Are you getting the right corrugated material for your products?

Corrugated cardboard is often the perfect material for protecting your products in transit. It’s strong, flexible and provides cushioning to make sure your items reach their destination in pristine condition. But getting the thickness and strength of corrugated material right is crucial: too thick and you will be paying for weight and material not needed; too thin, and your products may be damaged.

In this blog, we’ll look at the construction of corrugated board and the relative merits of the different thicknesses available.

Cardboard is made up of different layers designed to provide cushioning and strength for holding products securely during storage and transport. Liners are the flat ‘paper’ inner and outer layers and fluting is the wavy inner layer that adds strength and cushioning. These are glued together to create corrugated cardboard and vary in weight and thickness to provide different levels of protection.

Liners

Outward facing liner

The outer liner provides the main surface strength of a box and is often made from Kraft paper which is composed of virgin fibres, providing superior strength, protection from handling and durability.

Inward facing liner

The inner liner faces the contents of the box and is often made from Test paper which is composed of recycled fibre, which has sufficient strength for this purpose and is more economical.

Flutes

The wavy inner ‘fluting’ is commonly categorised by thickness and density across different types to allow for customisation between heavy-duty shipping strength and high-quality printing for retail. Each flute type varies in thickness, strength, cushioning, and printability, making it important for businesses to choose the right material for their specific application.

B Flute

B flute is around 2.5–3 mm thick. It provides good puncture resistance and a relatively flat surface so suitable for multiple uses. This flute type is commonly used for die-cut boxes, food packaging, and point-of-sale displays. It strikes a balance between strength and printability, making it a versatile choice for businesses that need both durability and branding impact.

C Flute

C flute is one of the most widely used corrugated profiles, with a thickness of approximately 3.5–4 mm. It offers a strong balance of cushioning, stacking strength, and print surface quality. Because of its versatility, C flute is often used for shipping boxes across a wide range of industries, including e-commerce, electronics, and consumer goods.

E Flute

E flute is much thinner, typically around 1–1.5 mm thick. Its slim profile allows for excellent print quality, making it ideal for retail-ready packaging and branded boxes. While it doesn’t offer the same level of cushioning as thicker flutes, E flute is perfect for lightweight products such as cosmetics, small electronics, and subscription boxes. It’s also commonly used where storage space and shipping efficiency are priorities.

Double Wall Options: Improved strength and applications

For more complex applications, it can be a better choice to combine flute types into double-wall constructions. These options significantly increase stacking strength and durability, making them suitable for industrial goods, bulk shipping, and export packaging. It is also possible to get different paper grades in flute types to also increase box performance.

EB Flute

EB is usually around 3.6 – 4.1mm and combines E Flute, a thinner grade, with B Flute, a thicker one. This double wall provides additional strength plus a more aesthetically pleasing and printable cover. It is possible to order with a white outer paper should the demands of the packaging require this.

BC Flute

BC is between 6 – 7.6mm thick. This double wall, made from two relatively thicker and more robust flutes, gives a better performance where enhanced protection is needed. This may be for heavier weight machinery or transit protection. This double wall is also available with a white outer paper.

CA Flute

CA is the thickest, around 8.7mm thick. This double wall, made from A Flute, the thickest and C Flute. CA Flute has high strength and rigidity and is primarily used for industrial parts, large furniture, and heavy machinery packaging. It is highly effective for shipping items that require strong, durable boxes for stacked storage and transportation.

Choosing the Right Flute – get good advice

Selecting the correct flute depends on your product’s weight, fragility, shipping and branding requirements. It’s important to find out which material, or combination of materials, is right for you. Our friendly, expert team are always on hand to look at your product requirements and suggest the best flute choice for whatever your product needs.

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