Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 24 ISSUE 3
Written by Jamel SALO, Emmanuel SICAT

Uncleaned and ungraded onions stored in sacks command low prices, a significant share of farmers' income. Manual cleaning and grading of stored onions are labor intensive, tedious, and provide inconsistent results. This study sought to develop a dry-scale cleaner cum grader for stored onion bulbs to simplify operations, reduce labor costs, minimize operation losses, and generate more income for the onion farmers. The design of the machine parts was computed based on the onions' average physical (shape, size, surface area, density, colour, and weight) and mechanical (hardness, compressive strength, impact, and shear resistance) properties. The study used locally available materials to fabricate the machine and conducted a preliminary performance test to ensure functionality and optimum machine speed settings. Based on the results, machine cleaning and grading speed of 71 rpm and 17 rpm can remove dry scales and grade them according to standard sizes at a rate of 493 kg/hr at 73 % efficiency. The machine reduced manual labor utilization from 3 man-day/100kg to 0.08 man-machine-day/100kg. Mechanical damage (2%), including slight bruises in the bulbs, and the noise level (82 dB) were lower than the maximum threshold of 3% and 92 db. The machine costs ₱125,000 with an operating cost of ₱40/100kg and power consumption of 14.41W-hr. It can break even after cleaning and grading 33,263 kg of stored onion bulbs at a custom rate of ₱1/kg per year. The study successfully developed the onion cleaning cum grading machine suggesting group ownership for utilization.

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