FROM PAPER TO CORRUGATED BOARDBasic raw materials- The types of paper used in the production of corrugated are specific grades called "Linerboard" and "Fluting Medium".- The adhesive that is applied to the tips of the flutes is starch that usually originates from products of natural origin, the most common being maize (corn).The corrugator machine:- A corrugator is a set of machines in line, designed to bring together three, five or seven sheets of paper to form a single-, double- or triple-wall board. This operation is achieved in a continuous process.- The reels of paper are fed into the corrugator; the paper is conditioned with heat and steam and fed between large corrugating rolls that give the paper its fluted shape in the Single Facer. Starch is applied to the tips of the flutes on one side and the inner liner is glued to the fluting. The corrugated fluting medium - with one liner attached to it - is called single-face web, and travels along the machine towards the Double Backer where the single-face web meets the outer liner and forms corrugated board. The corrugated board is then cut and stacked.The main parts of a corrugator are the splicer and reel stand:These are the machines that feed the paper rolls into the corrugator and enable rolls to be changed without interrupting the production of corrugated board.The single facer:This machine transforms the paper into a series of connected arches, called " flutes," thanks to the corrugating rolls that are large cylinders with a corrugated profile. If the flute profile has to be changed, then the corrugating rolls need to be changed.The double backer:It glues the outer liner to the fluting to obtain single-, double- or triple-wall board. The single-face web is pre- heated; starch is applied to the tips of the flutes. The outer liner is then bonded to the single-face web to form corrugated board. It is a complex operation that requires great expertise in the pre-heating, moisture control, and gluing processes.The bridge:This enables the Double Backer to run at different speeds from the Single Facer especially when reel or order changes take place. This is achieved by the single-face web forming festoons that are controlled at the Single Facer station.The glue unit and double backer:Here, the single-face web is prepared for gluing to the outer liner. This is roughly the same process as the single- facer unit with some variations in the pre-heating and gluing processes.BRIDGE FESTOONSThe hot plate section:It is at this stage that the single-face web is combined with the outer liner. The heating section ensures that the bond is strong by gelling the glue and removing moisture. The rotary shear:After the board emerges from the Double Backer, it passes under a rotary shear that cuts across the whole width of the web. This is used to chop out damaged lengths of board or to effect a change over from one grade of board to another.The slitter / scorer:This operation slits and scores the board in the machine's direction. The scoring determines the style of the finished box.The cut-off knives:These cut the board to the exact required lengths in order to provide the corrugated sheet that is used in the making of corrugated packaging.The stacker:Finally, corrugated sheets are automatically stacked. Then they are moved directly to the conversion machine or sent to a converting plant.THE CONVERSION PROCESS: THE LINE CONVERTERThis is the final stage of the process, and it consists of printing, slotting, folding and gluing the corrugated board to manufacture a corrugated container.Different operations are carried out according to the customer's specifications and to the type of packaging. The three main categories are the "regular-slotted case", the flatbed "die-cut" container, and the rotary "die-cut" container. Die cutting pertains to packaging that requires precision cutting, and which may have a complex design.The converting process varies according to the type of packaging:Whatever the type of packaging, printing on corrugated sheets is always possible.The flexographic printing process is commonly used for printing on corrugated.This process uses the relief printing technique and is characterized by:- High processing speed- High level of quality- Excellent quality/price ratioPrinting can be done either "in-line" or "off-line."Regular slotted cases (RSC):Most RSCs are produced with an in-line flexographic Printer/ Slotter Folder Gluer which, in one operation, prints, cuts, folds and glues the blank into its final shape. The packaging is then palletized and ready to be shipped flat to the customer. ROTARY DIE-CUTTING Die-cut packaging:Die-cut containers are manufactured on a die-cutter that cuts and creases the board. It is usually reserved for a more sophisticated pack style.This process requires a "form" that can be mounted around a cylinder, in which case the machine is called a rotary die-cutter. The other variant Is called a flatbed die-cutter, and asthe name indicates, it has a flat shape. Once the converting process is over, thecorrugated packaging is palletized and ready for delivery.。