the detailed study of plywood is here

1. SUBMITTED TO:
1. BANKIM DAVE
2. AMEE MERCHNAT
SUBMITTED BY :
1. AAKASH BAREJA
2. DIVYANG CHEVLI
3. PRATIK NASIT
4. RACHNA CHOVATIA
5. KRISHNA PANCHANI
6. PRATHNA VAGHASIYA

2. • Defination of Plywood
• Panels comprising of at least three layers (or ‘plies’) of thin wood bonded
together with an adhesive. Each ply is usually orientated at a right angle to the
adjacent layer in order to improve strength and reduce the probability of shrinkage.
• The outer layers of the board are commonly referred to as the ‘face’ and ‘back’ and
are graded based on quality. The intermediate layers are collectively known as the
‘core’. Plywood glue is graded for suitability for internal or external use.
• Plywood is a manufactured wood panel made from thin sheets of wood veneer. It
is one of the most widely used wood products.
• It is flexible, inexpensive, workable, and re-usable, and usually can be
manufactured locally.
• Plywood is used instead of plain wood because of plywood's resistance to
cracking, shrinkage, splitting, and twisting/warping, and because of its generally
high strength.

3. There are mainly two types of PLYWOOD
1) COMMERCIAL PLYWOOD.
Generally a red hardwood species is known
as commercial plywood. It is bonded together
with an interior grade UF resin. It provides a
veneered surface that can be stained to match
the predominant species in the construction.
Price Range : Rs38-78 (18mm) ,Rs31-50(12mm)
2) WATERPROOF PLYWOOD:Plywood reacts with both aluminum and marine
plywood is known as waterproof plywood.
It is for use on both interior and exterior
purposes.
It has black colored shades.
Price Range: Rs77-98(18mm),Rs54-75(12mm)

4. Marine Plywood – Exterior Glue
• Produced from moderately durable species with an exterior glue line allowing this
panel to survive longer in high moisture environments.
• The superiority of marine plywood for demanding end uses relates to the greater
control over types, thickness and quality of veneer and the manufacturing
processes which the marine standard imposes.
• These requirements make marine grade plywood more costly than the equivalent
general purpose 'exterior' type, a fact which should be borne in mind when
deciding which type to specify. Price : Rs 76 onwards
Uses
• General joinery, boat building, panels in exposed areas.

5. This ply is used to make curved surfaces ,
Furniture, model making, shopfitting,
barfitting, general joinery, scenery and
stage construction.
Thickness : 6 mm
Price: Rs 33(per sq feet) onwards
Useful for safety in public buildings ,
electric rooms ,
high temperature zones where
possibility of
catching fire is more
Price: 75 per sq feet for 18 mm

6. The Manufacturing of
Plywood

7. 1.
2.
3.
4.
5.
6.
7.
8.
9.
Selecting the Log
Stripping the Bark
Peeling the Log
Making a Continuous Ribbon of Wood
Cutting and Stacking
Gluing the Wood
Pressing the Wood
Trimming, Sanding, and Finishing
Conclusion to the Manufacturing of Plywood
• Plywood is made from several different
species of trees.
• The first step in the manufacturing process
of plywood is the selecting of the logs. The
logs that are selected are chosen for their
straightness and roundness.

8. • The selected logs are then stripped of their
bark. According to the following
picture, the logs are fed in from the right by
chain conveyors. The logs are going to be
stripped so therefore, they are rotated by
ridged wheels as the cutting head on the
track reverses the log from end to end.
• The next step of the manufacturing process
is peeling the log. The log sections, which
show the marks of the debarking knives, are
fed into the lathe loader where the log
revolves around on a huge lathe against a
long cutter blade which is reduced to a 6inch core or sawed into lumber or chipped
(44). The following illustration shows the
operation of the peeler.

9. • Following the peeler process, the next step
in the manufacturing process of plywood is
taking the logs and making them into a
continuous ribbon of wood. The cutting
edge of the lathe is forced against the
spinning log. The wood is unwound in a
continuous ribbon varying in thickness
depending on how its used
• The standard size for the pieces of wood to
be cut is 4’ X 8’. The thickness of the
plywood will be determined later when the
sheets are glued and pressed together to a
varying thickness of which ¼” to ¾” is the
most common. As the sheet emerges from
the peeler it is scanned automatically and
then it is stacked green and is prepared for
the transferring to the drying ovens

10. •
The next step in making plywood is the
gluing of the plies together in order to
determine the desirable thickness of the
plywood sheet. Modern methods of
manufacturing use synthetic plastics such
as urea resins or phenol-formaldehyde for
bonding the plies together. These glues
are mixed mechanically and then spread
on alternate layers of lumber by passing
between pairs of grooved metal or hard
rubber rollers
• The following step in manufacturing process is the procedure of pressing the glued
sheets together to a desired thickness. One example of a hot press machine.
• Hydraulic or pneumatic presses squeeze the plies together with heat and pressure
or with just pressure only. When heat is used the glue hardens within a few
minutes. The glue solidifies as the plies are pressed together; and once the
pressure is released, the boards are considered dry .

11. • Lastly the sheets have to go through a process that gets them ready to be shipped
out for market. This processes involves trimming, sanding and finishing the
sheets. This process also takes the sheets down to the proper size that is desirable
to the consumer. This is what makes the final smooth edges that are seen in the
modern lumberyard. The finished panels of plywood are then divided into two
groups indicating whether they are for interior or exterior use. Plywood may carry
a quality grade, which is indicated with the letters A through C, with A being the
highest quality. This grade is based on requirements set by U.S. Commercial
Standard CS - (35-36) (Wood 468).
• These are the steps of the manufacturing process of plywood from the original type
of tree chosen, clear to the completed sheets of plywood stamped and ready to be
shipped to your local hardware stores and lumber yards. This process shows how
the plywood, which the customer buys, comes from a variety of different tree
species. It also shows the mechanics of how the plywood you buy is made into
widths, lengths and a variety of different thicknesses depending on the use of the
material. Hopefully, this illustrates the process of how a tree is manufactured into
the plywood that is found in a local lumberyard.

