Are you about to undergo a package design? Or, perhaps you’re working with a customer on a packaging project. Regardless of which, you should be aware of the factors effecting ECT (edge crush test), understand why it is important to know about customers’ products and the customers’ distribution systems, and how ECT board combinations can best meet the customers’ needs.
The ultimate challenge of any corrugated box or package is to protect and contain the customer’s product throughout the total distribution cycle. Stacking performance has increasingly become the critical measure for product protection and correlates with Box Compression Testing (BCT). BCT is a dynamic measurement of the momentary force necessary to cause a box to fail (the corners buckle and sidewalls bulge to failure) or crush. Performed in a lab, compression test quantifies the maximum load the box can support at its initial failure point or at a pre-set deflection value.
What do I need to know about my customer’s products?
Actually, from A to Z. That means the complete package’s performance requirements as appropriate for the customer’s product and distribution environment. It’s imperative that the customer explain the performance requirements of the container to the corrugated box sales representative and ideally, to the design department. It is important that you lead the customer through the packaging need assessment process.
Here are the following factors to be considered in the final box design and construction:
- Weight of content
- Relative need for containment, puncture resistance and stacking strength
- Product fragility or strength (i.e., ability to internally add support to the stacking load
- Transportation mode (motor, freight, rail, ship, air, overnight or small parcel shipment)
- Storage and distribution environment (stacking pattern, maximum relative humidity, storage time, etc.)
What to consider next
The vast majority of transport packaging is stacked at some point during distribution and must meet those unique challenges. One approach to transport package development is to solve for stacking requirement first because it can be approached objectively via engineering methods. Then, using designer’s experience, solve for containment.
How to solve stacking
Start by calculating the maximum static load placed on the bottom-most box or layer in the stack. After this load is calculated, estimate the impact of environmental conditions such as time in the stacked mode, relative humidity, stacking pattern, pallet overhang, etc.
Once the appropriate environmental factor is determined, it can be used to adjust the static load to estimate the dynamic compression strength requirement of the package. A BCT (box crush test) is an ideal means of specifying package performance and can be used, in most cases, this will determine the combined board strength required to successfully stack that product in a given distribution environment.
By identifying the package size, weight and a product’s distribution environment, board combinations can be proposed with reasonable assurance of stacking success and cost effectiveness.
After suitable board combinations are determined, an experienced designer or packaging engineer will determine if prototyping and dynamic and logistic performance testing are necessary to assure that containment objective can be met.
However, all board combinations may work differently, depending on the plant. The manufacturing process can reduce the strength of the board, thus every corrugated box manufacturer should determine the impact of its process and factor this into their design.