Discussion on the misalignment of printing pattern

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On the misalignment between the printed pattern and the hot stamping position in the hot stamping process

the so-called hot stamping pattern alignment overprint is the process of hot stamping the anodized pattern on the paper surface first, and then overprinting the pattern on it. During the implementation of this process, there are often problems that the printing pattern is not aligned with the hot stamping position. It is analyzed from the following aspects

1. control of paper elasticity

paper elasticity is the most frequent and difficult factor to control in the printing process. In the printing process, it is impossible to completely eliminate the paper stretching, but it is possible to control its stretching value within a relatively stable range. How to control the expansion and contraction of the paper is the basis of the implementation of the hot stamping pattern registration process. The stability of newly imported paper is generally quite poor for the following reasons

(1) the interior of the paper is still in a rather unstable state (such as the water content), and it must be placed for a period of time before it can reach a stable state

(2) changes in ambient temperature and humidity during transportation will also lead to changes in the dimensional stability of the paper

therefore, the newly imported paper should be stored in the printing workshop for 23 weeks after cutting, so that it can stretch and deform to a stable state under the production environment, and then wrapped with shrink film, and then opened when in use

2. Control of hot stamping process

pattern positioning hot stamping is the key of this technology. We should adopt scientific process scheme and statistical principle to improve this process, and try to eliminate the problems in the bud. The following schemes can be used to control hot stamping

(1) film positioning method. In the process of hot stamping, the film is used for hot stamping, that is, the film is used to check the position of the hot pattern, so as to ensure that the position of the picture in the paper in recent years is accurate. In the process of adopting this method, it is necessary to press out the gauge line at the middle edge of the paper, so as to facilitate the stability inspection of the gauge line for hot stamping and the subsequent inspection of the industrialization process of degradable and renewable biological fiber such as flame retardant and high wet modulus regenerated cellulose fiber

(2) contour location method. Rework the outline of the pattern to be hot stamped (its size can be slightly improved) with the printing demand. The equipment first prints the light color outline, and then hot stamping against the printed outline. This method is conducive to the machine personnel to timely detect whether the hot stamping position is accurate

(3) special attention should be paid to the consistency of the two hot stamping rules (front rule and side rule) during the hot stamping process, otherwise the consequences will be unimaginable

3. Control of printing process

if the above two aspects are well controlled, then the printing process can be handled according to the rules. If problems occur in the control process, the following measures can be taken to remedy them

(1) for the products whose paper treatment is not in place, the humidification treatment method can be used to record the humidification treatment time and environmental state of the paper in the form of tables, and the treatment process can be recorded in detail. After the small batch test is successful, the humidification treatment process records and products can be analyzed. Then formulate a standard humidity control process plan, implement the process plan, and finally complete the printing process

(2) if the two specifications are unstable during the hot stamping process, you can use the method of drawing lines to print by different specifications (if the two specifications are too messy, the batch of products will be scrapped)

from the above analysis, it can be seen that if the problem is left to be solved in the printing process, it will be in a passive state, so it should be prevented and solved as soon as possible. At present, although the hot stamping process has been very profitable for building structures, there will still be some unexpected problems in many new application fields. These problems need to be seriously summarized by printing process researchers and studied tirelessly to make hot stamping more perfect

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