Evaluation of a Rubber Roller One-Pass Rice Milling Machine for Improving Milled Rice Quality

Abstract

A comprehensive evaluation of the SB-10D milling machine focused on two widely cultivated rice varieties: the long-grain Nerica-4 and the short-grain Shaga. The study revealed that the feed rate, drum clearance, and roller speed significantly affect the performance of the machines for both rice varieties. The Shaga variety achieved a remarkable maximum head rice recovery rate of 86.73% when milled at a roller speed of 700 rpm, using a drum clearance of just 1 mm while operating at the first shutter position. In contrast, the Nerica-4 variety had head rice recoveries ranging up to 84.46%, observed at the same roller speed of 700 rpm, with a drum clearance of 1 mm and the first shutter position. Regarding overall milling recovery rates, the Shaga variety reached its peak at 66.77% with a roller speed of 900 rpm, a drum clearance of 1 mm, and operating at the fourth shutter position. Meanwhile, the Nerica-4 variety achieved a notable milling recovery rate of 64.32% under similar conditions—at a roller speed of 900 rpm, with a drum clearance of 1 mm, and the fourth shutter position. The research identified the optimal milling conditions for both rice varieties. For the Shaga variety, known for its plump, tender grains, the ideal milling parameters were a roller speed of approximately 700 rpm, a drum clearance of 1 mm, and the first shutter opening. This configuration is designed to maximize the milling process while maintaining grain quality. Conversely, the Nerica-4 variety, recognized for its longer, slender grains, performed optimally at a roller speed of around 900 rpm, also with a drum clearance of 1 mm and the first shutter position. These specific settings are tailored to enhance the efficiency of the milling operation, ensuring that the grains are milled to perfection.