1.Manufacturing a corrugated cardboard box begins with the pulping of wood chips in the kraft (sulfate) process. First, tree trunks are stripped of bark and torn into small chips. Next, these chips are placed in a large, high-pressure tank called a batch digester, where they are cooked in a solution, or liquor, made of sodium hydroxide (NaOH) and several other ionic compounds such as sulfates, sulfides, and sulfites. These strongly alkaline chemicals dissolve the lignin, the glue-like substance that holds the individual wood fibers together in a tree trunk.
2. When the pressure is released after several hours, the wood chips explode like popcorn into fluffy masses of fiber.
3. After additional cleaning and refining steps, a consistent slurry of wood pulp is pumped to the paper[paper?:paper sample maker cutting machine]-making machine, also known as a Fourdrinier machine. Next, the paper is fed into massive, steam-heated rollers and wide felt blankets that remove the water. At the end, the finished medium, or liner, is rolled for shipment.
4. Rolls of kraft paper for corrugating are available in many sizes to fit the production equipment at different corrugating plants,be loaded into one railroad boxcar for shipment to a corrugating plant.
5. At the plant, the kraft paper[kraft paper?:kraft paper cutting machine] is separated into different grades, which will be used for the medium and the liner. These different grades of corrugated cardboard can be made by combining different grades of kraft paper.
6. Using powerful fork-lifts, skilled equipment operators select, move, and load rolls of kraft paper at one end of the corrugator, Corrugating is also done in a machine that utilizes heavy rollers. One roll of cardboard is corrugated and then glued between two other layers (liners) by the same machine. The glue is then cured by passing the cardboard over heated rolls.
7. One roll of medium is loaded to run through the corrugating rolls, and a roll of liner is fed into the corrugator to be joined with the corrugated medium. Liner from another roll travels up over the corrugating rolls along a flat structure called the bridge. This liner will be glued to the corrugated medium later in the process.
8 .For a large production run, additional rolls are loaded into automatic splicers. Sensitive detectors check the rolls of paper feeding into the corrugator. When a roll is nearly empty, the corrugator control system starts a splicer, and paper from the new roll is joined to the end of the paper going through the machine.
9 .The medium to be corrugated is fed into the giant, electrically driven rollers of the corrugator, first through the preheating rollers and then into the corrugating rolls.
10. The corrugating rolls are covered with I O flutes —horizontal, parallel ridges like the teeth of massively wide gears. When the hot paper passes between the corrugating rolls, the flutes trap and bend it, forming the middle part of a sheet of corrugated cardboard.
flute size
11 .The medium travels next to a set of rollers called the single-facer glue station. Here, one layer of liner is glued to the medium. Starch glue is carefully applied to the corrugated edges of the medium, and the first layer of liner is added.
12. At the end of corrugator, a slitter-scorer trims the cardboard and cuts it into large sheets called box blanks. Box blanks pop out of the slitter-scorer like wide slices of toast and slide into an automatic stacker that loads them onto a large, rolling platform. From here, they will be transported to the other machines that will convert them into finished containers.
13. Printing[Printing?:printing cutting finishing solution] dies and die-cutting patterns I 3 are prepared in a pattern shop on large, flexible sheets of rubber or tin. The dies and patterns are loaded onto the large rollers in the flexo.
