CORRUGATED COMPOSITION
Corrugated fiberboardis comprised of linerboard and heavy paper medium.Linerboardis the flat, outer surface that adheres to the medium. Themediumis the wavy, fluted paper between the liners. Both are made of a special kind of heavy paper calledcontainerboard. Board strength will vary depending on the various linerboard and medium combinations.
(A) Single Face:One corrugated medium is glued to one flat sheet of linerboard; flutes exposed.
(B) Single Wall:The corrugated medium is glued between two sheets of linerboard. Also known as doubleface.
(C) Double Wall:Three sheets of linerboard with two mediums in between.
(D) Triple Wall:Four sheets of linerboard with three mediums in between.
HOW TO MEASURE A BOX
Dimensions should always be stated in the sequence ofLength,WidthandDepth(exceptions include bookfolds, bin boxes and dividers, where the sequence is Width, Length and Depth).
Thelengthis always thelongerdimension, and thewidthis always theshortestdimension, measured along the opening of the box. Thedepthis the distance between the opening and the opposite panel.
Boxes are generally measured from theinside, with the dimensions referring to the opening of anassembledbox.Inside dimensionsare used for measuring because the corrugated board thickness may vary. A box constructed of B flute will not have the same outer dimensions as a box made from E flute. When measuring the inside of an existing box, make sure to measure from the center of the score (the crushed fold line).
Outer dimensionsmay need to be communicated for shipping and pallet configuration purposes. When listing outer dimensions, always include"OD"with the size (e.g., 10"x22"x12" OD).
BOX STYLE DEFINITIONS AND ABBREVIATIONS
The majority of box styles fall into one of the following general categories: Slotted Boxes, Telescope Boxes, Folders, Rigid (or Bliss) Boxes, Self-Erecting Boxes and Interior Forms. In addition, corrugated boxes can be custom designed to meet the specific needs of the customer.
SLOTTED BOXES
These boxes are generally made from a single piece of corrugated fiberboard. The blank is scored and slotted to permit folding. Boxes are shipped and stored flat and assembled as needed by the user. Some of the most common types include:
Regular Slotted Container (RSC)— All flaps have the same length, and the two out flaps are one-half the container's width, so that they meet at the center of the box when folded. The RSC is the most common box style.
Half Slotted Container (HSC)— Same as a Regular Slotted Container (RSC), but without one set of flaps.
Overlap Slotted Container (OSC) — All flaps have the same length; the outer flaps overlap by one inch or more. The box is usually closed with staples driven through the overlap area. This style of box is used when the length of the box is considerably greater than the width, resulting in a long gap between the inner flaps. The sealed overlap helps to keep the outer flaps from pulling apart.
Full overlap Slotted Container (FOL)— All flaps have the same length (the width of the box). When closed, the outer flaps come within one inch of complete overlap. This style is especially resistant to rough handling and provides extra product cushioning and stacking strength.
Center Special Slotted Container (CSSC) — Inner and outer flaps are cut to different lengths. Both sets of flaps meet at the center of the box. This style is especially strong because both the top and bottom have double the thickness of the corrugated board. The inner flaps, with no gap, provide a level base for products.
Center Special Overlap Slotted Container (CSO)— All flaps have the same length (one-half the length of the box). The length of the box can be no more than twice its width. The inner flaps meet at the center of the box, providing a level base and full top protection.
Center Special Full Overlap Slotted Container (SFF)— Inner and outer flaps are cut to different lengths. When closed, the inner flaps meet at the center of the box, and out flaps fully overlap. With three full layers of combined board over the entire top and bottom, this style provides extra cushioning and stacking strength.
TELESCOPE BOXES
These boxes usually consist of top and bottom pieces that fit over each other. "Telescope Style" generally describes a box where the cover extends over at least two-thirds of the depth of the bottom piece, where a Box with Cover indicates a box where the cover extends less than two-thirds of the depth. Common types include:
Full Telescope Design Style Container (FTD) and Design Style Container with Cover (DSC)— Two-piece boxes made from two scored and slotted blanks (trays).
Full Telescope Half Slotted Container (FTHS)— The two-piece body is made from two half-slotted containers.