13. MDF is an engineered wood product consisting of softwood fibres bonded
together under high heat and pressure. MDF is a very smooth, high quality
board with an equal density across all of the panel. It is easily machinable
and has no 'natural defects' such as knots as seen in other panel products.
MDF also has two major types
1)COMMERCIAL MDF
Commercial MDF is softer so it can be carved and textured MDF is also
available in the market.
The problem with this softer MDF is that colour does not set well over its
surface bubles will be visible if coloured .
Thickness : 3,4,6,8,12,18 mm
Price : 10 Rs-77Rs ( per square feet)
2)WATERPROOF MDF
This is used in places where the surface is exposed to water or places where
humidity is more than 65% . The advantage of waterproof MDF is that
colour or duco set well on the surface of this material so it gives a beter
look than commercial MDF
Thickness : 3,4,6,8,12,18 mm
Price : !6 Rs – 87 Rs (per square feet)

14. 1.
2.
3.
4.
5.
6.
7.
DEBARKING
CHIPPING
PULPING
THE BLOW LINE
MAT FORMATION
PRESSING
FINISHING

15. Once the MDF plant has obtained suitable
logs, the first process is debarking. The logs could
be used with the bark, as could any fibrous
material, but for optimisation of the final product
the bark is removed to; decrease equipment
damaging grit, allow faster drainage of water
during mat formation, decrease organic waste
load by 10-15 %, stabilise pH levels ( reduces
corrosion of tools ) and increase surface finish.
The most popular debarker used in MDF
manufacture is a ring debarker (shown
below), though rosser head and drum debarkers
can be used.
Though some plants accept chips directly from other operations, chipping is
typically done at the MDF plant. A disc chipper, containing anything from
four to sixteen blades, is used. The blades are arranged radially on a plate
and the spinning plate is faced perpendicularly to the log feed. The feed
speed of the logs, the radial speed of the knife plate, the protusion distance
of the knives and the angle of the knifes, control the chip size.

16. MDF takes much of its characteristics from the fact that it uses wood
cells, (tracheids, vessels, fibres and fibre-tracheids), rather than particles. This can
be done by a Masonite gun Process, Atmospheric or Pressurised Disk refiner. The
Asplund defibrator pressurised disk refinement being that primarily used in MDF
manufacture. The chips are compacted using a screwfeeder into small plugs which
are heated for 30 to 120 seconds (this softens the wood), then fed into the
defibrator.
After defibration fibres enter the blowline.
The blowline is initially only 40mm in
diameter with the fibres passing through
at high velocity. Wax, used to improve the
moisture resistance of the finished
board, and resin are added in the blowline
while the fibres are still wet, as dry fibres
would form bundles, due to hydro
bonding, and material consistency would
be lost. The blowline now expands to
1500mm in diameter and fibres are dried
by heating coils warming the blowline to

17. In order to form a continous and consistant mat the the following problems must
be over come: the fact that considerable air velocities must be maintained to
suspend fibres, fibre/air suspension does not flow laterally on a horizontal support
and fibre form lumps. One way of overcoming this is a Pendistor.
The mat can either be laterally cut to size as it leaves the pendistor or it can be cut
half way through its run by a synchronised flying cut off saw.
The density profile of the the panel is critical to acheiving satisfactory strength
properties. CAs an example for a 16mm board:
Press closed. 20 seconds to bring mat to 28 mm.
28 seconds at 26mm.
23 seconds at 25mm.
125 seconds at 18.3
Total time of 330 seconds to bring board to 16mm, then decompression time.
After pressing boards are cooled in a star dryer, and final trimmed and sanded.
They are given a few days storage to allow complete curing of resins. The boards
are commonly given a coloured melamine laminate, though natural wood veneers
and raw MDF are common.

18. PLYWOOD
MDF (Medium Density Fiber Board)
Plywood is made from solid wood and thin
layers of wood veneer are glued together
MDF board is made from wood fibres.
Plywood incurs some wastage during
manufacture
The wastage of wood is nil in MDF
manufacturing and it can be made by mixing
variety of wood fibres.
Plywood can not be coloured directly
MDF boards are more attractive and you can
paint it in whatever colour you want.
Plywood can be simply nailed or screwed in
making furniture
MDF needs certain technique to join.
Plywood furniture are more stronger than
MDF.
MDF Furniture is not as strong as that of
plywood

19. BLOCK BOARD
PARTICLE BOARD
Particle boards are made by glueing together
very small chips of wood (particles of wood)
and sawdust to each other using phenolic
resins, and pressing the mixture firmly
together to form flat boards.
Blockboards are made using solid rectangular
blocks of wood laid side by side and joined end
to end, and covered on either side by layers of
thin plywood sheets. The blocks used are
usually softwood
It can be quite safely said that blockboards are
stronger and more durable than the low
density particle boards
Not as strong as block boards
Working with blockboards is also much simpler Hand particle boards need only screws and
than with particle boards, since the traditional working with it using traditional wood working
methods of using nails as well as screws works tools is quite difficult.
with it.
while decorative laminates need to be
separately glued to the blockboard as is done
in the case of plywood.
Particle boards are usually laminated at the
time of their manufacture (pre-laminated
particle boards)
The cost of blockboards will be higher than
that of particle boards but still it is lesser than
the cost of plywood sheets of the same size.
Less cost