In the article "Basic Knowledge of Acrylic Bottles", the characteristics and applications of acrylic materials have been introduced in detail. This article is a more in-depth study of acrylic bottles combined with silk screen printing technology. If acrylic bottles are limited to printing simple lines and Words cannot meet people's increasingly demanding requirements for craft products. Today, acrylic bottle screen printing has begun to dabble in the field of color, and color printing of plexiglass craft products has also become common. The main difference between color printing and general line text printing lies in the dots, which is no different from other printing processes. The evaluation standard is also to see whether the original can be truly restored. Silk screen printing is one of the commonly used processes for acrylic bottle finished products, so the cost performance and process characteristics can complement each other with acrylic products.
1. Sample Analysis
Customers often provide plexiglass samples for the plexiglass processor to design the scheme, he simply explains his intention to you, and most of the tasks are done by you. It is very important to understand his intentions. In many cases, disputes arise because you do not really understand his true thoughts. You also need to figure out the type of plexiglass sample material and determine the printing process. Sometimes the customer knows the material type, but most of the time it doesn't, and you can identify it at your own discretion. The type of material also determines the choice of printing parameters, such as the number of screen lines, screen mesh, prepress, squeegee hardness, etc.
2. Select the ink decolorization tester
Choosing an ink bleaching tester is difficult and easy. You may be well versed in the adaptability of the substrate and know what resins are contained in the substrate. However, the social division of labor doesn't care how much you know. You often just need to choose according to the information provided by the manufacturer at hand. You only need to verify the authenticity of the information. It may be suitable for most occasions, but there are exceptions in some special cases, and you may wish to prepare a few more to experiment.
The right choice is first of all a simple understanding of theory, and the key is to test according to the existing varieties.
3. Consider the curing process
The vast majority of plastic substrates used are volatile drying types. After the solvent contained in the solvent type evaporates, it is fixed on the substrate. However, some prints need to be dried by a drying device before they can be dried, especially those involving metals, ceramics, and plexiglass.
Printing generally requires a drying device. It is very important to configure what kind of drying device. With UV printing, consider curing
Equipment and equipment, UV does not contain solvents, can only be cured under the irradiation of ultraviolet rays, whether it is a drying device or a UV curing machine, it can dry quickly. If the curing degree is too low, the ink layer will show poor adhesion and poor gloss; if the curing degree is too high, the film layer will be brittle and easily cracked and deformed.
4. About printing color sequence
Color prints reproduce the rich color and hierarchical information of the original through the superposition of the four primary colors. In theory, complete transparency can ensure the true restoration of the color, but it is composed of resin binders and pigments. The resin cannot be completely transparent, and the pigment itself There is also a certain amount of hiding power, and these factors ultimately affect the color.
The stacking order is related to the transparency of . Those with low transparency have strong hiding power and should be printed first. Initially, the transparency of yellow was the worst, and yellow should be printed first. Now the situation has changed, and it does not matter that yellow ink is printed first and then printed. Theoretically speaking, in addition to the difference in hue, the other indicators of the four primary colors should be as close as possible, but the fact is another situation. The saturation of cyan has a great influence on the color rendering of printing. It is suitable for cool colors, so when the saturation of cyan is high, cyan can be placed in a slightly earlier color sequence. The role of black is to increase the outline of the printed matter. If the graphics and texts have high requirements for contrast, then black is printed at the end. The density of black also has an impact on the printed matter. Excessive density will cover some layers, so black with a higher density can be printed in the first color sequence, and black ink with a lower density can be printed last.
5. Determine the number of screen lines
The higher the number of screen lines, the more rich layers can be reproduced, but too high a screen line number will make screen printing difficult. To determine the number of screen lines, we must first consider the visual environment, that is, what distance to observe the image from. The visual distance should be the most basic standard for determining the number of lines. The closer the visual distance, the higher the number of screen lines, which can improve the clarity; the farther the visual distance, the lower the number of screen lines, which can reduce the difficulty of printing. Sometimes customers don't know much about the characteristics of screen printing and blindly ask for unnecessary screen lines, you should persuade him to change his mind. The range of screen printing reproduction is usually below 80 mesh. If the number of screen lines is too high, dot loss will occur in the highlight area, and the details cannot be reproduced. In addition, the number of screen lines is too high will also bring difficulties to the selection of screen. According to the usual selection method, the number of screen meshes should be 4 times the number of screen lines of the printing film. Too high the number of screen lines will cause the ink layer to be too thin, and the contrast of the image and text will be reduced, which will also affect the expressiveness of the image.
As the number of lines increases, the dot size decreases until the dot is unprintable. Unlike offset printing, screen printing can copy 3% to 98% of the dots. Strictly speaking, it can only copy 15% to 85% of the dots. The dots higher than 15% will be lost, and the dots below 85% will be enlarged and changed. For the original with very fine layers, it needs to be corrected and compressed to be restored after scanning into the computer. Compressed image highlights and shadows are easily reproduced at a given line count. Of course, over-compression of the tonal range results in some loss of detail in the image.
6. Determine the output resolution of the film
If the output resolution (dpi) is set too low, the film will appear jagged. If the resolution is too high (the number of lines remains unchanged), the level of the printed film will be richer, but the number of gray levels will increase exponentially. The reproduction capacity of screen printing is limited,
This even makes screen printing impossible. Practice has proved that screen printing is difficult to reproduce more than 100 lines of print. Of course, the development of technology promotes the progress of screen printing, and this conclusion is not absolute.
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