RIGID (BLISS) BOXES
Rigid Boxesinclude two identical end panels and a body that folds to form the two side panels, an unbroken bottom and the top. Flaps are used to form the joints. Once the joints are sealed, the box is considered rigid.
SELF-ERECTING BOXES
Self-Erecting Boxestypically feature regular slotted container or telescope-style tops.
FOLDERS
These consist of one or more pieces of combined board, with an unbroken bottom surface and scored to fold around the product. Popular styles include:
One Piece Folder (OPF)— One piece of board is cut so that it provides a flat bottom, with flaps forming the sides and ends, and extensions of the side flaps meeting to form the top.
Five Panel Folder (FPF)— A single cut and scored piece features a fifth panel used as the closing flap, completely covering a side panel.
Traysare formed from a single piece of combined board, with the design featuring an unbroken bottom and several layers of corrugated in the end panels. They are frequently used as inner containers for parts, delicate produce or mail pieces.
INTERIOR FORMS
These include a wide variety of build-ups, dividers, partitions and other inner packing pieces. They can be used to separate or cushion products, to strengthen the box or to fill voids. They may be simple rectangle, scored, slotted or die-cut shapes. Common formats include:
Padsare plain shapes of corrugated or solid fiberboard, used to fill spaces or separate layers or sections of products.
Tubesare scored rectangles, folded to form a multi-sided structure.
Partitions(orDividers) provide a separate cell for each item in a box. Primarily used for packaging glassware or other fragile items.
Inner Packing Piecesare scored and/or folded pieces of fiberboard used for cushioning, suspension and separation, and to fill voids.
Inner Pack Formsare usually die cut fiberboard pieces designed to position and support products away from the walls of the box for added protection.
BOX CERTIFICATES
TheBox Maker’s Certificate (BMC)is placed on an outside bottom flap. This symbol identifies the manufacturer and serves as a symbol of compliance with the stated specifics. The stamp identifies the material and certifies the results of theMullen Bursting Testor theEdge Crush Test.
TheMullen Bursting Testmeasures a box’s ability to withstand external or internal forces, and to contain the contents during handling. The test certifies that the box can withstand the stated pressure (lbs. per sq. in.) as applied by a Mullen Tester.
The Edge Crush Test measures the amount of force (lbs. per in.) needed to cause the compressive failure of an on-edge specimen of corrugated board. The result is a primary factor in determining the compression strength of a completed box.
Material Strength Tests
Corrugated boxes are common for shipping and mailing purposes. They are subject to different kinds of stress and impact during the packing, shipping, and storage process. So corrugated material needs to be able to resist damage as much as possible to protect the products inside. There are different ways to test the strength of corrugated material. But which test should you use when selecting material for your corrugated boxes?
Edge Crush Test is one of the essential tests for corrugated packaging material. As the name implies, force is applied perpendicular to the edge of the corrugated board until it buckles. The results provide manufacturers the confidence for the material to have the strength and durability required to handle heavy loads and stack resistance. The resulting value is shown in pounds per linear inch of load-bearing edge and is reported in ECT ratings.
32 ECT is the most commonly used for corrugated material.
Flat Crush Testis similar to the Edge Crush Test. This test applies force directly on a surface area of the corrugated fiberboard until the flute flattens and compromises its structure. This test determines the compression and stacking resistance of the corrugated board required to carry heavy loads.
Burst Test, otherwise known as theMullen Test, tests the durability of the corrugated fiberboard’s surface. As the Flat Crush Test tests compression resistance, the Burst Test determines the amount of force required to puncture the linerboard. The resulting value is given in pounds per square inch.
200# means 200 pounds per square inch of force applied to the face of the linerboard.
Water Absorption Test, otherwise known as theCobb Test, determines the level of moisture that the material needs to remain below to maintain its structural integrity to protect the product. Measuring the absorbency of the box surface is also important because it may affect the printability of the box. On the back surface, the same test indicates how well the liner will adhere to the fluting. The test begins by setting a sample of the paper material above an open container with a specific measurement of liquid. The container is flipped, allowing liquid to absorb into the material for a certain amount of time before being removed and examined.
Ring Crush Testmeasures the compression of paper and board materials. A strip of paperboard with a standardized length and width is formed into a ring. Force is applied perpendicular to the paper’s edge until it buckles.
