Cap and Neck Finishes Glossary 

"T" DimensionThe outside diameter of the thread. The tolerance range of the "T" dimension will determine the mate between bottle and closure. "E" DimensionThe outside diameter of the neck. The difference between the "E" and "T" dimensions divided by two determines the thread depth. "I" DimensionThe inner diameter of the bottle neck. Specifications require a minimum "I" to allow sufficient clearance for filling tubes. Linerless closures, with a plug or land seal, and dispensing plugs and fitments require a controlled "I" dimension for a proper fit.

"S" DimensionMeasured from the top of the finish to the top edge of the first thread. The "S" dimension is the key factor which determines the orientation of the closure to the bottle and the amount of thread engagement between the bottle and cap.

"H" DimensionThe height of the neck finish. Measured from the top of the neck to the point where the diameter extended down, intersects the shoulder.

Screw thread cap sizes are generally expressed as two numbers. The first number refers to the cap diameter (in millimeters) and the corresponding Glass Packaging Institute (GPI)/Society of the Plastics Industry (SPI) finish diameter. The second number refers to the height and thread configuration of the closure or finish. Below is a selection of commonly used caps and finishes.

 

 

Cap & Bottle Neck DefinitionsApplication Torque:  The torque force, measured in inch-pounds, required to screw a closure onto a container. Applicator Cap:  A closure designed to apply the contents of the container.Back-Off:  A term used to denote relaxation of forward thrust, i.e. loss of torque following application of the closure. Back-off can be affected by top loading, compressibility and resiliency of the closure liner, consistency of application torque, and mechanical interaction of the closure and bottle. Backing Liner:  A compressible material, usually pulp or foamed polyethylene, to which the facing liner is attached or adhered. This compressible material compensates for any irregularities on the sealing surface. Band:  That portion of the closure that releases when the closure is removed from a bottle. The band is used for tamper indication. Bead:  A depressed or raised circle or ring around a container or closure. Binding:  Excess drag when the closure is applied to the bottle. Binding is usually the result of interference. Bottoming-Out:  A condition where the bottom skirt of the closure makes contact with the container (usually the shoulder or transfer bead) before the land area of the container and the closure (lined or linerless) create a seal.Cavitation:  The number of molding stations within a mold. Cavity:  A mold component which forms the exterior or external surface of the closure. Cellulose Band:  A band made of hydrated cellulose film extruded in continuous tubing form. The cellulose tubing is then processed and printed in this form and cut into individual bands of predetermined lengths. The celon is allowed to air dry when it is applied to the finish of the container. During the air-drying period, the cellulose band shrinks to form a skin-tight film over the finish of the bottle. Center Gated Mold:  A mold in which the cavity is filled with resin through an orifice interconnecting the nozzle and the center of the cavity area. Child Resistant Closure (Abbreviated “CR”):  A closure requiring dissimilar motions making removal by a child difficult. Child Resistant closures are subject to current government regulations. Chucks:  A component of a capping machine which holds the closure for application to the container. Closure:  Any structure or device designed to close off the opening of a container and prevent loss of its contents. Closure Lining Machine:  A high speed, specialized machine using a punch’s die or specialized cutters to automatically cut and insert liners into closures. Closure Height:  The overall height of the closure proper. Closure height is measured from the closure top to the open end of the closure. Closure height can be considered in terms of “inside height “or “outside height.?Closure Removal Torque:  The amount of force necessary to loosen, open, or remove a closure from a bottle. Closure Skirt:  The vertical wall of a closure. Closure Stripping Torque:  The amount of force required to cause the closure and/or bottle finish to distort and override the matching closure-bottle threads. Cocking:  Mis-application of a closure to a container. The closure’s appearance is uneven on the container or it is pulled off to one side, due to an uneven downward pull of threads. Cocking is normally caused by over torquing or an out of spec. “S” dimension container. Compression Molding:  A molding process whereby thermoset plastic material is dropped into a cavity and formed under pressure by a force. The process is primarily done on a rotary molding machine. Continuous Thread Closure (Abbreviated “CT”):  A non-interrupted spiral design threaded closure. The main purpose of a CT closure is to mate with corresponding bottle threads and provide sealing and re-sealing of the container. Core:  A mold component which forms the internal surface of the closure. The core also includes the threads. Curl:  A tubular structure formed at the open end of a metal closure to provide a smooth, strong edge. The curl facilitates automatic handling of the closure. Cycle:  The sequence of operations in a process to complete one set of parts. The cycle is taken at a point in the operation and ends when this point again starts. Cycle Time:  The time during which one molding cycle is completed. Cycle time comprises injection of melt, cure, recovery, part ejection, and clamping for next shot. Deep Screw Cap:  A cap having a deeper skirt (more “H”) and generally a heavier thread than the 400 finish series. Dispensing Closure:  A snap on or threaded closure which allows for product dispensing, and usually resealing, without removing the closure from the package. Dome:  A closure which has a rounded top surface. Dropper Cap:  A closure that includes an attached dropper and rubber bulb.

