Most people today have heard of corrugated cardboard. In fact, this material has become ubiquitous and is used in a wide range of applications. However, few people know how it is made and what a corrugator machine does. Here is important information on the process of corrugation, which helps to keep the wheels of industry in motion.
History
Corrugated material as we know it today all started in the late 1800s. A chemist from Sweden named Dahl invented a method for making strong and durable paper from wood chips. This paper does not tear easily like standard paper and is an excellent material for packing and bagging. It became known as the kraft process is and this is where the name “kraft paper” comes from.
Kraft paper is made into large rolls and shipped to processing plants all over. If you glue together several layers of this paper it will become even stronger, but it will still be paper (which is limp in nature). In order to stiffen the paper and turn it into a stronger material it is crimped in a corrugator machine.
Corrugation
In order to corrugate kraft paper, it is sometimes steam heated. In fact, the steam is under high pressure and can heat the paper to temperatures of 350 degrees Fahrenheit. The paper then passes between two corrugation rollers. These rollers contain special ridges or teeth which mesh together as they roll and this is what creates the crimping action on the paper. These crimps are known as flutes.
After corrugation, an adhesive is applied to the outer areas of the medium as it passes through a glue roller. On the other side of the process, pre-heated paper travels to a pressure roller which contacts the upper or second corrugation roller. Both the liner and corrugation are pressed together in the pressure roller and this is what forms the bond. To create cardboard, another liner is applied on the other side in a similar method.
Corrugation and the Power of Triangles
factAt first, glance, three sections of paper glued together should not be able to create a stiff and durable structure. However, it comes down to physics and the power which is taken from triangles.
Suppose you have a three dimensional triangle made from paper sitting on your table. If you press down on the top or peak of the triangle, the pressure or force is distributed evenly to the bottom. In fact, it will resist bending much more than simple paper. There are many triangles absorbing the forces around them in one tiny piece of corrugated cardboard. Now multiply this force by thousands and you will see why cardboard (created from a commercial corrugator machine) can be so strong and durable.