Short Span Compression Testhas become a popular alternative to the Ring Crush Test. A strip of standard-sized paperboard is placed between a set of compression plates which then clamp onto the paperboard to determine the material’s compressive strength. The test repeats throughout the length of the paperboard to determine the strength and durability of the material.
FLUTE AND ITS WEIGHT
Single Wall
Single-wall corrugated box styles vary in material strength and durability. This can be tested with theEdge Crush Test, as discussed later in this guide.
Single-wall corrugated boxes can carry weights from 23 ECT to up to 55 ECT. It weighs less and “weaker” single-wall corrugated boxes may hold up to a minimum weight of 20 lbs.
A-Flute – 1/4”is the first type of corrugated flute. This flute grade has the highest protection and cushion qualities. Very good at handling compression and stacking, it is often used to packagefragile items.
B-Flute – 1/8”this type of flute appears much thinner than others, but do not let its’ appearance fool you. B-Flute is quite strong, and it typically used for counter displays and canned food products. It also has a flatter surface for higher quality printing and is excellent for die-cutting. B-Flute has excellent puncture and crush-resistance properties while also consuming less space. It has excellent all-round performance forall types of packaging, but also commonly used as padding, dividers, partitions, and other forms of inner packing material.
C-Flute – 3/16” is flexible and one of the most versatile flute grades in cardboard boxes. It has average crush resistance, stacking strength, and printing properties. You have likely seen this type used forshipping boxesbut also used to package glass, dairy, and furniture products.
E-Flute – 1/16”is not typically used for shipping. As one of the thinner flute grades, E-Flute is often used as an alternative for paperboard folding cartons. E-Flute is also designed thinner and more condensed to reduce the outer box dimensions, which saves on storage space. Although thinner, E-Flute has excellent compression strength, crush resistance, and a relatively flat surface for high-quality printing applications. You may use E-Flute for cosmetics, fragile glass, ceramics, and othersmall and delicate products.
F-Flute – 1/32”has protective qualities similar to E-Flute but with an even smoother surface for high-quality printing. It is common for you to use F-Flute for clamshell packaging for fast-food chains in the United States. On the other hand, Europe has adopted this grade of corrugated fluting as a standard option forspecialty and retail packaging.
| SINGLE WALL | ||
| Max. Weight Box/Contents (lbs.) | Min. Burst Test (lbs. per sq. in) | Min. Edge Crush Test (lbs. per in. width) |
| 20 | 125 | 23 |
| 35 | 150 | 26 |
| 50 | 175 | 29 |
| 65 | 200 | 32 |
| 80 | 250 | 40 |
| 95 | 275 | 44 |
| 120 | 350 | 55 |
Double Wall & Triple Wall
Because there are at least two walls of corrugated sheets in this style of corrugated box, double-wall, and triple-wall boxes are, of course, more durable. The downside to this, if applicable, is that the box is less flexible. In some cases, this trait may be necessary for certain products. This type of corrugated box is ideal for shipping and storage, as they are quite durable and can withstand regular wear and tear.
Triple-wall boxes have three stacked corrugated sheets and four liner board facings. Triple-wall corrugated boxes are extremely durable and can typically withstand a maximum of 300 lbs.
Although it is possible to form many different combinations of double-wall or triple-wall corrugated boxes, here are a few standard double-wall combinations found within the industry:
AC Flute is a combination of the two most protective corrugated grades. The result is a very strong corrugation used when extra strength is needed. This is an excellent option if you need extra protection from the shipping and handling process. With A-Flute stacking and compression resistance, this combination also makes for an excellent storage option.
BC Fluteis an excellent all-round performer, this combination provides high-level transit protection and most often seen in shipping cases.
EBFluteprovides excellent transit strength and protection, while the outer E-Flute allows for an excellent high-quality printing surface.
| DOUBLE WALL | ||
| Max. Weight Box/Contents (lbs.) | Min. Burst Test (lbs. per sq. in) | Min. Edge Crush Test (lbs. per in. width) |
| 80 | 200 | 42 |
| 100 | 275 | 48 |
| 120 | 350 | 51 |
| 140 | 400 | 61 |
| 160 | 500 | 71 |
| 180 | 600 | 82 |
| TRIPLE WALL (minimum puncture test, oz. per in. of tear) | ||
| Max. Weight Box/Contents (lbs.) | Min. Burst Test (lbs. per sq. in) | Min. Edge Crush Test (lbs. per in. width) |
| 240 | 700 | 67 |
| 260 | 900 | 80 |
| 280 | 1100 | 90 |
| 300 | 1300 | 112 |
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Bale:A shaped unit of materials, enclosed in a fiberboard container or other wrapping, bound by strapping, rope or wire.
