Packaging 101

You say cardboard, we say corrugated


Welcome to Packaging 101. Here, we’ve compiled over 200 years of knowledge! Feel free to explore the information listed below to help enhance your understanding of the packaging industry and much more. Sharing knowledge is always a win.

Corrugated packaging and displays is a $33.1 billion industry that is vital to U.S. distribution systems. It is the most frequently used shipping material because it’s cost-effective, lightweight, functional, versatile and re-re-recyclable. In 2017, the industry manufactured 386 billion square feet of material used to make boxes and displays. This equated to nearly 38 billion packages that safely shipped and protected food, clothing and durable goods for delivery to millions of domestic and worldwide customers. There are over 1,154 corrugated manufacturing facilities with approximately 100,000 employees in nearly 1,000 cities and towns throughout the U.S.

ABC’s of Packaging

    • Made to order for a particular customer
    • The art, science and technology of protecting products for distribution
    • The act or process of filling a want or need

Common Corrugated Box Styles

Auto Bottom
The bottom diecut panels are folded and glued during production for easy assembly during fulfillment.

Auto Bottom BoxAuto Bottom Specs

Display Tray / High Wall Tray
Trays are not shipping containers, but are frequently used as inner containers.

Display Tray / High Wall TrayDisplay Tray Specs

Econo / Indestructo
Also called a Roll End Tray with Tuck Top and Interior Bottom Flaps. This style is frequently used when you need extra protection or stacking strength. They have full-closure front flaps, and most sides have at least two layers of corrugated.

Econo Style  BoxEcono Box Specs

FOL (Full Overlap Container)
All flaps have the same length that is equal to the width of the box. The overlapping flaps provide extra support and padding.

FOL BoxFOL Specs

FPF (Five Panel Folder)

A corrugated box style that features a single cut & scored piece that has a 5th panel used as the closing flap.

OPF (One Piece Folder)OPF Specs

HSC (Half Slotted Container)

Same as an RSC (Regular Slotted Container) without one set of flaps.

HSC (Half Slotted Container) BoxHSC Specs

RETF (Roll End Tuck Front)
A Roll End Tray with a top panel and an additional front panel with locking tabs and optional dust flap panels

Roll End Tuck Front BoxRoll End Tuck Front Specs

Roll End Tray / Tray with Self Locking Ends
A single piece of board with ends that roll over and lock into the bottom

Roll End Tray / Tray with Self Locking EndsRoll End Tray Specs

RSC (Regular Slotted Container)

Most common style of carton. All flaps are the same length and all meet in the center of the box when folded.

RSC (Regular Slotted Container BoxRSC Specs

OPF (One Piece Folder)

One piece of corrugated board is cut to provide a flat bottom with flaps forming on the sides and meeting on the top.

OPF (One Piece Folder)OPF Specs

Snap Lock / 1-2-3 Bottom
The four bottom flaps are die cut. To set up, the largest panel is folded first, then the two end panels. When the last panel is folded and pressure is applied near the center, it “snaps” into the slot created by the other panels.

Snap Lock / 1-2-3 BottomSnap Lock Bottom Specs

Corrugated Definitions

Basis Weight
    • Weight of linerboard or corrugating medium expressed in terms of pounds per 1,000 square feet (msf).
Blank or Box Blank
    • A flat sheet of corrugated or solid fiberboard that has been cut, slotted and scored so that, when folded along the score lines and joined, it will take the form of a box
Board Analysis & Identification
    • Customers benefit from regular combined board analysis to ensure compliance with specifications and any applicable industry, regulatory, or governmental standards. This level of testing allows us to explore alternative design and board combination options. Regular testing of combined board off the corrugator in conjunction with post converting production steps ensures the maintenance of caliper and performance throughout the process.
Box Compression Analysis
    • During the design process, it is often beneficial to experiment with different packaging designs and board combinations that are best suited to customers’ intended packaging use as well as their economic interests. The full size box compression tester gives us the ability to do sample analysis before a production run to make sure that the design is consistent with customer expectations. Further, this allows us to evaluate and estimate pallet, and load stack performance prior to arrival in the warehouse environment.
Box Style
    • Unique design of a box; does not indicate size
Bursting Strength
    • The force necessary to break combined board or linerboard. Usually measured to determine the box’s ability to withstand internal or external pressure and to securely contain the contents during rough or careless handling.
Compression Strength
    • A particular corrugated box’s resistance to uniformly exerted external forces.
Compression Tests
    • determine the maximum weight a package can support under controlled conditions before losing its structural integrity

A type of paperboard manufactured for the production of corrugated and solid fiberboard. The raw materials used to make containerboard come from trees that are grown specifically for the paper industry in sustainably managed forests.


