Corrugated Box Testing: Is Your Packaging Up to Spec?

Good packaging needs to survive the whole distribution chain, from producer to end consumer. Specifications depend on the hazards of your distribution chain.

Exceptional savings with the right transport packaging

Are your transport and product packaging solutions working together to be as efficient as possible? Our solutions are customized for your unique packaging supply chain and are designed to lower your total cost, reduce packaging damage during transport and create the impact your brand requires. The use of world-leading corrugated materials ensures you get strong and attractive transport and retail packaging.

Protection is the primary goal of all packaging. For brands shipping from Asia to European and North American Markets, this means withstanding a great deal of external forces in the transport chain (shock, vibration, compression, etc.) as well as environmental factors specific to that part of the world.

Corrugated board is well suited for the job, but only if it’s designed to withstand such forces. Unfortunately, lack of global performance standards can make it difficult for exporting companies to specify their needs when communicating with corrugated manufacturers overseas. Worse, packaging suppliers may sometimes deliver corrugated board that does not meet spec requirements, leaving exporters with sub-par packaging solutions unfit for the demands of their supply chain.

Testing Procedures for Corrugated Boxes

Corrugated boxes fail in many ways and for many reasons, but two very common failures that we see, especially in packaging made overseas, are collapse under a compressive top-load or by rupture due to rough handling. There are several tests that can predict the performance of corrugated boxes under these conditions, including the box compression test (BCT), edge compression test (ECT), short-span compression test (SCT), bending stiffness and the International Safe Transit Association's transportation testing procedures.

Box Compression Test

The box compression test itself is fairly unsophisticated: a fully converted, empty box is placed between two steel plates and compressed at a steady force until the box is crushed. However, it’s important that the environmental testing conditions (temperature and humidity) are similar to the actual conditions your packages are exposed to on their way from manufacturers in Asia to distributors and retailers in Europe and North America.

The maximum compressive load of corrugated containers decreases as surrounding temperature and relative humidity increase. Unfortunately, traditional compression testing doesn’t always take into account the actual transport conditions. This can be extremely problematic (and costly) for global brands with operations in humid environments, particularly Asia. Time is another critical element during box compression testing. The effects of stress and strain are not always immediately revealed, so in addition to complete collapse, boxes should also be held at a predetermined load for a given period to evaluate stacking loads.

Edge Compression Test

ECT is a short column test of the vertical compression load that measures the ability of a sample to sustain top-to-bottom load. After you know the strength of the board, you can use this number to predict the stacking strength of common box designs at various dimensions. It is measured by compressing a segment of board until a peak load is established (pounds per lineal inch of load bearing edge). Boxes built to ECT specifications are designed for stacking strength but may not withstand external or internal forces. Burst testing measures the containment and handling ability of a box (force of pounds per square inch required to rupture the side of corrugated board).

ECT vs Burst: Which is Better for Your Packaging?

ECT and burst are common specifications for transport boxes. Specifying ECT or burst depends on the nature of your supply chain. For example, if the environment is such where boxes are processed through harsh environments and subject to puncturing, build to burst; a more modern supply chain calls for ECT since boxes in this environment are not subject to as much handling because they are unitized. The key is understanding your distribution chain and requesting packaging materials that are specifically designed for that environment.

ECT and the McKee Formula

The McKee formula estimates box compression strength and is used by packaging designers and engineers to predict the overall stacking strength of simple packaging types (e.g., regular slotted containers and FEFCO’s #0201 box) at different sizes. The McKee formula requires ECT as an input (lbs./inch) to calculate the theoretical compression value for a box, but it can also help in “reverse engineering” a box—if you know the dimensions and have a target stacking strength, the McKee formula can tell you what ECT you need to manufacture your board to.

The Right Packaging for Your Supply Chain

How do you control your packaging from 8,000 miles away? How do you know your boxes are up to spec? How do you know your packaging solutions are fit to withstand the external forces throughout your distribution chain? You partner with BillerudKorsnäs.

With box testing laboratories in the United States, Sweden and China, our engineers can tell you exactly what kind of corrugated board your manufacturers are using and whether the specifications are appropriate for your supply chain. World-class equipment allows us to simulate real world conditions, with varying degrees of humidity and temperature so we can predict packaging’s true performance. When we develop and test packaging solutions, we focus on the entire supply chain to ensure packaging can withstand all it is exposed to on the long trip from factory to consumer.

We also examine color consistency, material composition and the unpacking experience. In total, we take a complete look at your packaging to make sure it’s the best for your supply chain.

BillerudKorsnäs Corrugated Testing Capabilities by Region 

Portland, Oregon Testing Lab

  • BCT, Fmax ~2000kg, platens 1000 x 1000 mm (ISO 12048, TAPPI 804)
  • ECT (ISO 3037, TAPPI 811)
  • 4-pt Bending Stiffness (ISO 5628, TAPPI 820)
  • FCT (ISO 3035, TAPPI 825) and FCTz (internal standard)
  • Ink Rub (TAPPI 830)
  • Ink Color (ISO 5631)
  • Transportation Testing ISTA 1A, 1C, 1G, 2A, 3A, 7D 
  • Optional temp and RH% in conditioning chamber 

Gruvön, Sweden Testing Lab

  • BCT, Fmax ~1000kg, platens 600 x 620 mm (ISO 12048, TAPPI 804)
  • ECT (ISO 3037, TAPPI 811)
  • 4-pt Bending Stiffness (ISO 5628, TAPPI 820)
  • FCT (ISO 3035, TAPPI 825) and FCTz (internal standard)
  • SCT (ISO 9895, TAPPI 826)
  • Tensile Properties TS, force & stretch at break, TEA (ISO 1924, TAPPI 494)
  • Bottom deflection trays UNE 49706 and internal standard
  • Creep testing on paper and packaging according to internal standards
  • Standard climate 23ºC, 50%RH and 90%RH in walk-in climate chamber, + optional temp and RH

Shenzhen, China Testing Lab 

  • ECT (ISO 3037, TAPPI 811)
  • 4-pt Bending Stiffness (ISO 5628, TAPPI 820)
  • FCT (ISO 3035, TAPPI 825) and FCTz (internal standard)
  • SCT (ISO 9895, TAPPI 826)
  • Burst (ISO 2759, TAPPI 810)
  • Tensile Properties TS, force & stretch at break, TEA (ISO 1924, TAPPI 494)
  • Transportation Testing ISTA 1A, 1B, 1C, 1D, 2A, 2B, 7D
  • Ink Rub (TAPPI 830)
  • Ink Color (ISO 5631)
  • Standard climate 23ºC, 50%RH in walk-in chamber + optional temp and RH in conditioning chamber

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