Corrugated 101

General Corrugated 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 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.

doublewallpicture

  • Single-wall carton
    This is a corrugated fiberboard carton made by gluing a sheet of fluted corrugated material between two flat sheets of linerboard.
  • Double-wall carton
    This is a corrugated fiberboard carton made of three sheets of linerboard interleaved with two sheets of fluted corrugated material.

 

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.

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

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.

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.

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 flutegraphic
  • 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 mm Is generally used for light applications such as Pizza Boxes, Mailers, Shoe boxes etc.
  • BC Flute: This 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 Flute: This 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.

 

Box Types

allboxHalf-Slotted Type Boxes: Consist of basically one piece with a glued, stitched or taped manufacturers joint and top and bottom flaps. They are shipped flat, ready to use and require closing using the flaps provided.

Slotted Type Boxes: Consist of basically one piece with a glued, stitched or taped manufacturers joint and top and bottom flaps. They are shipped flat, ready to use and require closing using the flaps provided.

Telescope Type Box: Consist of more than one piece and are characterized by a lid and/or bottom telescoping over the body of the box.

Folder Type Boxes & Trays: Usually consist of only one piece of board. The bottom of the box is hinged to form two or all side walls and the cover. Locking tabs, handles, display panels etc., can be incorporated in some designs.

Slide Type Boxes: Consist of several pieces of liners and sleeves sliding in different directions into each other. This group also includes outside sleeves for other cases.

Rigid Type Boxes: Consist of two separate end pieces and a body and require stitching or glueing of fibreboard or wood.

Partitions: Interior fitments such as inside liners, pads, separators, dividers, etc. , whether tied to Case Design or as singular items. Any shown number of panels is arbitrary and may be increased or decreased as required.

Fold-Up Pads: Interior fitments such as inside liners, pads, separators, dividers, etc. , whether tied to Case Design or as singular items. Any shown number of panels is arbitrary and may be increased or decreased as required.

 

Testing

Basis Weight Testing: A measurement of mass per unit of area that is expressed in pounds per thousand square feet. Basis weight is used to describe linerboard, corrugating medium, and boxes.

Burst Testing: A measure of the resistance to puncture and tear.

Edge Crush Testing: A measure top-to-bottom compression strength

ISTA Testing:  Performance testing specified by the International Safe Transit Association.  Generally includes testing of shock and vibration effects on packaging.

HAZMAT/UN Testing: Shipment of dangerous goods or hazardous materials are highly regulated. Based on the UN Recommendations on the Transport of Dangerous Goods model regulations, each country has coordinated design and performance requirements for shipment


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