How is cardboard manufactured?

They make cardboard out of outer flat sheets (liners) of

puncture resistant paper, sandwiching a central "filling" (fluting,

so called because it's fluted) of corrugated short fibre paper. The

paper used for the fluting may also be "Semi-Chem", so called

because chemicals are used to "stretch" the fibres, making it

stronger and stiffer. The paper used to make the "fluting" is

generally paper that weighs in around the 90 grammes per square

metre (gsm) mark, although it is not uncommon to use "Semi Chem",

that may weigh up to 171 gsm. Because "semi chem" is tougher and

drier than your average waste based fluting, there is generally a

lot of steam and heat applied in the actual corrugating machine.

For normal fluting paper, only a small amount of heat, and no steam

would be applied. Then, the "bottom-liner" and "medium" (outer and

inner portion of the final corrugated board product, which may not

necessarily be brown, they can be white, or "mottled") are glued

together along the outsides of the peaks and valleys of each flute,

normally using starch adhesives. There are endless possibilities to

finish, length and width of the board being produced. The width is

only dictated by the width of the machine bed, which may be

anything up to 3.5 metres (around 11 feet) wide. The length is

generally dictated by the length of the "dry end" of the machine,

but I personally have seen board being cut up to 4 metres long, and

as short as 600 millimetres. I hope that makes things a little

clearer for my fellow "Wiki-ers".