In the interior of the vertical roller mill, the material after the sorter is ground and dried enters the part along with the air flow from the lower part for sorting operation. The purpose of sorting is to obtain a better quality of the finished product. There are moving and static blades, and the welding must be firm, otherwise it will cause accidents such as downtime. The maintenance of this part is divided into the inspection and repair of the moving blades and the static blades.  LUM ultrafine vertical mill: https://www.gravelmill.com/product/grinding/lum-ultrafine-vertical-roller-mill.html When the moving blades are overhauled, they need to be vibrated and moved by a hand hammer one by one. See if there is any movement of the blade. If so, it needs to be fastened, marked, and welded and strengthened. If severely worn and deformed blades are found, they need to be removed, and new moving blades of the same size shall be installed according to the requirements of the drawing, and the blades shall be weighed before installation to prevent loss of balance.  When the stationary blades are overhauled, they must be overhauled. Remove five moving blades from each layer of the squirrel cage of the fine grinder to leave enough space to observe the connection and wear of the stationary blades. Rotate the squirrel cage to check whether there is open welding or abrasion at the connection of the stationary blades.