1. LONG GRAIN AND SHORT GRAIN
The sheet is in long grain if the larger dimension is parallel to the grain (MD) direction. The sheet is said to be in short-grain if the larger dimension is parallel to the cross direction (CD).
2. BASIS WEIGHT (GRAMMAGE)
The Basis Weight of paper is the weight per unit area. This can be expressed as the weight
in grams per square meter (gsm of g/m2)
3. SIZING/COBB
Resistance towards the penetration of aqueous solution/water is measured by sizing or
cobb values.
The Cobb size tester measures the weight, in grams, of water absorbed in a given length of
time, normally one minute (GSM/Minute).
4. CALIPER
Thickness or Caliper of paper is measured with a micrometre as the perpendicular
distance between two circular, plane parallel surfaces under a pressure of 1kg/cm2.
5. BULK
Bulk is the volume of the paper per unit weight and is expressed as cc/gm. It is the
reciprocal of density (weight per unit volume), It is calculated from caliper and basis
weight.
Bulk = Caliper in microns / Basis weight in GSM
6. TEARING RESISTANCE
It is the amount of work done in tearing the paper through affixed distance after an initial
out. Tearing resistance is more in cross direction than machine direction.
7. BURST STRENGTH/BURST FACTOR
The bursting strength is the resistance to puncture by a blunt object. The results are
reported in pounds per square inch or kgs. Per square centimeter or kilopascals required
to take the sample to rupture. Bursting strength indicates a composite of strength and
toughness. Hence, it is useful in testing for bags, wrapping papers and box boards where
the paper is subjected to stress similar to that exerted in the bursting tests.
8. TEARING STRENGTH /TEAR FACTOR/TEAR INDEX
Tear is the determination of the average gram force/milli newton required to tear a single
sheet of paper through a specified distance after an initial tear has been introduced.
9. TENSILE STRENGTH/BREAKING LENGTH/TENSILE INDES
Tensile strength is a measure of the force per unit width required to break a specimen in
either the machine or cross-machine machine direction.
10. CRUSH TEST
The crush test is used to determine the compression strength of a material. The crush test
also detects poor adhesive penetration spotty adhesion and carton board with low bond
strength.
1. MACHINE DIRECTION
That direction in a paper or a board corresponding to the direction of the flow of the
stock.
2. CROSS DIRECTION
That direction in the plane of a paper at right angles to the machine direction.
3. TOP SIDE
The face of a web or sheet of paper or board opposite to the wire side.
4. WIRE SIDE
The face of a web or sheet of paper or board which was in contact with the forming wire
during manufacture.
5. MACHINE – FINISHED (M.F) PAPER OR BOARD
Paper or board treated mechanically onthe making machine to improve the smoothness
and uniformity of appearance on both sides.
6. MACHINE-GLAZED (M.G.) PAPER OR BOARD
Paper or board which has had one side made smooth and glossy by dying in contact with a
heated, polished metal cylinder which forms part of the drying section of the machine. The
other side of the paper or board remains relatively rough).
1. To calculate the weight (in kilograms) of a ream containing 500 sheets of a give size in
inches and gram weight (substance)
Ream Wt = Length (inches) x Breadth (inches) x Gram Weight (gsm)/ 3100
2. To calculate the weight (in kilograms) of a ream containing 500 sheets of a given size in
centimetres (cm) and gram weight (substance).
Ream Weight = (Length cm) x Breadth (cm) x Gram Weight (gsm)/ 20000
3. To calculate the equivalent weight of different sizes of sheets; Multiply known ream
weight by length and breadth of sheet, the weight of which is required, and divide the
result by length and breadth of sheet the weight of which is known.
Ream Weight = (Length cm) x Breadth of Sheet of Unknown Weight / Length x Breadth of
Sheet of Known Weight
4. To calculate the length of paper in reel in metres.
Length of paper = (Weight of reel kg) x 100000(metres) / Reel Width (cm) x Gsm
5. To calculate the approximate number of sheets of a particular size.
No. of Sheets = Weight of Reel (kg) x 100,00,000 / Substance (gsm) x Width(cm) x Length(cm)
