The printing methods used in packaging include all major printing methods, including offset printing, gravure printing, flexographic printing, etc. And the supporting post-processing forms are diverse, making the printing process of paper packaging products very flexible.
The process flow of paper packaging printing processing is: packaging decoration design - plate making - printing - post press processing. Post printing processing includes surface finishing and molding, which are different for different paper packaging products, mainly including glazing, compounding, slitting, bag making, hot stamping, holographic hot stamping, cross cutting, die cutting, soft label cutting, winding, etc.
1. Printing process of carton
For cartons, there are mainly the following two printing and processing processes.
(1) Carton design includes plate making, printing, die-cutting and slotting. This is a traditional printing process. The main printing methods are offset printing and flexographic printing. The unit type sheet fed printing machine production line is adopted.
(2) Carton design, plate making, carton pre printing, cardboard processing, die-cutting and slotting are modern printing methods. The main printing method is flexographic printing. The preprint adopts satellite flexography, unit offset printing or gravure printing production lines.
2. Printing process of carton
For folding cartons, there are many different printing processing methods. Take cigarette packets as an example, there are at least the following printing processing methods, in which the printing method can be offset printing, gravure printing or flexographic printing, or a combination of different printing methods, such as:
Design - plate making - printing - die cutting;
Design one plate making one printing one hot stamping one die cutting;
Design - plate making - printing - hot stamping (I) - die cutting;
Design one plate making one compound (paper plastic) one printing one hot stamping (UV) one die cutting;
Design one plate making one compound (paper plastic) one peel one print one UV glazing one die cutting.
Post press processing of carton is the most complicated and important process in all printing products. Take the common aseptic packaging (such as Tetra Pak, Kangmei Box, roof bag, etc.) as an example, its post press process includes: compounding, slitting and bag making. The compounding process is the most important in the whole process, which plays a decisive role in the packaging function of the entire container. For example, the paper container Tetra Pak, the semi-finished products after printing are put on the unwinding rack of the laminating machine again. After four times of coating, the aluminum foil (which can prevent ultraviolet light and ensure the quality of the contents) is recombined, and finally it is rolled. The four layers of Tetra Pak plastic are made of polyethylene or modified polyethylene resin of different thicknesses from the outer layer, composite layer, inner layer 1 and inner layer 2 respectively. The films extruded by four extruders are bonded with paper and aluminum foil.
3. Printing process of paper bag
For paper bags, the following two printing processes are generally used.
Design one plate making, one printing, one cutting and one bag making;
Designs one plate making, one printing, one compounding, one slitting, one bag making, or designs one plate making, one compounding, one printing, one slitting, one bag making, that is, first compounding, then printing, or vice versa.
The decoration design of paper packaging is an important means to facilitate use, convey commodity information and promote sales. The decoration design of paper packaging is very important. When designing the decoration, we should first consider the requirements of commodity packaging and select the appropriate style; Secondly, we should consider the correct and appropriate use of patterns, words and colors, follow the principle of "scientific, beautiful, applicable, economic and promotional", and strive to design beautiful, with a sense of the times, decorative and national; In addition, factors affecting the production, use and transportation of products must be taken into account to select suitable printing and processing.
At the same time, in order to achieve the above design goals, we must use advanced technology, such as CAD (Computer Aided Design), CAM (Computer Aided Manufacturing), and professional software, such as packaging carton structure design professional software. Also consider the requirements of output file format and plate making system.
