MDF is a kind of excellecnt substitute for natural wood pnel with
wide application. Materials such as wood and other plant fiber
after being added suitable urea formaldehyde resin or other
adhesives forms 450-880kg/m3 panels on hot press. MDF is
characterized with tight and smooth surface,uniform core layer and
good wood working performcance. This productiong line consists of five technology process flows: 1) Chip preparation section Wood, branches and wood residues are cut into
chips of definite size. Chips from chips silo will be screened or
airgradeed 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. Steam
chips will be distintegrated 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
moisure in fiber via drying medium to ger dry fiber. Dry fiber
falls on belt conveyor through cylone 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 adotpted.Feed
molten paraffin and water-proof additive to fefiner. Paraffin is
mixed with fiber uniformly under the force of refiner plates. Glue
is transported to the below line of fiber discharge valve. With the
help of 28-30m/s high speed air-flow,glue mist meets and attachs to
the surface of fiber. This section can be controlled by PLC or
computer. 4) 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
transproted to loader passing through accelerating conveyor, stoage
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 coms to
terminal,boards have been into unloader,and mats also arrives to
due position.Carriage returns,conveying belt turns forward. Mats
are in 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 loader.
Outfeeding conveyor will unload boards one after another to next
section when cage comes down. 5) Cooling, sizing and sanding section Rough boards after air cooling are turned in to
cut-to-size boards via longitudinal and transversal saw. And then
cut-to-size boards are sanded, sorted, stacked and packed for
sorage. |