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An edge crush test (ECT) is a critical assessment method used to determine the strength and durability of corrugated cardboard, which is widely used in packaging and shipping industries. This test specifically measures the stacking strength of corrugated cardboard to ensure that it can withstand the rigors of transportation and storage.

Understanding and applying the edge crush test is essential for anyone involved in the manufacturing, packaging, or shipping of goods using corrugated cardboard boxes. The primary reason for this is the test’s ability to evaluate the quality of the cardboard material. By doing so, it helps in identifying whether the cardboard is strong enough to protect the contents during the various stages of transportation, including handling, stacking, and shipping.

The Importance of Edge Crush Test in Packaging

The edge crush test is particularly important because corrugated cardboard is not just a packaging material but also a critical component in the safety and integrity of shipped goods. The test ensures that the cardboard used in packaging is of a high standard and can reliably protect the contents from damage. This is especially vital for fragile or valuable items that require additional care during transit.

Moreover, the edge crush test helps manufacturers and shippers to improve their packaging solutions. By understanding the limitations and strengths of their cardboard material, they can make informed decisions about packaging design. This might include choosing the right thickness of cardboard, opting for additional reinforcing materials, or redesigning the box structure to enhance its strength.

How ECT impacts packaging design and material selection

The Edge Crush Test (ECT) significantly influences both packaging design and material selection in several key ways. Understanding how ECT impacts these areas is crucial for anyone involved in the packaging industry.

Impact on packaging design:

  1. Structural integrity: ECT results directly affect the structural design of the packaging. Designers use ECT data to determine how much weight and pressure a box can withstand. This is particularly important because goods often travel long distances and are subject to handling and transportation stresses.
  2. Optimization of material use: With ECT data, designers can optimize the use of materials. For instance, if the ECT rating is high, they might reduce material usage without compromising the package’s integrity. This approach is cost-effective and aligns with the growing environmental consciousness in the market.
  3. Customization for specific needs: Different products require different levels of protection. ECT allows designers to customize packaging solutions based on the specific needs of the product, whether it’s lightweight and fragile or heavy and robust.
edge crush test

Impact on material selection:

  1. Choice of Cardboard Grade: ECT is a deciding factor in selecting the grade of corrugated cardboard. Higher ECT ratings indicate stronger materials, which are essential for heavier or more valuable items.
  2. Sustainability Considerations: ECT allows manufacturers to select materials that are not only strong but also environmentally friendly, such as recycled or sustainably sourced cardboard.
  3. Cost-Effectiveness: Material selection is also about balancing cost and performance. ECT data helps manufacturers choose materials that offer the necessary strength without being excessively expensive.
  4. Innovation in Materials: As ECT is a standard test, it encourages continuous innovation in packaging materials. Manufacturers are always looking for new materials that can achieve higher ECT ratings, leading to stronger, lighter, and more cost-effective packaging solutions.

How is the Edge Crush Test Performed?

The Edge Crush Test (ECT) is a standardized method conducted in laboratories to evaluate the crushing strength of corrugated cardboard’s cross-section. This test provides essential insights into the corrugated cardboard’s capacity to withstand compressive forces.

In conducting an ECT, a force is applied perpendicularly to the corrugated cardboard until it collapses. This process determines the highest level of compression the material can endure before it fails.

By assessing the edge crush resistance of corrugated boxes, the test accurately determines the material’s durability. This information is crucial for producing boxes and packaging materials that effectively leverage the protective qualities of the cardboard.

The focus of the test is on the crushing resistance of the box’s edges and corners, as these areas are primarily responsible for supporting the load. Understanding the strength of these critical areas is key to gauging the overall durability of the box.

The edge crush test can be executed using specialized equipment within a manufacturing facility or outsourced to specialized laboratories and research centers dedicated to packaging.

Traditionally, the Bursting Strength Test (BST) was employed to measure the force needed to rupture corrugated cardboard, predicting its performance under rough handling. However, in more recent times, the ECT has become the preferred standard. This test is more aligned with current transportation needs, where boxes are often stacked on pallets.

