How to Design Boxes for Heavy Items

double wall cardboard box

From technology and household appliances to pipes, metal parts, bicycles, wine bottles and furniture – there are so many heavy items that a company might be looking to ship. Whether you’re sending a heavy package locally or internationally, you need a box that is up for the challenge.

We work with many industries who deal in heavy items – like automotive, machinery, beverage producers and wholesalers. Here are our top tips for packaging heavy items.

Why does box design matter with heavy items?

Heavy packages are more likely to be moved with equipment, such as a forklift. This means that your packaging should be prepared for rougher handling.

Finding the right strength to weight ratio is a good start. In other words, your box should be both strong and lightweight. Corrugated cardboard is an ideal material to meet these needs.

The flute profiles you choose determine both the strength and weight of your box. By mixing and matching flute sizes in a double-wall box, you can ensure you have packaging that is tough enough for a heavy item and light enough to optimise shipping costs.

Read our guide to shipping boxes for more on how to get the most out of your packaging.

Deciding weight with an ECT or Mullen test

There are two tests the packaging industry use to decide the weight and pressure capacity of a box. First is the Edge Crush Test (ECT) and second is the Burst Strength Test, which is also known as the Mullen Test.

During an ECT, a box or piece of cardboard is stood upright and slowly compressed between two rigid plates. The amount of pressure it can withstand before crushing helps determine how much weight your box can handle inside it and on top. This test is important for stacking strength – an essential when you palletise your goods.

machine performing an edge crush test (EC)

During the Mullen Test, a piece of cardboard is lying flat with pressure slowly applied to the board face until it ruptures. This gives you an estimate of how much force can be applied to a box. It’s a great measure for rough handling from conveyor belts to movement in transit and lifting on a forklift. With heavy items, it can tell you if your box is strong enough to withstand the force of the item if it were to fall against the box walls.

The following image shows some common ratings from both an ECT and a Mullen Test, plus the weight that each box should handle.

5 tips for heavy duty cardboard boxes

Over two decades of experience in the packaging industry, we’ve picked up a tip or two on how to make ideal boxes. When it comes to heavy items, here are a few things you should keep in mind.

Design custom packaging

Custom packaging is designed for a snug fit. It means we design the box to fit your items, not the other way around. A close fit ensures your goods are not moving around during transit.

Large, heavy and irregular shaped items are often safer in custom cardboard boxes because the packaging has been designed to keep them secure.

Add in extra strength features

From choosing a tougher paper weight to opting for a double-walled box, there are lots of tricks to designing stronger boxes.

A simple but effective method for heavy items is to add an extra stitch at the join. This provides more stability than glue or tape alone and provides extra protection that keeps your box from breaking at pressure points.

Palletise your shipment

Palletising your shipment makes it easier for large equipment like a forklift to move it around.

If you do choose the pallet route, it’s essential that your boxes have enough stacking strength to make it safely from point A to B. Check the ECT rating and ensure you’re not filling any box past the weight it can handle.

Regular Slotted Containers

Distribute weight when packing

Your box might hold more than one item with the combined weight making it a rather heavy package. When you have mixed weights, it’s good to distribute them evenly. You should pack the largest and heaviest items on the bottom and continue stacking so that the weight is balanced to the top. This helps prevent tilting when your box is carried.

Double box your items

Different types of boxes can serve different purposes. For example, a lightweight product box is meant to provide product information. Whereas a tough corrugated box is made for shipping and protection. Double boxing your items means each packaging can serve its true purpose.

We explain more in our blog on the difference between cardboard and corrugated boxes.

Boxes we recommend for heavy items

As experts in heavy items, from industrial packaging to beverages – our team have a few box styles that we would recommend.

An RSC is the classic shipping box. It is an ideal box style for gaining strength at the lowest price possible.

Another great option for heavy items is including pads and partitions. For example, a wine bottle on its own is not too heavy but a box of 6 or more is getting there. To keep your products safe and separate, you can use a cardboard divider.

Die cut boxes are popular for small orders, but they can also be designed for heavy items like small metal parts.

Talk to our packaging experts

Echo Cartons have been manufacturing corrugated boxes in Melbourne for over 20 years. We offer lots of great packaging advice on the blog, but nothing beats a chat with a true expert. For questions and personalised advice, get in touch with our team. If you’re ready to start a packaging order – simply request a quote.

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