Screen printing technology of the hottest packagin

2022-10-01
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The process of packaging trademark silk printing

I. prepress design and plate making

the process flow of packaging trademark silk printing can be basically divided into four parts: prepress design, plate making, silk printing and post press processing. Due to its low microwave dielectric constant, attention should be paid to the operation technology of each process in order to ensure the printing quality

1. Prepress design

in the design of packaging trademarks, designers must be familiar with plate making and printing processes, as well as post press processing technology, and be clear whether the designed packaging works meet the requirements of plate making and printing processes. For the design of general packaging trademarks, it is required to be concise and lively, suitable for printing; For some high-end packaging, or products with special design requirements, special personnel must be organized to tackle key problems during post press processing to try to meet the requirements of customers and designers

since the printing and use materials of packaging trademarks are completely different from the printing processes of general books and periodicals, the characteristics of the materials and printing processes of packaging trademarks should be fully considered in the design of silk printing packaging trademarks

2. Problems to be paid attention to in the production and design of printing plate

for printing packaging trademarks, due to the difference between silk printing and other printing, the production technology and design of the base plate are also different, and the following problems should be paid attention to:

(1) multi picture collage design

the overprint accuracy of plate making must be high because of the combination of one plate and one drawing. Manual joint drying is easy to cause serious point loss and inaccurate overprint; Although the problem of overprint accuracy is solved by using the combined drying machine, the problem of point loss cannot be fundamentally solved; The color desktop system makes the cumbersome manual production in the past easy, and solves the problems of point loss and inaccurate overprint

(2) hollow out and mosaic design

the process of hollowing out and inlaying are often encountered in the plate making of packaging trademarks, especially when gold and silver need to be printed on the manuscript surface, the printing plate must be made into hollowed out inlays, otherwise it is easy to cause problems such as insufficient gold and silver ink and dark color

(3) box size design

die cutting is an indispensable process for packaging trademark printing plants. The die cutting size is required to be accurate, and the design of box size is the guarantee. Therefore, during plate making, the matching size of the box shape should be variable according to the box size provided by the customer, as well as the thickness, box size and folding shape of the substrate paper, so as to produce an accurate multi splicing die-cutting knife line plate. At present, there are ready-made packaging box shape design software abroad. It is understood that the packaging box shape design software has been developed by founder of Peking University and Ziguang of Tsinghua University in China

3. Problems to be paid attention to in making silk printing plates by direct plate making method

in packaging trademark printing, the commonly used plate making method is direct plate making method, and its production process and technical problems that should be paid attention to are as follows:

(1) the basic process characteristics of direct plate making method. The technological process of directly making silk screen printing plate with photosensitive emulsion is as follows: drying and coating photosensitive adhesive template with silk degreasing silk, drying template with supplementary gelatinizing template, drying exposure, developing template, drying inspection and revision

(2) key points of photosensitive emulsion coating. The photosensitive adhesive layer of the template must be uniform, the emulsion completely covers the silk, and the adhesive layer on the printing surface should be thicker. Apply glue on the printing surface of the template for 1 ~ 2 times, and then immediately apply glue on the ink scraping surface for 2 ~ 4 times, wet to wet, and then dry. After drying, apply 1 ~ 2 times on the printing surface to make the photosensitive adhesive layer reach the final required thickness. Each gluing must be carried out after the previous glue layer is dried. The number of gluing is determined by the printing requirements and the fineness of the silk

II. Silk printing of packaging trademark

1 Selection of printing methods

silk printing mainly includes flat pressing type, flat pressing round type, round pressing flat type and round pressing round type (i.e. rotary silk printing). In the more advanced packaging and printing production line, in order to improve the decoration of packaging and product identification, the rotary silk printing unit can be used online. In this way, the speed of the packaging and printing production line will not be reduced, and the decorative effect of silk printing can be obtained. In the rotary silk printing, the silk plate is made into a hollow drum silk plate, and the scraper system driving the automatic ink supply device is installed in the silk plate drum. Then, the silk printing is completed by adjusting the angle and pressure of the scraper. The silk plate cylinder is equipped with an ink volume sensor. In production, once the ink volume is insufficient, according to the requirements of GB 4806.6 (see Table 2 for the limit requirements of GB 4806.6 for monomers in polystyrene resin), it should also ensure that the residue of ethylbenzene and styrene in its products meet the limit requirements, and the ink will be automatically supplied through the ink pump. High efficiency UV drying system is adopted for the rotary wire printing machine, and the normal printing speed can reach 60m/min

