Guarantee the basic skills of the production quality of gravure cigarette packets
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Designing originals - proofing - finalizing and developing process standards - material preparation - printing - finishing - product selection - finished product storage, which is the usual process for the production of gravure cigarette packets. Any omission or inadequate preparation in any part will cause irreversible damage to the subsequent process.
Original design, proofing and finalization
Often, designers rarely consider whether print quality can be achieved smoothly, and operators responsible for product realization rarely have a say in print design. More than ten years ago, our company processed a cigarette pack. The middle part of the picture was printed on a red field with a yellow sun. The registration requirements were extremely high, and the accuracy of the equipment at that time could not meet the design requirements. The consumption rate is 30%. We have also encountered a product, in the Komori Shangbang NL650 gravure printing machine to achieve 5% to 40% of the transition network, two-color dot overprinting, which for designers is to "effect", but for the production staff That is to say "life"!
Due to process problems, product production efficiency is low, which affects product development. This situation is not desired by design developers. Therefore, once the producer finds such problems in the product proofing process, he should actively communicate with the designer, which will effectively prevent the above problems.
After finalization, process technology standards must be developed for each product. Although the standard is not the same as the quality, there is no standard and the quality of the product is uncontrollable during the production process. The standard should include not only the dimensions, hue, materials, etc. of the product, but also the impact and results of these changes. Only in this way, the operator can effectively control the production during the production process. For example, the hue of a product, a qualified quality inspector must not only memorize the hue, but also remember the color difference and effect allowed by the product. This is also why some people can see at a glance whether there is any deviation or deviation of the products on duty.
Plate roll
The effect of different plate making processes on the formation of the cells and the characteristics of the cells is quite different. Among them, the problems caused by improper plate making process occupy a large proportion in printing, and there are many materials that can be referred to. No further details are mentioned here. Only the use of the plate roll in the printing process and the problems that should be paid attention to are introduced.
1. Storage of the plate roll
Excessive humidity is the biggest “killer” of the plate roll, even if the plate with the protective oil coated on the surface is placed in an environment with a relative humidity of 90%, after 2 to 3 months (or shorter) Corrosion and scrapping. Therefore, a dry, ventilated environment is ideal for storing plate rolls. For the printing companies, the humidity in the workshop is often difficult to control, especially during the rainy season. To this end, the first place should be selected as the plate roll warehouse, and the plate roll stereo library should be selected. If neither of these methods can be achieved, the roll holder should be made. It is not necessary to wrap it in a blanket and put it in the iron box of the platen roller.
In addition, it must be noted that the hollow plate roller cannot withstand heavy pressure, and regardless of the new and old plate rolls, it is necessary to check whether the protective oil is applied before storage.
2. Use of the plate roll
Before the plate roll is sent to the printing house, the plate making machine usually has completely processed the plate roll, including dirtying, polishing, etc. after plating, but this does not mean that the plate roll will not have problems during use. The following points are worth noting.
(1) After the shop receives the plate roller, it must be carefully checked, including overprint color code, crosshair, small text, etc., which are not easy to attract attention.
(2) In the case of normal use, as long as there is no obvious damage on the surface of the plate roll, such as large-area corrosion and deep bumps, it can be reused after re-chrome plating. However, for the plate roll which has been corroded by the poor storage environment, it is recommended to do the scrapping treatment because the copper layer structure of the plate roll has changed, and the original dense structure has ceased to exist. If it is chrome-plated, even if it is seen on the surface. No problem, the chrome layer will fall off after a period of use.
(3) When the plate roller is connected with the equipment, the shaft head part must be well lubricated and ensure a proper fit. If it is too loose or too tight, it will cause damage to the plate roller head.
3. About the issue of the diameter of the plate roll
A lot of data suggest that: due to the influence of tension and temperature during the gravure printing process, the longitudinal dimension will become longer, so the diameter of the plate roller on several units after the gravure printing machine should be increased according to a certain proportion to compensate for the printing materials. The stretching changes. But in fact, for paper, its tensile change is not obvious. Moreover, the tension balance can be easily achieved by adjusting the printing pressure between the units. The use of the incremental plate roller has no practical significance, and brings some problems in the production, such as the order of the plate rolls cannot be changed arbitrarily, and the intermediate unit cannot be vacant. . Therefore, for paper printing, you must be careful when choosing a plate roll. Unless the print is special and really needed, do not select an incremental plate.
Gravure paper
In the cigarette printing industry, printing materials are still mainly paper. Because paper-plastic composite materials are not environmentally friendly, they have basically withdrawn from the historical stage of cigarette packets. High-grade coated paper and laser transfer cardboard are the first choice for high-end cigarette packets.
The change in paper moisture has a great impact on gravure production. Since the moisture content of gravure paper is usually 6% to 7%, and the humidity in the workshop is usually 40% to 60% (the humidity will reach over 90% in continuous rainy days), the change of humidity has a great influence on the paper. The characteristics exhibited by humidity change are as follows: (1) Under the influence of the orientation of the paper fibers, the transverse shrinkage rate of the paper is usually higher than the longitudinal shrinkage rate; 2 after printing, the hygroscopicity and dehydration of the back of the paper are obvious. Faster than the front; 3 coated paper, gray board, and cardboard are sensitive to humidity.
In a high humidity environment, the longer the paper is placed, the more obvious the deformation, such as shrinkage, warpage, and ruffles. Moreover, the hygroscopicity of the paper is lagging. It is best if the product is processed before the paper reacts to the humidity change. Therefore, long single products should be processed as much as possible. Although the current investment in the production of connected lines may be relatively large, the returns from the product quality stability, output rate, raw material consumption and other indicators are considerable. Before 2009, a certain brand of cigarette packs produced by our company had a large-cut and die-cutting process after printing. The product processing cycle was 4 days, and the supply volume was 2,500 cases/day (two shifts). After the production of the connection, the delivery can be made on the same day, and the supply amount is 2,000 cases/day (single-shift production). In terms of material consumption, the production of the line removed the position of the cornice and the side gauge line, and the material consumption decreased by about 2% year-on-year (excluding the material saving caused by the reduction of the scrap rate).
In the case that connection production cannot be achieved, the following measures should be taken: 1 install constant temperature and humidity control equipment in the production workshop; 2 adopt the production mode of the whole workshop as much as possible; 3 reduce the number of turnovers of the products after slitting; The improvement of the cutting precision of the device makes the cutting error control within 2μm or 1.5μm, thereby reducing the problems of paper shrinkage and irregularity caused by the rule.