Edge crush test machines measure the compressive strength at the edge of corrugated cardboard, presenting the results in pounds per linear inch (lb/in), commonly referred to as ECT.

It’s important to note that these values are not absolute but vary, as different manufacturing processes can produce varying strengths in the same type of corrugated cardboard.

Safe Load Testing Technologies’ Solution for edge crush test

Designed for testing compressive strength of packaging, packaging materials or creep performance of shipping containers, pallets and unit loads

Loads are exposed to different compressive forces both vertical and lateral, during handling, warehouse automatic storage and transport. The innPress family provides necessary information for packaging characterization and design.

ASTM D4169: standards and procedures

Which standards include an edge crush test?

A variety of global standards incorporate the edge crush test as a key component in their guidelines.

In Europe, the predominant standard is DIN EN ISO 3037. This standard specifies a method that does not use paraffin for testing the edges and is applicable to all types of corrugated cardboard. Its primary objective is to assess the crushing resistance of the edges of corrugated cardboard.

Additional standards encompassing the edge crush test are:

  • APPITA/AS 1301.444s
  • FEFCO 8
  • ISO 13821
  • SCAN P33
  • TAPPI T811
  • TAPPI T823
  • TAPPI T838
  • TAPPI T839

Each of these standards aims to evaluate the crushing strength and its characteristics, though they differ in the specifics of the samples or tools needed. Standards like FEFCO 8, TAPPI T838, and TAPPI T839, for instance, necessitate unique shapes for the corrugated cardboard samples and distinct clamping tools for the tests.

Various transportation companies also mandate adherence to specific criteria:

For instance, UPS and FedEx stipulate that packages weighing up to 30 pounds (13.6 kg) must meet a minimum of 200 BST or 32 ECT and adhere to ISTA standards. For packages that are heavier, these organizations demand superior cardboard quality than what is typically used for rail or road transport.

Additionally, certain airlines have their own comprehensive standards, particularly for transporting specialized products. These standards are closely linked to the specific requirements of air transportation.

FAQs

What is the difference between the edge crush test and the compression test?

While both tests are used to assess the strength of packaging materials, the Edge Crush Test focuses specifically on the strength of the corrugated cardboard’s edge, which is critical for stacking strength. In contrast, the Compression Test evaluates the overall strength of the material under direct pressure, providing a more general view of its durability and protective capabilities.

How often should the edge crush test be performed on packaging materials?

The frequency of the Edge Crush Test on packaging materials is not one-size-fits-all and should be tailored to the specific needs of the production process, industry standards, and the end-use of the packaging. Regular testing is key to ensuring that the packaging material consistently meets the required strength standards. However, there are general guidelines that can be followed:

1. During Development and Selection: ECT is crucial when introducing or choosing a new type of corrugated cardboard, ensuring it meets strength requirements for its intended use.

2. Quality Control in Manufacturing: ECT should be a regular part of quality control in production, with testing frequency varying based on the manufacturer’s protocols and production volume.

3. After Material or Design Changes: Any alterations in materials or packaging design necessitate a re-evaluation through ECT to confirm that these changes don’t compromise the cardboard’s strength.

4. Compliance with Industry Standards: ECT frequency may be dictated by specific industry or client standards, requiring adherence to these guidelines.

5. Post-Transportation Analysis: Conducting ECT after shipping can be useful, particularly if there were shipping damages, to assess if the packaging material needs improvements.

Do you need more information? Please don’t hesitate to contact us with any questions regarding packaging or the distribution chain of your goods. Our specialists are more than happy to assist you!

Enrique de la Cruz

R&D Manager

Enrique, as the visionary director of R&D at Safe Load Testing Technologies, shines with over 11 years of experience at the forefront of research, development, and transportation simulation for distribution packaging.

His expertise is not limited to his primary role; he is also a recognized expert in the ISTA Stability Group and a distinguished member of IAPRI and EUMOS, making him a key figure in the evolution of the sector.

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