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If the compression ratio of the ring die in an aquatic feed pellet mill is excessively high, leading to issues such as low output, overly hard pellets, and frequent machine clogging, but the ring die cannot be replaced temporarily, the following remedial measures can be adopted for temporary adjustment and optimization:

✅ 1. Adjust Formula Composition to Reduce Pelletizing Resistance

• Decrease the proportion of crude fiber and high-fat raw materials, and increase starchy binding raw materials (e.g., wheat flour, corn flour);
• Add an appropriate amount of bentonite or molasses to improve lubricity and plasticity, thereby reducing friction in die holes;
• Reduce the hardness of raw materials (e.g., partially replace fish meal with soybean meal if the proportion of fish meal is too high) to lower the load on pressure rollers.
• Increase conditioning temperature: It is recommended to control it within the range of 85~95℃ to promote starch gelatinization and reduce resistance in die holes;
• Extend conditioning time: Prolong the length of the conditioner or reduce the feeding speed to ensure full maturation of materials;
• Appropriately increase moisture content: Raise the moisture content of materials after conditioning to 15.5%~16.5% to reduce dry friction (however, attention should be paid to subsequent cooling to prevent mildew).
• Appropriately increase the gap between pressure rollers and ring die from the conventional 0.1~0.3mm to 0.25~0.35mm to reduce extrusion intensity;
• Note: Excessively large gaps will result in loose pellets, so gradual fine-tuning through test runs is required.
• Before each shutdown, perform “die cleaning” with oil-based materials (e.g., a mixture of rice bran and oil) for 10~15 minutes to prevent die holes from hardening due to high temperatures;
• A small amount of vegetable oil can be sprayed on the outer wall of the ring die to temporarily reduce the friction coefficient of die holes (see ).
• If the pellet mill is frequency-converted, reduce the spindle speed (e.g., from 6Hz to 5Hz) to decrease the number of extrusions per unit time;
• Reduce the feeding amount to avoid machine clogging. Although this will lower output, it ensures stable operation.
• Shorten the distance of the cutter to reduce the length of pellets, thereby decreasing the residence time of materials in die holes;
• Use sharp and soft cutters to prevent pellet breakage or secondary pulverization.
• If die holes are clogged, clean them with a hand drill and kerosene, or soak them in hot oil to soften the clogged materials;
• For new dies that have not undergone running-in, run them at a low speed with high-oil-content raw materials (e.g., oil bran) for 1~2 hours for “running-in”.
• If the above methods still fail to solve the problem, it is recommended to customize a ring die with a more appropriate compression ratio (e.g., reduce from 1:13 to 1:10 or 1:8);
• Request the manufacturer to reduce the compression ratio of the 3 rows of holes at both ends of the ring die by 1~2mm to alleviate difficulty in material discharge (see ).

✅ 2. Optimize Conditioning Parameters to Enhance Material Softening

✅ 3. Adjust the Gap Between Pressure Rollers and Ring Die to Reduce Compression Intensity

✅ 4. Lubricate Die Holes to Reduce Frictional Heat

✅ 5. Reduce Spindle Speed or Feeding Speed

✅ 6. Cutter Adjustment and Pellet Shortening

✅ 7. Phased “Die Loosening” Treatment

✅ 8. Long-Term Recommendation: Replace or Customize the Ring Die

�� Summary: Emergency Priority Ranking

If you cannot replace the ring die in the short term, it is recommended to prioritize adjustments in three aspects: formula, conditioning, and gap. This can significantly alleviate the negative impacts caused by the excessively high compression ratio.