Three-layer, five-layer, or seven-layer? A comprehensive guide to corrugated cardboard box load-bearing standards and selection.
Finding the best corrugated cardboard box is often like a guessing game. With respect to shipping the product, there is a simple choice to make a selection 3, 5, or 7 layer box. Someone is going to get a crushed box and a product that is damaged and there is only one way to fix, a disappointed customer. The thickness choice is not the answer, the answer is finding the box's construction to meet the ideal. This is a guide to the load-bearing secrets making a complex box selection a simple one.
Understanding the Core: What the Layers Actually Mean.
The choice of 3 or 5 layers is not about the box construction glued together, but corrugated itself and corrugated is about the the fluted medium of the box. The flute a genius layer for a boxes construction and creates an airy cushion for shock and rigidity.
Three-layer boards, or single-wall boards, are the most common type. They have one fluted section in the middle with flat sheets on either side. Five-layer boards, or double-wall boards, are much stronger. They have two fluted sheets separated by a flat center sheet, with flat outer sheets on either side. Seven-layer boards, or triple-wall boards, have three fluted sheets with four flat outer sheets, and are very strong. Besides the number of sheets themselves, each additional wall added to a box increases it's ECT (Edge Crush Test) rating, or it's resistance to crushing and overall stacking satiability. Knowing this information can help you make a more informed buying choice.
Load-Bearing Standards and Real-World Performance
If you are wondering how much each type of box can hold, this information comes from standard tests, including the ECT and the Bursting Strength (Mullen) tests. ECT tests the pressure a box can hold before the edges are crushed, and is a common and reliable indicator of overall box performance, especially with modern shipping.
A standard three-layer box weighs less and is good enough for e-commerce and for all types books, apparel, lightweight electronics, and mailer boxes for lightweight to moderately weighted items. Well protects against impacts and rated at 32 to 55 ECT.
A five-layer box is warranted for heavy, fragile, and valuable items, On double-wall boxes, ratings are easily double that of single walls. This is most appropriate for small, fragile glass appliances, heavier auto parts, and products that are to be warehoused for a long time. Resists crushing and outside pricking.
For the most industrial-grade protection, a seven-layer box is warranted. Think shipping heavy machinery, large auto parts, and valuable high weight items for overseas. Survives extreme stacking pressures and rough handling to the very demanding of logistics environments. This is for high-security and high-risk shipping.
Making the Right Choice: It’s More Than Just Weight
There is a type of tradeoff when selecting the right box for a particular product. Boxes have a tradeoff between protection cost, and efficiency. Weight is the starting point but is far from the only one. Fragility and value, along with distance all have to be considered
Some key questions to ask yourself are: Is the product fragile or easily scratched? Fragile products benefit from the extra rigidity and cushioning of a five layer box even if they are not super heavy. How will it be stored and shipped? Boxes that are going to be moved between multiple carriers, or sitting for a long time in a warehouse, are going to have more stress placed on them, and are going to need greater stacking strength (higher ECT rating) meaning a five or seven layer box. What is the box size? Larger boxes even if they are only holding lighter products, need more structural integrity to prevent bulging or collapse.
Moreover, it’s amazing to collaborate with suppliers who have their own in-house design capabilities. These suppliers do not just sell boxes; they provide packaging solutions. They can customize their recommendations not only to product shape and weight, and distribution patterns, but also to the count and profile of the flute (e.g. B flute for better crush resistance or C flute for general purpose) as well as the box configuration.
Deeper Diversification: Customization and Design.
The baseline is the three, five and seven-layer constructions. However, the real optimization comes with the customization of the design. A structure that perfectly fits your product not only improves protection, but also reduces the material, and hence the cost, that can be used for the box.
A packaging specialist can customize the box to keep your items from shifting during transport. They can also customize the box to make the unboxing experience better for your customer by creating easy open perforations, adding handles, or closing the box in a specific way. If the product inside the mailer box is more lightweight but still premium, a three-layer box would make for a better mailer box option than a flimsy box. If a box is more heavy, a five-layer box strategically supports the product inside, while also not being bulky. The right partner on this packaging journey showcases your product in the best light.
Ultimately, the decision on the type of box to use is up to you. Running your company requires figuring out the balance between costs, big and small, on every decision. Cutting costs is important to running your company, but keeping your customer happy is most important of all. If you understand the expected journey and the box's strength, you can easily make the decision to protect the product during transport without pointless overpacking. Thin boxes can send the customer a bad message, while overpacking can also frustrate them.