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We filmed this fascinating movie on the way that cardboard is made from sheets of paper – and then transformed into cardboard boxes at the massive Corruseal factory in Johannesburg, South Africa.
How Cardboard Boxes are made
Today we’re in the Corruseal factory in Johannesburg to see how they make cardboard boxes
This factory produces the cardboard from scratch and then they design and make cardboard boxes of all shapes and sizes for the South African market.There’s a lot to see, so let’s get straight to it
The basic material used to make corrugated cardboard is paper. This arrives at the factory in large rolls which are handled and moved around the factory by forklift trucks fitted with special arms.
The cardboard manufacturing machine is huge, costing over 200 million rand and is imported from Italy. Rolls of paper are placed onto a feeder system which loads them into the machine.
The paper is loaded onto reel stacks and prepared to be fed into the machine.
There are a number of stations that feed paper into the machine. To make single wall cardboard they sandwich a sheet of corrugated paper between an inner liner, which will be the inside of the box and an outer liner which will be the outside of the box.
To corrugate the paper it is pressed between a corrugated roller, like this one here, and a pressure roller at high pressure and temperature. This creates a crinkle in the paper which is referred to asa corrugation.
This corrugated paper will form the centre of the cardboard and give it it’s strength.
Starch is used as the glue to join the sheets of paper together. Here enormous bags of powdered starch are loaded onto a mixing machine.
The starch powder is mixed with water and other additives to produce an adhesive of the correct consistency.
The adhesive is applied to the paper as it passes over a roller that is coated with adhesive and the corrugated paper is joined to the inner liner.
The paper is heated to between sixty five and eighty five degrees celsius by heated rollers. The heat turns the starch into a gel, bonding the two paper sheets firmly together.
The rollers are heated to 160 degrees celsius using steam which is generated in the factory.
After joining, the product is called a single phase web.
A double backer machine applies an outer liner, which will become the outside of the box, and a very long sheet of cardboard is formed.
The machine works at very high speed. Here it slows down from producing over 210 metres of cardboard each minute.
The long sheet of cardboard passes through a series of hot plates where the three sheets of paper are bonded together at high temperature and also at high pressure from the rollers.
It is slit to the desired width and cut to the correct length.
This machine is able to change to a new size of cardboard box by inserting new design parameters into the computer. Here we can see one run finishing and a new order coming off the production line.
The cardboard is complete.
Stacks of identical cardboard sheets are formed, ready to go off to be made into boxes.
Designing a box is an art. It must be of exactly the right height width and length and constructed from cardboard of a suitable strength and weight It also needs to be cost effective for the final user.
Firstly a design is created using CAD software. CAD stands for Computer Aided Design.
Once complete, the design details are fed into the computer of an automated cutting table.
The software controls the creasing and cutting tools, which create all the cut-outs and creases neccessary to make that particular box. This box has been designed to carry export grapes. Both the inner and outer linings must have a fair resistance to moisture.
Once the design has been perfected it’s loaded into the computer of a converter machine. This machine converts sheets of cardboard into boxes.
The first section prints the colour of the box as well as all of the information and design elements onto the cardboard sheets.
As is exits the machine it is creased and cut to shape.
The factory can produce over 200 tons of cardboard boxes each day to supply the enormous demand of the South African market.
Over 500 thousand tons of paper are kept in stock to ensure that the machines keep operating without pause 24 hours a day.
Here regular slotted cartons are made on a machine that uses glue to join the sides.
Other designs use die cut machinery to make boxes that clip together without needing to be glued. These can be made in many different styles and sizes.
Using a computer, the variety of cardboard box design is almost limitless. Now there’s and interesting job, cardboard box designer. Well, I hope that you’ve enjoyed the movie. I’ll see you in another one soon.