Corrugated Boxes
Corrugated boxes are storage and shipping containers that are constructed of corrugated materials. The term corrugated material refers to material (usually a type of paperboard) that is rippled, fluted or ridged. Corrugated containers are usually composed of a corrugated fiberboard, a common form of material that consists of a corrugated sheet sandwiched between layers of flat sheets. Despite the inaccuracy of the term, "cardboard box" is widely used to refer to this type of container.
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The History of Corrugated Boxes
A consistent, economic trend throughout history is that packaging supplies tend to be made from materials that cost the least. Because of this, paper and its products have not been used as packaging for most of human history. Only in the mid-1800s, with the advent of industrial pulping processes, did paper become widespread for packaging uses.
The first corrugated paper was patented in England in 1856 for use as a hat liner. Corrugated material used for shipping did not crop into usage until Albert Jones patented a single-faced corrugated board in New York City 15 years later (1871). Three years after Jones’s work (1874), Oliver Long built upon his design and added a second piece of liner to the single-faced board, thus creating the elemental version of the corrugated fiberboard all around us today. In the same year, G. Smyth built the first massive-production corrugator.
Corrugated packaging boxes as we know them today – both the material used to create them and the actual product - did not develop until the very end of the nineteenth century. In 1884, Carl F. Dahl, a Swedish chemist, pioneered the creation of a strong, tear-resistant paper from pulverized wood chips. The product of his process came to be known as kraft paper. By 1906, kraft paper was being regularly manufactured. Interestingly, corrugated shipping boxes did not really develop until an accidental discovery in 1890. Then, Brooklyn-based printer Robert Gair discovered the foundational technique for making such boxes when a creasing tool malfunctioned while working on paper seed bags and performed cutting actions instead. Initially corrugated boxes were primarily used for packaging glass and pottery. As time developed, more products came to be entrusted to corrugated boxes, such as farm produce.
Toward the turn of the millennium, paper-based products had come a vast way from their position during the previous century as a last-resort packaging option. In 1992, production volumes of corrugated fiberboard in the United States exceeded 25 million tons.
Differences Between Paper Products
Although the terms cardboard, paperboard, and corrugated material are all used interchangeably, technical differences do exist between them. The generic term cardboard can refer to any heavy material chemically based on paper-pulp and is often avoided in the packaging industry due to its lack of precision. Similarly, the term paperboard really describes heavy paper-based material whose main distinction from actual sheet paper lies in its greater average thickness.
Chipboard is a slightly more precise term that refers to a recycled-paper product pressed to a certain thickness. Packages used for light items such as board games or cereal are typically made of chipboard. According to the previous definitions, these boxes could technically also be described as cardboard or paperboard boxes.
Corrugated fiberboard is an accepted technical term for the most common material used to make corrugated boxes. This material is simply a three-layered form of kraft paper (a specific type of paperboard or cardboard) that consists of a corrugated (rippled) interior sandwiched between two flat liners. Although some sources may refer to corrugated material as any three-layered material, this is not really accurate, since the term "corrugated" refers primarily to the existence of ripples or pleats (known as flutes). The ripples which define corrugated material are similar to pleating and contain air, which acts as a strong cushion and also increases the durability of its products made from corrugated material. Ultimately, it is more accurate to simply say that corrugated (or rippled) material is an essential part of many three-layered material constructions.
Despite these technical differences, sometimes the packaging industry resorts to colloquial terms such as "corrugated cardboard" to avoid confusing consumers. Furthermore, different industries tend to refer to different materials with their own distinct labels. As a consumer, however, it is important to know these distinctions, especially for purchasing and recycling decisions.
Advantages of Corrugated Fiberboard
Some advantages of corrugated fiberboard include:
- Corrugated Boxes Cost
- One of the main benefits of corrugated boxes is that they are simply inexpensive. Modern industrial technology is responsible for this, having transformed paper-based products from one of history’s least preferential packaging options to one of the most highly valued. The cost to produce, fill and ship the containers is low, and the materials used to make corrugated boxes are inexpensive.
- Easy Handling of Boxes
- Because of their light weight, corrugated boxes are the preferred medium of transport for most packaging professionals.
- Reliability for Shipping Products
- Although they are formed from kraft paper, the fluting technology of corrugated boxes gives them much strength and cushioning ability. Products shipped inside corrugated boxes can be reasonably expected to survive any weather-related or other travel-related shipping hazards.
- Durability of Boxes
- Corrugated boxes are long-lasting. As long as they do not come in contact with moisture, corrugated boxes can be used for many years.
- Versatility of Corrugated Boxes
- The versatility of corrugated boxes plays a huge role in their popularity. Since these boxes can be customized in terms of shape, color, size, etc., they are ideal for a wide range of industries that have very different packaging needs. Additionally, corrugated boxes are reusable. For example, a large box that was originally designed as packaging for a microwave can be used to transport possessions during a move and later as a storage container in an attic or basement.
