When the loading factor exceeds 70%, the mixer begins to operate inefficiently—performing "nominal" work without effective results.

For horizontal mixers, the recommended loading factor is typically 60% to 70%. Exceeding this range leaves insufficient space within the mixing chamber for materials to tumble and circulate; the thrust of the mixing paddles is counteracted by the material's own weight, causing the mixing uniformity (CV value) to deteriorate rapidly. More critically, motor current rises with the load; prolonged overloading leads to gearbox overheating, belt slippage, and even motor burnout. NPK blending mixers handle granular materials; excessive loading intensifies inter-particle friction and causes breakage rates to skyrocket, while the resulting increase in fine powder further exacerbates segregation. No matter how high the batching precision of the entire NPK blending line is, if the mixer operates under overload, the nutrient consistency of the final product cannot be guaranteed. For twin-shaft organic fertilizer mixers handling high-moisture, sticky materials, an even lower loading factor—around 60%—is recommended; because wet materials have poor flowability, overloading makes them prone to wrapping around the main shaft and clogging the discharge outlet.

Incorrect temperature sensing in the dryer leads to the unexplained death of functional bacteria.

In biological organic fertilizer dryers, inlet air temperature is usually controlled between 60°C and 80°C. However, many factories install temperature probes on the inlet air duct, assuming that "if the inlet air is 80°C, the material temperature certainly won't exceed 60°C." This assumption is incorrect. The actual temperature of the material inside the dryer is determined by a combination of factors: residence time, the configuration of the lifting flights, and airflow volume. For instance, with an inlet air temperature of 80°C, the material temperature in the front section of the drum can rapidly exceed 65°C, causing massive die-off of the functional bacteria in that zone. The correct approach is to install an infrared thermometer or contact temperature sensor at the dryer's discharge outlet to directly measure the temperature of the discharged granules and use this as the control parameter—ensuring the discharge temperature does not exceed 45°C. If the discharge temperature is too high, the inlet air temperature should be lowered or the feed rate increased, rather than simply fixating on the inlet air temperature gauge.

Overfilling the mixer compromises mixture uniformity and shortens equipment lifespan; selecting the wrong monitoring point in the dryer harms the functional bacteria and degrades product quality. Both represent "invisible losses," yet their cumulative effect is sufficient to quietly erode the quality and profitability of a production line.