Manufacturing Engineering

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Browsing Manufacturing Engineering by Author "Getasew Ashagrie"

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    Simulation Based Modeling and Performance Evaluation of a Dairy Processing Plant: Case Study of Elemtu Milk Industry
    (Addis Ababa University, 2026-02-01) Dejene Mekonnen Tola; Getasew Ashagrie; Eshetie Berhan
    The Ethiopian dairy industry plays a critical role in national nutrition and food security, yet its growth is hindered by equipment failures, production bottlenecks, inconsistent capacity utilization, and limited product diversification. Elemtu Milk Industry, a medium scale processor with a design capacity of 5,000 L/h, has struggled for years with underperformance and low profitability. This study develops a detailed discrete-event simulation (DES) model using Arena 14.0 to analyze the plant’s operations and evaluate opportunities for improvement. Two scenarios were examined: the current system and an optimized system integrating preventive maintenance, structured spare-part inventory management, upgraded utilities, automation technologies, and additional processing and packing machinery. Simulation results show that the optimized scenario substantially enhances production performance. Annual milk throughput increased from 2.41 to 5.19 million liters, yoghurt production rose from 49,370 L to 274,340 L, and butter output expanded from 280 kg to 2,570 kg, supported by additional cream recovered from sour milk. New cream production reached 4,190 L. Cheese and local cheese volumes increased to 2,540 kg and 4,340 kg, respectively. Total packed batches grew from 24,623.8 to 54,795.5 demonstrating a significant expansion in the plant’s ability to diversify and scale production. Operational efficiencies also improved markedly. Utilization of major machines, including the homogenizer, HTST and ESL pasteurizers, cream separator, and refurbished milk and cream packers reached increased by 46% and average downtime of selected machines reduced by 89.8%. The introduction of a cream pasteurizer and vacuum packing machines enabled continuous cream, cheese, and local cheese processing. Preventive maintenance and structured spare-part management reduced overall downtime by 61%, while automated conveyors lowered manual handling time and minimized human contact with finished products. Upgraded utilities, particularly a high-capacity diesel generator and screw air compressor, effectively eliminated power-outage delays and compressed-air shortages. Economically, the optimized scenario demonstrated strong financial benefits. Total revenue increased from 278.29 million ETB to 625.33 million ETB (a 124% rise), and total profit improved from 19.4 million ETB to 91.23 million ETB, despite higher operational costs driven by increased production scale and broader product variety. These findings indicate that a coordinated improvement strategy combining maintenance planning, automation, spare-part control, and targeted machinery investments can dramatically enhance throughput, resource utilization, and profitability in small- and medium-scale dairy processing plants.