Processed Wood
-
Upload
dhananjay-singh -
Category
Documents
-
view
223 -
download
0
Transcript of Processed Wood
-
7/30/2019 Processed Wood
1/49
-
7/30/2019 Processed Wood
2/49
PLYWOOD
DefinitionA board formed of three or more layers of veneer
cemented or glued together, usually with the grain
of adjacent veneers running at right angles toeach
other.
Plywood was developed to provide panels with
a dimensional stability lacking in sawn timber,
extra width without jointing and good strength
properties along and across the sheet.
-
7/30/2019 Processed Wood
3/49
GRADES
There are two grades of plywooddepending upon the bond strength
developed by the adhesive used for
bonding the veneers.
1. Boiling water resistance or
BWRGrade2. Moisture resistance orMR
Grade
-
7/30/2019 Processed Wood
4/49
AUSTRALIAN AND NEW ZEALAND
GRADING SYSTEM OnlyA grade surface veneers are suitable for aircraft
construction 'A' a high quality appearance gradeveneer suitable for clear finishing. Marine plywood to
AS/NZS 2272 has two A grade faces and an A or Bgrade core.
'S' an appearance grade veneer which permitsnatural characteristics such as knots as a decorativefeature subject to agreement.
'B' an appearance grade suitable for high quality paintfinishing.
'C' a non-appearance grade with a solid surface. Allopen defects such as knot holes or splits are filled.
'D' a non-appearance grade with permitted openimperfections. Limited numbers of knots and knot holes
up to 75 mm wide are permitted.
-
7/30/2019 Processed Wood
5/49
CLASSIFICATION BY APPREARANCE
Plywood for general purposes shall be
classified into three types, namely,AA, AB and
BB based on the quality of the two surfaces,
namely, A and B in terms of general permissibledefects.
The type of plywood shall, therefore, be
designated by the kind of surfaces of thepanels. The better quality surface shall be
called face, and the opposite side shall be
called back.
-
7/30/2019 Processed Wood
6/49
Permissible Categories of Defects
Type of
surface
Max. No. of categories
of permissible defectsper Sq. m
A 3B 5
-
7/30/2019 Processed Wood
7/49
MATERIALS
TimberAny species of timber may be used for plywoodmanufacture.
1.
Indian Oak2. Cinnamon
3. Maple
4.
Mango5. Neem
6. Teak
7.
Rosewood etc.
-
7/30/2019 Processed Wood
8/49
ADHESIVES
1. The adhesive used for bonding theveneers in different grades of plywood
shall be the corresponding type of
adhesive as specified in IS 848: 1974.2. Extenders (A substance added to the
adhesive either to reduce the cost of
gluing or to reduce penetration throughthe veneers or both) conforming to IS
1508 : 1972 may be used with the
synthetic resin adhesive(amino resins ).
-
7/30/2019 Processed Wood
9/49
-
7/30/2019 Processed Wood
10/49
MANUFACTURING PROCESS OF PLYWOOD
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 FINAL PRODUCT
http://localhost/var/www/apps/conversion/tmp/scratch_3/1.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/2.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/3.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/4.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/5.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/6.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/7.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/7.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/6.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/5.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/4.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/3.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/2.jpghttp://localhost/var/www/apps/conversion/tmp/scratch_3/1.jpg -
7/30/2019 Processed Wood
11/49
AS PER IS 303 POINTS TO BE REMEMBER DURING
MANUFACTURING
The veneers for all the grades shallbe either rotary cut or sliced. The
veneers shall be sufficiently smooth
to permit an even spread ofadhesive.
-
7/30/2019 Processed Wood
12/49
TREATMENT
Treatment given to the plywood either at the
veneer stage or after converting the veneers into
boards.
Veneers from non-durable species and sapwood of
all species when used for plywood manufactureshall be soaked in 1.25 percent solution of boric
acid or 1.9 percent solution of borax at a
temperature of 85-90C for a period of 1O-40minutes depending upon the thickness of the
veneers or the veneers may be dipped in 2 percent
solution of boric acid or 3 percent borax solution
for 2 minutes and block stacked at least for two
-
7/30/2019 Processed Wood
13/49
ASSEMBLY
1. Thickness
The thickness of all veneers shall be uniform
within a tolerance of 5 percent.
Face and back of veneer shall be of same
species having similar mechanical and
physical properties.