“E” Dimension:  The smaller diameter of the inside of the closure measured “thread to thread.” The “E” dimension corresponds to the “E” (outside wall) of the container. See the Cap and Neck Finishes page for more information.Facing Liner:  The liner material attached or adhered to the backing liner. The facing acts as a barrier to the chemical reaction of the product. Finish:  The configuration of a container top shaped to accommodate a closure. Fitment:  A plastic component that snaps over the land area and functions as an orifice reducer or blocker. Flash:  Excessive undesirable plastic materials on containers or closures formed along mold seams or parting lines. Flash results from plastic flowing into the clearance between mold components. Flowed-in:  A method of applying fluid sealing compounds with a nozzle. Friction cap:  A closure held on by friction upon application to the container, building up resistance to the movement of the closure.G-cap (G-450):  A 70 millimeter cap with a deep screw threaded skirt (450). Gasket:  A liner applied between the sealing surface of container lip and closure. A gasket provides the ultimate seal. Gate:  An orifice through which the molten resin enters the cavity. A gate is the small restricted opening connecting the runner to the cavity. Glued-In Closure Liners:  Closure liners attached to the inside roof of the closure by a hot melt adhesive.GPI:  Glass Packaging Institute“H” Dimension:  The height of the bottle finish, measured from the sealing surface, in a line parallel to the axis of the finish and tangent to the threads on the finish, down to a point where the line intersects the body (shoulder) of the container. The “H” dimension is also the inside height of the closure, measured from the bottom of the closure, in a line tangent to the threads of the closure, terminating at the inside, top of the closure. The “H” dimension does not include any liner (if used), or “linerless” seal, ribs, membranes, or any other sealing element dimensions. See the Cap and Neck Finishes page for more information.“I” Dimension:  The diameter of the opening of the container measured from the inside wall to the inside wall. See the Cap and Neck Finishes page for more information. Induction Seal Liners:  A specialized laminate containing aluminum foil and a plastic heat sealable film which hermetically seals a container through use of an “Induction Capsealing Machine.”Inner Seal:  An additional seal of moisture proof material applied to the top of container prior to or during the application of the closure.Interference:  A condition where an exterior diameter in the finish area of the bottle is larger than the mating interior diameter of the closure. Internal Threads:  The threads on the interior of the closure. Interrupted Threads:  Non-continuous threads on the closure causing gaps. Interrupted threads are normally used in beverage closures thread on (neck) finish of bottles in which the thread has gaps or discontinuities. The gaps are at the parting line of the mold. Injection Mold:  A mold into which a plasticated material is introduced from an exterior heating cylinder. Injection Molding:  A process by which a plasticized material is forced into a mold. Knurl:  The indented or crimped portion on the skirt at the top of the cap used for holding the liner in the cap. The knurl is also used as a grip for removing the cap. The knurl provides a non-skid surface during the threading operation. “L” Dimension:  The vertical distance from the sealing surface to top part of neck bead, i.e., where the upper most part of bead intersects the container neck. Land:  The lip of the container to which the closure liner or land seal linerless feature compresses or conforms to tolerance. Land Seal:  A sealing device which seals by applying pressure to the top or land of the container finish. Liner:  A disk of paper, cork, foam, plastic, etc., retained in a closure to provide a flexible barrier between the closure and the sealing surface of the container. Liner Well:  The space provided in a closure for a liner. Linerless Closure:  A thermoplastic closure incorporating a molded-in sealing feature which, when applied to a container with the appropriate finish, seals most liquids within the container. Lug Cap:  A closure with raised internal impressions that inter-mesh with identical threads on the finish of container.Matte Finish:  A coating surface that displays no gloss when observed at any angle. Matte finish is also referred to as a “flat finish.”Mechanical Breakaway Bands:  A closure with a portion or section of the skirt perforated or weakened in some manner so when the closure is opened, the section is designed to break apart and either remain on the container or attach to the closure to indicate the package has been opened. Metallizing:  Applying a thin coating of metal to a non-metallic surface. Metallizing can be done by chemical deposition or by exposing the surface to a vaporized metal in a vacuum chamber.

