Corrugated paperboard is made using large corrugation machines that are able to create paperboard at a speed of 500 lineal feet per minute. To create corrugated paperboard, the paper[paper?:paper sample maker cutting machine] is subjected to high pressure steam, which softens the fibers. The fibers are bent to create the required thickness of flute between thepaperboard sheets.
Next, pressure is applied to the top and bottom of the corrugated paperboard to increase the strength of the material. The flat liner boards are brushed with an adhesive on one side and then the corrugated paperboard is sandwiched between the two layers of flat liner board. Corrugated paperboard can be made in different colors, but is most commonly manufactured in brown, white or mottled white.
The thickness of the flute can be modified to create different degrees of strength in the corrugated paperboard. There are 5 standard thickness in the US, indicated by letters A through F. The letter indicates when it was invented, and not the relative size.