Corrugated fiberboard or “combined board” has two main components: the liner and the medium. Both are made of a special kind of heavy paper called containerboard.

Corrugated Adhesives

MRA (Moisture Resistant Adhesive )

  • MRA most closely resembles domestic adhesive in formulation and application. A typical MRA starch will contain approximately .5% to 1% liquid resin relative to the liquid volume of the batch.
    This level of resin would typically be used in a lightweight board combination where no exposure to increased humidity may occur.

WPA (Waterproof Adhesive)

  • WPA is the highest level of “wet strength.” This in itself is a misnomer in that all starch is water soluble. This type of adhesive would typically be used in the most demanding applications. In addition to using 1.5% to 2% “wet strength” resin in relation to the liquid volume of the batch, it is essential that additional starch be applied to the board. It must be allowed to cure in its original stack for a minimum of 4 hours before processing.

WRA (Water Resistant Adhesive )

  • WRA probably has the widest range of applications due to the fact that most corrugated box plants only have the ability to make one type of “wet strength” adhesive. Water Resistant Adhesive will have between 1% and 1-1/2% resin relative to the liquid volume of the batch. This adhesive formula can be used on lightweight boxes using normal or domestic starch settings. When running heavyweight boards, 250pound test and above with greater end use demand, it is necessary to open the glue gap settings, at least an additional .004”, especially at the singlefacer. Also, a minimum stack cure time of 4 hours is essential for optimum results.
Double Wall

Three sheets of linerboard with two mediums in between. This style is designed for holding/stacking heavier items and items that may be subjected to a lot of damage.


The Design Style Tray (DST) is a cost-effective tray that uses the smallest material footprint. DSTs have flaps on the sides and the ends are folded and fastened to produce a tray.

ECT Stacking Strength Test

measures the resistance of the cardboard to crushing and to identify the board grade needed to meet stacking strength requirements

    • Architects have known for thousands of years that an arch with the proper curve is the strongest way to span a given space. The inventors of corrugated fiberboard applied this same principle to paper when they put arches in the corrugated medium. These arches are known as flutes and, when anchored to the linerboard with an adhesive, they resist bending and pressure from all directions.
    • When a piece of combined board is placed on its end, the arches form rigid columns, capable of supporting a great deal of weight. The flutes act to keep the linerboard sheets separated, maximizing the bending rigidity of the board.
    • The wave shape combined with the corrugating medium. The most common flute shapes and profiles include A, B, C, E and F.

A flute

was the original flute profile for corrugated board. It has about 33 flutes per foot.

B flute
    • corrugated board is 1/8 inch thick and is typically used for smaller cartons. It is a good surface to hold print and is easily folded into intricate shapes.
    • Developed for canned goods that were self-supporting, and so did not require boxes that supported much load. It has about 47 flutes per foot.
C flute
    • By far the most common form of corrugated board. It is suitable for holding print and is durable enough for normal shipping and everyday use. It is a little thicker than B Flute at 3/16ths inch. It has about 39-40 flutes per foot.
E flute
    • 3/32nds of an inch thick. This board is typically only used for smaller cartons. Due to the close fluting, it is an excellent board for printing. It has about 90 flutes per foot.
F flute
    • was developed for small folding carton type boxes. It has about 125 flutes per foot.
Joint (Manufacturer’s Joint)
    • The part of the box where the ends of the scored and slotted blank are fastened together by taping, stitching or gluing.

Word of German origin meaning strength; designates pulp,paper or paperboard produced from wood fibers by the sulfate process.


is the thick flat rigid material on the outer facing walls of corrugated boxes, typically on the outer surfaces of the board but also on the inside for some structures, that adheres to the medium


Containerboard material consisting of a fluted corrugated is the paper that is formed into arches or flutes on the single facer and glued between the linerboard facings.