Basis Weight: An attribute of containerboard, but the values may be determined from the combined corrugated board. When determining the basis weight from the combined board, the take-up factor of the corrugated medium, which varies with flute size, and the weight of the adhesive must be considered.
Bending:The ability of containerboard or combined board to be folded along scorelines without rupture of the surface fibers to the point of seriously weakening the structure.
Blank or Box Blank:A flat sheet of corrugated board that has been cut, scored, and slotted, but not yet glued together.
Box Manufacturer: An establishment that has the equipment to score, slot, print and join corrugated or solid fiberboard sheets into boxes, and that regularly uses that equipment in the production of fiberboard boxes in commercial quantities.
Box Manufacturer's Certificate (BMC):A statement printed in a round or rectangular design on a corrugated box flap that certifies the box conforms to all applicable standards, and identifies its manufacturer. Sometimes referred to as a class stamp or cert stamp.
Box Style:Distinctive configuration of a box design, without regard to size. A name or number identifies styles in common use.
Boxboard:The types of paperboard used to manufacture folding cartons and set up (rigid) boxes.
Built-up:Multiple layers of corrugated board glued together to form a pad of desired thickness, normally used for interior packing.
Bulk:Unpackaged goods within a shipping container. Also, a large box used to contain a volume of product (e.g., “bulk box”).
Bundle:A shipping unit of two or more articles or boxes wrapped or fastened together by suitable means.
Caliper:Usually expressed in thousandths of an inch (mils) or sometimes referred to as "points." Caliper measurements are also used as an indirect measure of manufacturing quality.
Cardboard:A thin, stiff pasteboard used in the creation of playing cards, signs, etc. Term is often misused to refer to Boxboard (folding cartons) and Containerboard (corrugated boxes).
Carton:A folding box made from boxboard, used for consumer quantities of product. A carton is not recognized as a shipping container.
Case:As used by the packaging industry, a corrugated or solid fiberboard box.
Chipboard:A paperboard generally made from recycled paper stock. Uses include backing sheets for padded writing paper, partitions within boxes and the center ply or plies of solid fiberboard.
Combined Board:A fabricated sheet assembled from several components, such as corrugated or solid fiberboard.
Compression Strength:A corrugated box's resistance to uniformly applied external forces. Top-to-bottom compression strength is related to the load a container may encounter when stacked. End-to-end or side-to-side compression may also be of interest for particular applications.
Containerboard: The paperboard components (linerboard, corrugating material, and chipboard) used to manufacture corrugated and solid fiberboard. The raw materials used to make containerboard may be virgin cellulose fiber, recycled fiber, or a combination of both.
Corrugated Board, Corrugated Fiberboard:The structure formed by gluing one or more sheets of fluted corrugating medium to one or more flat facings of linerboard. There are four common types:
- Single Face:Combination of one fluted corrugating medium glued to one flat facing of linerboard.
- Single Wall:Two flat facings of linerboard, one glued to each side of a corrugated medium. Also known as Double Face.
- Double Wall:Three flat facings of linerboard, one glued to each side of two corrugated mediums.
- Triple Wall:Four flat facings of linerboard, one glued to each side of three corrugated mediums.
Corrugator: The machine that unwinds two or more continuous sheets of containerboard from rolls, presses flutes into the sheet(s) of corrugating medium, applies adhesive to the tips of the flutes, and affixes the sheet(s) of linerboard to form corrugated board. The continuous sheet of board may be slit to desired widths, cut off to desired lengths, and scored in one direction.
Design Style: A style of fiberboard trays or caps having flaps scored, folded, and secured at flange side walls forming the depth, as opposed to a slotted style having a set of major and minor closing flaps.
Die Cut: The act of cutting raw material (such as a combined board) to the desired shape (such as a box blank) by using a die.