2. Packaging trademark silk printing features

① the size of paper opening is not fixed. The characteristics of packaging trademark determine that the size of printing paper is difficult to be fixed. This requires the production scheduling to try to put the same number of printed manuscripts in the same batch when arranging printing operations. Because for printers, changing rules often costs both labor and money

② the thickness of the paper is different. Due to the wide variety of packaging trademarks, the variety and thickness of printing paper are different, which brings great trouble to the printing operation. Paper thickness gb/t 3098.11 ⑵ 002 mechanical properties of fasteners are different from that of self drilling and self tapping screws, and the pressure needs to be adjusted frequently; If there are many kinds of paper, the probability of failure is high, and problems may occur at any time due to the replacement of paper varieties

③ high requirements for the quality of printing. The packaging trademark pays attention to the display effect. A row of packages should be placed in a dazzling and consistent color, which requires that the printing color should be accurate when printing. Therefore, printing operators should master the ink matching technology and understand the color matching relationship between inks. The spot color printing ink volume should be sufficient, the hue should be accurate, and the large ink floor should not have defects, and it is not allowed to stick pages

④ the pre press, printing and post press rules should be consistent. Packaging trademark printing often has a post press process, which requires deep processing, such as hot stamping anodized aluminum, embossing, die cutting indentation, etc. Therefore, when printing, pay attention to the same batch of printing operations, and the rules of each process must be consistent, otherwise the subsequent process will fail and cannot continue production. Therefore, when printing, the left, right and rear ends of the printing plate should be crossed, so that the printing marks can be checked frequently during the printing process. If they are inconsistent, they should be placed separately and marked

III. post press processing of packaging trademark

post press processing of packaging trademark printing mainly refers to processes such as glazing, film covering, hot stamping anodized aluminum, engraving relief, die-cutting indentation, mounting corrugated, box pasting, etc. The main process characteristics are briefly introduced below

1. polish. The glazing methods mainly include printing machine glazing, casting glazing, ultraviolet glazing, cover varnish and Cuban glue glazing, and various glazing methods have their own characteristics

2. Film covering. There are two kinds of packaging film, light film and matte film. Due to the many spot colors and thick ink layer of the packaging box, the amount of powder sprayed is increased in order to prevent sticking during printing, which has a great impact on the quality of the film coating. Before the film coating, wipe it with a soft cloth, otherwise it is easy to have the phenomena of weak film coating, many bubbles, white powder reverse and so on. In addition, special attention should be paid to the front side of the printing gauge. The covering film cannot be out of the edge, otherwise the die-cutting overprint accuracy will be affected during die-cutting

3. Hot stamping anodized. Hot stamping electrochemical aluminum is a common process after packaging trademark printing. The general requirements of hot stamping are no paste, no blindness, no flower and no lead loss. Attention should be paid to the vitrification of the layout in large ink printing, otherwise the quality of aluminum ironing will be affected. Temperature is the key to hot aluminum

4. Engraving relief. Engraving relief plate is also called embossing, and the embossing should pay attention to the following two points: ① the engraving plate should pay attention to the sense of hierarchy and three-dimensional, and the fine levels and lines should be clearly displayed. ② During embossing, the plaster mold should reflect all the lines on the original engraving plate. High quality embossing requires hot pressing. Chairman Cui Lixin attended the opening ceremony of China International Aluminum Industry and Shanghai International Industrial Materials Exhibition. The advantage is that the embossed lines are not deformed, with a sense of hierarchy and three-dimensional

5. Die cutting indentation. The quality of die cutting indentation is the key to the forming quality of packaging trademark

6. Mount corrugated. Corrugation is generally divided into type A, type B and type E based on the height and width of corrugation. Type a corrugated is mostly used for outer packaging, while type B and e corrugated are mostly used for medium and small packaging. At present, E-type color corrugated boxes are popular, which are generally used for gift packaging, wine packaging, small household appliances and glassware packaging. The quality of corrugated board is mainly reflected in: the corrugated board should be straight, evenly glued, self-adhesive, impervious, and straight without bending

7. Paste box. Paste box is the last process of packaging and printing, which is divided into manual and mechanical methods. The mechanical pasting speed is fast and the quality is good. Box pasting machine is one of the necessary post-processing equipment for large and medium-sized packaging and printing enterprises

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