-
7/30/2019 Processed Wood
14/49
Dimension Tolerance
a) Length +6mm -0mm
b) Width +3mm -0mm
c) Thickness
1) less than 6mm 10%
2) 6 mm and above 5%
d) Squareness 0.2 %
e) Edge straightness 0.2%
-
7/30/2019 Processed Wood
15/49
THICKNESS
Board Thickness mm3 ply 3, 4, 5, 6
5 ply 5, 6, 8, 97 ply 9, 12, 15, 16
9 ply 12, 15, 16, 1911 ply 19, 22, 25
Above 11 ply As ordered
-
7/30/2019 Processed Wood
16/49
METHODS OF TEST FOR PLYWOOD
IS 1734 (Part 1): Determination of densityand moisture content.
IS 1734 (Part 2): Determination of resistance
to dry heat. IS 1734 (Part 3): Determination of fire
resistance.
IS 1734 (Part 4): Determination of glue shearstrength.
IS 1734 (Part 6): Determination of waterresistance.
-
7/30/2019 Processed Wood
17/49
IS 1734 (Part 8): Determination of pH value.
IS 1734 (Part 9): Determination of tensile
strength.
IS 1734 (Part 10): Determination ofcompressive strength.
IS 1734 (Part 18): Impact resistance test on
the surface of plywood.
IS 1734 (Part 20):Acidity and alkalinity
resistance test.
-
7/30/2019 Processed Wood
18/49
-
7/30/2019 Processed Wood
19/49
Class Type Designation
Flat pressed, single layer - FPS
Flat pressed-three layer 1 FPT 1
Flat pressed multilayer and
graded
2 FPT2
Extrusion pressed, solid - XPS
Extrusion pressed, tubular - XPT
-
7/30/2019 Processed Wood
20/49
Any species of wood or any other ligno-cellulosic material may be used in the
manufacture of particle board.
Adhesive -Any suitable type of synthetic resinconforming IS : 848 -1974 may be used for thepurpose of bonding. However, for flat-pressed
three layer, multilayer and graded boards of
Type I, BWR or BWP type adhesive should beused.
-
7/30/2019 Processed Wood
21/49
1.
Wood particles for the manufacture of particleboards shall be produced by cutting wood
and/or any other suitable ligno-cellulosic
materials into shavings, flakes, splinters or
slivers on a suitable chipping machine.
2. The wood particles shall be dried in a
mechanical drier.
3. The dried particles shall be graded to required
sizes and thoroughly blended with the requisite
quantity of adhesives in mechanical mixers or
applicators.
-
7/30/2019 Processed Wood
22/49
-
7/30/2019 Processed Wood
23/49
PRESERVATIVE TREATMENT
A suitable preservative may be added to the
particle mix at the stage of rinsing of
adhesive.
a) Sodium pentachlorophenate to the extent of
0.2 percent, and
b) Pentachlorophenol to the extent of 0.2
percent.
-
7/30/2019 Processed Wood
24/49
THICKNESS
The thickness of particleboards are 6, 9, 12, 15,
18, 19, 22, 25, 27, 30, 35and 40 mm.
-
7/30/2019 Processed Wood
25/49
Dimension Tolerance
Length - for all lengths 8 mm
Width - for all widths 8 mm
Thickness - Above 25 mm 2.5 %
Thickness up to and including
25 mm
5 %
-
7/30/2019 Processed Wood
26/49
Density - The mean density of the boards, shallbe between 500 to 900 kg/m3. The densityshall not vary from one sample to another by
more than ten percent of the mean density.Moisture Content -- The mean moisture
content of the boards, shall not be less than 5
percent and not more than 15 percent. Themoisture content of individual test specimenshall not vary from the mean percentage by
more than 3 percent.
W t Ab ti Th t
-
7/30/2019 Processed Wood
27/49
Water Absorption - The mean waterabsorption of the boards, shall not exceed the
prescribed limits given in table for various types
of boards after both 2-hours and 24 hoursimmersion.Water
Absorption, percent
FPS FPT1 FPT2 XPS XPT
2 Hours 25 10 40 40 40
24
hours
50 20 80 80 80
Workability - The particle boards shall not crackor split when drilled, sawed and nailed
perpendicular to the surface.
S lli g i W t Th lli i
-
7/30/2019 Processed Wood
28/49
Swelling in Water - The mean swelling inthickness, length and width, shall not exceedthe limits given in table for various types of
boards.Thickness Swelling, percent2 h soaking
FPS FPT1 FPT2 XPS XPT
Thickness 10 8 12 5 5Length 0.5 0.5 0.5 2 2
Width 9 6 9 4 4
Swelling Due to Surface Absorption The
-
7/30/2019 Processed Wood
29/49
Swelling Due to Surface Absorption - Themean swelling in thickness due to surface
absorption, shall not exceed the limits given in
table for various types of boards.
