Optimization of slitting cutters used for gutting Trachurus japonicus

Abstract: An experimental study on mechanized gutting for Trachurus japonicus was conducted, faced with equipment shortages for the pre-processing of trash fish. A self-developed test platform was employed for slitting Trachurus japonicus to avoid fish damage and increase the gut removal rate in the gutting process. Preliminary studies showed that the parameters of the slitting cutters had a significant effect on the gutting process of trash fish. In addition, the subsequent operations of gutting were directly determined by the slitting process. The various trash fish gutting operations should be equipped with different parameters of slitting cutters to achieve the best gutting effect. The relationships between gutting effect and cutter external diameter, cutter tooth structure, cutter rotation direction, cutter thickness, and cutter rotation speed were studied. The results showed that cutter external diameter, cutter thickness, and cutter rotation speed were the key factors in the gutting process of Trachurus japonicus. Using a toothless disc cutter had the best slitting effect that could achieve a smooth and flat slitting surface and a higher getting proportion. Under the same conditions, converse slitting had a better effect than consequent slitting, while a high rotation speed was better than a low rotation speed. When the slitting cutter's external diameter was 190.0 mm, it had a better acceptability evaluation of 9.68. The getting proportion had no significance when the thickness of cutter was less than 3.0 mm. With the increasing of the cutter's thickness, there was a tendency of growing weight loss of trash fish during the gutting process, which led to a lower getting proportion. An orthogonal test showed that: The best parameters of the gutting process of Trachurus japonicus were: cutter external diameter 190.0 mm, cutter thickness 3.0 mm, and cutter rotation speed 1 100.0 r/min. Under these conditions, the maximum value of acceptability evaluation and getting proportion of gutting effect was achieved, and thus it could meet the needs of the gutting process. The productivity of a mechanized processing method was 8-12 times as much as the productivity of a manual processing method. The study also showed that the gutting effect was closely relevant to the size and body characteristics of the trash fish, so their pre-processing required a heavy workload. However, replacing the manual gutting process with the mechanical gutting process could be achieved through proper size grading and the development of a general fish gutting device with the optimization of slitting cutter parameters. This study can provide reference for the design of gutting equipment for trash fish.