Understanding Corrugated Boards: The Key to Perfect Packaging

Table of Contents

• Understanding Corrugated Flutes in Packaging Boxes.

• Top 3 Major Problems with Corrugated Flutes.

• Corrugated Board Structures and Applications.

• Paper Type for Corrugated Board.

• Type of corrugated-flute.

• Most Common Use and its benefits of Corrugated Flutes.

• Key Takeaways.

Understanding Corrugated Flutes in Packaging Boxes.

What are Corrugated Flutes?

Corrugated flutes, those wavy layers you see when you look at the side of a cardboard box, are the key to its strength and protective qualities. They're made from a sheet of paper called the "medium" that's been shaped into a series of arches. This medium is then glued between two flat sheets of paper called "liners," creating the familiar three-layered structure of corrugated cardboard.

The Role of Flutes in Packaging

Flutes act like tiny columns, providing vertical support to the box and resisting crushing forces. The air trapped within the flutes also acts as a cushion, absorbing shocks and vibrations during handling and transport. Different flute sizes and types offer varying levels of strength, cushioning, and printability, making corrugated cardboard a versatile packaging material suitable for a wide range of products.

Beyond Shipping Boxes

While corrugated cardboard is commonly associated with shipping boxes, its unique structure makes it suitable for a wide range of packaging applications beyond just shipping. Corrugated flutes can be found in retail displays, product packaging, dividers and inserts, and even furniture. The versatility of corrugated flutes allows for creative and functional packaging solutions that go beyond the traditional shipping box.

Top 3 Major Problems with Corrugated Flutes.

1. Loss of Strength & Compression: Over time or under heavy loads, corrugated flutes can lose their structural integrity, leading to box collapse or damage to the contents.

   • Solution: Choose a flute type with appropriate strength for your product's weight and stacking requirements. Consider reinforcing critical areas with additional layers or inserts.

2. Moisture Damage & Warping: Corrugated cardboard is susceptible to moisture, which can weaken the flutes, cause warping, and compromise the box's protective qualities.

   • Solution: Opt for moisture-resistant coatings or treatments for boxes exposed to humid environments or potential spills. Proper storage and handling practices can also mitigate moisture damage.

3. Printing & Labeling Challenges: The uneven surface of corrugated flutes can present difficulties for printing high-quality graphics or applying labels accurately.

   • Solution: Utilize advanced printing techniques like flexography printing, which are designed to accommodate corrugated surfaces. Pre-printed linerboard or labels can also ensure consistent and attractive branding.

Most Common Use and its benefits of Corrugated Flutes.

B-Flute:

• Most Common Use: Die-cut boxes and displays

• Benefits: Offers excellent puncture resistance and crush strength, allowing for intricate designs and shapes while protecting the contents.

C-Flute:

• Most Common Use: General-purpose shipping boxes

• Benefits: Provides a balanced combination of cushioning, stacking strength, and printability, making it suitable for a wide range of products and shipping needs.

E-Flute:

• Most Common Use: Retail packaging and small boxes

• Benefits: Offers a thin profile with excellent printability, enabling high-quality graphics and branding while minimizing packaging size and weight.

G-Flute:

• Most Common Use: Inserts, pads, and dividers

• Benefits: Extremely thin and lightweight, making it ideal for space-saving applications and providing cushioning and protection for delicate items within packaging. In some cases, G-Flute can replace thicker paperboard (over 300 gsm.) to achieve lighter weight while maintaining similar strength, leading to potential cost savings in shipping.

BC-Flute:

• Most Common Use: Heavy-duty shipping boxes

• Benefits: Delivers exceptional strength and cushioning for large and heavy items, ensuring maximum protection during transit and storage.

Key Takeaways.

• Corrugated flutes are essential for strength and protection. The wavy structure of flutes provides vertical support and shock absorption, making corrugated cardboard ideal for various packaging needs.

• Different flute types offer unique advantages. Choosing the right flute type is crucial, considering factors like product weight, stacking requirements, and printing needs.

• Corrugated board structures cater to specific applications. From single-face for delicate items to triple-wall for heavy-duty shipping, each structure offers distinct benefits.

• Paper types influence strength and printability. Selecting suitable linerboard and medium paper grades is vital, balancing cost-effectiveness and performance.

• By understanding the different corrugated boards, their properties, and common applications, you can make informed decisions to optimize your packaging solutions.

Corrugated Board Structures and Applications.

1. Single Face Corrugated Board

• Structure: One layer of corrugated medium glued to one flat linerboard. Flutes are exposed.

• Outside Liner: Kraft paper for moderate strength and printability.

• Inside Liner: Not applicable (single liner).

• Applications:

  • Wrapping and cushioning delicate items

  • Protective layer inside boxes

  • Art and craft projects

2. Single Wall Corrugated Board (Double Face)

• Structure: One layer of corrugated medium glued between two flat linerboards.

• Outside Liner: Kraft paper or Test liner for general purpose packaging and printing.

• Inside Liner: Test liner or recycled paper for cost-effectiveness

• Applications:

  • Shipping boxes for lightweight to moderately heavy items

  • Retail displays and packaging

  • Dividers and inserts

3. Double Wall Corrugated Board

• Structure: Two layers of corrugated medium glued between three flat linerboards.

• Outside Liner: Kraft paper or high-performance liner for demanding applications and printing.

• Inside Liners: Test liner or recycled paper for the center liners.

• Applications:

  • Shipping boxes for heavy and bulky items

  • Industrial packaging

  • Pallets and bulk bins

4. Triple Wall Corrugated Board

• Structure: Three layers of corrugated medium glued between four flat linerboards.

• Outside Liner: High-performance liner for maximum strength and durability.

• Inside Liners: Test liner or recycled paper for the inside liners, and center liners.

• Applications:

  • Heavy-duty shipping containers

  • Crates and export packaging

  • Construction and furniture applications

Paper Type for Corrugated Board.

The most commonly used linerboards and medium paper grades, is being made to ECT system.

• Kraft Paper: Manufactured from softwood trees. This consists of 70-80% “virgin” fibers which makes it both durable and easier to print on. Offers good strength, printability, and tear resistance. Suitable for most packaging applications.

• Test Liner: Manufactured from 100% recycled fiber, but often includes a small percentage of virgin fibers to improve strength and printability. More economical than kraft paper, with moderate strength. Suitable for inside liners, medium and less demanding applications.

• High-Performance Liner: Manufactured from high-quality cellulose fibers, often with added strength enhancers and coatings. Provides superior strength, moisture resistance, and puncture resistance. Ideal for heavy-duty and demanding applications.

• Recycled Paper: Manufactured from a wider range of recycled paper products, including old newspapers, magazines, office paper, and cardboard. The specific composition will vary depending on the intended use of the recycled paper. Suitable for inside liners, medium and less critical applications.

The specific paper type selection will depend on the intended use, product requirements, and budget considerations.

Type of corrugated-flute.