LaiZhou ChengDa Machinery Co., Ltd.

The output speed of a pellet mill primarily depends on the physical state of the raw materials, with moisture content being the core variable. Generally, the optimal moisture content should be maintained between 13% and 18%. When the moisture content is too high (e.g., exceeding 18%), the material tends to slip inside the pressing chamber, resulting in insufficient extrusion pressure, which can lead to die hole blockages and cause the output to slow down or even stop. Conversely, if the material is too dry, the frictional resistance between particles increases significantly, which not only reduces the output speed but also raises energy consumption and equipment wear. Additionally, characteristics such as fiber length, hardness, and ash content directly affect the compression time and molding resistance within the die holes, thereby determining the output speed.

Matching Degree of Die Compression Ratio and Hole Diameter

The compression ratio of the ring die or flat die (the ratio of the effective length of the die hole to its diameter) is a critical mechanical parameter that determines the output speed. If the compression ratio is too large, the extrusion resistance on the material inside the die hole becomes excessive, making discharge difficult and reducing production capacity. If the compression ratio is too small, the material does not receive sufficient pressure, resulting in loose and poorly formed pellets, which also fails to achieve efficient output. Different raw materials require specific compression ratios; for instance, the compression ratio needed for wood sawdust is entirely different from that for straw. Only when the die's compression ratio perfectly matches the characteristics of the raw material can the material be smoothly extruded from the die holes, achieving stable and rapid output.

Adjustment of the Gap Between Rollers and Die

The gap size between the rollers and the die directly affects the efficiency with which material is pressed into the die holes. If the gap is too large, the rollers lack sufficient extrusion force, preventing the material from fully entering the die holes, which leads to slow output and a high powder content. If the gap is too small, intense friction occurs between the rollers and the die, accelerating component wear and increasing operational resistance, ultimately causing poor discharge. A properly adjusted gap (typically between 0.1 mm and 0.3 mm, depending on the specific raw material) ensures that the material is pushed evenly and forcefully into the die holes, thereby maintaining a stable output speed.

Uniformity and Stability of the Feeding System

The output speed depends not only on the pressing stage but also on the control of the feeding system. If the feeding rate is too fast and exceeds the equipment's instantaneous processing capacity, material will accumulate in the pressing chamber, causing the main motor's current to spike and potentially leading to a jam. Conversely, if the feeding rate is too slow or uneven, it will cause the equipment to idle or experience uneven localized stress, resulting in intermittent output. Utilizing a variable frequency feeding system to adjust the feed rate in real-time based on the main motor's current and operational status ensures that the pressing chamber remains consistently and controllably filled. This is crucial for maintaining high-speed, continuous output.

Wear Condition of Core Components

As the equipment operates over time, the wear of the die and rollers will directly lead to a decrease in output speed. When the inner walls or die holes become rough due to wear and the hole diameter enlarges, the frictional force and extrusion pressure experienced by the passing material change, reducing the molding rate and naturally slowing down the output. Similarly, wear on the roller surface reduces friction between the rollers and the die, decreasing their gripping ability. Therefore, regularly inspecting and replacing dies and rollers that have reached the end of their service life is a necessary maintenance measure to sustain high pellet mill output speeds.