Factory Insights: Manufacturing of Rang Dong’s Vacuum Flasks

From glass melting to the final stage of assembly, the production of high-quality vacuum flasks involves more than just assembling metal and glass. It is a meticulous process requiring advanced technology and skilled labor. Rang Dong, Vietnam’s leading manufacturer of vacuum flask products, has developed a comprehensive eight-step process from mixing raw materials to quality inspection and packaging. The following article explores insights of the company’s manufacturing process. 

Rang Dong has been exporting vacuum flasks to more than 30 countries and territories. 

Producing vacuum flasks that meets international quality standards and which has won the mind and heart of consumers in some 30 import destination countries requires a precise and efficient workflow.  

The eight production steps have been designed to guarantee that every flask delivers excellent thermal performance, durability and safety for daily use. 

Step 1. Mixing Raw Materials 

It begins with carefully weighing and mixing raw materials to produce the inner glass liner, the core of a vacuum flask. The materials include high-purity silica sand, borax, soda ash and some other additives.  

The exact formulation determines the durability, transparency and thermal efficiency of the final product. 

Step 2: Glass Melting 

The raw material mix is heated in a glass furnace at temperatures exceeding 1,300 degrees Celsius (2,372 degrees Fahrenheit) to become a homogeneous, molten glass. The resulting glass is ready to be molded into the inner component of the vacuum flask. 

Step 3: Outer Flask Processing 

While the inner liner is being prepared, the outer stainless steel or plastic body of the flask is also manufactured. This involves cutting, shaping, and surface finishing. Depending on the model, this body may include powder coating or laser-etched branding, ensuring both style and function. 

Step 4: Quality Check and Storage of Outer Flasks  

Each outer flask is inspected for shape accuracy, material defects and finish quality. Once approved, the components are stored in the warehouse until ready for final assembly. 

Step 5: Inner Flask Processing 

The molten glass from Step 2 is formed into glass liners, which are then silvered or aluminized to create the reflective inner surface needed for thermal insulation. A vacuum is created between the inner and outer walls, forming the core of the vacuum flask’s heat retention capability. 

Step 6: Quality Check and Storage of Inner Flasks  

Each inner flask undergoes vacuum integrity testing and thermal insulation assessment. Flasks meeting Rang Dong’s standards are stored for final product assembly. 

Step 7: Final Assembly  

At this stage, the inner glass liner is carefully placed inside the outer body. The components are sealed, assembled with lids, bases and accessories.  

A tight seal is placed to preserve the vacuum layer so the flask can perform at its best.