Modified Buttress Thread:  Commonly referred to as “M” style. The modified buttress thread was developed, with a 10 degree pressure angle, to offer more closure-to-bottle thread contact. Mold:  The combination of mold frame and tooling components needed to form a closure. Mold Frame:  The plates and components required to direct plastic to the tools that form closures and remove the closures from the mold. Molding (compression):  A process of shaping or forming material through the use of molds, heat, and pressure. Molding (injection):  A process of shaping or forming plastic objects from powder or granule form in a mold by cooling the previously heated plastic. Mouth:  The open end of the cap opposite the top.Neck:  The part of a container where the shoulder cross section area decreases to form the finish. Neck Rings:  That part of the mold equipment which forms the finish of the bottle. 'Non-Threaded:  Designates items which do not require threading action when applied to glass or plastic containers. Examples of non-threaded closures are snap caps, sifter fitments, pour-out fitments, etc.“O.D.”:  The abbreviation for Outside Diameter. Offset Neck:  The vertical axis of the neck finish is off center from the vertical axis of the container. Orifice:  An opening in a plug, fitment, or dispensing cap through which the product is dispensed. Overseal:  An additional closure that tamper-proofs the primary closure. The overseal is usually made of foil or aluminum.Phenolic:  A type of thermoset plastic. Pipette:  The glass or plastic tube portion of a medicinal dropper closure. Pitch:  The number of turns a thread would circle a neck if the neck were extended one inch. Pitch is commonly referred to as threads per inch. (T.P.I.) Plastisol:  A liquid mixture of resins and plasticizers solidified by the application of heat. Pour-out Finish:  A bottle finish having uniform undercut lips. The pour-out finish is designed to facilitate pouring without dripping.Removal Torque:  The torque force, measured in inch-pounds, required to unscrew a closure from a container.“S” Dimension:  Locates the position of the bottle thread with respect to the sealing surface. The “S” dimension is the vertical distance from the sealing surface to the intersection of the finish wall and the top part of the first part of bottle thread where full depth contour exists. See the Cap and Neck Finishes page for more information. Sealing Surface:  The lip portion of the finish which makes contact with the sealing gasket or liner and forms a seal. Shell:  The hat shaped, preliminary form of a metal closure prior to being threaded and knurled. Shrink Factor:  The change in dimension which a closure undergoes after being molded. Shrinking is generally caused by cooling and subsequent contraction of the plastic material. Sifter Fitment:  A plastic component of a package designed to allow the shaking out of dry products, such as a table salt shaker. The sifter fitment snaps over the glass bead with a metal or a plastic cap applied over the fitment. Skirt:  The vertical wall of a closure. Snap Fit Closure:  A closure held in place through the use of beads or undercuts rather than threads. SPI:  Society of Plastics IndustrySpout Cap:  A closure designed to facilitate the pouring of the contents of the container. Stacker Cap:  A closure designed specifically to nest with the bottom plate of a container to facilitate the stacking of filled containers one on top of each other. Stress Crack:  An external or internal crack in the plastic caused by tensile stress less than that of its short-time mechanical strength. The development of such cracks is frequently accelerated by the environment to which the plastic is exposed. The stresses which cause cracking may be present internally or externally or may be combinations of these stresses. The appearance of a network of fine cracks is crazing. Stripping Torque:  The amount of application torque that causes the threads of the closure to override the container threads.“T” Dimension:  The major diameter of the thread on a Continuous Thread closure. See the Cap and Neck Finishes page for more information. T.P.I.:  See Pitch. Tamper Band:  The tamper-evident feature of the closure. The tamper band is usually connected to the closure skirt by leaders or bridges. Tamper Evident Breakaway Band Closure:  The section of the closure skirt that is weakened or perforated in some manner. When the closure is opened that section is designed to either remain on the container or stay partially attached to the closure. The tamper evident breakaway band closure is designed to reveal removal of the closure was attempted.

