Under normal circumstances, the reason for this phenomenon is that the hammer of the hammer mill feed grinder is severely worn, causing dynamic imbalance, or the hammer is stuck in the crushing chamber and is not thrown away during operation. In addition, if the pulverizer is overloaded for a long time, it will cause the main shaft to bend and the bearings to wear. The above problems will also occur. Therefore, the equipment should be checked regularly and the equipment should not be used in violation of regulations.