회사 소식 Full analysis of cardboard box production process

Paper boxes are the most common packing materials we use on a daily basis; they are used for everything from huge household appliances to express goods. The manufacturing of this seemingly straightforward cardboard box is actually a system engineering process that combines process control, precision technology, and material science.
The creation of corrugated cardboard, printing and forming cardboard, and gluing/bonding cardboard boxes are the three key steps in the fabrication of cardboard boxes.

Phase 1: Corrugated cardboard production
The ability of the cardboard box to withstand pressure and provide cushioning is determined by this crucial link in the entire production process. This step's objective is to transform the paper mill's roll raw paper into corrugated cardboard with a particular structure.
1. Preparation of raw materials
The primary raw materials are corrugated paper, which is used for the central core paper, and box board paper in roll form, which is utilized for the inner and face papers. The finished cardboard box's performance is directly impacted by the raw paper's quality, including its weight and moisture level.

2. The flow of the core process
The main character of this stage is the contemporary corrugated cardboard production line, whose main operation is as follows:
Preheating and paper feeding: To modify the moisture content of the paper and guarantee future firm adherence, place several rolls of raw paper on the paper return rack and preheat the paper web using the preheating roller.
Pressing: The single-sided machine receives the corrugated paper. A pair of meshing corrugated rollers push the base paper into wavy corrugated core paper while heating and applying pressure. The many physical characteristics of corrugated cardboard are determined by its form (U, V, or UV) and specifications (A, B, C, and E). For instance, B ridges are smoother and more suited for printing, whereas A has the largest corrugation and the finest cushioning performance.
Glue application and bonding: First, coat the top of the corrugated board with adhesive (often corn starch glue), and then use preheated face and inner paper to secure it. This procedure is repeated for five or seven layer corrugated cardboard by mixing corrugated core paper with several layers of paper.
Drying and shaping: The composite cardboard is placed into a tens of meters-long drying machine. The glue rapidly solidifies at high temperatures and pressures, resulting in flawless cardboard adhesion.
Cutting and Stacking: Following drying and cooling, the continuous cardboard is first cut longitudinally and creased as necessary by a longitudinal cutting and creasing machine; next, the cross cutting machine cuts horizontally in accordance with the predetermined length; and lastly, the stacker neatly stacks the cut cardboard in preparation for the next step.
At this point, quality issues including foaming, poor bonding, and cardboard warping are likely to arise if the raw paper quality, temperature, adhesive ratio, or equipment speed are not appropriately regulated.

Phase 2: Cardboard printing and slotting
Following the completion of the cardboard production process, it must be printed and initially made in accordance with the needs of the customer.
1. Printing: Printing is the primary method used to complete the text, patterns, and barcodes on the surface of cardboard boxes. Currently, the most used technique is flexographic printing, which transfers text and images onto cardboard using rubber or resin plates and water-based ink. It has the benefits of being environmentally friendly and moving quickly. Offset or gravure printing techniques are also utilized for cardboard boxes that need very high printing quality.
2. Slotting and creasing/die-cutting: These are the crucial processes that establish the cardboard box's ultimate shape.
Slotting and indentation: Slotting (cutting off the box's tongue and rocking cover), corner cutting, and pressing the cardboard line (preparing for folding) are all done simultaneously on a printing slotting machine using a number of cutting instruments and pressure wheels.
Die cutting: A die cutting machine is used to press and shape cardboard in one go using pre-made molds, similar to cookie molds, with greater precision for cardboard boxes with complex shapes or those that need precise shaping (like display boxes).

Phase 3: Paper Box Joining and Forming
The cardboard is now an unfolded "box blank" following the preceding procedure; the last stage is to put it together to create a three-dimensional cardboard box.
Nail box: Use flat U-shaped or C-shaped metal nails to secure the cardboard box's tongue joints together using a nail box machine. This technology is frequently used for heavy-duty or large-sized packaging boxes since it is robust and has an excellent load-bearing capacity.
Glue box: To attach the tongue using adhesive (such polyvinyl acetate latex), use a glue box machine or manually apply glue. This technique is lovely, flat, and more environmentally friendly and convenient for recycling because it doesn't require metal nails. It is becoming more and more common in lightweight packaging and e-commerce packaging.
The constructed cardboard box will go through a final quality inspection (compressive strength, size, printing quality, etc.) after the joint is finished. After that, it will be wrapped, tied, and kept for shipping.

Generally speaking, the process of creating a corrugated cardboard box begins with a roll of raw paper and continues through "pressing the corrugated core → multi-layer bonding → slitting and indentation → printing slotting → nail bonding and forming". In the end, how hard and protective the cardboard box is in our hands depends on how precisely each procedure is controlled.