How Is Corrugated Cardboard Made?

Have you ever wondered about the humble shipping box? Well, they're made of a special type of cardboard, called corrugated cardboard. Unlike regular cardboard, it has a wavy layer, called a "flute", sandwiched between two flat sheets. This unique structure makes the box both lightweight and sturdy, perfect for protecting the stuff inside during transit.

Here's how it's made. It starts with a roll of thick, flat paper called the "Medium". This roll gets pushed through a machine that crimps it into waves, transforming it into a "flute". Then, glue is spread on both sides of the flute. It gets sandwiched between an inner liner and an outer liner, and heated to seal everything together. This extra flute layer not only makes the box stronger but also allows air to cushion and support the contents.

Sometimes, a box needs to be extra sturdy. In that case, the machine will create a double-layered box. This box includes two flutes between three liners. It looks like this: outside liner, flute, inside liner, flute, inside liner. This super strong box is perfect for heavy-duty products and shipping.

The story of the cardboard box is quite an interesting one. It was accidentally invented by a printer and bag maker named Robert Gair in the late 1800s. While trying to crease a paper bag with a metal ruler, he accidentally cut it. Instead of seeing this as a failure, he realized he could cut and fold the paper to create a box. As time went on, he started making corrugated shipping boxes and built a successful business. His invention has been a game-changer in shipping products for over a century!