How are Corrugated Boxes Made?

How are Corrugated Boxes Made?

Corrugated boxes are everywhere,carrying products from all

over the world and just down the street. Your favorite pizza prob-          

ably comes delivered in a brightly colored corrugated box. Your

little brother or sister might use a big corrugated washer, dryer

or dishwasher box for a playhouse.You miatten and collect

corrugated boxes for recycling. Where do all those boxes come

from?

Do boxes come in boxes?
Boxes are about the only product not often shipped in boxes.
They’re usually shipped in bundles. They are made in special
factories called “box plants.”

Corrugated boxes are designed to be very strong. They are
made of corrugated paperboard, which is different from the
stiff paper known as “cardboard.” Look at the edge of corrugated
paperboard, and you will see a row of air columns. The air acts
as a cushion, while the paper columns make the material strong.
Each box is made to hold something just right, protect it from
banging around, and keep it from spilling. Boxes are made with
important information printed on them about what’s inside, or
how to lift or move them. Carefully designed inserts hold items in
place so they won’t spill or become damaged.

How many ways are there to build a box?
There’s a box for practically every purpose, and building it
begins when the box-plant salesperson asks the box-buying
customer just what kind of box is needed, how many, and
how soon?
Then a box designer starts planning. He or she has plenty
to consider: the size and shape of the customer’s product,
the size and shape of the finished box, the strength of the
material it’s made of, the color of the corrugated board, the
size of the flutes or paper ridges within it, the number of
boxes to be made, the coatings and printing they’ll bear, and
just when they need to be made and shipped.How will the 

customer put the box together, fi ll it, and close
it? How will the customer’s customer open the box? Will the
product-fi lled box be moved by hand or by fork lift? Stacked in
tall piles or singly? How roughly will it be treated?
A computer helps crunch the numbers. The box designer adds
human creativity and insight. The design, drawn on paper or a
computer screen, might look like a puzzle.

What is the first step in box building?
As you’ve learned, boxes are made of corrugated paperboard, or simply “board.” for short. There are
several kinds of corrugated board, all made by combining paper, heat, adhesives, and pressure.
It starts off as rolls of liner or paperboard, similar in appearance to the brown paper in grocery bags.
These rolls can weigh more than two tons each, and hold paper that could stretch several miles.
Corrugated board can be made up of one, two, or even three layers of flutes and liners, depending
on how strong the box needs to be.

Who’s who? What’s
what?
First, a little vocabulary lesson.
The wavy paper inside the corrugated board is called the corrugating medium. The fl at sheets on the outside are called liners.
Liner paperboard can be a natural brown color, mottled white, or all white. Most is made with about 35 percent recycled fiber, but recycled content can
be up to 100 percent.There are standard sizes of
flutes, the ridges in the cor-
rugated medium. Some corrugated boards have small
numbers of very large flutes; others have higher numbers of very small flutes. The use of the box determines which flute style is best.

A single liner, glued to corrugating medium, creates single face corrugated board. This flexible
material is sometimes used to cushion items such as light bulbs.
Corrugating medium glued between two fl at liners forms a single wall corrugated board. Most of
the boxes we see every day are made of this material, and in fact about 90 percent of corrugated
board is single wall.
Adding another corrugating medium and a third fl at liner creates a double wall corrugated board.
Stronger than the single wall board, it’s also heavier and more expensive. Furniture, appliances
and products such as nails, meat, and bulk peanuts are packed in boxes made from double wall
corrugated board.
There are also triple wall corrugated boards, big tough boards with three layers of corrugating
medium and four fl at liners, used for very large or very heavy products.

Roll ‘em!
Let’s start making a box by making corrugated board, on a long series of linked machines called
a corrugating line.
The corrugating medium, which will become the wavy middle layer in the typical three-layer corrugated board “sandwich,” is pre-heated and steamed so its temperature nearly reaches the boiling
point of water, 212ºF. This softens the natural ingredients in the paperboard, making it easier to
form into flutes.

The web, or long sheet of paper unwinding from the roll, is drawn between a pair of gear-like
cylinders called corrugating rolls. This shapes the paper into a series of precise waves. Glue is
applied to the tips of these flutes on one side — just the right amount, and at just the right places —
and the flute tips are pressed against a fl at liner.
This creates a single face web, a continuous sheet of fl at paper with fluted paper glued to it. To make
single wall corrugated board, the exposed flutes of the single face web have glue applied to them, and
they’re pressed against a second fl at liner.
Other parts of the corrugating line press creases into the corrugated board at precise places, so later
it will fold on these creases to create a three-dimensional box.
The continuous web of corrugated board is now so stiff that it can’t be rolled up. Instead, it’s cut
into fl at sheets, just the right size for making the boxes that have been ordered. The sheets are then
stacked and set aside so the glue can dry properly.
How swiftly does all this happen? Modern corrugating lines can move at more than 1,000 feet per
minute—more than 11 miles per hour, or three times as fast as a comfortable walk!

How does a board become a box?

Converting machines “convert” fl at corrugated boards into
boxes. The most common kinds of converting machines are flex o-folder gluers and die cutters.
Flexo-folder gluers print, crease, slot, trim, fold and glue the box so that it can be shipped fl at and then be easily formed by the customer and packed. Die-cut machines cut the corrugated board into a pattern the
customer will fold and glue into the box shape. A rotary die cutter uses cutting edges called dies, and creasing
rules, on a big roller to cut and score the corrugated board as it moves beneath it.

A fl at die cutter presses knives and creasing rules against a stationary board, the same way you
press a cookie cutter into cookie dough.
Whichever converting system was used, the corrugated box is now complete, and ready to carry,
contain and cushion a product that might be on its way to you!