Uneven mixing in a organic fertilizer double axis mixer mainly stems from issues related to structure, materials, rotation speed, blades, and operation. The causes are relatively clear and easy to diagnose:

1. Worn, deformed, or incorrectly installed spiral blades: Shortened or severely worn blades reduce feeding and mixing capacity, resulting in material movement without proper mixing. Inconsistent blade angles lead to different feed speeds on both sides, causing localized poor mixing.

2. Unstable material moisture content, either too wet or too dry: Overly wet materials tend to clump together, making them difficult to break up; overly dry materials cause stratification and scattering, both resulting in uneven mixing. Large fluctuations in moisture content are a common cause of uneven mixing.

3. Uneven feeding, one-sided feeding: If raw materials are added only from one side, the twin shafts experience uneven force, with one side receiving more material than the other, making uniform mixing difficult.

4. Asynchronous twin shafts, mismatched rotation speeds: Inconsistent rotation speeds between the twin shafts cause chaotic material flow within the machine, resulting in some areas being mixed more than others. 5. Insufficient mixing time, excessively long or short drum: A fast feed rate and short residence time result in materials being discharged before they are fully mixed. An unreasonable drum structure can also lead to dead zones and poor material return.

6. Dead zones and severe material accumulation inside the machine: Material easily accumulates at both ends, shaft base, and bottom, forming "dead zones." New material passes directly through while old material accumulates, leading to large fluctuations in the finished product.

7. Large differences in raw material specific gravity: Organic fertilizer raw materials vary in weight. If they are fed directly into the mixer without crushing or premixing, stratification and uneven mixing are very likely to occur.