Dimensions: The three measurements of a box: length, width, and depth. Inside dimensions are used to assure proper fit around a product. Outside dimensions are used in the carrier classifications and in determining pallet patterns.
Double Wall: A corrugated board construction where two layers of the medium are glued between three layers of flat linerboard facing.
Edge Crush Resistance/Short Column Compression (ECT):The amount of force needed to crush on-edge combined board is a primary factor in predicting the compression strength of the completed box. When using certain specifications in the carrier classifications, minimum edge crush values must be certified.
Facings:Sheets of linerboard used as the flat outer members of combined corrugated board. Sometimes called inside and outside liners.
Fiberboard:A general term describing combined paperboard (corrugated or solid) used to manufacture containers.
Flaps: Extension of the sidewall panels that, when sealed, close the remaining openings of a box. Usually defined by one scoreline and three edges.
Flexo Folder Gluer: A machine, usually capable of running at high speed that prints, folds, cuts, and glues sheets of corrugated board, converting them into shipping boxes.
Flute: The wavy layer of the corrugated medium that is glued between the flat inner and outer sheets of linerboard to create the corrugated board. Fluting generally runs parallel to the height of a shipping box.
Joint:The opposite edges of the blank glued, stapled, wire stitched, or taped together to form a box.
Kraft: German word meaning “strength”; designating pulp, paper, or paperboard produced from wood fibers.
Liner: A creased fiberboard sheet inserted as a sleeve in a container and covering all sidewalls. Used to provide extra stacking strength or cushioning.
Linerboard:The flat sheets of paper that comprise the outer surfaces of a sheet of corrugated board.
Medium:The paperboard used to make the fluted layer of corrugated board.
Mullen (or Burst) Test: The Mullen Test is a standard industry measure of the bursting strength of the corrugated board.
Overlap:A design feature wherein the top and/or bottom flaps of a box do not butt, but extend one over the other. The amount of overlap is measured from flap edge to flap edge.
Pad:A corrugated or solid fiberboard sheet, or sheet of other authorized material, used for extra protection or for separating tiers or layers of articles when packed for shipment.
Palletizing:Securing and loading containers on pallets for shipment as a single unit load, typically for handling by mechanical equipment.
Panel:A "face" or "side" of a box.
Paperboard: One of the two major product categories of the paper industry. Includes the broad classification of materials made of cellulose fibers, primarily wood pulp, and recycled paper stock, on board machines. The major types are containerboard and boxboard. (The other major product group of the paper industry is paper, including printing and writing papers, packaging papers, newsprint, and tissue.)
Partition:A set of corrugated, solid fiberboard or chipboard pieces that interlock when assembled to form a number of cells into which articles may be placed for shipment.
Ply:Any of the several layers of linerboard or solid fiberboard.
Point: Term used to describe the thickness or caliper of paperboard, where one point equals one-thousandth of an inch.
Puncture Resistance: The puncture resistance of the combined board indicates the ability of the finished container to withstand external and internal point pressure forces and to protect the product during rough handling. This method is used on heavy double walls and triple walls as an alternative to burst.
Regular Slotted Container (RSC):A box style created from a single sheet of corrugated board. The sheet is scored and slotted to permit folding. Flaps extending from the side and end panels form the top and bottom of the box. The two outer flaps are one-half the container’s width in order to meet at the center of the box when folded. Flute direction may be perpendicular to the length of the sheet (usually for top-opening RSCs) or parallel to the length of the sheet (usually for end-opening RSCs).
Score or Scoreline:An impression or crease in corrugated or solid fiberboard, made to position and facilitate folds.
Scored and Slotted Sheet: A sheet of corrugated fiberboard with one or more scorelines, slots, or slits. May be further defined as a box blank, a box part, a tray or wrap, a partition piece, or an inner packing piece.
Seam: The junction created by any free edge of a container flap or panel where it abuts or rests on another portion of the container and to which it may be fastened by tape, stitches, or adhesive in the process of closing the container.
Set-up Boxes:Boxes that have been squared, with one set of end flaps sealed, ready to be filled with product. An article that is packed for shipment in a fully assembled or erected form.
Sheet: A rectangle of the combined board, untrimmed or trimmed, and sometimes scored across the corrugations when that operation is done on the corrugator. Also, a rectangle of any of the component layers of containerboard, or of paper, or a web of paperboard as it is being unwound from the roll.
