How can the grinding process be precisely controlled in an aquatic extruder pellet machine?

Nov 24, 2025

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The core principles of grinding turtle and tortoise feed are "extreme fineness, nutrient density, and water stability." The grinding precision must reach 120-150 mesh, and the grinding process must avoid damaging the nutrients of high-protein raw materials. The grinding method requires a "refined operation" mode, divided into three stages: raw material selection, multi-stage precise grinding, and post-grinding conditioning, each requiring precise control.

Raw material selection and pretreatment are fundamental in small electric fish feed extruder machines. Turtle and tortoise feed mainly uses high-protein raw materials, such as fresh fish paste, shrimp paste, silkworm pupa powder, and soybean protein concentrate. Fresh fish paste and shrimp paste must first undergo dehydration treatment, reducing the moisture content to 20%-25% to prevent paste loss during grinding; silkworm pupa powder must have its shell removed and be ground separately to prevent coarse shell particles from affecting the feed's fineness; soybean protein concentrate needs to be deodorized to improve palatability. All raw materials must be initially sieved through a 20-mesh sieve to remove any possible hard impurities, ensuring the safety of turtles and tortoises. Vitamins, minerals, and other additives must be added after grinding to avoid the high temperature and friction during the grinding process damaging their activity.

Multi-stage precision grinding is key, requiring a "three-stage grinding" mode to ensure extremely fine particles. The first stage, pre-grinding, involves mixing dehydrated fish paste, shrimp paste, and silkworm pupa powder, feeding them into an animal feed extruder machine. The grinding disc gap is adjusted to 1.0mm, and the spindle speed is 1500 rpm, yielding a 40-60 mesh wet powder. During this stage, the raw materials must be kept moist to prevent dust generation. The second stage, intermediate grinding, involves mixing the pre-ground wet powder with soy protein concentrate. The gap is adjusted to 0.3mm, and the speed is increased to 1800 rpm, yielding an 80-100 mesh fine powder.

During this grinding process, the cooling system is activated to control the temperature below 35℃ to prevent protein denaturation. The third stage, fine grinding, involves feeding the intermediate-ground fine powder back into the machine. The gap is adjusted to 0.1mm, and the feed speed is reduced to 10kg per hour, allowing the raw material to be fully stressed within the grinding chamber, ultimately yielding an ultrafine 120-150 mesh powder that feels smooth to the touch.

Post-grinding conditioning and precautions are the final steps in ensuring feed quality. The ultrafine powder after grinding needs immediate conditioning, with the addition of an appropriate amount of starch as a binder to improve water resistance, and fish oil to supplement unsaturated fatty acids. The conditioning process should be carried out at a temperature below 60℃ for 5-10 minutes to ensure starch gelatinization without damaging the protein. For pet food extruder maintenance, the grinding chamber should be cleaned with warm water after each grinding session, followed by disinfection with food-grade alcohol to prevent residual raw materials from breeding bacteria and affecting the health of turtles and tortoises. The grinding disc is made of imported wear-resistant ceramic material to reduce wear, and the grinding gap should be calibrated quarterly to ensure accuracy. Grinding quality testing requires professional instruments, with at least 90% of the particles being 150 mesh. The stability of the feed in water should also be tested, with no particle breakage after 30 minutes of soaking. Furthermore, the grinding precision needs to be adjusted for different sizes of turtle and tortoise feed; 150 mesh is required for juvenile turtle feed, while adult turtle feed can be reduced to 120 mesh, balancing fineness and production costs.