Defibrated wood mass can be produced from most kinds of conifers as well as wood wastes:
1. Shreddingtochipsof10-40 mm.
2.Washing to remove impurities.
3.Steam treatment to soften the natural bonds in the wood material. 4. Grinding (defibration)toapulpwithfibresofabout1.5 mm.
The wet process is the classical process for the production of wood fibre boards wherethe lignin itself is released and bonds the product. Fresh wood must be used. Stiff boards up to 30 mm thick are produced, that can later be laminated to thicker ele-ments.The process is as follows:
1. Mixing with water and spreading on to a rolling conveyor. 2.Squeezing to remove about half the waterand pressing tothin sheets.
3.Rolling at around 200 °C to remove the remaining waterand glueing of the sheets.
In the dry process glue is added as a binder; this means thatold and deficient timber can also be used. Boards can be produced up to 200 mm thickness.
1. Dryingofthemassataround170 °C.
2.Mixing with glue and spreading into sheets on a conveyor.
3.Curing the sheets with warm humid air.
4.Cutting to standard mat and board dimensions.
Additives are mixed in at different stages depending on the type.
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