- Compatibility With Graphic Design
- The flatliners composing the outer layers of corrugated fiberboard are ideal surfaces to place marketing text and graphics, as opposed to other materials that are more expensive and harder to annotate.
- Boxes are Recyclable
- Corrugated boxes can be recycled, making them very appealing in today's environmentally-concerned industries. Over 70% of corrugated material is recovered, recycled and made into new corrugated boxes and other products. In 2006 alone, 25.2 million tons of corrugated material were recycled.
Disadvantages of Corrugated Boxes
- Limitations on Range of Packaged Products
- A main disadvantage of corrugated boxes stems from its lightweight. Heavier products sometimes cannot be shipped in these types of containers and must be moved with heavier containers (e.g. plastic ones) instead.
- Sanitary Concerns
- In some industries, the porous nature of corrugated fiberboard poses sanitary concerns. For example, some members of the hospital food storage and medical supply industries seek to reduce dependence on corrugated containers for fear of contamination due to liquid absorption, insect infestation, etc.
Production Process of Corrugated Boxes
As stated earlier, corrugated boxes are usually made from a specific form of high quality paperboard known as kraft paper. Although corrugated boxes or containers are usually made out of a paper-based material, they can be made out of other materials as well. After paper or wood products, corrugated plastic containers are commonly used, especially when a stronger material is needed.
Kraft paper is produced from elements such as recycled paper, sawdust and wood chip through a sophisticated process. During this process, the elements are adhered together with heat, pressure and an adhesive to produce heavy-duty paper. Although kraft paper forms the foundation of corrugated boxes, kraft paper and corrugated boxes are usually produced in separate environments (paper mills and corrugating plants, respectively) due to economic considerations.
More strictly speaking, the foundation of corrugated boxes is the humble pine tree. It is not uncommon for the largest manufacturers to own thousands of acres of pines as well as the paper mills to process the branchless trunks that are harvested from them. In these paper mills, pine trunks are initially stripped of their barks and reduced to small wood chips. The wood chips then undergo the kraft (or sulfate) process, in which they are"cooked" in a highly alkaline, sodium hydroxide (NaOH) based solution and dissolved into a fibrous pulp. After further refinement, this pulp is transported to a special type of paper-making machine known as a Fourdrinier machine. These machines form the pulp into paper, largely by massive dehydration.
Corrugated box manufacturers typically maintain an inventory of kraft paper reels which they receive from paper mills. In order to actually corrugate the paper, they use massive, football-field length machines known as corrugators. The kraft paper is humidified at high pressures in preheating rollers to soften it, making it easier to form the ripples or flutes. Next, the fluted board is formed by pressing corrugated molds on either side of the cardboard. A following set of rollers, comprising the single-facer glue station, joins the first flat liner with the newly corrugated material. The double-backer glue station adds the second flat liner to the other side of the corrugated material to form a complete piece of corrugated fiberboard. (The fluted paper is joined to both of these layers with a corn starch-based adhesive, effective for creating permanent bonds.) For the newly formed corrugated fiberboard to be ready for use, it must dry over steamy hot plates. The surface is often sanded until smooth and sometimes coated with a glossy, waterproof finish. At the end of the corrugator, the continuous fiberboard is divided into large sheets (or box blanks). The high-precision corrugators in use by many corrugated box manufacturers are typically able to produce 500 feet of corrugated fiberboard per minute.
Although raw material for corrugated fiberboard is usually processed in a separate location, the products of corrugated fiberboard are often not. After being formed in the corrugator, corrugated fiberboard is typically fed to another set of machines (box makers) for the production of actual boxes or containers. Most corrugated cardboard boxes are manufactured in high volumes and sold in bulk bundles, usually around 20 to 50 at a time. They are always sold flat, which saves space during the shipping process.
Design of Corrugated Boxes
- Flute Types in Corrugated Boxes
- The material used to construct corrugated boxes can be highly customized according to its ultimate end purpose of the box or container. For example, the material used to make the corrugated box, the corrugated material’s flute size, and the binding adhesive used in the corrugator are all variable.
- Flute types, in particular, are a key factor in the customization of corrugated containers. To use one illustration, larger flute sizes typically offer better cushioning, while smaller flute sizes offer better structural integrity and opportunities to include marketing text. Flute types are signified by a lettering scheme (A, B, C, E and F) which denotes when the different flutes were invented and not a comparison of their sizes. The different types of flutes do contain different numbers of flutes per linear foot; the most common type of flute is the "C" flute, which contains approximately 39 flutes per linear foot and is mostly used in shipping containers. Compression strength, cushioning strength, and combined board thickness are all affected by the size and number of flutes.
