Tinplate printing process design process and control points

Tinplate printing products with its innovative binding design and special exquisite printing effect, mainly used for packaging products such as oil cans, spray cans, beverage cans, food cans, miscellaneous cans, batteries, toys, pots, film boxes and so on. Metal packaging products more varieties of complex specifications, the main products are aluminum two cans, tin drinks three cans, food cans, aerosol cans, 1-20 liters of various types of chemical and chemical bottle caps, easy to cover, all kinds of miscellaneous cans, 35-208 liters capacity hot and cold rolled steel drums and tinplate barrel printing. According to incomplete statistics, 35% are large state-owned enterprises owned by state-owned and state-owned holding companies and historically left over, 30% by private-owned enterprises, 28% by Sino-foreign joint ventures and 7% by wholly foreign-owned enterprises. The industry already has good equipment, the United States advanced two-tank production line 26 imported tinplate three-piece can production line of about 300 bottles of imported equipment for more than 300 Taiwan (sets), as well as Indian iron, coated iron equipment up to 600 About half, imports and domestic accounted for half. There are quite a few other domestic equipment with better performance. Metal containers industry already has a good foundation.

The development of metal containers is not easy to weather ups and downs more than 30 spring and autumn. During the period of "June 5", the market was just beginning to develop slowly. During the "Seventh Five-Year Plan" period, the market supply and demand were relatively normal and showed a tendency of great development. During the "8.5" period, the heyday of metal container printing was: "Nine Five" was Stable period; "ten five" is a critical period of development; "eleven five" is the quality of metal printing competition period, that is, to win the market with a special period of quality. Therefore, the principle of printing as the theoretical basis for printing technology as the research object, access to high-quality metal printing products is the key process of printing process quality control. Tinplate printing from color separation, copy, proofing, printing began until the completion of printing and paper products printing process has many similarities, but after all, a printed iron is a special process of each process if similar to the design but operation But different from the following to briefly talk about the process of tinplate printing process design and control points.

1, color separation

At present, most of the domestic and foreign printing equipment are mainly monochrome printing machines and two-color printing machines. Due to the limitations of printing equipment and printing materials and the special packaging effect of customers, the printing color effect by using the traditional color separation method may be related to the customer Provided a lot of manuscripts, but also for the follow-up imprint of iron laid a hidden danger. In order to avoid multi-color printing overprints are not allowed, abrasion, color obvious color is not bright, defective and so on phenomenon of multi-purpose printing iron instead of multi-color overprint, such as Pantone. In addition to the network back to the rough and coarse network-based, so that the total area of the network to reduce the number of print outlets to expand the smaller. So color separation is the key to printing metal products.

2, proofing

Printing on both the Indian iron color test is the separation of color film and iron products in advance of quality analysis and grasp. Its printing method using the traditional offset printing method. In the process of proofing if you want to leave dyed as a reference in the printing process control, so that the stable quality of the print color can truly reproduce the proofs confirmed by the customer. At the same time, since the printed iron is rarely an integral part of the final product, it is often a part of the processing of various containers, covers and various miscellaneous articles that are used for proofing as well as testing the processing performance and matching of the paint. Therefore, in this process we need to process into finished products, put the contents, that is, forming test, such as food cans on the tank sealing, shelf life, preservation of the test.

3, determine the drawings

Printed iron drawings secluded to determine the rules of tinplate product arrangement and coating of the product used when the rubber roller 3 to turmoil. Which tinplate positioning rules refers to the bite, the body by the direction and size of their printing is the basis for printing; product arrangement is based on the type of drying products are different in the nature of its arrangement in the process of determining the arrangement need to consider the printing iron Acceptable minimum size and maximum size at the same time to make it the most economical arrangement; Cots are coating tools, for the need to be coated with a full version of the coating method, Empty coating products less, and the outer coating products are three kinds of coating methods are used for food Hao commonly used horizontal empty spraying spray cans with vertical empty coating, miscellaneous cans and capping products are usually coated with a full version: There are two types of coating methods, such as vertical blank coating and full coating.

4, copy

For the cans, covers printing, making lithography most of the same screen according to the specified product drawings into a group made of negative or positive map, the use of tanning machine for exposure plate. This can be printed on the same sheet of dozens of the same image in the production process using the PS version, the same with ordinary paper printing plate-making methods such as exposure time, development, fixing, washing and so on.

5, determine the printing material

Due to the different uses of the products and the forming equipment's different requirements on the thickness of the tinplate, tin layer, hardness and annealing method, we determined the above factors according to the nature of the product. It not only meets the printing requirements, Punch boxes and other requirements, and determine the final printing surface.