Tamper Evident Closure:  A closure or liner system incorporating a feature that visually indicates if the closure has been removed or the product has been exposed. Removal of the closure or liner system activates the indicating feature. Tamper Evident Tear Band:  A closure with a band, usually with a tab for grasping, designed to be detached by the consumer. The tamper evident tear band is designed to reveal removal of the closure was attempted. Thermoplastic:  A plastic material that repeatedly softens when heated and hardens when cooled. Thread Profile:  The cross section configuration of a closure thread. Thread Engagement:  The actual contact made by the closure and bottle finish thread. Thread engagement is usually specified in number of turns. Thread Start:  The position at which the full thread depth toward the open end of the closure first occurs. Thread Turns:  The measurement of thread revolutions in a closure or on a container finish. Thermoset:  A material that will undergo or has undergone a chemical reaction by the action of heat, catalysts, ultraviolet light, etc., leading to a relatively infusible and cross-linked state. Typical of the plastics in the thermosetting family are the epoxies, glytals, melamines, urea formaldehyde resins, and phenolics. Thermosets are typically supplied in powder, granules, or modules, and are normally processed by compression molding. Thermosets cannot be remolded once processed. Thread:  Complimentary, helical protrusions on the closure and the container. Tinplate:  A thin sheet of steel with a layer of tin used in manufacturing metal closures. Tolerance:  The permissible maximum deviation from specified dimensions, quantities, or specifications. The amount of variation allowed from the nominal dimension. Tooling:  The specific components in contact with the plastic that form the closure. Top Load:  The amount of weight bearing on the top of a package. Torque:  The rotational movement used during application or removal of a continuous thread closure from a container. Torque Meter:  A devise used to measure application and removal torque. It is expressed in pound-force inches and commonly referred to as “inch-pounds.” Unlined Closure:  A closure without a liner disk inserted, but designed to accept one.Valve Cap:  A closure that includes a valve to regulate the flow of the product from the container. Value Seal:  A sealing devise which seals on the inside of the neck finish of the container in the fashion of a plug. A controlled inside finish diameter is required to accomplish a seal.

Glossary of Packaging TerminologyListed below are brief definitions of terms commonly used in the packaging industry.

 

Metal, Plastic and Flexible Packaging Definitions

← 2P - Aluminium cans are 2P (two piece) cans, comprising a top and body. The body is formed from a sheet of aluminium and drawn to the required height, decorated in the round (up to six colours) and coated internally. The customer adds the top (second piece) after filling.

← 3P - Steel cans are 3P (three-piece) cans comprising a top, a body and an end (base). The body is formed into a cylinder from a sheet of pre-printed or plain tin-coated steel and the end is seamed to it prior to delivery to the filler. The customer adds the top (third piece) after filling.

← Blow Moulding - Formation of a bottle from a molten plastic tube by blowing air into the mass, forcing the material to follow the shape of the mould.

← Closures - Closures are caps or lids used to seal beer and soft drink bottles and food jars and cans. Closures are made from plastic, steel or aluminium and can be screw, twist or pop-up style. Another type of closure is a plastic seal, which is used to reseal a metal can after opening. 'Closures' also refers to machinery used to apply the closures to containers after they are filled.

