Three stamping processes reduced to one, effectively solving the production problem of diamond cigarette packs!

Ma GuangshengMa Guangsheng has worked in the cigarette packaging printing industry for 26 years, starting as an operator in offset printing, gravure printing, screen printing, die-cutting, and hot stamping, then moving into technical R&D, production scheduling, and quality management. He has taken initiative, leading the establishment of a "product cost accounting method based on the printing process," helping the company secure orders worth over 70 million yuan. He has also led multiple QC quality management and lean project task forces within the printing teams, carried out 12 QC quality management activities, and proposed over 100 rational suggestions. Innovatively seeking changes, he has implemented dozens of technical renovation projects within the company, obtaining one invention patent and four utility model patents. Skilled in summarizing and sharing knowledge, he has published over 60 articles in his spare time, organized and compiled training materials for internal process and technical training, actively playing a mentoring role.In recent years, with continuous advancements in science and technology and the tireless efforts of post-press equipment manufacturers, post-press equipment has developed significantly, with the emergence of dual-station hot stamping machines, fully clean scrap die-cutting machines, inline cylinder-to-cylinder hot stamping workstations, and other high-function, high-precision, high-speed, and easy-to-operate domestic equipment, providing strong technological support for cigarette packaging printing. Here, the author takes a dual-station hot stamping machine as an example to share the prominent role of new equipment and new technology in new product development and process improvements.Craft Features and Challenges of Diamond (Red Soft) Cigarette Packaging ProductsAt the end of 2010, through bidding, our company secured the production and processing order for Hebei Tobacco's Diamond (Red Soft) cigarette packages. Subsequently, process technicians conducted research and analysis on all aspects including material application, plate and die production, machine performance, selection of process parameters, and process sequence arrangement.01Product Process FeaturesThe outer pack material is 232g/m² laser transfer silverboard, and the inner pack material is 97g/m² laser transfer silverboard. Both use 5-color UV offset printing and UV coating. The subsequent processes include three stages of hot stamping (two stages of special anti-counterfeit stamping and one stage of holographic pseudo-position stamping), followed by embossing and die-cutting for the outer pack, and small sheet cutting for the inner pack.02Printing Process Technical Challenges(1) Due to hot stamping process limitations, inline UV coating cannot be used and coating can only be applied after the three hot stamping stages. Currently, if UV coating is applied before hot stamping, the brightness and smoothness of the UV varnish layer suitable for stamping do not meet the standards. Even if they meet the standards, the aluminum foil used for stamping must be specially made for UV-coated surfaces, substantially increasing cost, and the quality is unstable. Hence, the risk of applying inline UV coating prior to stamping is too high and infeasible.(2) The hot stamping process is complex, and significant moisture loss during stamping can cause various "complications."(3) To highlight the multi-layered holographic effect of the anti-counterfeit positional stamping, the cigarette factory requires that the anti-counterfeit positional pattern must be left uncoated (allowed overlay tolerance ±0.3 mm) during UV coating, increasing the difficulty of UV coating registration.Problems with Using Ordinary Hot Stamping EquipmentBased on past work experience, to facilitate stamping operations, we generally do not stamp two different types of aluminum foil on the same machine (except dual-station machines). If stamping both types of aluminum foil on the same machine, we must consider foil feeding and plate installation to prevent any conflicts, as well as the directionality of patterns and text on the special aluminum foil.

When starting the sample production, the metallized aluminum foil provided by the manufacturer could only be fed in a horizontal direction (machine drive side to operation side), suitable only for single foil stamping. Combined with the company's limited dual-station equipment and the heavy production tasks for other products that occupy equipment for long periods, we could only schedule the foil stamping process for this product on a conventional foil stamping machine in three separate passes. Although the appearance of the patterns stamped in all three passes was flawless, the overall product quality was not optimistic. The specific issues were as follows:(1) After the three passes of stamping, due to multiple high-temperature baking cycles and the extended processing period, the paper warped severely, directly affecting the registration accuracy of holographic anti-counterfeit patterns with UV varnish die-cut positions, reducing the yield. After sample production, statistical data showed that the actual yield was only about 70%.(2) The three passes used three different machines, resulting in high energy and labor costs, and a long processing cycle, which severely affected product delivery schedules.(3) The three passes used three machines; while producing cigarette cartons and small boxes simultaneously, six machines were occupied, disrupting the production plans of other products and affecting their delivery timelines.Even more serious, due to the long production cycle and repeated high-temperature stamping, the paper lost significant moisture and warped, causing misalignment of UV varnishing on cartons and small boxes; incorrect embossing on the cartons; small boxes failing foldability standards, causing breakage during tobacco factory packaging; and various degrees of curling and deformation in both cartons and small boxes, resulting in frequent packaging jams and poor formation during the factory process.Process Improvement Measures and Advantages of the Dual-Station Foil Stamping MachineTo address these quality issues, our process technicians re-evaluated the stamping process and promptly adjusted it, scheduling this product on a dual-station foil stamping machine to complete all three stamping operations in one pass. The specific plan and optimization effects are as follows:(1) According to the position of the stamping patterns, the feeding direction of the metallized foil during the stamping process was redesigned: the "Diamond Sun and Moon Pattern" and "Diamond Gold Floral Pattern" foils were changed from horizontal to vertical feed. Communication with the foil manufacturer was conducted to adjust the layout of these anti-counterfeit foils so that the pattern text would appear correctly in vertical feed. The stamping plates for these two foils were mounted on the same unit of the dual-station stamping machine to complete both patterns in one pass.(2) The "holographic anti-counterfeit registration stamping" requires an optical scanning head to read the "markers" beside each hologram for accurate registration. As all stamping equipment with registration systems, including the dual-station machine, use horizontal feed, this stamping was separately assigned to the other unit of the dual-station machine using horizontal feed.(3) By adjusting the process to arrange all three stamping operations on one dual-station foil stamping machine, we saved three conventional stamping machines, reducing energy consumption by ~30 kW/h per machine, saving two laborers per day, increasing foil stamping production efficiency threefold, thereby effectively ensuring product quality and delivery schedules.(4) After process adjustments, although the product's cartons and small boxes each used one dual-station unit, production efficiency substantially improved with shorter machine occupancy times, simultaneously saving six conventional stamping machines and ensuring timely delivery of other products.Re-sampling with the improved process, due to the shortened production cycle and stamping high-temperature baking times, problems like registration misalignment and insufficient foldability were resolved. The products passed the tobacco factory's trial packaging; energy and labor costs were greatly reduced, with a yield exceeding 95%, ensuring a reasonable profit margin. This order could increase the company's annual sales revenue by approximately 35 million yuan.As the saying goes, "To do a good job, one must first sharpen one's tools." To improve production efficiency and product quality and produce exquisite products, advanced supporting equipment, strong technical capabilities, and flexible application according to actual conditions are indispensable prerequisites.