Ethiopia Institute of Technology- Mekelle
Permanent URI for this communityhttps://repository.mu.edu.et/handle/123456789/58
Browse
3 results
Search Results
Item Enhancing Labor Productivity of Garment Firms by Mixed Arena Simulation and Taguchi Design of Experiments (Case Company: MAA Garment and Textile Factory)(Mekelle University, 2025-09-08) Medhin HaleslaseThis study presented a mixed Arena simulation and Taguchi experimental design approach to improve productivity in garment factory, with a focus on the round neck T-shirt production line at MAA Garment and Textile Factory. This production line was observed to influence the overall performance of the company highly for its low operator output, longer idle times and lower average resource utilizations. Realistic modeling of the production environment was ensured by fitting appropriate statistical distributions (e.g., normal, triangular, exponential and etc.) to each operation’s processing time, based on data collected through time studies. These distributions were selected using Arena Input Analyzer, which applies goodness-of-fit tests with the Kolmogorov Smirnov test method to determine the best fit for the observed data. Informal interviews with operators and line supervisors were conducted as well to gain an understanding of the variability and operational arrangements. The development of a verified simulation model and the development of dependable Taguchi experiments were made feasible with these inputs. Discrete-event simulation was used to model the existing production system using Arena software, enabling detailed analysis of flow dynamics, bottlenecks, and resource utilization. Two key operational factors; batch size and operator skill level were selected for experimental analysis using the Taguchi method with an L9 orthogonal array. Performance was evaluated based on three response parameters: throughput, average waiting time, and resource utilization. Signal-to-Noise (S/N) ratio analysis and main effects plots were employed to identify optimal factor settings that deliver stable and improved system performance. The results revealed that a batch size of 20 and high operator skill level yielded the most consistent gains in throughput and utilization while reducing delays. The optimized scenario, when re-simulated, showed notable improvements; 835-860, 779-743 and 68.3-70.8 (i.e., +3% throughput, -4.6% Average Waiting Time and +2.5% utilization) respectively, compared to the existing system model. This study demonstrated the effectiveness of integrating Arena Rockwell simulation and Taguchi design of experiments (DOE) in identifying data-driven productivity strategies, offering a practical framework for performance enhancement in garment production lines. However, points such as estimated input distributions due to lack of secondary data sets, limited factor analysis because of the limitations of Taguchi method were seen as the basic limitations of this study.Item Improving Yarn Quality Through Process Optimization using the Taguchi Approach and GRA (Case study: MAA Garment and Textile Company)(Mekelle University, 2025-06-21) HAREGEWEYNI HAILAYIn today’s competitive textile market, yarn quality plays a critical role in ensuring product performance, reducing waste, and maintaining customer satisfaction. This study focuses on improving yarn quality in the carding machine section of MAA Garment and Textile Company by optimizing key process parameters using the Taguchi Method and Grey Relational Analysis (GRA). The research identifies and investigates the influence of four key carding parameters: cylinder speed, flat speed, cylinder-to-doffer gauge, and cylinder-to-flat gauge on yarn imperfections such as neps, thick places, and thin places. A Taguchi L9 orthogonal array was used to design controlled experiments, and GRA was applied to handle multiple quality responses simultaneously. The analysis revealed that flat speed has the most significant effect on yarn imperfection. The optimal parameter settings (CS = 780 rpm, FS = 260 mm/min, CTD = 0.15 mm, CTF = Level A) led to substantial reductions in yarn defects. The confirmation test validated these findings, showing a significant improvement in yarn quality, as the Grey Relational Grade (GRG) increased from 0.41 to 0.61. The study demonstrates that a systematic, data-driven approach can effectively enhance yarn quality while minimizing experimentation cost and time. The findings provide valuable insights for textile manufacturers aiming to implement robust quality improvement strategies in their spinning processes.Item Optimization of Dyeing Process Parameters on Cotton Knit Fabric Using Taguchi Method (Case Study: MAA Garment and Textiles Factory)(Mekelle University, 2025-06-16) Ashenafi KahsayThe research focus on optimizing the dyeing process parameters on knit fabric by applying the Taguchi method in the selecting case is in MAA Garment and Textiles Factory. Taguchi method is used to find the overall optimum dyeing condition and to investigate which machining parameters significantly affect the performance characteristic. Dyeing in the textile industry is all about giving color to fabrics. It's a process that uses dyes to permanently color finished fabrics. The goal is to achieve a specific shade with good colorfastness, meaning the color should resist fading or bleeding during washing and use. The study has identified the optimal conditions for dye concentration, temperature, time, PH, Material Liquor Ratio, salt, alkali, and fixing agent and L27(38) orthogonal array by using Minitab and Response factor is washing fastness. Accordingly, the product dye concentration, temperature, MLR, salt concentration, alkali concentration, PH, fixing agent, and time (A3, B2, C2, D3, E2, F2, G3 and H2) can be replaced. The main effect plot and the ANOVA has jointly showed that, dye concentration for the experiment is found to be highly influential of the performance for it attains an F value 25.56, higher than each dyeing parameter. From the ANOVA table has also displayed the minimal role of some of the process parameters such as temperature, MLR, and salt concentration under the selected alpha value of 0.05