← Composite Cans - Cans made from paperboard (cardboard). A variety of barrier materials and fittings enable composite cans to be used for packaging food, powdered beverages, wine, spirits and perfume.

← Flexible Packaging - Covers a wide range of packaging that can be single and multi-layered and is supplied in reels or bags. It can be paper/poly/foil or nylon or a

combination of materials which are supplied either plain/printed/coated and/or laminated to provide long shelf life properties. End products packaged include confectionery, snack foods, frozen foods, soups and pharmaceuticals.

← Gravure Printing - This printing medium is the transfer of ink from an etched cylinder such as a sunken surface to the substrate, eg. paper/film/foil. The equipment is a multi-station (up to nine) printing machine to print and/or coat up to eight colours on to a fast-moving web of material.

← HDPE - High-density polyethylene.← Injection Moulding - The process of converting plastic pellets by using heat and

pressure to inject the molten material into a water-cooled mould. The equipment can produce a number of products in the one injection.

← LDPE - Low density polyethylene.← Metallising - Applying, through a vacuum process, a thin aluminium layer onto

flexible plastic film substrates used to package a variety of foods.← Offset/Lithographic Printing - This printing medium is the transfer of ink from a

sensitised plate, offset to a rubber blanket then transferred to the substrate. The equipment is a multi-station (up to eight) printing machine to print and/or coat up to six colours on to sheets or a fast-moving web.

← PET - Polyethylene Terephthalate.← PP - Polypropylene.← PVC - Polyvinyl chloride.← Retort - The process of cooking food in the package it is sold in eg. baby food or

soups that have meat or vegetables that need to cook at a temperature to kill off the micro-organisms and avoid botulism. The temperature is generally around 121o C. Amcor is the only company today that has this capability in PET.

← Rigid Plastic Packaging - Freestanding plastic bottles and plastic fittings. The main raw materials used are PET, HDPE and PP.

← Thermoforming - The process of shaping a plastic sheet of styrene or PVC under heat and pressure.

Fibre Packaging Definitions

← Broke - Paper trimmings, paper damaged due to breaks on a paper machine or not manufactured to the required quality specification. Broke is usually fed back into the paper manufacturing process.

← Carton Dimensions - Dimensions refer to the interior of a carton, measured in millimetres of Length x Width x Height. Length (L) is the longer side of the opening and Width (W) is the shorter. Height (H) is the length between the openings on either end.

← Cellulose - The main fibrous material in paper.← Corrugated Box Plant - An operation that has both corrugating capability and

converting equipment. Most corrugated boxes throughout the world are produced in integrated box plants.

← Corrugated Fiberboard - This material refers to the composite structure formed by gluing one or more sheets of fluted, corrugated material to one or more flat facings of linerboard.

← Single-wall cartonThis is a corrugated fiberboard carton made by gluing a sheet of fluted corrugated material between two flat sheets of linerboard.

← Double-wall cartonThis is a corrugated fiberboard carton made of three sheets of linerboard interleaved with two sheets of fluted corrugated material.

← Flute, Corrugation - This refers to the wave shapes, or ridges, that are pressed into a sheet of material that has been softened by steam. This material is then sandwiched between flat sheets of material to form corrugated fiberboard. Flute serves as protective cushioning and helps strengthen a carton. Different widths and configurations offer distinctive performance advantages. Corrugated cartons feature either of the types below.

← A-Flute : Flute thickness of 4.7 mm

← B-Flute : Flute thickness of 2.5 mm ← C-Flute : Flute thickness of 3.6 mm - Depending upon the stacking

strength, puncture resistance , crush strength required for the carton, one of the above three commonly corrugations are used in single-wall, general-purpose cartons. A-Flute has excellent stacking Strength, B-Flute has good puncture resistance and C-Flute has the optimum combination of both.

← E-Flute : Flute thickness of 1.5 mmIs generally used for light applications such as Pizza Boxes, Mailers, Shoe boxes etc.   

← BC FluteThis flute is a double-wall combination made from one B-flute, single-wall sheet and one C-flute, single-wall sheet. The result is a strong corrugation used when extra thickness or stacking strength is needed.   