Mullen Bursting Strength Test

measures the bursting strength, or pressure (psi), required to blow a hole through the corrugated cardboard

    • A design element that features top and bottom box flaps that do not join, but extend over one another. The amount to which a box features overlap is measured from flap edge to flap edge.
    • A plain piece of corrugated that is used as padding or to separate products.
    • Roll-end tuck top with cherry locks and dust flaps
Paper Grades
    • Bleached White
    • Coated SBS
    • Flood Coated Colors
    • Foil Laminated Liners
    • Kemilite
    • Mottled White
    • Mullen and ECT
    • Regular and Havyweight Mediums
    • Tissue Laminated Liners
    • Wet Strength Liner and Medium
    • a reverse tuck end box or RTE box is a type of end opening box that is glued on one side. The opposite ends tuck in opposite directions.
Shelf Ready

Containers filled with products that have been configured to allow for immediate placement on a store shelf, usually to serve as a dispenser, and without the need to remove each item individually when restocking.

Single Face
    • One corrugated medium is glued to one flat sheet of linerboard.

Single Wall

One medium is glued between two sheets of linerboard. Also known as Double Face. This is the most common type of board and is available in an array of different strengths.

    • a straight tuck end box or STE box is a type of end opening box that is glued on one side. The top and bottom flaps close on the same side of the box, whereas with reverse tuck end boxes the opposite ends tuck in opposite directions.
TAPPI Standards Testing Lab
    • SMC Packaging’s Springfield location is home to our TAPPI Standards Testing Lab. This temperature and humidity controlled environment allows us to accurately test packaging and combined board for Mullen. ECT, Pin Adhesion, Top to Bottom Compression among other tests. Our lab utilizes an oven for conditioning, a fixed beam compression tester, a mullen tester, a full size box compression tester, and the fixtures necessary to perform in house materials testing and analysis.
Triple Wall
    • Three mediums between four sheets of linerboard. Triple wall packing is most commonly used for heavy, bin-style boxes in industrial settings. It is the strongest style for cartons.
Wax Cascaded or Wax Saturated

Combined board that is treated by cascading molten paraffin wax or wax blend over vertical box blanks so that it seeps down the flutes as well as over the facings.

Wax Curtain-Coated
    • Combined corrugated board that has been surface coated on one or both sides with a hot-melt wax blend.
Weight of Facings

The sum of the weights per 1,000 square feet of all facings of combined board, excluding the weight of corrugated medium, corrugating adhesive and any coatings or impregnants. Usually cited as the minimum combined weight of facings of combined board.

Manufacturing Definitions

Assembly Line
    • a process for turning out a finished product in a mechanically efficient manner
BMC (Box Manufacturer's Certificate):
    • A statement printed within a bordered shape on a corrugated or solid fiberboard box that identifies the manufacturer and guarantees that all applicable construction requirements of carrier classifications have been fulfilled.

    • Clay Coated News Back
    • This material is typically coated with a thin layer of kaolin clay to improve its printing surface. It is produced from 100 percent recycled paperboard including old containers, newspapers, box board clippings and selected whites.

      Typical uses for CCNB include soap and laundry detergent, cereal cartons, light bulbs, paper goods (facial tissue), and dry food stuffs.

Cold Chain
    • refers to the distribution of temperature-sensitive products along a supply chain involving insulated and refrigerated packaging systems and the logistics required to protect the integrity of the product to customer delivery.
Corrugated Plant

A corrugator plant manufactures combined board sheets, just like a sheet feeder, but then processes the combined board into boxes or other finished products.

