Quality control of cigarette packets, process design is the key!
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The control of product quality is the core of enterprise management, and cigarette printing enterprises are no exception. Process design is the forefront of quality control of cigarette packages, and excellent cigarette package design can better support the stability of product quality. Below, the author talks about the quality control of cigarette packages from the perspective of process design.
Image-based process design points
In theory, the richer the image hierarchy, the higher the image resolution, and the better the image rendering. However, in the actual printing process, the reproduction of the image effect is closely related to the color gamut of the printing ink, the smoothness and whiteness of the printing paper, and the dot reduction of the printing device. Therefore, in the process design of the cigarette pack, we must consider these factors in order to make a relatively good cigarette package design. Below, the author will talk about the image design process points from the following three aspects.
(1) The color rendering of printing is actually based on the principle of color reduction. The more colors are overprinted, the darker the color. Therefore, in the design of the cigarette package process, try to use the spot color ink for color reproduction, so that the color of the image presented is more beautiful, avoiding the use of multi-color ink coloring or multi-color superposition process to reproduce the dark tone of the image, if the image is indeed Need to reproduce the dark color, you can use the background color removal process to make the dark tone part, so that the image effect is not too dark, the color saturation will be much better.
(2) Image layer reproduction and image resolution are closely related. The richer the image hierarchy, the higher the image resolution requirements. The reproduction of the image hierarchy is inseparable from the smoothness and whiteness of the printed paper. When printing a rich layer of images, 3% to 5% of the dots are not lost, 80% to 90% of the dots are not pasted, the dots are flat, there is no white point inside, and the dots are round and neat. If the smoothness of the printed paper does not reach the required index for dot reduction, the 3% to 5% dot in the highlight portion of the image layer cannot be transferred to the surface of the printing paper, so that the high-definition portion of the image is missing.
In this case, the gradation curve of the image must be adjusted according to the condition of the printed paper, and a plurality of screen line number schemes are proofed to determine which screen line number should be used on the current printing paper. Taking offset printing as an example, in the case of using amplitude-modulated circular dots, the number of screen lines for ordinary printing is 100-150 lpi, the number of screen lines for fine printing is 150-200 lpi, and the number of screen lines for offset-print images is generally 150- 175lpi. This is mainly because the cigarette pack design is mostly abstract design, and the real-life image is rarely used, so the image level is relatively low, and the cigarette pack printing usually has less than 200 lpi of printed products.
(3) The choice of printing method is directly related to the quality of the image level. At present, the printing methods commonly used by cigarette printing enterprises include offset printing, gravure printing and screen printing. These printing methods have their own advantages and disadvantages. The offset printing process is better for image layer reproduction, but the hue stability of large-area solid printing is weak, and almost no special effect printing is supported; the screen printing process can reproduce a variety of special printing effects, but the reproduction effect on the image level is poor; The gravure printing process supports the hue stability of large-area solid printing, and has certain support for image level and special effect printing. Therefore, in the process design of the cigarette pack, it is necessary to develop strengths and avoid weaknesses, and give full play to the advantages of the above three printing methods. When the design draft requires high image level, the offset printing process can be used; when the design draft has high requirements for solid printing, the gravure printing process can be used; when the design draft needs special effects, the screen printing process can be adopted. In fact, in order to reflect the brand value of high-end cigarette packets, cigarette package printing companies often need to use a variety of printing methods to achieve the desired artistic effect.
Process design points based on mass production
The process design of proofing products and the process design of mass production products are different. The former is for bidding, and there are samples. The latter's focus is on ensuring the quality of batch products. Therefore, the process design ideas of the two are certain. The difference. Below, the author briefly talks about the process design points of mass production of cigarette packages.
1. Multicolor overprinting process parameter setting
Multi-color overprinting is very common in cigarette package printing. For example, seams between color patches or between patches and images. If the overprint parameter setting is large or small, it will affect the overall effect of the cigarette pack. When setting the cigarette printing overprint parameters, the following two aspects are mainly considered.
