The production efficiency of hot stamping for "Yuxi (hard)" cigarette strip boxes has skyrocketed, yet these secrets are hidden!
Hot stamping technology is widely used in the packaging printing industry, but in some special printing fields, especially in the tobacco packaging field, the application proportion of hot stamping technology is higher. Positioning hot stamping technology is developed on the basis of traditional non equidistant hot stamping technology. It uses cursor positioning scanning and step axis control to set the jumping distance to achieve the positioning of the aluminum pattern and the hot stamping plate position, allowing holographic aluminum to complete positioning hot stamping under hot pressing conditions. The distance of the positioning cursor for holographic positioning hot stamping foil should be comprehensively considered and calculated based on various factors such as the layout method, number of plates, and number of hot stamping points of the printed product, in order to ensure that it can meet the requirements of uniform jumping hot stamping.
Generally speaking, the flat pressing multi-point one-time positioning hot stamping process requires that the distance between the hot stamping points be equidistant. In non equidistant situations, the positioning hot stamping pattern cannot be correctly positioned, or it may cause additional consumption of electroplated aluminum. The general solution is to increase the number of positioning hot stamping passes and divide them into two or more hot stamping to achieve. However, this will inevitably lead to an increase in production processes and production costs, resulting in lower production efficiency.
In order to improve the efficiency of hot stamping, printing companies often adopt the method of multiple splicing simultaneously when hot stamping specific positions on cigarette packaging, that is, to achieve the same graphic and textual hot stamping operation on several packages at once, commonly known as "multi splicing hot stamping". The four splicing strip box layout is shown in Figure 1. Multi splicing hot stamping can greatly improve the efficiency of hot stamping under the condition that the size and spacing of the required text and image are completely consistent, and the hot stamping jumping step is stable; In addition, at the current level of technology, it is necessary to align the anti-counterfeit graphics and text on the electroplated aluminum with the printed graphics and text on the printing paper when performing multi splicing hot stamping, and the alignment method usually uses cursor detection.
Figure 1 Four piece box layout
Analysis of hot stamping registration problem
However, when conducting multi pack hot stamping for cigarette strip packaging, assuming that the same label needs to be hot stamped on both the front and back of each strip box for N-pack hot stamping, a total of 2N anti-counterfeit aluminum labels are required. If the spacing between each label on the same or adjacent strip boxes is consistent and the spacing between anti-counterfeit labels on the aluminum is set to a fixed value, continuous hot stamping can be achieved in sequential steps; However, in actual production, the spacing between two labels on the same strip box is consistent. However, due to the presence of cutting areas between adjacent strip boxes, the spacing between the second label on the first strip box and the first label on the second strip box will be greater than the spacing between any two labels on any strip box. In other words, the spacing between 2N labels that are hot stamped simultaneously is inconsistent. If the spacing between anti-counterfeiting labels on the aluminum foil is still set to a fixed value, there will be a problem of inaccurate alignment of subsequent hot stamping label patterns.
The traditional approach of "one identifier corresponds to one cursor" requires an additional process of setting the cursor, which increases production costs. Moreover, using this method for registration and hot stamping requires detecting a specific fixed cursor for each registration, which also increases usage costs; Secondly, these registration methods can only use the method of detecting after hot stamping, that is, after completing the hot stamping, scanning and detecting the position deviation of the identification pattern on the product to determine whether the error is within the range. If the positioning pattern deviation is too large, it needs to be adjusted, which has a significant lag; At the same time, if the anti-counterfeit labels on the aluminum foil film are arranged completely in correspondence with the positions and intervals of the parts to be hot pressed on the printing paper, it can indeed be easily aligned during hot stamping. A single hot stamping only requires setting and reading the cursor in sequence, but it greatly increases the difficulty of aluminum foil film production. Due to the large spacing between anti-counterfeit labels, it will cause great waste of aluminum foil materials, and the distance of aluminum foil film jumping per unit time during the hot stamping process will greatly increase, which is also a major test for the stability of the process and the service life of the equipment.
