The water content of the grinding material is too high (usually 2.0%), and the ventilation in the cylinder is poor, so that the water vapor and fine materials generated during the grinding process cannot be taken out of the vertical roller mill in time.

It is too large and adheres to the surface of the steel ball and the lining plate of the vertical roller mill, which slows down the flow rate, makes the discharge of the vertical roller mill difficult, and the wet material easily blocks the gap between the partition plate and the discharge grate plate.

If the feeding amount remains unchanged at this time, it will inevitably cause an imbalance between the feeding and discharging, resulting in the "full grinding" of the vertical roller mill.

The gradation of steel balls is unreasonable, too many small balls, too small ball diameter or too low filling rate will affect the grinding ability in the cylinder, which will also cause the "full grinding" phenomenon of the vertical roller mill.