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Animal feed production depends on the size of the particles. The fineness of your feed directly influences the rate of feed conversion, the quality of pellets, and animal performance overall. When your hammer mill fails to produce the consistent particle size required for your operations, you are leaving money on the table in terms of both feed efficiency and operational costs.
At Shanghai Yuanyuda International Trade Co., Ltd., that is a subsidiary of Liyang Yuda Machinery Co. we handle precision Grinding equipment and wear parts that help the feed producers to achieve the optimum size reduction. International certifications like ISO9001:2015, CE, and the SGS, technical collaboration with the institution like the Nanjing Agricultural University and so on we do know the science behind the effective grinding. Four strategies for optimizing the grinding fineness of your hammer mill are outlined below.
Optimize Screen Selection and Condition
The first parameter that determines the final particle size in a hammer mill is the screen (or screen plate). It acts as a gatekeeper that admits properly ground material and recycles larger particles back for further size reduction.
Screen Hole diameter: Another more direct method of controlling fineness is using smaller screen holes. Research has confirmed that perforated plate screens regulate the size of ground material. To achieve a smoother finished product, reducing the screen hole diameter from 3.0mm to 2.0mm (or 1.5mm) will result in a smaller particle size.
Open Area Percentage: Making the holes smaller alone is not sufficient; it is also necessary to maintain the optimal open area ratio to avoid reducing throughput. Screens with a 60° staggered hole pattern offer the best balance between open area and structural support. A larger open area allows a greater volume of material to pass through the machine in less time, reduces the time material remains in the grinding chamber, and eliminates overgrinding.
Screen Condition: Worn screens with elongated or irregular holes impair fineness consistency. A tight, predictable particle size distribution can be achieved by regularly inspecting and replacing worn screen plates.
Adjust Rotor Speed and Hammer Configuration
Key factors that affect the amount of energy transferred to the material upon impact are your hammer mill’s rotor speed and the condition of its hammers.
Optimal Rotor Speed: Research has shown that rotor speed is a key factor that greatly contributes to grinding fineness. An experiment grinding barley and corn found that an optimal speed (e.g., 2154 rpm) produced the finest grind for these grains. Increasing rotor speed leads to higher productivity but also increased energy consumption; the optimal speed for your specific material and desired fineness must be determined through experimentation.
Hammer Edge Design:Your hammer mill hammers feature a precision-engineered design. An experiment on hammer edge inclination angles has determined that a 60° inclined hammer edge yields the lowest fineness modulus value, i.e., the finest grind, compared to other angles. This means the hammer design can be optimized to achieve a specific desired fineness.
Wearing: Wear causes a reduction in the cutting efficiency of the hammers.Dull hammers result in inconsistent particle sizes and excessive fines. The cutting edges of the hammers are kept sharp, and grinding performance remains consistent, by regularly rotating or reversing the hammers.
Control Feeding Rate and Material Flow
How material flows within the grinding chamber significantly affects the fineness of the final product.
Effect of Feeding Rate: Research has shown that as the feeding rate is optimized, productivity increases and energy consumption decreases. The optimal feed rate must be maintained, and the grinding chamber must be operated at this rate—not too empty (which wastes energy), nor overloaded (which limits its ability to deliver effective impacts).
Uniform Distribution: Material must be fed into the mill evenly across the entire rotor width. Uneven feeding results in uneven hammer wear and inconsistent grinding. Inlet and feeding mechanisms should be designed to ensure material is distributed evenly.
Material Characteristics: Feed moisture content and density affect material behavior in the grinding chamber. For standard operation, feed moisture content should not exceed 14% to achieve optimal grinding performance.
Implement Proper Maintenance and Wear Part Strategies
Grinding fineness always depends on the condition of the equipment. A wear part-focused maintenance strategy will ensure consistent long-term grinding performance.
Hammer Hardness and Durability: The abrasion resistance of your hammer mill hammers is directly related to how long they can maintain their grinding efficiency.Hammer surfaces are coated with tungsten carbide, providing a hardness of over 60 HRC and superior wear resistance. Although their production cost may be twice that of standard quenched hammers, their service life may be more than twice as long, which delivers an excellent cost-performance ratio.
Regular Inspection Schedule: It is recommended that operators perform hammer inspections every 250 operating hours. For hidden wear on visible components: cutting edges should retain a minimum of 1/32 inch of material thickness, and all fasteners should be securely tightened to maintain performance.
Complete System Approach: Remember that your hammer mill is part of a larger production system. The interaction between grinding, conveying, and classification equipment determines the final particle size. Conveying equipment must be properly sized, and downstream sifting equipment must be efficient to ensure the correct particle sizes are separated and directed to their respective processing channels.
At Shanghai Yuanyuda International Trade Co., Ltd., we offer customization for wear parts compatible with both domestic and international hammer mill models, including hammer mill hammers, screen plates, and other related accessories.
