Corrugated boxes have a long and rich history that coincidentally originated in The Boxery’s hometown of Brooklyn, NY. In 1890, Robert Gair, a Brooklyn printer, invented the pre-cut paperboard box – flat pieces manufactured in bulk that folded into boxes. Gair’s invention came about as a result of an accident: As a paper-bag maker during the 1870s, while he was printing an order of seed bags, a metal ruler normally used to crease bags shifted in position and cut them. Gair discovered that by cutting and creasing in one operation he could make prefabricated paperboard boxes.

Corrugated boxes are sometimes referred to as cardboard boxes albeit incorrectly. A corrugated box consists of a wavy sheet of recycled paper called a flute sandwiched between two paper liners that together form a corrugated sheet. However, cardboard simply refers to sheets of paper compounded together with no reference to the wavy flute in between that provides superior engineered protection to a whole host of items. The flute and paper liner thickness in corrugated boxes are available in various thicknesses and strengths depending on the required application. The most common industry used flute type is a C Flute @ 4mm in thickness. Corrugated boxes are also available with a double flute for even greater protection aka Double Wall Corrugated Boxes that consists of 2 flutes and 3 liner boards – the additional third liner would be used to separate the flutes.

Isn’t Corrugated fascinating

Customers wonder all the time ‘’Which bubble size should we use?

Small (3/16’’), Medium (5/16’’), or Large (1/2’’) ?

To help answer this question, we’ve decided to provide Bubble 1.1 on things to consider when choosing your bubble packaging and best practices

Small Bubble (3/16’’) – When packaging lightweight, small items this is the bubble to go with. It is also great for light surface protection. Keyword here for this type of bubble would be ‘’light’’

Medium Bubble  (5/16’’) – This is a great size to use for mild shock absorption & surface protection for semi-rugged items. Can be used as a void fill too.

Large Bubble (1/2’’) – This size bubble is primarily to be used as dunnage and void fill. Of course, this has also been rated #1 among both children and adults for bubble popping

Ps: Please email any article suggestions or inquiries to info@theboxery.com We are always interested in hearing from our customers and providing the most up to date, relevant packaging information and tips to enhance your shopping experience at The Boxery

A newer standard that has achieved widespread acceptance is the Edge Crush Test (ECT). This is a true performance test and is directly related to the stacking strength of a carton. ECT is a measure of the edgewise compressive strength of corrugated board. It is measured by compressing a small segment of board on edge between two rigid platens or plates perpendicular to the direction of the flutes until a peak load is established. This is measured in pounds per lineal inch of load bearing edge (lb/in), but usually reported as an ECT value (for example, 44 ECT).

There are currently two tests used throughout the corrugated industry to determine strength. Historically, the long time industry standard has been the Bursting (Mullen) Test, which is related to the rough handling durability of corrugated material. Bursting Test is a measure of the force required to rupture or puncture the face of corrugated board and is measured by a Mullen Tester. This force is indirectly related to a carton’s ability to withstand external or internal forces and thus to contain and protect a product during shipment. Bursting strength is reported in pounds (for example, 275#).A newer standard that has achieved widespread acceptance is the Edge Crush Test (ECT). This is a true performance test and is directly related to the stacking strength of a carton. ECT is a measure of the edgewise compressive strength of corrugated board. It is measured by compressing a small segment of board on edge between two rigid platens or plates perpendicular to the direction of the flutes until a peak load is established. This is measured in pounds per lineal inch of load bearing edge (lb/in), but usually reported as an ECT value (for example, 44 ECT).

Here it is important to point out that the equivalent ECT values are give as a minimum value. This is because corrugators may use one of many different “recipes” to make each type of corrugated. Each makeup will vary slightly in overall strength. For example differing formulas for a 200# single wall corrugated will cause the equivalent ECT board to vary between 32 ECT and 44 ECT. It is important to understand what type of corrugated you are using before deciding to substitute any equivalent.

For example, if you are shipping a product that weights between 50-65 pounds, a 32 ECT single-wall carton should be sufficient, in most cases. If your carton is going to be subjected to severe handling, the 200# carton might be a better option. It would be equivalent to a carton with an ECT of 32 or higher, and the bursting test is more of a true measure of rough handling.

The fundamental difference between the two tests is that under the Burst Test a minimum board basis weight is required. That is, the Burst Test requires that the base papers used to make corrugated fiberboard weigh at least a certain minimum number of pounds per given unit area. The ECT eliminated this requirement, which allows the use of lighter weight materials while still providing high performance. When you are comparing two identically sized cartons with equivalent strengths, one being Burst Test rated and one being ECT rated, the ECT rated carton will weigh less. In other words the ECT rated carton will use less corrugated material.

For example compare a 275# single wall to an equivalent 44 ECT single wall corrugated board. On average, the 275# Burst Test rated single wall carton will weigh 175 pounds per 1000 square feet of material used. An equivalent 44 ECT rated single wall carton will weigh on average 149 pounds per 1000 square feet of material used. The 44 ECT board will reduce the material used by 14.8%.