    • A customized manufacturing tool used to cut or shape material using a press
    • to depress below the surrounding surface especially for decoration or lettering opposed to emboss
Die Cutting
    • any process where you use a machine to mass produce a single cut-out shape.
    • to raise in relief from a surface opposed to deboss
Flexo Folder Gluer
    • (FFG): A machine that, in one operation, prints, scores, slots and folds a box blank, and then glues the side seam (manufacturer’s joint) to complete the manufacture of a KDF box. The KDF boxes are collected at the end of the FFG and bundled for stacking on a pallet for shipment to a box customer.
Foil Stamping
    • A method of applying colored foils to a surface for an elegant look. Much like embossing, foil stamping uses a combination of heat and pressure to stick foil to a printed substrate.
    • The process of receiving, packaging and shipping orders for goods
    • Applying any natural or synthetic adhesive
    • Honeycomb is a material consisting of kraft liner formed into continuous uniform hexagonal cells. Honeycomb, when expanded, can be faced with a kraft liner. It can also be faced with numerous other substrates.
    • Minimum Order Quantity. The least amount of products or units that a supplier is willing to produce at one time. MOQs are set by suppliers to cover their costs of production and ensure they make a profit off of each production run.
Perf Score
    • A scoreline in which recurring cuts have been made either partially or completely through the material to aid in folding
    • Solid Bleached Sulfate
    • SBS is the highest quality and most expensive paperboard substrate. It is produced from bleached virgin wood pulp that is produced with a chemical pulping process.Most bleached paperboard grades are clay-coated to enhance the smoothness and receptivity of the printing surface. SBS can be treated with a moisture barrier for use in liquid and food packaging. Bleached cellulose pulp has high whiteness, brightness and light stability. Thus, SBS is white throughout the sheet and is ideal for packaging requiring high impact graphics.The softness and flexibility of SBS provides superior creasing, embossing, and cutting properties with low dust generation, allowing for a wide scope of structural designs. However, the bleaching process also adds cost and reduces stiffness. SBS paperboard has the highest purity and provides food products with the best odor taste and taint protection. SBS is typically used in high-end packaging, where the impact and quality of the printed image are essential. It is also used in food packaging to ensure taste protection. Common uses are health and beauty packaging, pharmaceutical packaging, and frozen foods.
Sheet Feeder
    • Also called cut-sheet feeder, manufactures combined board exclusively to supply sheets to box plants for conversion into boxes or other finished corrugated products.
Sheet Plant
    • A sheet plant purchases the combined board sheets from a sheet feeder or corrugator plant to manufacture boxes or other finished products.
Supply Chain
    • the sequence of processes involved in the production and distribution of a commodity.
    • Solid Unbleached Sulfate
    • SUS, usually created with softwood pulp, results in good tear resistance and the greatest stiffness and strength in relation to basis weight of the paperboard substrates. SUS allows for the use of a lower caliper paperboard relative to other substrates. It also has cost advantages over bleached virgin paperboard.

      SUS is used in many folding carton applications, especially when strength and durability are essential. Typical uses are consumer electronics packaging, beverage carriers, dry food packaging, hardware packaging, and packaging for powdered detergents and soaps.

      SUS board generally has a better stiffness in comparison to other boards with the same caliper.

    • avoidance of the depletion of natural resources in order to maintain an ecological balance.
Wax Cascaded
    • Combined board that has been treated by cascading molten paraffin wax or wax blend over vertical box blanks ensuring that it flows down the flutes and over the facings.
Wax Curtain-Coated
    • Combined corrugated board that has had its surfaces coated on one or both sides with a molten wax blend.

Printing Definitions

    • To print a space beyond the scored edge to allow for the design to be cut or folded.
Flexography or Flexo
    • A type of rotary letterpress printing using flexible plates and fast-drying, water-based inks.
Four Color Process
    • Full-color images are created by four halftone plates, using the four subtractive primary colors: cyan, yellow, magenta and black.
    • A color matching system developed by the Glass Container Manufacturers Institute to demonstrate how specific ink will appear on containerboard liner.
Key Line
    • An outline image of something on artwork or plans to show where it is to be placed
    • A printing technique in which the inked image is transferred from the plate to a clean cylinder, which in turn transfers the image to the sheet of paper or paperboard. The term is usually combined with the printing method, as in offset lithography.
Litho or Lithography
    • A printing process using a plate that has been chemically treated so that the image to be printed is receptive to ink, while blank areas repel ink. Used primarily for fine reproduction, including labels for fiberboard boxes.
    • Pantone colors are color codes that stand for a specific shade.
    • A web (roll) of linerboard that has been printed and re-wound prior to the manufacture of combined board. Use requires special equipment on a corrugator to assure precise slit, score and cut-off operations.
Spot Varnish
    • A varnish applied only to portions of a printed piece after printing, rather than to the entire sheet, typically for aesthetic purposes. Spot varnishing is commonly found on portions with high in gloss, in contrast to the surrounding matte texture.