In order to solve the above problems and address the special requirement of one-time positioning hot stamping of non equidistant patterns in the process of multi splicing hot stamping, it is necessary to make special technical improvements to the arrangement, spacing, and registration cursor of anti-counterfeiting labels on the aluminum foil film, so that it can achieve simultaneous hot stamping of multiple non equidistant patterns after one positioning. Therefore, after comprehensive consideration, a one-time positioning hot stamping technology solution that meets multiple non equidistant patterns is adopted.
Determine the number of splices for a single hot stamping and the position and spacing of the hot stamping icons on the printing paper
Based on the longitudinal length of the single splicing, determine the number of longitudinal splicing plates for a single hot stamping of the flatbed hot stamping machine, that is, divide the longitudinal length of the flatbed hot stamping plate by the longitudinal length of the single splicing paper, and the result is taken as the number of longitudinal splicing plates for a single hot stamping, which is the so-called "multi splicing hot stamping" quantity.
According to the longitudinal spacing between the single splicing hot stamping marks, with the geometric centerline of each hot stamping mark as the measuring endpoint, two or more hot stamping marks are set on each splicing, and the spacing between the same splicing hot stamping marks is marked as L1. The spacing between the last hot stamping mark of the first splicing of adjacent splicing and the first hot stamping mark of the second splicing is marked as L2. Due to the existence of die-cutting and cutting positions between adjacent splicing, L2>L1 and the value is constant in L2.
The setting of aluminum foil film involves the following three steps:
(1) Figure 2 is a schematic diagram of the distribution structure of aluminum oxide; Figure 3 is a schematic diagram of the separation of anti-counterfeiting labels on a single-sided strip box and an electroplated aluminum film; Figure 4 is a schematic diagram of the overlap between the hot stamping pattern of the four piece box and the anti-counterfeiting mark on the aluminum foil film.
Figure 2 Schematic diagram of distribution structure of aluminum oxide
Figure 3 Schematic diagram of the separation of anti-counterfeiting labels on the single-sided strip box and the aluminum foil film
Figure 4 Schematic diagram of the overlap between the hot stamping pattern of the four piece strip box and the aluminum foil logo
(2) Mark the first hot stamping mark on the first printing paper as AT1, the second hot stamping mark as AT2, and so on, with the Nth hot stamping mark as ATN; Mark the first hot stamping mark on the second printing paper as BT1, the second hot stamping mark as BT2, and so on, with the Nth hot stamping mark as BTN; Then, following this pattern, continue to set the first hot stamping mark on the third printing paper as CT1, the second hot stamping mark as CT2, and so on, with the Nth hot stamping mark as CTN; Mark the first hot stamping mark on the fourth printing paper as DT1, the second hot stamping mark as DT1, and so on. Mark the Nth hot stamping mark as DTN, and repeat this process.
(3) The specific location settings are as follows: first, determine the first positioning cursor to be scanned for the first hot stamping on the electrified aluminum film, and set the anti-counterfeiting hot stamping mark AT1 at its corresponding position. Then, set the anti-counterfeiting hot stamping mark AT2 at the interval L1, the anti-counterfeiting hot stamping mark AT3 at the interval L2, and the anti-counterfeiting hot stamping mark AT4 at the interval L1; The first hot stamping performed based on the first positioning cursor can complete the hot stamping of even numbered printed paper sheets; Following the pattern of setting anti-counterfeiting hot stamping marks for the first hot stamping, continue to set the anti-counterfeiting hot stamping cursor BT1, BT2, BT3, BT4 for the second hot stamping, and repeat this process.
When working, the first positioning cursor is scanned during the first hot stamping process, and AT1, AT2, ATN, and 2N anti-counterfeiting labels are hot stamped on the first and second printing papers according to the set fixed spacing. Then, the aluminum foil film is moved forward a specific distance L3 to move the second positioning cursor to the "first positioning cursor" position, which is the starting hot stamping point. Similarly, the subsequent anti-counterfeiting labels are hot stamped on the third and fourth printing papers according to the fixed spacing, and a uniform and stable continuous jumping and hot stamping process is carried out during this process.
Multiple non equidistant patterns at once
Design and production of positioning hot stamping foil
The spacing between the first and second hot stamping marks on each printing paper is set to L1=135.9mm, and the spacing between the first and second hot stamping marks on the first and second paper is set to L2=159mm. The layout is determined as "four piece hot stamping".