Swelling due tosurface absorption,
percent
FPS FPT1 FPT2 XPS XPT
2 Hours 9 6 9 4 4
-
7/30/2019 Processed Wood
30/49
METHODS OF TEST FOR PARTICLE BOARD
IS 2380:1977 (Part 1 to Part 23)
-
7/30/2019 Processed Wood
31/49
LOW DENSITY PARTICLE BOARD
Timber and other Iigno-cellulosicmaterial like bagasse, solapith, jute
sticks, rice husk, pea-nut shells, etc,
may be used for the manufacture ofthese boards. These shall be light
weight materials of bulk density
preferably not exceeding 400 kg/m3
and shall be free from extraneous
matter and dust.
-
7/30/2019 Processed Wood
32/49
-
7/30/2019 Processed Wood
33/49
HIGH DENSITY PARTICLE BOARD
Type o fresin
Grade
Type 1 BWR Grade AGrade B
Type 2 WWR or
CWR
Grade A
Grade B
-
7/30/2019 Processed Wood
34/49
-
7/30/2019 Processed Wood
35/49
FIBER HARDBOARD
Sheet material generally exceeding1.5 mm in thickness, manufactured
from lignocellulosic fibres with the
primary bond deriving from the feltingof the fibres and their inherent
adhesive properties. Bonding
materials and/or additives may be
added.
-
7/30/2019 Processed Wood
36/49
Medium Hardboard -A homogeneous fibrebuilding board havinga density exceeding 0.35
g/cm3 but not exceeding 0.8 g/cm3.
Standard Hardboard -A homogeneous fibre
building board havinga density exceeding 0.80
g/cm3.
Tempered Hardboard -Hardboard which has
been further treatedin the course of
manufacture in order to modify one or more of
their properties ( this may have the effect of
altering the density ).
-
7/30/2019 Processed Wood
37/49
-
7/30/2019 Processed Wood
38/49
-
7/30/2019 Processed Wood
39/49
BLOCK BOARD
A board having a core made up ofstrips of wood, each not exceeding 25
mm in width, laid separately or glued
or otherwise joined to form a slabwhich is glued between two or more
outer veneers with the direction of the
grain of the core blocks running at
right angles to that of the adjacent
outer veneers.
-
7/30/2019 Processed Wood
40/49
GRADES
Grade 1:- Exterior grade of blockboard which ismeant for bus bodies, railway coaches,
prefabricated houses, etc, where it is likely to
be exposed to high humidity.
Grade 2:-Interior grade of blockboard which ismeant for furniture, partition, panelling, ceiling,
etc.
Each of the grades specified have of the
-
7/30/2019 Processed Wood
41/49
Each of the grades specified have of the
following two types:
Type 1 Blockboards, Decorative Type:-These are blockboards with decorative face
veneers on one or both sides for use in high
class furniture, panelling, interior decoration,
partitions, etc. Type 2 Blockboards, Commercial Type :-
These are blockboards with veneers of
commercial timber on both sides and are usedfor ordinary furniture, table tops, partitions and
panelling to be painted over, flooring and seats
of bus bodies, railway carriage, etc.
THE GRADES AND TYPES OF BLOCKBOARDS BY
-
7/30/2019 Processed Wood
42/49
THE GRADES AND TYPES OF BLOCKBOARDS BY
SYMBOLS
Grade and Type SymbolExterior grade, decorative
type
XDEC
Exterior grade, commercial
type
XCOM
Interior grade, commercialtype
ICOM
Interior grade, decorative IDEC
-
7/30/2019 Processed Wood
43/49
SOME ADDITIONAL INFORMATION
Structural plywood:- A plywood of thehighest grade of structural exterior capability
used between joists and such to create
rigidity and provide a base for other surfacefinishes.
-
7/30/2019 Processed Wood
44/49
PLYWOOD FOR CONCRETE SHUTTERING WORKS
TYPES (IS 4990: 1993)
Types
Description Designation
1 Plywood for concrete shuttering
work ( plain )
CS
2 Plywood for concrete shuttering
work with plastic coating ( coated )
CSC
3 Plywood for concrete shuttering
work with suitable overlay ( film
faced )
CSFF
-
7/30/2019 Processed Wood
45/49
-
7/30/2019 Processed Wood
46/49
The size of plywood is not restricted by the size of
the tree it came from, but the size of the presstable used to make it.
Solid wood is 20 times stronger along the grainthan across. Plywood over 10mm thick is almostequal in strength in both directions.
Timber shrinks mostly across the grain. Shrinkageis almost eliminated in plywood due to the layers
being in alternate directions. Plywood can be formed or bent to make a curve.
Plywood does not split at the edges when nailed orscrewed.
-
7/30/2019 Processed Wood
47/49
-
7/30/2019 Processed Wood
48/49
BLOCK BOARD HARD BOARD
-
7/30/2019 Processed Wood
49/49