Associations Definitions

    • Association the Independent Packaging Association represents the independent North American manufacturers of corrugated, folding carton and rigid box packaging products and the suppliers to the industry.
    • Fibre Box Association is a non-profit trade association that represents North American corrugated packaging manufacturers and strives to grow, protect and enhance the overall well-being of the industry.
    • The Forest Stewardship Council is a nonprofit organization that encourages the responsible management of the world’s forests. FSC uses the power of the marketplace to protect forests for future generations.
  • International Safe Transit Association (ISTA) is the author of test procedures that define how packages should perform to ensure protection of their contents.
Item 222
    • A rule in the National Motor Freight Classification of the motor common carriers containing requirements for corrugated and solid fiberboard boxes. Used for the specific rule, and sometimes for the series of related rules designated Items 222, 222-1, 222-2, 222-3, 222-4, 222-5 and 222-6.
Rail Rule 41 or Rule 41
    • A rule in the Uniform Freight Classification of the rail carriers containing requirements for corrugated and solid fiberboard boxes.
    • Sustainable forestry initiative is an independent certification program that works with environmental, social and industry partners to improve forest practices in North America and fiber sourcing worldwide.
    • The leading association for the worldwide pulp, paper, packaging, tissue and converting industries.





The first continuous paper making machine was patented.


The first known corrugated material was patented for sweatband lining in tall hats of Victorian Englishmen.


Unlined corrugated (now called, medium) first appeared as a packaging material for glass and kerosene lamp chimneys.


A liner was added to one side of the corrugated material to prevent the flutes from stretching.


Corrugated was slotted and cut to make the first boxes.


Wells Fargo began using corrugated boxes for small freight shipments.


Solid fiber boxes were developed.


Corrugated was first approved as a valid shipping material and was used to ship cereals. A 10% freight charge penalty was imposed on goods packaged in corrugated boxes instead of wood boxes.


Rubber printing plates were developed which allowed for greater design creativity.


The freight charge penalty was dropped on west bound freight


Tariffs imposed on corrugated shipping containers were ruled discriminatory. Interstate Commerce Commission ruled in favor of the R.J. Pridham Company of Los Angeles and deleted the last of the punitive freight charges on corrugated boxes. This set the stage for a rapid expansion of the corrugated industry.


Rail classifications were combined, forming Rule 41, which specified the minimum caliper and Mullen (burst strength) of individual facings.


Corrugated containers overtook solid fiberboard as the packaging of choice.


The Stein Hall Company reconverted the corrugated industry to starch adhesives.They replaced cooked starch paste with a mixture of cooked and uncooked starch. They applied heat at the glue line, which solidified the starch and created an instant bond.


The railroad rules changed to require the minimum combined weight of the facings versus caliper.


Flexographic printing was introduced. This method of printing virtually replaced letterpress and oil based ink by the 1970s.


The flexo folder-gluer and flexo rotary die cutter were invented. Photopolymer printing plates were introduced allowing for improved accuracy in creating printing plates from original artwork


Item 222 appeared, providing truck shipping rules.


The Occupational Safety and Health Act (OSHA) was passed, regulating packaging machinery and plant operations.


The corrugated industry attempted to update Item 222 and Rule 41.


The Universal Product Code (UPC) bar code was introduced.


Congress directed the Department of Transportation (DOT) to control the distribution of hazardous substances.

Early 1980s

Preprint printing emerged.

Late 1980s

New developments in the anilox roll, plate and press design drove the industry into short-run, high graphic products.


The edge crush test was added to Item 222 and Rule 41 as an alternative to burst strength and basis weight, allowing the manufacture of lighter weight liners.


130 inch corrugator was introduced. Converting equipment was designed for very fast short automated setups, and consistently high run speeds.

ISO Certification