How OSB Is Made
- Loggers come into a designated area to select and cut down trees that
are ready to be harvested. Branches are taken off and the trees are
transported to an OSB mill.
- Trees are de-barked (with the bark and
any remaining limbs being burned for
fuel), then placed on a “strander” that
has a set of knives within a circular
wheel. The knives spin as the wood goes
through a ring, cutting the tree into
individual strands with specific target
width, thickness and length.
- Wood Strains are dried at high
temperatures. Then, in a separate
operation, they are passed over mesh
screening to filter out different sizes.
Larger strands are selected for the
surface layers of OSB panels while
smaller strands are used for the core
layers.
- The different strand sizes are blended in a rotating drum with resins
and wax. Strands with resin and wax are then transported to the
orienters. The orienters align the strands so that strands for the top
and bottom surfaces of the panel go one way while the interior
strands go in the opposite direction. This adds stability to the panels.
- Before it goes into the press, the mat can be up to eight inches thick.
After the mats go into the press, they are pressed at about 600 PSI, at
up to 425 degrees Fahrenheit. Pressure brings the strands into close
contact with one another and the heat cures the resin. Pressed mats
come out from 3/8-inch to over an inch tall, depending on the product
we’re manufacturing at the time.
- Each press opening has
platens and the press platens are
heated with a hot oil system. It’s the
combination of pressure and heat
applied in the closed press process
that cures the resins. When the OSB
panels come out, they can be more
than 300 degrees F
- Panels go from the press to
the finishing line where they are cut
to the length and width needed.
Depending on which product we’re
creating there may be additional
steps. For example, at the facilities
where flooring panels get tongue
and grooved, or EdgeGold has the
DownPore system cut in, these final
steps are taken. All products are sampled and tested for quality.
- After putting single panels into unites, the product goes into the paint
booth for edge sealant to be applied to ends and edges. After that the
units get strapped and they’re prepared for shipping. Bar codes and
unit information are added. From start to finish, the entire process
generally takes less than an hour to complete.
Figure 3 : How OSB is made