Put differently, the proper ECT rated corrugated provides an equivalent level of strength, but uses less material. This translates into fewer raw materials, lower energy requirements, and reduced pollution, in all stages of the package’s life cycle. Combining lighter materials in a properly sized carton with increasing amounts of recycled content means ECT rated corrugated reduces waste even further.

info from www-stat.stanford.edu

Recycling

Old corrugated containers are an excellent source of fibre for recycling. They can be compressed and baled for cost effective transport. The baled boxes are put in a hydropulper, which is a large vat of warm water for cleaning and processing. The pulp slurry is then used to make new paper and fiber products.

Mill and corrugator scrap, or broke, is the cleanest source for recycling. The high rates of post-consumer recycling reflect the efficiency of recycling mills to clean and process the incoming materials. Several technologies are available to sort, screen, filter, and chemically treat the recycled paper.

Many extraneous materials are readily removed. Twine, strapping, etc are removed from the hydropulper by a “ragger”. Metal straps and staples can be screened out or removed by a magnet. Film-backed pressure sensitive tape stays intact: the PSA adhesive and the backing are both removed together.

Materials which are more difficult to remove include wax coatings on corrugated boxes and “stickies”, soft rubbery particles which can clog the paper maker and contaminate the recycled paper. Stickies can originate from book bindings, hot melt adhesives, PSA adhesives from paper labels, laminating adhesives of reinforced gummed tapes, etc.

Recycling corrugated fiberboard helps countries without sustainable wood resources build a paper and packaging industry locally.

Packaging engineers design corrugated boxes to meet the particular needs of the product being shipped, the hazards of the shipping environment, (shock, vibration, compression, moisture, etc), and the needs of retailers and consumers.

The most common box style is the Regular Slotted Container (RSC). All flaps are the same length from the score to the edge. Typically, the major flaps meet in the middle and the minor flaps do not.

The manufacturer’s joint is most often joined with adhesive but may also be taped or stitched. The box is shipped flat (knocked down) to the packager who sets up the box, fills it, and closes it for shipment. Box closure may be by tape, adhesive, staples, strapping, etc.

The size of a box can be measured for either internal (for product fit) or external (for handling machinery or palletizng) dimensions. Boxes are usually specified and ordered by the internal dimensions.

Manufacturing

Boxes can be formed in the same plant as the corrugator. Part of the scoring and cutting takes place in-line on the corrugator. Alternatively, sheets of corrugated board may be sent to a different manufacturing facility for box fabrication; these are sometimes called “sheet plants”.

The corrugated board is creased or scored to provide controlled bending of the board. Most often, slots are cut to provide flaps on the box. Scoring and slotting can also be accomplished by die-cutting.

The “Flexo Folder Gluer” is a machine that in one single pass prints, cuts, folds, and glues flat sheets of board to convert them to boxes for any application, from storing old family pictures to shipping the biggest of plasma TV sets to the global market. The most advanced of FFG’s can run at speeds of up to 26,000 boxes per hour (about 433 per minute).

Manufacture of Corrugated Board

Corrugated board is manufactured on large high-precision machinery lines called corrugators, usually running at 500 lineal feet per minute or faster. These machines over time have become very complex with the objective of avoiding some common problems in corrugated board production, such as warp and washboarding.

The manufacturing process begins with pulping, the separation of wood (hardwood and sapwood) into individual fibers, as accomplished by mechanical methods or chemical treatment.

In the classical corrugator, the paper is softened with high-pressure steam. After the board is formed it is dried in the so-called dry-end. Here the newly formed corrugated board is heated from the bottom by hot plates. On the top, various pressures are applied by a load system on the belt.

The corrugated medium is often 26 lb/1000 sq.ft basis weight in the U.S. At the single-facer, it is heated, moistened, and formed into a fluted pattern on geared wheels. This is joined to a flat linerboard with a starch based adhesive to form single face board. At the double-backer, a second flat linerboard is adhered to the other side of the fluted medium to form single wall corrugated board. Linerboards are test liners (recycled paper) or kraft paperboard (of various grades). The liner may be bleached white, mottled white, colored, or preprinted.

Common flute sizes are “A”, “B”, “C”, “E” and “F” or microflute. The letter designation relates to the order that the flutes were invented, not the relative sizes. Flute size refers to the number of flutes per lineal foot, although the actual flute dimensions for different corrugator manufacuturers may vary slightly. Measuring the number of flutes per lineal foot is a more reliable method of identifying flute size than measuring board thickness, which can vary due to manufacturing conditions. The most common flute size in corrugated boxes is “C” flute.

Corrugated fiberboard can be specified by the construction (single face, singlewall, doublewall, etc), flute size, burst strength, edge crush strength, flat crush, basis weights of components (pounds per thousand square feet, grams per square meter, etc), surface treatments and coatings, etc. TAPPI and ASTM test methods for these are standardized.

The choice of corrugated medium, flute size, combining adhesive, and linerboards can be varied to engineer a corrugated board with specific properties to match a wide variety of potential uses. Double and triple-wall corrugated board is also produced for high stacking strength and puncture resistance.

(Thanks WikiPedia for you help)

We will update this blog regularly with information about corrugated packaging and boxes, mailers for any item, protective bubble wrap or anything packaging related.