MDF is a kind of excellent substitute for natural wood panel with
wide application. Materials such as wood and other plant fiber
after being added suitable urea formaldehyde resin or other
adhesives forms 450-880 kg/m3 panels on hot press. The panels are
characterized with tight and smooth surface, uniform core layer and
good wood working performance.
The line consists of chip preparation, fiber preparation, glue
mixing and applying, mat-forming and hot-pressing, cooling and
1. Chip preparation
Wood, branches and wood residues are cut into chips of definite
size. Chips from chips silo will be screened or airgraded to remove
fines, soil and stones.
2. Fiber preparation section
Chips are transported to upper bin of refiner, and positively fed
to digester by screw feeder for steaming. Steamed chips will be
disintegrated to fiber under the force of heat and mechanism. Mix
drying medium and wet fiber which is in the state of suspension
with the help of high pressure air flow, and thus exhaust moisture
in fiber via drying medium to get dry fiber. Dry fiber falls on
belt conveyor through cyclone discharge valve, and then be
transported to dry fiber bin for storage.
3. Glue mixing and applying section
Process of glue applying before drying is adopted. Feed molten
paraffin and water-proof additive to refiner. Paraffin is mixed
with fiber uniformly under the force of refiner plates. Glue is
transported to the blow line of fiber discharge valve. This section
can be controlled by PLC or computer.
4. Fiber drying section
The fibers after mixing with glue is transported to drying ducts
along with steam, and transported to cylcone separator by hot air.
And thus the water in the fibers is drained out with hot air. The
dried fibers and air is separated and then transported to silo.
5. Mat-forming and hot-pressing section
The fiber after drying is transported to the above of forming
machine, and uniformly spread on the conveying mesh belt in the way
of air-flow. Vacuum box equipped below the mesh belt provides
negative pressure and air will be removed via mesh belt, fiber
stays on mesh belt and thereafter forms mats gradually. Fluffy mats
will be pressed by pre-press. Pressed mats are cut into definite
length by longitudinal and transversal saw, then transported to
loader passing through accelerating conveyor, storage conveyor and
extension conveyor. When finishing loading mats, carriage in the
loader will feed conveying belt and mats into hot press, at the
same time, shovel head at the front end of conveying belt pushes
out pressed board. When carriage comes to terminal, boards have
been into unloader, and mats also arrives to due position. Carriage
returns, conveying belt turns forward. Mats are in the relative
still state and stay on the platen of press when velocity of
conveying belt is the same as the returning speed of carriage. Glue
in the mats cures, thanks to temperature and pressure in hot press,
and hence boards with definite intensity and thickness form. Rough
boards will be put on support via unloader. Outfeeding conveyor
will unload boards one after another to next section when cage
6. Cooling, sizing and sanding section
Rough boards after air cooling are turned into cut-to-size boards
via longitudinal and transversal saw. And then cut-to-size boards
are sanded, sorted, stacked and packed for storage.