are gathered and analyzed using the MINITAB 19 commercial software program. To create a connection between the chosen drilling parameters and the quality attributes of the drilled holes, linear regression equations have been established. Signal to noise (S/N) ratio analysis and analysis of variance (ANOVA) were performed to identify the rank, percentage contribution and optimum values of these machining parameters such as spindle speed, drill diameter, and feed rate to reduce the roundness error and surface roughness. Based on the analysis the best combination of the optimum machining parameter values (1600rpm, 25 mm/min, and 6mm) are selected to reduce both roundness error and surface roughness of the composite. Finally, verification of the recommended machining parameters have been achieved and the values of roundness error and surface roughness obtained are 0.1mm and 64.8μm Ra respectively, which satisfies the objective of lowest roundness error and surface roughness. The verification result shows that the recommended machining parameter values to reduce roundness error and surface roughness based on Taguchi’s analysis were precise and fitted to the optimum values.Item Design, Analysis, and Performance evaluation of Cellular Manufacturing System for Conventional Manufacturing Factory : A case of Addis Machine Spare Parts Manufacturing Industry(Addis Ababa University, 2023-10) Paulos Girma; Desalegn Wogaso (PhD)This thesis assessed the performance problems at the Addis Machine Spare Part Conventional Manufacturing Factory (ASPCMF) under the Ethio Engineering Group (EEG). The case factory has been faced a number of manufacturing system challneges according to the data collected from the operations department of the factory. After the analysis performed based on the existing layout evaluation, problems identified were higher idle time of machines and longer travel distances of parts that lead to lower performance. From the study of the previous performance survey done in 2021, the overall performance recorded was 38.03%. After analyzed the existing layout performance using FlexSim software 31.8% performance recorded. This lower performance identified necessitates the requirement to design a new layout and analyzed the performance based on machine utilization and travel distance of parts. Therefore, the purpose to assess the existing manufacturing system based on machine utilization and travel distance of parts led to design, analysis, and evaluate the performance by proposing a cellular manufacturing system. In the design work a 22 part family was created using the Optiz coding system, which was based on hybrid coding system. A method of machine grouping in an incident matrix was developed to form 20 cells. The rank Order clustering algorithm was used to cluster parts and machines within the cell. This minimized 45 duplicated machines in bottlenecks, while increasing the machine utilization of 43 machines in the cluster formed. The designed cell in the cluster was evaluated through grouping efficacy (GE) of parts allotted in cells to achieve optimal effectiveness in cell utilization which was 91% cell efficiency. The CRAFT algorithm used to identify the part flow within the department and the effectiveness of machine arrangement analyzed based on part travel distance that was reduced into 1,425 m from the existing layout 2,236.10 m which increased floor space available so that, an improved layout was proposed. The analysis was performed to evaluate the designed cell, the performance simulation shows that 88.37% of the proposed cellular layout demonstrates significant enhancemenent compared to the existing layout, which was only 31.8 %. The performance simulation was conducted using FlexSim software. Finally,the individual machine utilization percentage was determined and compared between the proposed layout and the existing layout.Item Development and Characterization of the Mechanical Properties of Al2024 alloy Reinforced with SiO2 and Bagasse Ash Composite(Addis Ababa University, 2021-07) Senait Menbere; Shantha Kumar (Assoc. Prof.); Henok Zewdu (Mr.) Co-AdvisorSilica sand and sugarcane bagasse-ash (BA) are used as reinforcement for Aluminum alloy (Al2024) based hybrid composites. The Aluminum matrix hybrid composites were fabricated by stir cast at 750°C. The reinforcement weighted by volume fraction ratio 5%, 10% & 15% of matrix and reinforcements, <63μm particle size, stirring the slurry at 650rpm for 10 minutes were the parameters used for the fabrications of aluminum matrix hybrid composites. The development and experimental findings of aluminum matrix hybrid composite mechanical properties were performed by adding silica sand and bagasse ash as reinforcement with different composition proportions. The addition of this reinforcement with nine compositions proportion, in range of 5-15% with 5% interval. For a maximum improvement of the material properties, solution heat-treatment (T3-temper) was performed. The effects of the reinforcements have been examined through different mechanical tests. These tests were implemented using Rockwell hardness indenter, bending, and tensile strength by universal testing machines, and optical microscopy was used to characterize the microstructure of composite specimens. Specimens were prepared as per the ASTM E18-15 for Rockwell hardness and E8M/16a for tensile, E290 for bending test specimen standards. The samples are modeled using Solid works 2017, and its analysis was performed by ANSYS 19.2. The analysis result showed a higher effect of the reinforcing bagasse-ash with different compositions in aluminum matrix reinforced composites. Enhanced mechanical properties have been achieved in the 3rd case compared to the 1st and the 2nd BA & SiO2 combination. It shows that the selection of BA & SiO2 as reinforcement has one of the essential criteria for fabricating aluminum matrix reinforced composites. The result showed that the hardness of the composites increased slightly with an increase in bagasse ash content with a maximum increment of 15%. The maximum mechanical properties were observed for the Al2024 reinforced composite at 5% bagasse ash and10% silicon dioxide compositions. Tensile strength increased to a maximum value of 560MPa, and also flexural strength increased to a maximum value of 482MPa at 10% SiO2 and 5% bagasse ash compositions. Hybrid composite superior properties are observed in tensile strength, flexural strength, and hardness than single reinforced Al2024/ SiO2 metal matrix composites. Also, for the application of fuselage-skin panels, the reinforced and heat-treated Al2024/SiO2/BA-T3 improved a better stress resistance performance than the unreinforced Al2024- T3/T351 through FEA.Item Fabrication And Evaluation of Mechanical Properties of The Hybrid Coffee Husk and Enset Fiber-Epoxy Reinforced Composites(Addis Ababa University, 2023-06) Shambel Dibaba; Desalegn Wogaso (PhD)in modern times there is a growing concern about replacing polluting and not recyclable synthetic fibers, as well as rare wooden fibers, with sustainable lignocellulose fibers derived from agricultural leftovers for reinforcement bio-composites. Currently in Ethiopia, the accident rate of vehicles on the road is increasing. Along with that, Vehicle security is a significant topic of study to safeguard. not only structures but also occupants in the event of a crash. In the other side the fast increase of population and development of cities required demand for transport, hence to full fill the demand recently the vehicles are imported in large amounts at the same time which requires accessory’s for replacement of their parts, so the front bumper of those vehicle is the most parts demanded due to it is the most exposed part during crash. The Enset fiber and coffee husk were collected from Ethiopia's Southern Nations, Nationalities, and People's Region (SNNPR) Gedeo zone, Yirgachefe district. Sun-dried Eset and coffee husk were treated with a 5% sodium hydroxide mixture to remove more cellulose, hemicellulose, lignin, and additional fiber chunks to increase binding and facial shear strength. Following that, Enset-coffee husk fibers reinforced hybrid composite was created utilizing a hand layup method on the 40-60%, 30-70%, and 20-80% fiber weight percentages of matrix weight to total fiber volume. Tensile, compressive, its impact, flexural, and absorbance of water tests were then performed to determine which constituent of the composite had higher strength under load. While the mechanical and physical properties of the composites were assessed, the composite C5 with E20%-CH10%-E70% possessed the best mechanical and physical properties, with a tensile strength of 43.30MPa, flexural strength of 93.38 MPa, compression strength of 21.23MPa, impact energy of 3.5J, and water absorption percentage of 3.55%. In addition, the front bumpers was modeled in ANSYS 19.2 and composite C5, yielding an optimal von missed stress of 39.119MPa and distortion of 15.09mm. According to the findings and analyses, the chosen Enset-Coffee husk-Epoxy hybrid composite might be explored subsequently as a low-speed crash replacement material for the front bumper.Item Effect Of Fiber Orientation & Volume Fraction On The Mechanical and Thermal Properties Of Bamboo Fiber Reinforced Epoxy Composite For Laptop Case Application(Addis Ababa University, 2023-03) Tigist Mesfin; Dessalegn Wogaso (PhD)Protecting one‟s laptop is an undeniable thing because of its massive personal data stocking, it being one‟s working media (tool) and its expensiveness to replace it if it got physically damaged by any means. This work aims to investigate the effect of fiber volume fraction and orientation on mechanical (tensile, flexural, and impact) strength, thermal resistance and water absorption properties of bamboo fiber reinforced epoxy composites experimentally. It aims to explore its applicability as a