- It is possible to combine different types of flutes within the same board. This is largely due to the fact that the number of layers, or walls, within corrugated fiberboard is also able to be customized. A single face fiberboard will only have one liner attached to a sheet of corrugated material, while double walled boards and triple walled boards will have the corresponding layers of corrugated medium sandwiched between two outside liners.
- Appearance Options for Boxes
- Corrugated boxes come in many varieties and sizes, depending on how they will be used. Some are a single piece construction, while others have a detachable lid. These boxes often assume a rectangular, square, or cylindrical shape. Most boxes are square or rectangular. Once it is ready for a specific application, a box or container is assembled from corrugated fiberboard. A typical way to form a box is to fold flaps on both ends of flat pieces of corrugated fiberboard. Many corrugated boxes and containers are folding boxes, meaning they are held in place by folded flaps instead of tape or fasteners.
- The most common type of corrugated box is known as a Regular Slotted Container (RSC) and belongs to the "Series-02" family of boxes according to the European Federation of Corrugated Board Manufacturers (FEFCO). These boxes contain flaps of identical length from the score to the edge. Other families of boxes (according to FEFCO) include:
- Telescope type boxes defined by a movable lid (Series 03)
- Folder type boxes which are formed by folding a single piece of cardboard from the bottom (Series 04) rather than from the side (Series 02)
- Boxes with a sleeve-like lid that is slid into place (Series 05)
- Rigid, three-piece boxes that require stitching and gluing together (Series 06)
- Custom boxes can be specially-shaped to fit objects of unusual shape. Die cutters are the machines responsible for producing this wide variety of boxes by either a sharp metal blade or infrared laser.
- Corrugated boxes can be multi-colored and have a number of different finishes. Sometimes the exterior is bleached or mottled, which takes away the dark brown pigment and replaces it with an attractive white finish. Corrugated boxes that contain commercial products like cereal, soap and toothpaste usually have a laminated, glossy exterior that is often very bright and colorful with a company's logo, brand name and informational text. Overall, however, natural brown cardboard boxes and white cardboard boxes are by far the most common.
- Specialty corrugated boxes are an ideal solution to many storage, handling and shipping requirements. Working with their customer, corrugated box manufacturers can create custom printed corrugated boxes, corrugated boxes with dividers, waxed corrugated boxes and many more sizes and styles.
Usage of Corrugated Boxes
Container materials are formed from corrugated fiberboard because the corrugating process significantly strengthens the material without adding significant weight. Corrugated boxes are strong, durable and long lasting. While most corrugated boxes are used for storage and shipping, they can also be used for short term organization, such as in mail delivery applications.
Corrugated boxes are used for a wide variety of containers that most people encounter every day.
Many different kinds of commercial products are contained in corrugated material, including toothpaste, cereal, soap, computer paper and check refills, among many others. Pizza boxes, retail and clothing store boxes, gift boxes, jewelry boxes, bakery and cake containers, various display boxes, and many other boxes are all made of corrugated paper material. Some of the thousands of industries that depend on corrugated boxes include food processing, toys, automotive, publishing, electronics, and construction.
Corrugated Box Types
- Cardboard Bins
- Cardboard containers that are usually trapezoidal or rectangular and do not include a lid.
- Cardboard Storage Boxes
- Cardboard containers that are used for storage purposes.
- Corrugated Cartons
- Corrugated containers, many of which are specially designed to fit a specific product.
- Corrugated Trays
- Often used for display purposes or used with a shrink-wrap covering.
- Five Panel Folder Boxes
- Shipped flat without any folding joints. The box has five long panels, one of which fully overlaps. The ends also fully overlap.
- Full Overlap Boxes
- Made with the major flaps fully overlapping, increasing the stability of the seal.
- Full Telescope Boxes
- Have two telescoping sections. The sections may be formed using staples, die-cut locks or adhesive.
- Partial Telescope Boxes
- Have two sections. The top telescopes partially over the bottom.
Standards and Specifications for Corrugated Packaging
The corrugated packaging industry commonly follows standards set by ASTM International, a US-based organization involved in the collection and publishing of technical standards based on voluntary consensus. The following standards are the majority of ASTM’s criteria to assess various properties (e.g. breaking strength, tear resistance, etc.) of corrugated fiberboard and products made from them.