← AC FluteThis flute is a double-wall combination made from one A-flute, single-wall sheet and one C-flute, single-wall sheet. The result is a very strong corrugation used when extra strength is needed.

← Die Cutting - The process of cutting a corrugated sheet into a shape which will convert to the required box size when assembled. A rotary die cutter uses a cylindrical die and is generally capable of higher speed than a flatbed die cutter, as the sheet flow basically continues. A flatbed die cutter uses a flat die and the corrugated sheet momentarily stops to enable the required cutting. This method provides both high accuracy and intricate shapes not available from the rotary process.

← Double-facer - A double-facer, or double backer, is the part of a corrugator which bonds single-face board to another liner to produce a double-faced corrugated sheet.

← Folding Cartons - Multi-layer paperboard cartons which are printed/coated and cut into carton blanks. The carton blanks also incorporate creases, which enable the carton to be formed for packaging the customer's product.

← Functional Coatings - The lamination of polyethylene and/or plastic or foil films to paper substrates, providing a water or greaseproof barrier. Typically used in high humidity applications in both tropical and cold temperatures, for use with meat, seafood, pet food, fruit and produce.

← Kraft - This term describes the natural, unbleached corrugated fiberboard used in making cartons

← Linerboards - Linerboards form the inner and outer facings of corrugated fibre boxes and are chosen for their structural and/or decorative properties. They can be made from white or brown, kraft or recycled fibres, or a blend of both.

← Mechanical Pulp - Pulp produced by reducing pulpwood logs and chips into their fibre components by the use of mechanical energy, via griding stones or refiners.

← Pasting - Two, three or four plies of paper and paperboard are glued together to form a solid fibreboard with a thickness ranging between 0.8mm to 3mm. The boards are used for a variety of applications such as shoe boxes, screen printing, display boxes, board games, book covers and ring binders.

← Printing - Most printing of corrugated board is done by the flexographic method, which can be thought of as a sophisticated method of printing with rubber stamps. Flexo printing is used for both pre-print and post-print applications. Most printing on corrugated boxes is done in the conversion process after the corrugated sheet is produced, ie. post-printing. Pre-printing refers to the process of printing a design or pattern onto a roll of paper before it proceeds to the corrugating stage. This process is typically used for high volume jobs where quality printing is required.

← Pulp - Primary raw material from which paper is made. A fibrous product produced by mechanical or chemical processes, or a combination of both.

← Sheet Feeder - A corrugating plant that has no converting equipment and produces only corrugated sheet. Its customers are typically independent sheet plants. The term 'sheet feeder' can also mean the device at the front of die cutters/flexo folder gluers.

← Sheet Plant - Comprises converting equipment and does not produce its own corrugated board. Typically, sheet plants are smaller operations offering their customers personalised service.

← Single-facer - The section of a corrugator which forms the corrugated shape in the medium, applies adhesive to it and then bonds it to the flat linerboard. The output from a single-facer is referred to as single- face board. Most corrugators have more than one single-facer to enable different flute sizes to be used.

← RSC - This is the abbreviation for Regular Slotted Carton, the most commonly used style of carton. One side is glued, taped or stapled during manufacturing, making this carton well suited for easy set-up, filling, and closure.

All About Corrugated

Box StructureCorrugated fiberboard, or combined board, has two main components: the linerboard and the medium. Both are made of a special kind of heavy paper called containerboard. Linerboard is the flat facing that adheres to the medium. The medium is the wavy, fluted paper in between the liners.. The following illustrations demonstrate four types of combined board.

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

Single Wall: The medium is between two sheets of linerboard. Also known as Double Face.

Double Wall: Threesheets of linerboard with two mediums in between.

Triple Wall: Four sheets of linerboard with three mediums in between.