6, paint

Indian iron is not the ultimate goal, but rather the beautification of metal packaging, the purpose is to make all kinds of metal containers, such as cans, all types of caps, toys and so on. To make the printed graphics on the metal plate fresh and eye-catching, inseparable from the special role of paint, which increases the tinplate with ink film between the Cape, the ink film played a good protective effect while increasing the pattern The brightness of the product has a metallic color and in the final molding process does not change color, paint off. For food can coatings, it prevents chemical and biological contamination of the contents, reduces the possibility of tank leakage, preserves the original color of the food, extends the shelf life of the contents and allows the contents to be easily poured out of the container. In addition, it also has some special visual effects such as Kim Ke-ding, explosive varnish, wrinkle oil, pvc varnish, matte oil, etc. These coatings are used for wine cans, boxes and so on.

Printing iron paint is mainly composed of film-forming substances, pigments, driers, adjuvants, solvents, etc., from the coating methods and functions can be divided into internal coating, coating and varnish 3 kinds of paint usually according to the nature of the product and drawings to determine The paint and coating used. Due to the tin coating a certain thickness of the paint after the remote to enter the drying room for baking, and the baking temperature is essential.

Drying tunnel usually consists of 3 parts, namely preheating zone, heating zone and cooling zone. In the warm-up area at room temperature, gradually warming the printed piece of the required heating temperature, from a technological point of view, the smaller the area, the shorter the better. The heating zone is a dry main area, requiring uniform temperature distribution: cooling zone requires rapid cooling. And we stipulated in the process is a district, the second district temperature. The first zone is the heating zone, which takes the temperature of the hot metal in this zone from room temperature to the desired temperature. All solvent volatilization on the tomb is carried out in this interval. Zone 2 is the baking zone. Its main function is to maintain the set temperature reached in zone 1, also known as the paint specified in the product specification of the PMT supplier. The baking temperature in the oil is usually PMT. We do not regularly on the oven temperature to be corrected so that the baking temperature in line with process requirements, while baking time is also very important, we broadcast before using the PMT and time to determine, and time mainly through the speed limit to achieve. If the time is too short coating with powder is not good, soft; too long it becomes brittle when the tank will cause fracture yellowing.

7, printing

① ink

As the printing ink is printed directly on the smooth surface without absorption of the metal so the printing ink drying depends mainly on the ink itself, the oxidation of conjunctiva reaction and the evaporation of the ink solvent. It should mainly have good adhesion, process resistance to cooking bactericidal resistance, high temperature baking, water resistance and other properties, but also have the printability of offset printing inks, such as liquidity, fineness and so on.

② color sequence

Printed iron and more to monochrome or two-color machine-based, in the printing sequence usually follow the following principles: first printed dot coverage area is small, the back printing dot twist large area; poor transparency of the ink dark first printing, good transparency Bright after India; India first printed flat net color after printing: mainly to the warm red after the print yellow, cold-based post-print cyan.

③ press regulation

The specifications of tinplate, the thickness of the changes often shake to the rules of the printing press, single and double sheet detector printing pressure, suction nozzle adjustment, at the same time, blanket should be replaced frequently.

8, standardized process control

Quality inspection of the main process of printing and finished product testing of two parts. Inspection in the production process includes raw material inspection and printing inspection. Inspection of raw materials, including tinplate, ink, paint according to national standards or industry standards for testing. At the same time printing process, paint construction performance testing is also essential. Routine testing of paint are hardness test, with special test anti-sulfur acid test, impact resistance test. At the same time also increased for food cans boil retort sterilization test for stationery, cigarette case cover, etc. need to increase the resistance deep drawing of the pilot project.

In the course of process design, we must first understand the nature of the product and the condition of the secondary equipment. Secondly, we must determine the pre-press process, printing material, coating system and printing color sequence according to the characteristics of the original and the printability of the original, and also consider the raw materials and processes Economy: re-develop product standards and acceptance criteria Pre-production test to make the rationality of the test process; the last batch, production by strengthening the process control, and the need for process feedback, the process is more reasonable and standardized.

The use of 0.07-0.14mm film (iron, aluminum) laminating iron production process developed in Xi'an University of Technology. This new Fumo iron production process is the main trend of development. My country is a large country with a population of 1.3 billion. Although its economy is developing rapidly, it is very difficult to reach the level of international consumption due to its large population in a short period of time. However, precisely because China is the world's largest population, the space for development of the packaging industry is even greater.