MDF production line

1.      Material preparation section

The raw material is reduced into sized wood chip by chipper. Then the wood chip is conveyed by belt conveyer into a chip silo for temporary storing. Wood chip feed out from the chip silo, passing through swinging screen to remove small particles, mud and sand, then transported into pre-heat silo of refiner by a bucket conveyor.

2.      Fiber preparation section

Wood chip in pre-heat silo is pre-heated by saturate steam, then evenly entering digester via screw feeder to cook and soften the chips, so fiber is easy to be separated. The cooked wood chip is reduced into fiber by the function of heat and mechanical movement. Then the reduced fiber is transported to dryer or cyclone by blow valve via fiber-spray-tube. Glue jetting device is set on the fiber-spray-tube. Paraffin wax adding hole is set on the defiberator-housing, it can feedback glue applying volume according to the chip volume in the refiner.

Fiber mixed with hot drying medium, is suspended in such a high-pressure and high-speed air-flow that water staying in the fiber is evaporated by the drying medium in the dryer. Then through the lower discharging-opening of cyclone, the fiber falls onto the forward-reverse belt conveyer and transported to dried-fiber-silo for temporary storage.

Spark detector is set on the drying pipe for fire extinguishing system.

 3.      Glue regulating and applying section

Our technique is glue applying before drying. Melt paraffin wax and other waterproof-agent are sent to the refiner, mixed evenly with the fiber by grinding and squeezing of grinding plates. Glue jets into the fiber-spray-tube under a certain pressure via pipes. The glue mist adheres to the surface of fiber by the high-speed air-flow in the pipe.

 4.      Forming and hot-pressing section

This section including forming, pre-pressing, mat conveying, mat cutting, hot-pressing, cooling and trimming, to produce quality board.

Dried fiber is transported at a certain speed to the upper part of forming machine (the spreader/former), then spread evenly onto annular screen-belt conveyer by spike-rolls. There is vacuum box under the screen-belt, air is sucked through the screen-belt and fiber is adhered on the screen-belt, thus forming a loose mat. Pressed by the pre-press, the loose mat is reduced into a relatively density mat, then cut into sized mat by mat-transversal-and-longitudinal saw. Transported by synchronous conveyer, acceleration belt conveyer, and fast-speed belt conveyer, the mat is carried to board loader. The cauless belt-trolley of the loader transports the mats into hot press, meanwhile, the pressed rough board is pushed out. When the cauless belt-trolley of the loader reaching its terminal point, the pressed rough board enters unloader completely, at the same time, mat reaches its position in hot-press. The mat stays on the press-platen of a hot press, then it is pressed into a certain thickness by the hot press. Meanwhile, the inner adhesive is hardened, thus a piece of fiberboard (rough board) with certain strength is produced. After pressing, the fiberboard is transported to the next section.

 5.      Cooling and trimming section

The board after hot pressing, passing a board-turning-coolin g machine, inclined roller-conveyer, then entering transversal-longitudinal saw, is cut into size medium density fiberboard, stacking for short storing.

 6.      Sanding Section 

The rough board is transported by forklift truck, and placed on hydraulic lift. Pusher pushes board into feed-roller, sanding by wide-belt sander. Hardened surface is removed, and obtain required thickness and roughness. After checking, rating, stacking, packing, finally, the board is sent into ware-house for storage.