Wood ,hardwood softwood

1. PGDP COURSE 33RD BATCH
Dr. Hemlata
Asst. Professor/Deputy Director
Lecture 1
wooden containers

2. WOODEN CONTAINER

3. WHAT IS WOOD
 Wood is porous and fibrous
structural tissue found in
stem and roots of trees and
other woody plant.
 it has been used for thousand
of year fuel, house hold things,
construction and as a container.
 It is organic material ,a natural composite of
cellulose fibers (which are strong in tension ).

4. CLASSIFICATION OF WOOD
 Natural wood Engineered wood

5. CLASSIFICATION OF NATURAL WOOD
 wood is classified in two section
 Hard Wood soft wood

6. HARD WOOD
 Hard wood is wood from dicot
angiosperm trees .
 The term may also be used for
the trees from which the wood is
derived; these are usually
board-leaved.
 They are mostly deciduous, but in
tropics and subtropics mostly evergreen.

7. HARD WOOD CHARACTERISTICS
 Hard wood have more complex structure than
soft woods.
 Dark in colour.
 Expensive.
 Slower growth rate.
 Higher density.
 Heavy in weight.
 More fire resistant than softwood.
 Strong in compression and tension.

8. HARD WOOD EXAMPLES OAK
 Light in colour
 Heavy
 Ring porous open grain
 Hard to work with
 When treated it looks classy and elegant

9. HARD WOOD EXAMPLE MAPLE
 Maple is so hard and resistant
to shocks that it is often used
For blowing alley floors.
 Its diffuse evenly sized pores
give the wood a fine texture
and even grain.
 Maple that has a curly grain
is often used for violin backs.

10. HARD WOOD EXAMPLE –MAHOGANY
 An easy to work wood
 Reddish brown in colour
 Expensive
 Strong
 Poorly defined annul rings

11. EXAMPLE OF HARDWOOD -CHERRY
 Hard
 Strong
 Light to red –brown wood
 Resists warping and checking
 Easy to carve and polish

12. SOFTWOOD
 Softwood is a wood from
gymnosperm trees such as
conifers.
 Soft wood is a source of
about 80% of the worlds
production of timber.

13. SOFT WOOD CHARACTERISTICS
 Cheap comparative to hard wood.
 Faster rate of growth
 Lower density
 Softer than hard wood
 Light in colour
 Light in weight
 Poor fire resistant
 Strength in tension but week in sheer

14. SOFTWOOD EXAMPLES-PINE
 Soft
 White or pale yellow in colour.
 Light in weight.
 Straight grains.
 Lack figures
 Resists shrinking and swelling
 Knotty.

15. SOFT WOOD EXAMPLES-CEDAR
 Knotty soft wood
 Red brown colour with
light steaks
 Aromatic and moth repellent
 Popular wood for lining drawers
,chests and boxes.
 Brittle wood

16. ENGINEERED WOOD
 Also called composite wood, man
made wood, or manufactured board
including a range of derivative wood
products which are manufactured by
binding or fixing the strands, particles,
fibres or veneers or boards of wood, together with a
adhesives, or other methods of fixation from composite
materials
 Engineered wood products are used in a variety of
applications from home contraction to commercial
builidings to industrial products.

17. ENGINEERED WOOD PLYWOOD
 Plywood is a sheet material manufactured
from thin layers or plies of wood veneer
that are glued together with adjacent layers
having there wood grain rotated up to 90 degrees
to one another.
 This alternation of the grain is called cross-graining and has
several important benefits.
 It reduces the tendency of wood to split when nailed at the edges
 It reduces expansion and shrinkage providing improved
dimensional stability
 It makes the strength of the panel consistent across all directions


18. ENGINEERED WOOD VENEERS
 Veneer refers to thin slices of wood ,
usually thinner than 3mm ,that
typically are glued onto core panels
Veneer is obtained either by ”peeling”
the trunk of a tree or by slicing large
rectangular blocks of wood known as
flitches
 The appearances of the grain and figure
in wood comes from slicing through the
growth rings of a tree and depends upon
the angle at which the wood is sliced.

19. IDENTIFICATION OF WOOD
 Colour-A darker colour in wood indicates
greater durability.
 Odour -it is present only freshly cut tree.
 Hardness- is the ability of wood to withstand
identification caused by harder bodies.
 Density-densest woods are generally the
strongest.

20.  Moisture content –is a percentage of the
mass of water over the mass of wood fiber in
a piece of timber.

21. QUALITY CONTROL OF WOOD

22. MACHANICAL PROPERTIES OF WOOD
 The mechanical properties of wood are its
fitness and ability to resist applied or external
forces.
 The mechanical properties of wood consider
are.
 Stiffness
 Tensile strength
 Bending strength
 Compressive strength
 etc.

23. CHEMICAL PROPERTIES OF WOOD
 Wood is chemically inert as compared to
other materials but is affected by some acids
and bases.
 Some species have proven very useful for
containers ( boxes and crates ) because they
are nontoxic and impart no taste to the foods
contained there in.

25. OTHER PROPERTIES OF WOOD
 Heat conductivity
 Electrical conductivity
 Colour
 Moisture content