In recent years, as competition in the tobacco industry has become fiercer and external pressure from tobacco control has increased, people’s aesthetic standards have also risen. This has led to higher expectations for the quality of cigarette packaging, pushing the design and production of cigarette packs to continuously evolve. To better reflect brand personality and achieve unique visual effects, the use of combined printing processes has become more widespread in cigarette packaging.
One example is the "Seven Wolves" (blue) cigarette pack produced by a company, which employs a complex combination of six key printing techniques: offset printing, gravure printing, hot stamping, UV offset printing, pressure embossing, and die cutting. The specific production sequence is as follows: first, three-color blue is printed via standard offset; then, silver text is added using sheet-fed gravure; followed by hot stamping with a silver background; next, two-tone gradient blue is applied through UV offset printing, along with water-based varnish; after that, pressure embossing is performed to create a raised effect; finally, the outer frame of the Seven Wolves logo is embossed with concave-convex hot stamping, and the final step is die cutting.
This article will focus on the seven main steps in this combined process, discussing key quality control points and sharing insights with colleagues.
1. **Standard Offset Printing (Three-Color Blue)**
The three colors used here—shading blue, gradient blue, and dark blue—are challenging to control due to their sensitivity to color variation. Ink color must be kept within ±1.5 ΔE, while issues like ink skin, water splash, scratches, and powder fall should be carefully monitored. Since the surface is not glazed at this stage, the ink tends to turn red when dry. A spectrophotometer is used to measure L, a, and b values to track color changes. Sufficient drying time is essential to prevent problems like nozzle imprinting in later stages.
2. **Sheet-Fed Gravure (Silver Text)**
Gravure printing involves high plate-making costs and the use of toluene-based inks, which are harmful to both the environment and health. During this process, solvents such as slow-drying agents may be added to improve ink performance, but volatile solvents like isopropyl alcohol or n-butanol are strictly prohibited. Proper ventilation is required in the printing area. Operators must monitor ink viscosity, text clarity, and ink consistency across color groups to maintain stable print quality.
3. **Hot Stamping (Silver Background)**
Key factors to monitor include registration accuracy, color stability, and the strength of the silver base. High temperatures can cause discoloration, and incomplete stamping or scalding must be avoided. Pressure should be moderate to prevent damage to the UV offset printing layer. Hot stamping fastness is crucial, as poor adhesion can lead to ink pulling during subsequent steps, causing image loss and damaging equipment.
4. **UV Offset Printing + Water-Based Varnish**
During UV printing, issues like ink drawing, incomplete graphics, and false printing should be prevented. Varnish application must be balanced to avoid scratches or nozzle marks. The ink color from the initial offset printing may shift toward blue or yellow after glazing, so strict control is necessary to minimize color fluctuations.
5. **Pressure Embossing**
When embossing the wolf logo, pressure should be controlled to avoid line bursting. Alignment between the embossing plate and the mold is critical to ensure a clean, consistent result.
6. **Concavo-Convex Hot Stamping (Outer Frame of Logo)**
This step is one of the most complex in the process. Common issues include jagged edges and ink pulling. To reduce these, temperature and pressure must be adjusted, and anodized aluminum should be allowed to rest before stamping. Ensuring strong adhesion of the silver base is key to preventing ink from being pulled off during hot stamping.
7. **Die Cutting**
Final checks should focus on edge smoothness, indentation pressure, die-cutting precision, and registration accuracy to ensure a clean, professional finish.
By understanding the strengths and weaknesses of each technique, companies can develop effective quality control systems, streamline operations, and apply quality management tools to meet the evolving demands of the cigarette packaging industry.
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Yiwu Shengshang Stationery Co., Ltd. , https://www.ss-stationery.com