Medium-density fiberboard (MDF) is made of wood fiber or other plant fiber, and processed (through the material preparation section, fiber preparation section, fiber drying section, glue supply section, pavement hot pressing section, post-treatment section, sanding section) boards with a density of 450-880kg/m³. The raw materials are wood, branch wood, wood processing residues, etc.
1. Material preparation section
The raw materials are cut into wood chips of certain specifications by the chipper and stored in the silo. After screening, impurities such as fines, soil and sand in the wood chips are removed.
2. Fiber preparation section
We adopt the process of sizing first and then drying. The molten paraffin or other waterproofing agents are directly sent to the heat mill, and the paraffin is evenly mixed with the fibers under the extrusion and kneading of the two grinding discs. Adhesives are conveyed through pipes under certain pressure to heat: mill fiber spraying and fully mixed with fibers, and in the drying pipe with 28-31m/s high-speed airflow to make glue mist and fibers meet and adhere to the surface of fibers.
The wood chips are sent to the upper hopper of the thermal mill through the transportation equipment, and then evenly enter the preheating digester through the screw feeder, and the wood chips are cooked and softened to make the fibers easier to separate. After cooking, the wood chips are separated into fibers under the action of heat and machinery. The wet fiber is mixed with the heated drying medium, and the high-speed action of the high-pressure airflow is used to keep the fiber in a suspended state in the dry matter, so that the moisture in the fiber is taken away by the drying medium to achieve the purpose of drying. Then it falls on the forward and reverse belt conveyor through the cyclone separator discharge valve, and is sent to the dry fiber silo for temporary storage.
3. Paving hot pressing section
The dried fibers are sent to the upper part of the forming machine by the air delivery system, and the air-flow paving machine is evenly sprayed on the circular mesh belt by airflow, and a vacuum box is installed under the mesh belt to form a negative pressure, and the air is sucked away through the mesh belt. , the fiber is adsorbed on the mesh belt and gradually forms a slab. Vacuum mechanical paving adopts mechanical plus vacuum paving and forming. After the fluffy slab is pre-compressed and compacted by the pre-pressing machine, the slab is cut longitudinally and transversely to make a slab that meets the specified length, and then it is passed through the sawing conveyor, the acceleration belt conveyor, and the storage board.
The conveyor, telescopic conveyor, etc. are continuously transported to the loading machine. After the loading machine has loaded the slabs layer by layer, the small car in the loading machine enters the cantilever conveyor belt together with the slab into the hot press machine. The shovel head at the front end of the middle conveyor belt pushes out the pressed fiberboards at the same time. When the trolley reaches the end, all the fiberboards have entered the unloader, and the slabs have also reached the predetermined position. At this time, the trolley moves backwards and the belt runs forward. When the linear speed of the conveyor belt is equal to the backward speed of the trolley, the slab is relatively static and is left on the hot-pressing plate. Under the temperature and pressure of the hot-pressing plate, the slab is pressed to a specified thickness and the internal glue is pasted. The agent is cured to make a board with a certain strength. After pressing, the finished board is unloaded to the bracket by the unloading machine, and unloaded by the building block of the board when the cage descends layer by layer, and transported to the next process.
4. Post-processing, sanding section
The hot-pressed raw boards enter the vertical and horizontal edge sawing machine through the flap cooling machine and the roller table conveyor, and the edges are sawed into qualified medium density fiberboards, and then sorted, stacked and packaged after sanding.