D1974 / D1974M -16 Standard Practice for Methods of Closing, Sealing and Reinforcing Fiberboard Boxes
D2658 – 04 (2013) – Standard Test Method for Determining Interior Dimensions of Fiberboard Boxes (Box Gage Method)
D3951 – 15 Standard Practice for Commercial Packaging
D4727 / D4727M – 17 Standard Specification for Corrugated and Solid Fiberboard Sheet Stock (Container Grade) and Cut Shapes
D5118 / D5118M – 15 Standard Practice for Fabrication of Fiberboard Shipping Boxes
D5168 -12 (2017) Standard Practice for Fabrication and Closure of Triple-Wall Corrugated Fiberboard Containers
D5639 / D5639M – 11 (2015) Standard Practice for Selection of Corrugated Fiberboard Materials and Box Construction Based on Performance Requirements
D6804 – 02 (15) Standard Guide for Hand Hole Design in Corrugated Boxes
Things to Consider When Purchasing Corrugated Boxes
There are well over a thousand corrugated box manufacturers in the United States alone. Thus, finding the right manufacturer for your packaging needs is critical.
- Customized Packaging and Manufacturers
- The right manufacturer will work with their customer to find the packaging solutions which fit their specific needs. Important things to discuss with a manufacturer include the ultimate purpose of your corrugated packages, preferred corrugated box design, the timeline for manufacturing your corrugated packages, how the packages will be transported, etc. The right manufacturer will work with a customer to develop solutions such as custom printed corrugated boxes, corrugated boxes with dividers, waxed corrugated boxes and many more sizes and styles.
- Manufacturer’s Certification and Standards
- Discuss with your manufacturer their adherence to the aforementioned ASTM standards. Also, consider whether a manufacturer has a recognized quality management certification like an ISO 9001 certification.
- End Usage of Corrugated Containers
- Corrugated containers can be measured internally or externally. If you are going to use corrugated containers for in-house uses (e.g. with pallets or machinery), order by external dimensions. If you are going to use corrugated containers for shipping products to an end user, focus on internal dimensions.
- Consider Product Security
- Proper packaging is essential to the security of the products contained inside. Container strength is a key factor determining the type of corrugated box you ultimately need, and such strength is dependent on the different grades of kraft paper that are used in the manufacturing process. A good corrugated box company will provide the needed specialists, engineers, etc. to determine and create a container strong enough for your specific purposes.
- Discuss with your manufacturer the ideal edge crush test ratings your type of corrugated paper box should have. The edge crush test is a relatively recent standard that measures a container’s compressive strength by compressing its edges between two plates positioned contrary to its flutes. ECT standards make it easier for the corrugated box industry to produce strong containers with less even less material.
- The Box Maker’s Certificate (BMC) is a type of seal that has commonly been used on corrugated boxes to indicate a box’s strength in compliance with certain regulations. However, the BMC is increasingly seen as obsolete since it is not legally required and creates an extra liability for shippers. Furthermore, it is inconvenient for important aspects of the packaging industry (such as on-demand packaging systems). Thus, while a BMC may indicate a higher level of professionalism on a manufacturer’s part, its presence is not absolutely necessary.
- Consider Your Brand
- A company’s brand and image is inextricably linked to their packaging. Consider whether your packaging solution enhances or harms your brand in the eyes of customers.
Proper Care for Boxes
Moisture undermines one of corrugated boxes’ main advantages – durability. As a result, keeping corrugated boxes dry is a fundamental part of their care.
Corrugated fiberboard should always be handled in accordance with its anisotropic qualities. Anisotropic material refers to material whose physical properties depend on directionality and orientation. Corrugated fiberboard will behave differently based on the directional orientation of its macromolecules, its flutes, etc. Consult with your corrugated box manufacturer to ensure you handle your corrugated fiberboard according to its anisotropy and not contrary to it.
Corrugated Box Terms
- Box Plants
- A factory that produces corrugated and/or cardboard boxes.
- Cardboard
- Any heavy paper-pulp based board. Cardboard is not necessarily corrugated. To be "corrugated", the board must have fluted paper with air pockets in the middle of its outer layers.
- Converting Machines
- Convert flat corrugated boards into boxes. Machine types may include flexo folder gluers and die cutters.
- Corrugated Boxes
- A misspelling of "corrugated boxes," containers made of a corrugated material.
- Corrugated Paperboard
- Two sheets of stiff paper joined by a middle sheet of pleated paper.
- Corrugating Medium
- The wavy "fluted" paper inside the corrugated paperboard.
- Corrugating Rolls
- Gear-like cylinders that shape paper into a series of waves or "flutes."
- Die-cut Machines
- These are machines that cut the corrugated board into a pattern that will later be folded into a box shape.
- Flutes
- Ridges pressed or folded into a paper. Flutes are very similar to pleats and come in sizes A, B, C, E, F and microflute. The most common size flute is size C.
- Liner
- Also known as paperboard, this material has a similar appearance to the brown paper that composes grocery bags.
- Single Face Web
- A continuous sheet of flat paper with fluted paper glued to it.
- Web
- A long sheet of paper on a roll, the web is drawn into corrugating rolls to begin forming a corrugated paperboard.