Do you think a cereal box would survive the shipping process? Most likely not, as the folding cartons made of cereal or mac and cheese paperboard are easily crushed and sent through the mail alone. Fortunately, corrugated boxes don’t face the same fate.

They are designed to withstand the shipping process. And this is the reason for their prominence in the industry. The Corrugated Boxes Market is expected to be $90.7 Billion in 2030 per GMI Research. This shows the importance of corrugated boxes in the e-commerce, logistics, and retail industries.

So what is their secret?

What Gives Corrugated Boxes Their Strength?

Corrugated boxes are made of layers, 3 in most cases. The outer liner is flat, the middle is flute which is a rippled layer, and the last layer is another liner.

The layer in the center with the waves is where all the magic occurs. It provides both cushion and strength. It also absorbs and distributes pressure, and it functions as a protective layer for what is packed inside the box.

Some boxes come with additional layers which can be called double-wall boxes, or triple-wall boxes, and these boxes are made for heavy-duty use.

The Paper Used in Corrugated Boxes

Kraft and test paper are the two types used in most corrugated boxes.

Because it is made from virgin wood pulp from softwood trees such as pine or spruce, kraft paper is stronger and of higher quality. It is also more durable, more water resistant, and is easier to print on. This is why it is used most often for the outer liner.

In contrast, test paper is used most often for the inner liner. While it is more affordable, it is still functional and works well for many applications.

Often, determining which paper to use is a matter of budget and strength needs.

What Are Flutes in Corrugated Boxes?

Te flute, or the C-shaped wavy liner is what provides reinforcement to the box and also additional stacking strength.

Different sizes of flutes provide different benefits.

The A flute is the thickest flute at about 1/4 inch and provides really good cushioning, and is the best for fragile items.

It may come as a surprise, but the B flute is thinner at 1/8 inch, yet offers more strength. This flute is most often used for retail displays or for canned goods.

C Flute is the most common and is around 3/16 inch thick. If you got a standard shipping box, it was most likely C Flute.

E Flute is thinner and is around 1/16 inch. It prints better and is sometimes used in place of regular folding cartons.

F flute is 1/32 inch and is again thinner. It offers an even better surface for high quality printing.

The size of the flute determines the thickness, stacking strength, and printing quality. It is not simply a design choice, it affects overall performance.

What are the walls of corrugated boxes?

Once you have settled on choosing a flute, you have another choice to make. Wall construction.

Single face uses one liner and one flute layer. These are often used for additional padding.

Single wall is the most common, with one flute layer sandwiched between two liner sheets.

Double wall construction adds one more flute and liner layer. These are stronger, but less flexible. They are ideal for heavier items.

Triple wall is extremely heavy duty with three flute layers and four liners. These are often used in industrial packaging.

More layers mean more protection, but they also mean more weight and a higher cost. Its always a balance.

Different Styles of Corrugated Boxes

Strength is important but so is the fit.

Boxes come in many styles, each one addressing a specific need.

The Regular Slotted Container (RSC) is a standard transport container. The container's flaps are all the same length and when the container is closed they meet in the middle.

With the Full Overlap Container (FOL) the outer flaps fully overlap and as a result, the top and bottom of the container have double thickness.

The One Piece Folder (OPF) is typically used in the shipping of books and other flat objects as it wraps neatly around the item.

The Full Telescopic Design (FTD) has an upper and lower portion that slide over one another which is good for added strength.

The right style of container that is selected for shipping will protect the products from shifting or being too tightly packed.

Conclusion

At first glance an ordinary corrugated box may seem unremarkable, but actually possesses sophisticated engineering for the purpose protection, efficiency and flexibility.

The selection of flute and wall design, as well as box style, are all integral in ensuring the reliability of the box.

As global e-commerce continues to grow, the industry of corrugated packaging will grow alongside it, especially considering industry forecasts suggesting that it will be increasingly relied upon for protective transport and logistics in the future.