Types of Corrugated Material Flutes

Did you just start a business and need custom packaging for your product? If so, Bolt Boxes is here to help. If you want to design a custom box — whether for e-commerce shipping, mailing or transporting heavy or fragile items — it’s essential to learn about the different types of packaging required for the job.

Eco friendly box with black print

While cardboard boxes are commonly used for packaging small items — think cereal boxes — the corrugated board is used to transport heavier objects due to its strength and durability. Corrugated boards contain both a liner and a medium. While the liner is the flat material typically found on the outside surfaces of the board, the medium can be found between the liners and creates the arch shapes, or “flutes.”

Flutes are significant contributors to the overall strength of the board and can affect its performance, weight and cost. The weight and type of material you desire to ship will help you determine the appropriate flute type. Knowing the difference between various flutes will help you decide which type would be best for your custom box.

What Is a Corrugated Material Flute?

The material flute is the corrugated or curved section between the two liners, and by changing its height, it’s possible to achieve different performance characteristics in the cardboard.

Because different flute types signal a variation in packaging weight, different sizes are used to create boxes for all kinds of merchandise — both heavy and light. For example, very fine flutes denoted as “E” material flutes are used to manufacture lightweight retail cartons. A more coarse material flute like an “A” or “B,” on the other hand, is most often used for transit packaging.

Using double-walled material, manufacturers can combine one or more flutes to create a grade such as “EB” or “BC” flute. Combining one or more material flutes can have several purposes, including to improve the outer appearance of a printing surface and create a rigid structure that’s perfect for more substantial items.

Material flutes are most often manufactured from a waste-based fluting, or WBF. These materials have been fully recycled. Flutes can also be constructed from semi-chem fluting, or SC material. Commonly used flute sizes are as follows:

  • A flute — 5 mm: This is the thickest type of flute. It’s ideal for products that need extra cushioning. However, because of the extra space between flutes, it’s not suitable for intricate packaging designs.
  • B flute — 3 mm: This flute is the most commonly used for shipping boxes, and it’s ideal if you’re looking for a mixture of strength and printability. The flutes make the boxes smoother for printing, while the density gives extra cushioning. Most mailer boxes use B flutes.
  • C flute — 4 mm: This is the standard flute for regular slotted containers, or RSC boxes. As the most common type of corrugated box, these containers are excellent packaging solutions for stacking, durability and crush resistance.
  • E flute — 1.5 mm: The E flute has an excellent printing surface but is not recommended for heavy objects.
  • F flute — 2 mm: F flutes are half the thickness of E flutes but are denser. F flutes have approximately 30% more flutes per foot than E flutes.
  • BC flute — double wall — 6 mm — combination of B and C flutes: As one of the thickest flute types, corrugated boxes with BC flutes can hold large, heavy items.
  • EB flute — double wall — 4.5 mm — combination of E and B flutes: This flute provides an excellent balance between transit protection, strength and finish.

Take Advantage of Designing Solutions for All Your Shipping Needs

If you’re interested in learning more about the types of corrugated box material fluting choice that will work best for your product, feel free to reach out to our team of designers at Bolt Boxes.

For almost 60 years, Bolt Boxes has been committed to helping our clients take their branding efforts to the next level with custom packaging. Choose from a variety of custom mailing boxes, including C-series, end-loading boxes and standard mailing RSC packages for your product line. You can also browse our work — which showcases various printing capabilities — for inspiration on which corrugated mailing box is right for you.