protective casing for personal computers. Bamboo fibers were treated with 6% NaOH for 2 hours and 1600c temperature for 3 hours. Laminates were fabricated by hand lay-up technique in a mold and cured under light pressure at room temperature followed by curing for two days. Bamboo laminates were prepared by varying three orientations (0/450, 0/300 & 0/900) of fiber and four fiber volume fractions from 20%, 30%, 40%, and 50%. Specimen preparation and testing were carried out as per ASTM standards. The highest tensile, flexural and impact strength were obtained from composite with 30% fiber 70% epoxy matrix composition at 00/900 orientation having 48.85MPa, 38.17MPa and 170.57 J/m2 respectively. The lowest water absorption percentage was obtained from treated composite with 20% fiber 80% epoxy matrix composition at 00/900 orientation having 1.71% of absorption. Evidently 30% bamboo fiber reinforced epoxy composite has very high thermal resistivity almost equal with wood, which makes it non-conductive material. Based on the results and analysis, the selected bamboo fiber -epoxy composite has the potential to be further developed as protective case for laptops.Item Optimization of process parameters in Friction Stir Welding of dissimilar aluminum alloys (AA6061–T6 and AA5052–H32)(Addis Ababa University, 2023-03) Wondu Tesfaye; Henok Zewdu (Mr.)Friction stir welding (FSW) is a solid-state welding method mostly used to join aluminum and aluminum alloys that has been used in aerospace, railway, automotive, and marine applications. This process is used for welding dissimilar aluminum alloys. Solid-state welding processes solve several problems that occur during fusion welding of Al-alloys like heat affected zone liquation cracking, porosity, and segregation. Aluminum Alloys of two different series AA5052 and AA6061 thickness of 6mm are Friction Stir welded using process parameters like tool rotational speed (900,1100,1400) rpm, transverse speed (40,50,60) mm/min, and pin profiles (cylindrical, conical, and square). This thesis aims to optimize the mechanical and metallurgical properties of the above dissimilar combination to evaluate the performance and characteristics of the welded joints. The combined Taguchi and Grey relation analysis experimental method was chosen to construct the number of welding experiments. Analysis of variance was performed to obtain the effect of the parameters on the Friction Stir welded joints strength. The plates are successfully welded, and the welded plates are tested at room temperature to examine their tensile strength and hardness. The findings indicate that the square pin profile, the rotational speed of 1400 rpm, and the transverse speed of 40 mm/min are the optimum parameters for joining these dissimilar joints. A fine and uniform distribution of strengthening precipitates was found in the stir zone.Item Process Evaluation and Performance Enhancement of Corrugated Board Fabrication. (A case of Burayu Packaging and Printing Industry)(Addis Ababa University, 2023-07) Yohannes Eshete; Getasew Ashagrie (PhD)The materials utilized, the conversion process, and other factors could all have an impact on the corrugated board performance. The objective of the thesis to quantify the mechanical strength of the corrugated board, the adhesive strength, the paper compression strength at fabrication process of investigated the pin adhesive, edge crush, box compression strength and material properties test at standardize methods. Based on the experimental result the reel size of 165,185,205,220 cm at fabrication speed on 50,65,80,95 m/min which can be used to determine varies result of compression strength exhibited at 50 m/min, and the fabricated board was the maximum, pin adhesive 356,352,351,349 Newton, edge crush 4.5,4.3,4.2,4.4 KN/m, pure box compression 112- 114 kg strength were shown. Reel size 220 cm fabricated at 80 m/min refers to the laboratory results minimum strength were performed. The Maltenfort model by correlating the measured ring crush test with the theoretical edge compression test enable to know the board strength of how much the variables degraded the strength of the combined board as of reel size 185,205,220 cm at 80 and 95 m/min during the process. The regression equation which can be used to evaluate the linear effect of the process and can be used to predict the performance of the box and enable it to enter into optimum fabricating process as well as strength improvement decisions. Boards will have better strength if they follow optimum process can be achieved by balancing and selecting the variables of fabricating speed, reel size, and material properties which helps to identify the strength of the board and evaluate the fabrication process. Overall, this study provided experimental and McKee box prediction are done for the evidence of structural performance and delamination strength of the corrugated fiber board by aligning a process through runnability.