As shown in Figures 2, 3, and 4, the first hot stamping performed by scanning the first positioning cursor can complete the hot stamping of two vertical and all four printed paper sheets. The second positioning cursor scanned during the second hot stamping is set at a distance of L3=240mm from the first positioning cursor. During the process of uniform and stable jumping and hot stamping, except for the first, third, and fifth anti-counterfeit marks that may be missed at the beginning of hot stamping, the anti-counterfeit marks can be sequentially and intermittently hot stamped, greatly reducing the waste of aluminum foil film. The schematic diagram of aluminum foil is shown in Figure 5.
Figure 5 Schematic diagram of the upgraded version of Yuxi (hard) strip box with 4 red lens electroplated aluminum
Application examples
As shown in Figures 2, 3, and 4, taking the upgraded version of the "Yuxi (Hard)" strip box (4-pack) as an example, a single packaging strip box is rectangular in shape and bent into a rectangular box. During the production process, laser anti-counterfeiting marks AT1 and AT2 need to be hot stamped at the trademark positions on the front and back sides of the bent packaging strip box, respectively. That is, hot stamping is carried out on the flat surface of the unfolded rectangular paper. The corresponding anti-counterfeiting marks set on the conventional aluminum foil film are arranged equally. If the distance between these two hot stamping positions on the strip box is constant, several anti-counterfeiting marks can be set equally within the corresponding constant distance on the aluminum foil film. This way, during hot stamping, several anti-counterfeiting marks can be set equally on the aluminum foil film. The anti-counterfeit labels on the film are hot stamped one by one onto the hot stamping positions on the strip box, which can achieve high-speed hot stamping and maximize the saving of aluminum foil film.
However, due to the requirements of the production process, the packaging strip box uses roll cardboard for gravure printing during production, and after large sheet cutting, flat sheet hot stamping, embossing, and die-cutting are carried out. Therefore, the layout process requires leaving a suction knife position. This results in the distance L2 between the hot stamping positions of adjacent anti-counterfeit marks AT1 and AT2 on the connected two strip box patterns being greater than the distance L1 between the two hot stamping positions on the same strip box. As a result, the anti-counterfeit marks on the aluminum foil film cannot be arranged equally. Whether it is continuous hot stamping or single hot stamping according to the hot stamping position on the strip box, it will cause a lot of waste of aluminum foil film. The re technical transformation of the entire production equipment will lead to the production of the entire set. The cost is too high.
For this purpose, the product adopts multi-point non equidistant pattern one-time positioning hot stamping technology, including redesigning and producing parameters such as the layout of the packaging paper box, the corresponding positioning cursor and anti-counterfeiting mark settings on the aluminum foil, and the jumping distance of the aluminum foil. The schematic diagram of the aluminum foil jumping of the product is shown in Figure 6. Through mass production verification, this technology has made minimal changes to the original production process and achieved one-time positioning and hot stamping of multi splicing, multi-point, and non equidistant patterns on the basis of minimizing the waste of electrolytic aluminum. The holographic positioning is accurate, the production continuity is good, and the production efficiency is high.
Figure 6 Schematic diagram of aluminum electrolysis separation
In summary, through the calculation and research of the positioning cursor distance for flat and non equidistant one-time positioning hot stamping aluminum foil, the correct cursor distance and arrangement method have been found. A specialized positioning hot stamping aluminum foil has been produced and tested on a flat and non equidistant hot stamping equipment, and corresponding control techniques, parameters, and methods have been identified. After testing, it was found that the flat and non equidistant one-time positioning hot stamping pattern is accurately positioned, with a pattern deviation of ≤ 0.2mm; there are no sand defects, bubble points, or sticking phenomena in the hot stamping.
This method effectively solves the technical problem of flat and flat multi-point non equidistant one-time positioning hot stamping process, and realizes the mass production of multi-point non equidistant one-time positioning hot stamping (red cat eye positioning electrochemical aluminum) technology under the normal splicing mode of "Yuxi (hard)" upgraded version strip box 4-pack. Compared with the two time positioning hot stamping process, its production efficiency has been improved by nearly twice.