Why do feed pellets produced by fish feed making machines crack easily?

 

- Insufficient gelatinization: If starchy raw materials such as corn and wheat have a gelatinization rate below 75% in the barrel, a tight, viscous network cannot form inside the granules, leading to cracking due to uneven shrinkage upon cooling. Too low a starch content in the raw material means that protein alone cannot support the granule structure, also causing cracking.

 

- Temperature malfunction in fish food making machine: Excessively high temperature in the rear section of the barrel (above 120°C) causes over-carbonization of the raw material, resulting in loss of viscosity; or a sudden temperature drop, with the front section at 90°C and the rear section plummeting to 70°C, causes uneven heating of the raw material within the machine, leading to internal stress concentration.

 

- Abnormal pressure: When the die pressure is below 5MPa, the raw material is not fully extruded, resulting in many voids inside the granules; when the pressure is above 10MPa, the granule density is too high, leading to a large temperature difference between the inside and outside during cooling, with the surface shrinking faster than the interior, causing cracking; wear and enlargement of the die orifice diameter can also cause a drop in pressure.

 

Improper cooling of fish feed manufacturing machines: The extruded high-temperature particles (above 60°C) are directly exposed to room temperature for rapid cooling, or the cooling fan speed is too high, causing the surface moisture to evaporate rapidly, while the internal moisture cannot be discharged in time, forming a "dry outside and wet inside" structure, which eventually cracks.

 

 

1. Improve the gelatinization rate of fish food manufacturing machines: Adjust the raw material formula to ensure that starch-based raw materials (corn + wheat) account for no less than 60%; set the barrel temperature in a gradient of "85℃ in the front, 95℃ in the middle, and 105℃ in the rear" to extend the heating time of the raw materials in the machine, thereby increasing the gelatinization rate to over 85% (the gelatinization effect can be judged by testing the water solubility of the particles).

 

2. Stabilize die pressure: Replace worn dies to ensure that the orifice diameter meets production requirements; increase the die pressure by adjusting the extruder spindle speed, stabilizing the pressure at 7-8 MPa, with pressure fluctuations controlled within ±0.3 MPa; if the pressure is still too low, a pressure regulating valve can be installed at the die for fine-tuning.

 

3. Optimize the cooling process of the manual fish feed making machine: Adopt a "gradient cooling" method, first sending the high-temperature pellets to the pre-cooling zone (temperature 35℃) for slow cooling for 3 minutes, then into the cooling zone (temperature 25℃), with the cooling fan speed adjusted to 2-3 m/s; the temperature of the cooled pellets is controlled at room temperature ±2℃, and the moisture content is stabilized at 12%-13%.

 

4. Formula adjustment: Add 2% wheat flour (containing gluten, which can enhance viscosity) or 0.5% sodium alginate to the raw materials to improve the pellets' crack resistance; avoid using too much high-fiber raw material (such as rice husk powder), its proportion should not exceed 10%.

 

 

 

 

 

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1. What is the price of the mini fish feed machine?

The price ranges from approximately $4,500-$35,000

2. Do you provide maintenance services for your customers?
Yes, we offer comprehensive after-sales maintenance services to our customers.

 

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