Slit:A cut made in a fiberboard sheet without removal of material.
Slit Score:Shallow knife cuts made in a box blank to allow its flaps and sides to be folded into a shipping box.
Slip Sheet: A flat sheet of material used as a base upon which goods and materials may be assembled, stored, and transported.
Slot:A wide cut, or pair of closely spaced parallel cuts including removal of a narrow strip of material made in a fiberboard sheet, usually to form flaps and permit folding without bulges caused by the thickness of the material. Common widths are 1/4 in. (6 mm) and 3/8 in. (9 mm).
Stacking Strength:The maximum compressive load a container can bear over a given length of time, under given environmental/distribution conditions, without failing.
Tensile Strength:Indicates the containerboard's resistance to breaking when it is pulled into or through equipment during the converting and printing processes.
Tube:A sheet of combined boards, scored and folded to a multi-sided form with open ends. It may be an element of a box style or a unit of interior packing that provides protection and compression strength.
Unit:A large group of bundled or unbundled boxes, banded and/or stretch filmed together for shipment.
Unitized Load:A load of a number of articles or containers, bound together by means of tension strapping, plastic shrink or stretch films.
Web:A continuous sheet of paperboard or paper.
Wrap-around Blank:A scored and slotted sheet of corrugated fiberboard that is formed into a box by folding it around its contents. The user makes both the flap and joint closures.
Corrugated Boxes are Cost-Effective
The bottom line is important to all businesses. No one wants to waste money – especially on practical necessities.
Corrugated boxes are relatively low cost to manufacture. Most of the time,custom boxes costless than you might expect.
Also, because they’re lightweight and can be easily stored,you can save moneyon storage and transportation costs.
Options for Custom Corrugated Boxes and Endless
Corrugated box options are almost limitless.
You can choose from all types of boards, weights, adhesives, coatings, treatments, flame resistance, static control – the list goes on.
These packaging boxes can also be folded into all kinds of different shapes and box sizes. And we haven’t even touched on the exhaustive graphic design optionscorrugated boxesafford.
There are all kinds of printing options so you can make your corrugated boxes unique to your brand.
Corrugated Packaging Boxes are Environmentally-Friendly
Corrugated cardboard material looks like it fits the bill for consumers’ thirst to do right by the environment. Accenture recently surveyed 6,000 consumers in 11 countries and found the following:
- 83% of respondentsthought it was important or extremely important for companies to design products that could be reused or recycled.
- 77% thoughtplastic was the least environmentally friendlytype of packaging.
- But the good news for corrugated boxes, 55% thought paper products were thebest option for the environment.
Let’s look at some of the reasons,corrugated boxesget high marks for protecting the environment:
Corrugated boxes are easy to recycle
You have no excuses. In most places, you can just break down your boxes and put them in your curbside pick-up.
- According to the EPA, in 2018, around32.1 million tons of corrugated boxeswere recycled out of 33.9 million tons of total paper and paperboard recycling.
- That year therecycling rate for corrugated boxeswas96.5 percent.
Corrugated cardboard boxes are renewable
Corrugated packagingis made from a high percentage of recycled material (mostly in the 70-100% range). It can be manufactured from paper pulp that comes from fast-growing pine trees, or made from wood chips and other leftover materials.
Most corrugated box manufacturers get their paper from sustainable forests. No reputable paper company is going to be clear-cutting old-growth forests.
Nope, quite the opposite.
After all, it’s in the interest of paper companies to keep their supply going, so they’ll take actions like replacing harvested trees with seedlings.
Corrugated shipping boxes are reusable
Corrugated boxesare easily collapsible, so you can break them down and store them in the garage until you need one for your next move or another future use.
Corrugated packaging boxes save energy
Since corrugated boxes are mostly made using recycled materials, it takes less energy to produce them.
Most are made without dyes and bleaches, so that’s one less step in the production cycle. They’re also relatively light so you can save on transportation costs.
Corrugated boxes are efficient
A corrugated box offers a lot of protection so you don’t need it to be giant-sized or filled with excessive padding inside.
Additionally, corrugated cardboard boxes are easy to stack or collapse when not in use – so you don’t need as much space to store them.
