Screen printing technology of the hottest aluminum

The silk printing technology of aluminum alloy signs

there are many metals and metal products. For the convenience of narration, this book still takes the silk printing technology of aluminum alloy signs as a typical process to introduce the silk printing technology of metals. The silk printing process of other metal products is roughly the same as that of aluminum alloy products, which is not introduced in this book

the silk printing process of aluminum alloy signs is roughly as follows:

silk screen printing plate production (draft drawing, base plate making, selection, stretching, coating (pasting) photosensitive film)

substrate material preparation (blanking, prepress processing, positioning)

silk screen printing drying, coating protective paint, pasting protective film, punching and forming (high gloss processing), inspection and packaging

in the production process, the most critical is the three processes of base plate making, pretreatment and silk plate production. Plate making process determines the quality of signs

1. Base plate making. Most of the text and graphics plates of the signs are made by Phototypesetting and photographic plate making. First, a single original is made, and then it is made up by continuous drying machine. The number of shops that can participate in the "Green Plan" during the assembly is more than 1000. According to the accuracy required by the parts, the non spacing assembly and the spacing assembly are adopted respectively. If the size requirement of the sign is not high, it can be made up without spacing, as shown in Figure 4-12. After printing, it can be cut directly or stamped after cutting

if the size accuracy of the label is required to be high, it should be made up with spacing. After printing, it should be punched and formed according to the position of the positioning hole, as shown in Figure 4-13. The distance between each part can be 2mm, the positioning aperture is not easy to be damaged can be 2mm, the hole spacing can be 4mm, and the overall area can be 400 400mm, or it can be determined according to the process design

if the color of the silk screen sign is two or more colors, the photographic base plate should have a positioning rule line, and the positioning hole can be painted on the photographic base plate of the main pattern of the sign, so as to ensure the positioning accuracy during blanking

2. Positioning. The rules on the printing plate of silk screen signs are a technological means to ensure that the position of graphics on the surface of the same workpiece to be printed is accurate, unified and meets the requirements of color overprint accuracy. According to the material and shape of the substrate, the positioning methods of silk screen signs are also different. The following are commonly used:

① positioning by the side. It is suitable for straight edge workpieces, such as nameplate, panel, various dial plates, etc. during silk screen printing, the two right angle edges of the workpiece can be close to the positioning strip

② trim positioning. It is applicable to the silk screen printing of shaped shaped workpieces. The workpieces can be shaped, processed and blanking. All of them are the outer frames of the main aircraft and aviation aluminum alloy manufacturing countries in the world. After trimming the gap, the outer frame is adhered to the position required by the spring tide of the platform according to the side positioning method. During the silk screen printing, only the shaped workpieces need to be put into the blanking outer frame

③ hole positioning. Hole positioning is applicable to the jigsaw screen printing of the same figure, that is, punch the positioning hole on the plate first, position it with the hole during the screen printing, and finally blanking and forming the workpiece with the positioning hole

④ coincidence positioning. Suitable for screen printing chromatic patterns on transparent materials. When positioning, the second color pattern can be silk printed on the cardboard and covered with a film printed with the first color pattern, so that the same bit package of the two color patterns meets the size requirements of the design, and then the film printed with the first color pattern can be glued to the platform. When printing the second color pattern, only the transparent workpiece printed with the first color pattern can be overlapped with the first color pattern on the platform to achieve the purpose of positioning

3. ink blending. The requirements of silk screen printing ink for metal signs are strong adhesion, good wear resistance, clear graphics after printing, fast drying and unsealed. Silk screen printing inks for metal signs are usually special inks made of synthetic resins such as alkyd and phenolic resin as binders and some pigments and additives. This kind of ink has good printing performance. It can be dried naturally after printing or baked at 120 ℃ for 2 hours. The surface of the ink film is bright, three-dimensional, and has excellent adhesion and wear resistance with aluminum plate. The ink film of this kind of ink is tested with jm-l paint film abrasion tester. The rubber grinding wheel with a load of 7509 can be pressed for more than 500 times, and the cloth wheel can be used for more than 5000 times

if the silk screen color label is printed, the ink can be matched according to the color sample of the relevant color printing ink, and an appropriate amount of ink mixing oil and desiccant should be added during ink mixing. The addition amount of ink desiccant is about 5 ~ 8% of the total amount of ink. It is not easy to dry if it is added less, and it will affect the adhesion of ink if it is added more

4. Quality requirements for silk screen signs. The text, scale, graphics, positioning holes and color of the silk screen label shall meet the requirements of the drawing, the surface of the finished product shall be free of obvious scratches and stains, and the adhesion of the ink film shall meet the requirements