What strength of box do I need?

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A man buffing this box to avoid void fill

Corrugated cardboard has been in production since the 18th Century, a time when raw materials had to be improvised in order to create ingenious constructions providing both support and protection. While the formula used to make cardboard boxes has had little change over the years, the packaging manufacturing process has however gone through a number of innovative changes.

This commitment to continuous improvements has brought a greater awareness to the way a product is packaged as well as how packaging is sourced. This has made packaging sustainable, stronger and sturdier to withstand wear and tear, and has brought the industry the varied range of cardboard styles and options that we have today.

To gauge the right strength of box needed to package a product in, there are a number of options that need to be considered; however without getting too technical, Davpack have narrowed it down to the top 3.

No. 1: The fluting profile; the paper in-between that makes up what looks like waves, available in single, double or triple layers. This is all about weight capacity; generally single wall can hold up to 10kg, double wall 30kg and triple wall 50kg.

No. 2: The 2 paper type, available in Kraft or Test paper. Kraft is commonly used for external and Test paper used for the inside of the box.

No. 3: The paper weight, with grades starting from 125gsm. The thickness of the paper contributes to the strength of the box.

Fluting Profile

Corrugated boxes come in different variations. For a single wall cardboard box there is only one layer of fluting that makes up the box, with double wall having two layers of fluting and triple wall boxes having three layers. This means as the layers increase, the thickness increases, improving the strength.

Available in different types, the fluting on corrugated box wall can be improved by enhancing the fluting thickness (90fl as standard up to 150fl), or by chemical treatment (known as semi-chem). Although a strong cardboard box doesn’t eliminate the need for void fill for delicate items, it does provide an initial layer of protection for your product.

Paper Type vs Paper Weight

Made out of soft wood and commonly used on the outside of the box to offer a smooth, attractive finish, standard Kraft paper comes in varied grams per square meter (gsm), starting from 125K up to 300K. As this increases, the strength of the box increases also, with 300K boxes generally being used for larger, bulkier items. Kraft paper can also provide a good quality finish for printing onto, in addition to a solid board which has no fluting at all.

Test paper on the other hand is made from a cheaper pulp, without the machine finish and shine of Kraft. This doesn’t have the same strength, but is often used on the inner layer of the box, where the appearance isn’t as important and where the strength is made up elsewhere. This can be why the inside of a corrugated box is usually a different shade of brown to the outer layer.

With new innovations arising, additional chemicals can be applied to the paper to provide durability and strength. Find out exactly what you need your boxes to hold, and ask your supplier which type of corrugated box would best suit your product!

What To Do Next…?

Still unsure about what size box or type of cardboard you need? Is all this just a bit too technical?

Why not call or use our online chat system to speak to one of our friendly sales team, simply inform them of your requirements and they would run through various options for you.

Should you then go on and decide to place your order with us and spend over £50 be sure to quote BLOGFREEBIE and receive a goodie from us.

*T&C’s apply


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Rick Stanford

Rick has been a salesman in the packaging supplies business for more than thirty years. Now semi-retired, he divides his time between tending his allotment in north Devon, getting depressed at the continuing travails of his home-town football club Macclesfield Town, and sharing his considerable experience and knowledge with the readers of the Davpack blog. Davpack

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