Transcript PowerPoint® Presentation Unit 4 Lumber Manufacture Sawmill Operations • Sawing Methods • Seasoning Methods • Planing and Grading • Lumber Defects • Wood Protective Treatment Unit 4

PowerPoint® Presentation
Unit 4
Lumber Manufacture
Sawmill Operations • Sawing
Methods • Seasoning Methods •
Planing and Grading • Lumber
Defects • Wood Protective Treatment
Unit 4 — Lumber Manufacture
Trees are cut using a
feller buncher that grasps
a tree as it is sawn off at
the base. Trees sustain
less damage when felled
in this manner.
Unit 4 — Lumber Manufacture
Log loaders stack logs on a truck for transport to a
sawmill.
Unit 4 — Lumber Manufacture
A log can be cut
into many
shapes and
sizes of lumber.
Unit 4 — Lumber Manufacture
Logs are conveyed into the sawmill from a log
merchandising deck.
Unit 4 — Lumber Manufacture
The logs pass
through a
debarker to
remove bark
and dirt, which
may dull saw
blades used in
subsequent
operations.
Unit 4 — Lumber Manufacture
Boards are fed into
the trimmer by
conveyor belts. A
trimmer consists of a
series of saw blades
that remove defects
and cut the boards
to standard lengths.
Unit 4 — Lumber Manufacture
Lumber sawing methods include plainsawing,
quartersawing, and rift sawing.
Unit 4 — Lumber Manufacture
Lumber is stacked
on tram cars and
transported into a
kiln for seasoning.
Note the stickers
placed between
rows of lumber to
allow for complete
circulation of air.
Unit 4 — Lumber Manufacture
Lumber is graded and sorted according to thickness,
width, and length as it moves along a conveyor belt.
Unit 4 — Lumber Manufacture
Knots are found in most grades of lumber. A small
number of sound knots will not significantly affect the
lumber strength.
Unit 4 — Lumber Manufacture
Splits and wanes are among the lumber defects that
occur from natural causes.
Unit 4 — Lumber Manufacture
Warpage can occur during
the evaporation of water
from wood cells.
Unit 4 — Lumber Manufacture
Dry rot is the breakdown of wood caused by a
wood-destroying fungus.
Unit 4 — Lumber Manufacture
Levels of wood
deterioration vary
depending on humidity
levels and temperature.
Unit 4 — Lumber Manufacture
Waterborne preservatives are used for residential,
commercial, marine, agricultural, recreational, and
industrial construction applications.
Unit 4 — Lumber Manufacture
Untreated lumber
is placed in large
cylinders and
impregnated with
preservative.
Unit 4 — Lumber Manufacture
Grade marks for
pressure-treated lumber
include information
about the exposure
conditions for proper
use of the lumber, and
also indicate the type of
preservative used on
the lumber.