Production process of five-layer corrugated cardboard
First, five rolls of raw paper are placed on the unwind stand in a certain direction. Each paper is separately preheated by a preheater to heat the surface for better adhesion. The corrugated raw paper is preheated and adjusted in moisture content and flatness before entering the single facer to press the corrugation, apply adhesive, and bond with the liner to form single-faced corrugated cardboard. The single-faced corrugated cardboard is then transported on the lifting conveyor to the bridge conveyor and enters the triplex preheater through a brake. Next, the two types of single-faced corrugated cardboard are separately fed into the gluer to apply adhesive, while the inner paper is preheated again. The three layers are then sent to the drying device of the double-backer unit for bonding and drying. The paperboard is bonded by heat and cooled to evaporate its moisture content. After cooling on the conveyor belt, the paperboard is cut transversely by a computerized cross cutter according to specific specifications before being stacked neatly by a stacker.
In fact, manufacturing corrugated cardboard is a complex process that involves many factors that need to be considered simultaneously. During production, the corrugated raw paper, temperature, adhesive, speed, etc., must be synchronized. Any deviation in any step can lead to quality issues. If the adhesive ratio is inappropriate, or the corrugating rolls, pressure rolls, and heating rolls are not properly adjusted, bubbles, delamination, or poor adhesion may occur in the corrugated cardboard. As I have only practiced for a few days, my understanding of the production process of cardboard is relatively shallow, and I only have a general familiarity with it.
Production process of paper carton box
This process includes trimming and creasing. Trimming and creasing are separate processes. Sheet cutting is done using a sheet cutter to make the cut edges of the board smooth and neat. The sheet cutter blade must be sharp and free of notches. If the blade is not sharp, it may result in paper scraps, impurities, etc., which may cause the printed product to not meet the required specifications. Creasing is done using a creasing machine.
Ink printing includes single-sided printing, which uses a chain feed to directly feed the cardboard into the printer, making it a simple type of printing. There are other types of printing, such as double-sided printing. Due to different paper-making materials, their absorption capacity is different. Some have low absorption capacity, which results in slower drying of the ink, while others have high absorption capacity, which results in faster drying of the ink. During the printing process, there may be many issues, such as printing quality and printing errors. Some minor errors can be remedied, such as when a word is printed incorrectly, the customer can be contacted to see if they agree to have a correct one placed on top of the wrong one. If the customer does not agree, that batch of products is considered waste because the printed cardboard cannot be recycled.
The printed cardboard is slotted using a slotting machine, which follows the same principle as the creasing machine.
Nailing or Pasting the Box
When assembling the paper box, nailing or pasting the box is done according to the customer’s needs. A nailing machine is used for nailing the box, and a pasting machine is used for pasting the box.
After the paper box is sealed, it is distributed by a conveying rack for packaging and bundling.
The packaged paper boxes are sent to the warehouse for storage.