This article will be a crash course in corrugated……or cardboard, or containerboard, or boxes……whatever you call it. .

For many, this might be overkill. Some customers have told me: “a box is a box.” For many, that’s a fair assessment. On the flip side, some situations will require less common board grades, flute sizes, and styles. If floor space is key and/or you’re experiencing damages, you might start to hear terms like ECT and mullen (#) or different types of flutes. Shucks, just looking at Uline, you’ll see ECT and mullen both referenced.

What this is article is not going to cover though is everything on the backend. Different types of production equipment, the supply chain & manufacturing dynamics, adhesive types (though maybe I should’ve included that), and so on.

This article will go over the below topics in order:

ECT - Edge Crush Test. How much weight you can stack. Technically, how many pounds will an inch (width) of corrugated hold….in lab conditions.

Mullen - Often abbreviated by “#”. How many pounds per square inch does it take to burst through the corrugated.

Theoretically, ECT should be used when your boxes will be stacked and palletized. For parcel shipments, Mullen makes more sense. That said, we don’t live in a world where it’s always feasible to get the EXACT box you need. You might already be thinking “Nathan, I’ve bought the same size box in 32ECT and 200#….and both worked.” Especially on “stock box” sizes, 32ECT and 200# are often used or interpreted as equals. And most of the time, that’s fair. BUT…..

If you’re using stock box sizes, be aware of games that some will play.

Technically mullen grades have standard “recipes” for the inside liner, medium, and outside liner whereas to achieve an ECT rating, that stack requirement just needs met in lab conditions. Meaning, a company can play games with their ECT grades. Most companies will offer high quality 32ECT boxes that work in 95% or more of the same applications as 200# while showing a price advantage. However, a few will provide a 32ECT that is dramatically lower than a 200#. Not knocking them but Uline’s 32ECT is one example of that dramatic drop-off.

I’ve had too many conversations to count where someone was utterly convinced that 32ECT wouldn’t work and they needed 200#. All because they’d tried both from Uline and understandably, Uline’s 32ECT wasn’t adequate. But ours was.

The above picture is somewhat self-explanatory but I’ll give some background and context.

To start with — why does it go big, smaller, bigger, smaller, smaller, and smaller? It’s supposed to be in the order they were invented. And I’m sure that’s the case but there’s so many different ones. I’ve even seen a Z-flute! We can’t really start going to AB or BC because those would indicate a doublewall.

The most common flute size is by far, C-flute. Pretty much every singlewall stock box available is in C-flute. Even beyond stock boxes, C-flute is the most common for regular boxes. The next most common would be BC-flute for doublewall boxes.

Some reasons you might see or need a different flute size than the standard:

There are others but I’ll go through the three most common print types. A good supplier rep will guide you in your project but this is a quick overview.

The beauty of corrugated is almost anything is possible to make. That said, there are some common styles. The below list is NOT all-encompassing but it covers some of the most common styles and terms.

RSC (Regular Slotted Carton) — This is what everyone thinks of when they think of a box. Flaps that meet in the middle on the top and bottom. Most efficient way to make a standalone box.

HSC (Half Slotted Carton) — It’s an RSC but without top or bottom flaps. Maybe you need to cover an item that bolted to a pallet. Or you need a bulk container/gaylord…which if square, is technically a HSC.

FOL (Full Overlap Slotted Container) — similar to a RSC, it fully encloses the product but the flaps fully overlap. Often used if there is concern of a product busting through the ends.

OPF (One Piece Folder) & 5PF (Five Panel Folder) — one piece of corrugated that folds up into a box. Difference between the two is what sort of enclosure and strength is required. And accordingly, how many panels it takes.

Auto-Lock bottom — There is a traditional auto-lock style and a 1-2-3 style. In short, this reduces labor & time spent manually assembling boxes. A 1-2-3 doesn’t require a die but takes longer than a traditional auto-lock.

Speaking of dies - why do some boxes need dies and why do others not? Very generic answer but special holes/slots will require die cuts. Which in turn require dies. Yes, they can be costly. Windows, slots for fold overs, holes for ventilation, and special handholes are some of the common reasons for die cuts.

What does a die cost? It depends on the size of the die. The size of the hole/cuts, type of equipment the corrugated item is ran on, and the order volume (because it also could factor into the machine required) are all factors to consider.

Awesome! Stick with it.

On the flip side, if you could wave a magic wand and would change something about your corrugated, it might be worth reaching out to someone else. Every plant has different capabilities and specialties.

I recently partnered with a company who was experiencing damages during the summer months due to higher humidty. Not at all unique to them. Unfortunately, their supplier wasn’t set up to run anything other than 32ECT with standard adhesive. We were able to run their product in a plant where the volume and product requirements made sense though.

A couple other examples of unique solutions corrugated can offer:

All to say, a box may be just a box to the end-user, but there is a lot that goes into finding the right box & corrugated for your application and producing it the most cost-effective way.

If you have questions, want to learn more, are designing a new product, or want a second opinion on your current corrugated program - reach out! You can reply to this email, book a conversation here, or reach out to me at the info below.

(812)244-9393 & [email protected]

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