1. Introduction: Corrugated
fiberboard as a light weight structure composed of liners separated by the
corrugating medium which give adequate protection for the product during the
transportation, storage, distribution and handling. Corrugated fiberboard of middle
layer called a corrugated medium a one and two flat papers called the liners
which are glued at the tips of the medium. The flute comes in fours standard
size. B flute which is most commonly used give better crush resistance, fold
more easily. Printing of the corrugated board by flexography printing. Corrugated
fiberboards are usually designed by the maximum mullen bursting test of board.
Bursting strength is used to determine the amount of hydrostatics pressure in
kg/cm2 required to obtain rapture of the material. The pressure is applied at a
controlled increasing rate though a rubber diaphragm.
2. General information: If one each liner & fluting are used it is
called as single face board or a 2 ply board. If two liner & one fluting
medium are used it is called as double faced board or a 3-ply board. The
combination of two medium and three liner is called as five
ply. The combination of three medium & four liner is called as seven ply.
Corrugated board is generally made in one of nine flute size which are named as
A, B, C, E,F,N and k. The Grammage of Kraft paper is normally 100, 120, 150 GSM.
The Corrugated fiberboard box strength depends upon paper quality, moisture
content, number of plies, Types of flute. Corrugated fiberboard box defects are
wrap, delimitation because of excess gluing, wash boarding, bubbles, cut flutes
etc.
· 2.1
Normal shipper: Corrugated
Boxes are made up of corrugated paperboard. The surface colour of Kraft paper
is brown, non bleached and not any kind of surface treatment is done. The Kraft
paper on without any surface treatment so water absorption and cob value of Kraft
paper in high. The normal shipper only one colour printing done by flexography
printing process. The bursting strength and bursting factor poor compare to
printed shipper. Corrugated Boxes are light weight and thus are very convenient
to handle while packaging, loading and unloading.
· 2.2
Printed shipper: The
surface of printed shipper is single or multicoloured. The upper liner of
shipper needed white paper with good bursting strength and bursting factor.
These papers are china clay coated paper. Clay coating create good surface
printing and multicolour ink adsorption is fine. They use wet offset printing
process for printing of board. Corrugated cardboard boxes have better printing
and graphics capabilities. As such, they can be used as effective marketing
tools for brand awareness and promotion.
3. Test parameter:
· Appearance: Corrugated box is neatly cut, properly creased staples with
rust free staples and no separation of layers.
· Text matter: Compare text matter of sample with approved artwork.
Acceptance
criteria: Text matter should be as per approved artwork
· Weight: Weigh the corrugated box on weighing balance.
Acceptance criteria: Tolerance for
weight: ± 5%
· Dimension:
Acceptance
criteria:
Tolerance
for Length : ± 10 mm
Tolerance
for Breadth : ± 10 mm
Tolerance
for Height : ± 10 mm
· Grammage:
Cut the sample in 10cm x 10cm piece, dip the cut piece of 10
cm square in water and peel off layer one by one. And dry it carefully. Weigh
it each layer and calculate the Grammage with following formula
Weight of 10 cm x 10 cm piece in gm
Grammage = -------------------------------------------------
x 10000
10 cm x 10 cm
Acceptance
criteria:
Grammage: Not less than 100 gsm.