FlutesArchitects 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

paperwhen they put arches in the corrugated medium. These arches are known as flutes and when anchored to the linerboard with a starch-based

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. When pressure is applied to the side of the board, the space in between the flutes acts as a cushion to protect the container's contents. The flutes also serve as an insulator, providing some product protection from sudden temperature changes. At the same time, the vertical linerboard provides more strength and protects the flutes from damage. Flutes come in several standard shapes or flute profiles (A, B, C, E, F, etc.). A-flute was the first to be developed and is the largest common flute profile. B-flute was next and is much smaller. C-flute followed and is between A and B in size. E-flute is smaller than B and F-flute is smaller yet. In addition to these five most common profiles, new flute profiles, both larger and smaller than those listed here, are being created for more specialized boards. Generally, larger flute profiles deliver greater vertical compression strength and cushioning. Smaller flute profiles provide enhanced structural and graphics capabilities for primary (retail) packaging. Different flute profiles can be combined in one piece of combined board. For instance, in a triple wall board, one layer of medium might be A-flute while the other two layers may be C-flute. Mixing flute profiles in this way allows designers to manipulate the compression strength, cushioning strength and total thickness of the combined board.

Box DimensionsDimensions are given in the sequence of length, width and depth. Internationally, the words length, breadth and height may be used to express these dimensions. The dimensions of a box are described based on the opening of an assembled box, which can be located on the top or the side, depending on how it is to be filled. The opening of a box is a rectangle; that is, it has two sets of parallel sides. The longer of the two sides is considered its length, the shorter of the two sides is considered its width. The side perpendicular to length and width is considered the depth of the box. Dimensions can be specified for either the inside or the outside of

the box. Accurate inside dimensions must be determined to ensure the proper fit for the product being shipped or stored. At the same time, palletizing and

distributing the boxes depends on the outside dimensions. The box manufacturer should be informed as to which dimension is most important to the customer.

All About Boxes

The BasicsWe have included this section to help you select the proper style and type of box to meet your packaging and shipping needs.

MeasurementsBox sizes are measured by using inner dimensions unless otherwise specified. The size of your contents actually determine the inner box dimensions. Domestically (within the United States), those dimensions are listed in the following sequence: Length (L) x Width (W) x Depth (D)*. Internationally, the dimensions are stated as Length (L) x Breadth (B) x Height (H).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 "depth" of the box.*Exceptions are bookfolds, bin boxes & divider bins where "width" precedes "length" & "depth" of the measurement sequence.

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How To Measure A Box - The Quick WayLooking 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 side wall, 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.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.

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Box Construction - What you need to know

The "Manufacturer's Joint" is where the two ends of the side panels meet to form the box. At that point, the panels are fastened together with tape, staples or glue. This description applies to regular slotted shipping cartons (RSCs). The side panel thickness and content weight determine the type of seal used for the manufacturer's joint. For example, glue is used for most single wall boxes, but staples are found in some double wall and in most triple wall boxes. In contrast, die-cut boxes are one-piece panels scored and folded together. They do not have a manufacturer's

joint.Back to Top

Box StrengthThe strength of a corrugated box starts with its material. A corrugated sheet consists of two major components - linerboard 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 linerboards 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.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 side wall 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.The amount 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 linerboard. 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. The following chart shows Bursting Test and Edge Crush Test performance standards of corrugated box liners based on the combined weight of a box and its contents.

Back to TopLinerboard Performance Standards

Max Wt. Box/Contents(lbs.)

Min. Burst Test Single/Double Wall(lbs. per sq. in.)*

Min. Edge Crush Test (ECT)(lbs. per in. width)

Single Wall Corrugated Boxes20 125 23

35 150 26

50 175 29

65 200 32

80 250 40

95 275 44

120 350 55

Double Wall Corrugated Boxes80 200 42

100 275 48

120 350 51

140 400 61

160 500 71

180 600 82

Triple Wall Corrugated Boxes240 700 67

260 900 80

280 1100 90

300 1300 112

* Minimum puncture test, Triple Wall board (in. oz. per in. of tear)Back to Top

Look for the Manufacturer's StampA 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 "singlewall," "doublewall" or "triplewall." 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 linerboard while the Edge Crush Test measures linerboard 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 linerboard cannot be altered. For example, 200# Mullen Test linerboard 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.

