Why There are Different Sizes of Corrugated Flutes

Corrugated Boxes

Over 90% of all products shipped throughout the world are shipped in corrugated boxes (also referred to as cardboard boxes).  By changing the box’s design, a corrugated box can be made to efficiently ship and store almost any product.  In order to provide a wide variety of box styles, there are generally four style of flutes to choose from during the manufacturing process.

What are “flutes” you ask?  If you look closely at the edge of a corrugated box, the flutes are the arches of corrugated board in a zigzag pattern sandwiched between two pieces of fiberboard.  Once again there are four styles of flutes to choose from – A, B, C, and E.  (Yeah that’s right. There is no “D” flute.)  Each has a different dimension:

A Flute = 3/16″ height with 36 flutes per lineal foot

B Flute = 1/8″ height with 50 flutes per lineal foot

C Flute = 5/32″ height with 42 flutes per lineal foot

E Flute = 1/16″ height with 94 flutes per lineal foot

A flute is ideal for single faced corrugated rolls due to its thickness and cushioning ability.  B flute is used widely with die cut corrugated mailers since it allows for easier folding and creasing than C flute.  C flute the choice for normal RSC (regular slotted cartons) corrugated shipping boxes while E flute is used in retail corrugated packaging where vibrant graphics are used since it provides the best printing surface at 94 flutes per lineal foot.

Two flutes (B and C) can be employed in different combinations to form double-wall boxes with the B flute on the outside on the outside and the C flute on the inside. In this double wall construction, the flutes always run parallel to each other.

Flute type is closely related to cushioning ability and the resistance of the board to crushing compression forces.  For instance, when weight is applied direct down on a sheet of flat corrugated,  B flute, having a greater number of flutes per foot, can support a greater weight than A or C flute.  If you take a corrugated sheet and stand it upright and then apply weight directly down on the side of the sheet of corrugated with the corrugated flute pattern showing on the top and bottom, A flute, having the largest columns, can support a greater weight than B or C flute.   If you stand up a sheet of corrugated and have the flutes show to the left and right and apply weight directly down on the side of the sheet, B flute is capable of supporting the greatest amount of weight.

A flute has the best cushioning qualities because of its greater height or thickness. Conversely, A flute does not fold or crease as readily as B flute because of its greater thickness. Puncture and tearing resistance are influenced by flute height, with A flute having greater puncture resistance than B while B actually has better having somewhat better tearing resistance than A.  In all of these properties, C flute is about midway between A and B.

With the constant demands of customers to reduce costs at any expense,  many box styles are available in stock utiliizing the four flutes discussed in this blog.

How Corrugated Cardboard Shipping Boxes were Invented

Corrugated cardboard shipping boxes are any of the cardboard shipping boxes that contain at least one layer of fiberboard that has been ‘fluted,’ or repeatedly folded along its length so that it creates an accordion-like effect. The fluted sheet is then usually fashioned between one or two thin flat sheets of fiberboard, which are simply thick paper-like material, to make something of a corrugated ‘sandwich,’ or wall. The folds of the corrugated sheet provide the wall, and the cardboard shipping boxes are made creating a protective, sturdy thickness without sacrificing much in the way of lightness.

 

The corrugated fiberboard that makes up most cardboard shipping boxes can be traced to mid-nineteenth century England, where the stuff that’s now used in cardboard shipping boxes was used to line hats, especially those tall ones that many English gentlemen were fond of wearing. But it wasn’t until 1871 when a New York merchant, Albert Jones, realized that he could cheaply secure the bottles and glass lights he sold by wrapping them in a single-faced corrugated board (that’s a corrugated sheet glued only on one side to a flat sheet of fiberboard—kind of like an open faced sandwich.) Wrapping goods in corrugated fiberboard soon became a popular shipping option.

 

In 1890, a Scotsman living in Brooklyn named Robert Gair realized that you could stick six of those corrugated sheets together and you’d have yourself some corrugated cardboard shipping boxes. It wasn’t long before corrugated cardboard shipping boxes replaced wood boxes for shipping most goods, especially delicate ones like glass and pottery products. It was later discovered that corrugated cardboard shipping boxes were superior to wood boxes for shipping fruit and vegetables, as the corrugated cardboard shipping boxes led to less bruising of the food products.