(1) Differences in printing methods
Offset printing, gravure printing and screen printing are the three mainstream printing methods for cigarette package printing. The registration accuracy is quite different. The setting of the overprinting parameters must be carried out according to the situation.
The manual manual adjustment accuracy of the imported offset printing machine is ±0.01mm, but the registration accuracy in the actual printing is above ±0.05mm, and the registration accuracy is the highest among the three printing methods. When setting the offset printing parameters of offset cigarettes, it should be set between 0.05 and 0.15mm according to the requirements of the design draft.
The manual manual adjustment accuracy of the imported gravure printing machine is ±0.02mm, but the registration accuracy is ±0.10mm in actual printing. When setting the overprinting cigarette pack overprinting parameters, it should be set between 0.10 and 0.25mm according to the requirements of the design draft.
The actual registration accuracy of screen printing is relatively low, usually ±0.15mm.
It should be noted that in the actual setting, the larger the overprinting parameter, the better the better the design effect of the product should be followed. Especially in the design proofing, the relationship must be clarified and the initiative should be mastered. It is more passive when producing cigarette packets.
(2) Precision of printing equipment
The accuracy of the printing equipment is also an important factor in the setting of the overprint parameters. When setting the overprint parameters, the accuracy of the printing equipment must be taken into consideration. Otherwise, the normal production of the cigarette pack products will be affected. However, the qualification rate of the products cannot be guaranteed, and there is a risk that the batch products will be scrapped.
2. Post-press process parameters and process settings
In order to reflect the value of high-end cigarettes, such cigarette packs are often very complicated, and it is common practice to use a variety of processing techniques. Below, the author describes a typical case, how to set the post-press process parameters and process in the case of a combination of multiple processing techniques.
The latest "Furong Wang (hard fine branch)" cigarette pack (shown in Figure 1) of our company adopts a variety of processing techniques, including gravure printing, positioning hot stamping, offset printing, hot stamping, holographic hot stamping, and embossing twice. , printing and die cutting 9 processes. Before the process design, we must understand that the production process and product quality of the multi-process products are interlocking, and the pre-process has a certain restrictive effect on the post-process.
First of all, to ensure the normal production of the "Furong King (hard fine branch)" cigarette package is a prerequisite for ensuring the stability of the side gauge and the bottom gauge of the gravure printing part, which is the most important in the gravure printing process, the precision deviation Must be kept within 0.15mm, in order to ensure the stability of the quality of the post-press process.
Secondly, the cigarette package uses the processing technology of first positioning hot offset printing. According to the design characteristics of the process, the precision deviation of the positioning hot should be controlled within 0.30mm. In fact, this precision requirement is already very low for the positioning hot. Allowing such a large degree of tolerance depends on the subsequent positioning and printing process to modify and cover the positioning of the positioning deviation. However, since the positioning printing is directly printed on the positioning hot stamping pattern, in the process of positioning hot pressing, it is necessary to focus on controlling the adhesion of the anodized aluminum, and also pay attention to the control of the hot stamping pressure, which is directly related to whether the seaming edge of the positioning hot stamping is Hot stamping is good. Therefore, for the positioning hot process, the control focus is not the hot stamping rule, but the adhesion of the electrochemical aluminum and the hot stamping pressure.
In fact, the process design of cigarette pack products has certain brand characteristics, that is, the craft design of each brand is not the same. In the mass production of multi-process products, we must use the characteristics of the brand and systematically consider the control focus of each process to achieve the ultimate goal of stable quality and efficient production.
Although there is no fixed pattern in the process design of the cigarette package product, it is "everything changes." Before mass production, cigarette package printing enterprises must follow the design thinking of “all considerations and key monitoring” in order to be able to know how to design them in the process design. Only by mastering the essence of process design can we design scientific and reasonable flow smoothly. Excellent program.