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Carton Boxes made up of corrugated boards

A carton is one of those everyday items you might take for granted, or perhaps you have asked yourself as you push your shopping cart past aisle after aisle of products on the shelves. It is a standard sheet of corrugated board is made from three components; a sheet of corrugated fluted paper sandwiched between an outside liner.


Corrugated Board

carton boxA standard sheet of corrugated board is made from three components; a sheet of corrugated fluted paper sandwiched between an outside liner. Each side of the fluting (medium) is glued to a sheet of flat liner paper. This gluing fixes or anchors the flutes to the linear boards with adhesive, it resists bending and pressure from all directions thus capable of supporting a considerable amount of weights and also gives the lightweight paper especially high stability.

Albert L. Jones is the father of corrugated board. Born in America, Jones discovered the idea while manufacturing neck ruffs and frills on a pleating machine. Instead of using fabric he put paper through the milling cylinders to produce an elastic packaging material. In December 1871 he was granted a patent. In 1874 Oliver Long achieved a considerable improvement by gluing a fluted sheet of corrugating medium onto a linerboard, thus creating single face corrugated board. The first attempts to make corrugated board in Europe were started in 1883, in London. This was followed three years later, in 1886, by the first corrugated board factory on the continent at Kirchberg in Germany.

Types of Paper used for making Cartons

corrugated paper sheetsBasic material for the production of corrugated board is the paper-board. There are two main type of paperboard. There are two main types of paperboard: Kraft and Test.

  • Kraft Paper: Comes from softwood trees – the strongest form of paper and the best to print on this is the most common outside liner for corrugated boxes.
  • Test Paper: This is so-called double layer paperboard (duplex paper). Most standard cartons use recycled paper for the fluting and the inside liner.

Each sheet of liner paper is commonly composed of two layers. The finer cover layer is ideal for printing and aesthetics, and the basic layer is excellent for adhesion strength.

Thickness: After the paper type, the next thing to look at is the Thickness. This is measured the same way for all papers. Take one square meter of your paper and weight it. The result is XX grams per square meter (which is abbreviated to GSM). Example photocopy paper = 80gsm

Board Grades

Combining all of the above, it is possible to specify a simple short description that defines the board grade of a box. For example 125K/B/125T. This means a corrugated box, made from 125gsm Kraft outer liner, B fluting, and 125gsm Test inner lining.

Types of Cartons

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.

Full Telescope Design Carton (FTD)

A two-piece box with a separate lid that that fits over a bottom tray. For telescope type boxes the height (h) of the upper part (lid) should be given as a fourth measurement after an oblique stroke i.e.

350 (L) x 200 (B) x 120 (H) / 40 (h)

Two-Piece Carton with Separate Lid (CSL)

The “Manufacturer’s Joint” is where the two ends of the side panels meet to form the box. At the point, the panels are fastened together with tape, staples or glue. The side panel thickness and content weight determine the type of seal used for the manufacturer’s joint. For example, glue is used for the most single was boxes, but staples are found in some double was and in most triple wall boxes.

International Fiberboard Case Code

This code which is prepared in collaboration with ESBO (The European Solid Board Organization) contains a methodical presentation of all existing box design styles, a code number being assigned to each design. As a reference document, the code is used worldwide and it has been adopted by the United Nations.

Drawing Symbol Code Description
Cuts, Scores, Slits etc. CL Contours of erected cases or cutting lines of case blanks
SC Slotted Cuts
CI Crease Lines (inward bend)
CO Crease Lines (outward bend)
SI Slit-score lines (inward bend)
SO Slid-score Lines (outward bend)
DS Double score lines
PL Perforation lines
SE Soft Edge cutting lines
TP Tear perforation
Manufacturer’s Joint PC Stitched Joint
UC Taped Joint
NC Glue Joint
Openings PC Handholds Stripped
UC Handholds non-stripped
NC Handholds non-stripped
Flute Direction FD Flute direction indicator

Manufacture’s Stamp

A way to be sure that the material of the box that you’re purchasing meets industry standards is to look for the Manufacture’s Certification Stamp, usually printed on one of the bottom flaps of the box. The stamp identifies the material as “single wall”, “double wall” or “triple wall”. It also certifies the Mullen Bursting Test (most common in 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 Crust Test measures linerboard stacking strength.

Carton Dimensions

All dimensions are expressed as internal dimensions and can be specified in mm, cm, or inches depending on buyer’s specs.

Example L350 x W200 x H120

  • Length (L) = Longer dimension at the opening (Longer of the two slides)
  • Breadth (B) = Shorter dimension at the opening (shorter of the two sides)
  • Height (H) = Dimension from the top of the opening to these (perpendicular to length or width)

Carton Markings

Carton markings are printed in clear black lettering and must be in accordance with the given layout. The contents of each export carton must be clearly indicated that the front end and at the back end. Generally, the info contains info like Shipper’s Address and Consignee Address, PO No. Style No., size/s, dept no., Color, carton Number, Total quantity, Factory ID, SKU No., Gross weight, Net weight, Country of Origin, Cartons must be properly marked for MIXED quantity, ODD Packing, Lot No. and packing list.

Linerboard Performance Standards

Max Weight Box/contents (lbs.) Min Burst Test single/double wall (lbs, per sq. inch) Min Edge Crush Test (ECT) (lbs. per in. width)
Single-Wall Corrugated Boxes
20 125 23
35 150 26
50 175 29
65 200 32
80 250 40
95 275 44
120 350 55
Double Wall Corrugated Boxes
80 200 42
100 275 48
120 350 51
140 400 61
160 500 71
180 600 82
Double Wall Corrugated Boxes
240 700 67
260 900 80
280 1100 90
300 1300 112

Common Flute Sizes

The corrugated board has five common sizes of fluting, ‘A’,’B’,’C’,’E’ and ‘F’. The letter designation refers to the order they were invented, not their relative size.

Corrugated Board Size Corrugated Sheet Size Flute Height Flute per linear foot
A 5mm 4.7mm 33+/-3
B 4mm 3.6mm 39+/-3
B 3mm 2.5mm 47+/-3
E 2mm 1.5mm 90+/-3
F 1mm 0.6mm 120+/-3