Boxes start out as trees. Even when manufacturers use recycled paper, this originally came from trees. Once the tree has been cut down, the wood is pulped. The basic process of pulping wood is to separate it into chips that are then broken down into individual fibers. The fibers are washed and bundled. They are then shipped out for processing into paper or other products. This is just the beginning of the journey for wood that will become boxes.
Once the pulp has arrived at the paper manufacturer, box paper is created. There are several types of paper used for boxes. The outside of the box requires a smoother finish and more strength. It must resist any outside elements and the consumer must be able to write on it. The outside paper used for boxes is called Kraft. While recycled paper is used in this process, much of the outside of the box is made of paper in its first use. This contributes to the strength of the box and helps it resist environmental factors such as dampness.
The inside of the box is also made of paper. This paper is nearly 100% recycled product and is called the liner. It is not quite as smooth as the outside of the box, but that is not necessary. Consumers generally have no reason to write on the inside of a box and rarely notice the difference in texture. Strength and durability as a packaging material are important for boxes. This is why there is more paper between the liner and the outside of the box. This is called a flute and is made by a machine. Rolls of paper go into a fluting machine and come out corrugated.
Once the inner liner, flute and outer coverings have all been made, the box is ready for assembly. The flute goes through a machine that adds glue to both sides of it. The inside liner and outside box cover are added. A machine is then used to cut the finished cardboard into the correct size for the box being manufactured. Once that occurs, the box is glued into a square and the tops and bottoms are scored so the cardboard is easy to fold into a cube. Finished flat boxes are placed on pallets and shipped.