The surface treatment technology for stainless steel vacuum flasks primarily revolves around two main goals: basic protection and decorative enhancement. The diagram below clearly illustrates the complete process flow from basic treatment to final decoration:

Detailed Explanation of Each Process Step

1. Surface Pre-treatment: The Critical First Step

This step lays the foundation for subsequent coatings, determining the adhesion and final effect of the coating.

Cleaning and Inspection: This is the crucial first step. Ultrasonic cleaning equipment is required to thoroughly remove oil stains, and cup bodies with smooth, defect-free surfaces are selected.

Polishing: The purpose is to obtain a smooth metal surface. The industry is upgrading from traditional sandbelt manual polishing to fully automatic, multi-station continuous polishing technology. This new technology offers high efficiency, stable quality, and significantly reduces dust pollution during production.

2. Coating and Decoration: The Core of Appearance and Function

This is the core stage for forming the final appearance and feel, involving a wide variety of techniques.

Primer and Baking Paint:

Traditionally, oil-based baking paint was often used, but its high volatile organic compound (VOC) content makes it less environmentally friendly and it may face restrictions in the future.

The trend is towards using water-based amino baking paint. This type of paint offers better performance in terms of adhesion, resistance to alcohol wiping, and high-temperature resistance (e.g., boiling water disinfection), and is also more environmentally friendly.

Special Coatings:

Ceramic Coating: Mainly composed of silicon dioxide (SiO₂), it is formed through high-temperature sintering (e.g., 850°C). It offers a glassy luster, high hardness, thermal shock resistance, and corrosion resistance, making it a high-performance surface treatment solution.

Functional Coatings: These include hydrophobic coatings (which prevent water droplets from adhering, making cleaning easier) and thermochromic paint layers (which become transparent when heated, revealing underlying patterns, adding an element of fun).

3. Emerging and Specialty Processes

Artistic Effect Treatment: To achieve unique, random artistic effects like marble patterns, craftsmen first manually apply colorants to the cup surface. Then, they use water from a tap at a specific pressure to create natural patterns, followed by baking for curing.

Emerging Polishing Technologies: Such as plasma nano polishing, a more precise surface treatment technology for which the industry has begun developing group technical specifications.

Selection Suggestions

For different scenarios, you can choose the corresponding process based on your priorities:

Prioritizing Durability and Classic Texture: Choose a cup with a ceramic coating process, as it offers high hardness and is more wear-resistant.

Focusing on Environmental Friendliness and Durability Combined: Look for products using the water-based baking paint process.

Preferring Unique Personality and Artistic Sense: You can choose styles with special artistic effects like marble patterns.

Valuing Fun Interaction: You can try a cup with a thermochromic function.

In summary, the external surface treatment of modern vacuum flasks has evolved into a comprehensive technology integrating materials science, precision manufacturing, and creative design.