Single Wall Double WallTriple Wall

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When & What Box to UseWhen to use a single wall 200# test box - when the box and contents weigh less than 65 lbs. This weight limit works fine for multiple light-weight items in a box or for a masterpack box where individual boxes are packed tightly in organized rows and stacks. If a single heavy item is to be shipped in a single wall, 200# test box, we recommend a weight limit of 45 lbs. or an upgrade to a 275# test single wall box. Simply apply common sense and always err on the conservative side.

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Box Styles

Regular Slotted Carton (RSC)Also called shipping boxes, RSCs are the most commonly used boxes. They are usually kraft brown in color, have four flaps on the top and bottom and the side walls are sealed at one corner known as the "Manufacturer's Joint." This design is highly functional for most packing applications.

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Multiple-Depth Carton (MDC)The same box design as an RSC, but with horizontal scores (creases) at selected depths along all four side walls. This feature gives you depth flexibility when packing a box. A Multiple-Depth Carton can be several boxes in one.

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Half Slotted Carton (HSC)A variation of the RSC, the Half Slotted Carton has only one set of flaps. The opposite side of the box is completely open, allowing it to slide over an item. Envision the use of the box turned over so that the flaps are on the top. The covered item is usually attached to a pallet or other type of surface that serves as a separate bottom.

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Full Overlap Slotted Carton (FOL)

With a Full Overlap Slotted Carton, all "length" flaps are also equal to the width of the box. The flaps actually fold over one another to provide added strength and protection to the top and bottom.

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Five-Panel Folder (FPF)

A Five-Panel Folder actually resembles a shallow-depth box when assembled. It is a one-piece box with an over-lapping top and over-lapping end panels. The functional design is also economical.

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Snap-Bottom Carton (SBC)Available with tuck-in top or with RSC-style top flaps (shown). Also referred to as an "auto bottom" box. The bottom of the box snaps into place without tape for quick assembly. Best suited for light-weight products.

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Full Telescope Design Carton (FTD)

A two-piece box with a separate lid that fits over a bottom tray.

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Half Telescope Design Carton (HTD)

Two half-slotted cartons with one box slightly smaller to enable it to be inserted into the other box. Offers the ability to adjust the height or length of the box to fit your needs. Especially suitable for large, heavy items. For depth flexibility with smaller items, visit the "Multiple-Depth" box section of this web site.

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Two-Piece Carton With Separate Lid (CSL)Die-cut box with open top and tray-style lid. Similar to a File Storage Box, but without the hand holes on either end. See "File Storage Boxes" section of this Web Site if you are looking for a box to store paper files.

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Double Cover Carton (DC)

This style of box is frequently used for tall or large, heavy items. A three-piece box, the Double Cover Carton is constructed of a four-panel tube that serves as the side panels and two interchangeable trays that serve as the top and bottom of the box.

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One-Piece Folder (OPF)

Commonly called, "Bookfolds" or Bookwraps," the One Piece Folder has a flat bottom with two short flaps forming the sides at each end and two longer, wider flaps that form the front, back and top of the box. The wider flaps either meet or overlap on the top, depending on the depth of the contents. The four panels of a Bookfold are usually scored (creased) at multiple depths. One-Piece Folders are used to package shallow depth items such as

books and pictures. Usually manufactured with white board. Back to Top

Mailer-Style Boxes (MSB)A one-piece die-cut box that is assembled without tape. Construction includes double-layer protection on the sides and bottom of the box. Available in two popular styles - with a tuck-in top or with a locking cover, also known as a "cherry lock" design. (See illustrations) Mailer-Style Boxes are exceptionally strong and can withstand the most rigorous treatment during shipment.

Tuck-In TopLocking Cover

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Bin Boxes (BB)Another one piece die cut box that can be assembled without tape or glue. Often referred to as shelf boxes for parts and other small items, Bin Boxes have an open top to allow you to see and reach inside. Measured by width, length and depth. These long, narrow boxes can significantly increase storage space. Available in multiple widths and in four different lengths.

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Divider Bins (DB)

Divider Bins are smaller, open top boxes. They are usually used in conjunction with Bin Boxes to create multiple compartments within a Bin Box.

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06-20-11

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