AI PACKAGES
MEASUREMENTS
Box sizes are measured by using inner dimensions unless otherwise specified. The size of your contents actually determines the inner box dimensions. These dimensions are usually listed in the following sequence: length (L) x Width (W) x Height (H).
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Dimensions are based on the opening of an assembled box. Looking at the opening, the longer of the two sides is considered the “length”. The shorter of the two sides is the “width”. The side perpendicular to the length and width is the “height” of the box.
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* Exceptions are book folds, bin boxes & divider bins where “width” precedes “length” and “height” of the measured sequence.
HOW TO MEASURE A BOX – THE QUICK WAY
Looking at the opening of the box, measure the longest or length panel first. Using a tape measure, place it in the bottom of the box approximately one inch from the back wall and measure from left to right. Repeat the process for the shorter width panel. Then, folding a side flap inward until it is perpendicular to its vertical sidewall, place the tape measure at the end of the flap and extend it downward until it rests on the inner flap at the bottom of the box (see illustration). This exercise will give you the depth dimension of the box.
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One-piece, Die-Cut boxes, such as the “mailer-style” with a tuck-in top, do not have flaps when assembled, but the measuring procedure is basically the same. For the box depth, use the inside back panel as it has a visible Score line (crease separating back panel from lid). For the width of a die-cut box, measure between the Score lines found on the inside of the top or lid. And, of course, for the length of the box, place your measuring rule on the bottom of the box approximately one inch from the back panel. Measure from left to right.
BOX STRENGTH
The strength of a corrugated box starts with its material. A corrugated sheet consists of two major components – liner board and medium. Linerboard is the flat paper that covers both sides of the sheet and the medium is the “fluted” or arched paper found between both liners. The flute, when anchored to the liner boards with a starched-based Adhesive, resists bending and pressure from all directions. When placed vertically on its ends, the flutes form vertical columns, capable of supporting considerable amounts of weight.
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Flutes come in five basic heights and shapes – the most common are “B-flute” (used for Die-Cut boxes) and “C-flute (used for RSCs). B-flute is compressed and appears thinner, but don’t be fooled. It is made with more paper to provide stronger sidewall protection from blows and punctures. C-flute is taller, with more air space, but offers enhanced stacking strength. For excellent graphic reproduction, consider E-flute.
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The number of virgin pulp Fibers and the length of those Fibers in a corrugated sheet substantially contribute to box strength. For example, the difference between a 200# test box and a 275# test box is that the latter has more pulp Fibers in its corrugated liner board. The 200# test box is rated to hold up to 65 lbs. of box and contents while the 275# box can hold up to 95 lbs. A 350# test box is rated to hold up to 120 lbs. of box and contents.
LOOK FOR MANUFACTURER’S STAMP
A way to be sure that the material of the box that you’re purchasing meets industry standards is to look for the Manufacturer’s Certification Stamp, usually printed on one of the bottom flaps of the box. The stamp identifies the material as “single-wall,” “double-wall” or “triple-wall.” It also certifies the Mullen Bursting Test ( most common is 200 lbs. per square inch) or the Edge Crush Test (ECT 32 lbs. per inch). The Mullen Test measures the bursting strength of the corrugated liner board while the Edge Crush Test measures liner board stacking strength. The 200 lbs. Mullen box and the 32 ECT box are comparable in stacking strength. But that is where the similarity ends. The Mullen Test box is better suited for the protection of heavier contents while the Edge Crush Test box provides lighter weight Cartons with good stacking characteristics. When in doubt as to which box to use, always select the Mullen Test box because the construction of the liner board cannot be altered. For example, 200# Mullen Test liner board must be made of 42# per square inch basis weight paper and the medium or flute paper cannot be less than 23# per square inch basis weight.