Manufacturing Process of Stainless Steel Vacuum Insulated Bottles

Stainless steel vacuum insulated bottles are made of double-layered stainless steel, evacuating the air between the inner liner and the outer shell to achieve the vacuum insulation effect.

The process of making a vacuum insulated bottle includes the production of the outer shell, the production of the inner liner, the assembly and welding, the evacuation and the decoration.

Manufacture outer bottle

Pipe cutting: Cutting the raw stainless steel tube to the right length.

Press-welding seams: To prevent breakage of the bottle.

Expansion: Forming the stainless steel into the shape of a bottle. There are basically two different methods: water expansion and stretching.

Shaping: A large press is used to ensure that the outer bottle is pitted, sized and shaped as required.

Necking: Use a machine to squeeze the upside of the bottle into the neck.

Cleaning: Removing lubricants and dust during molding.

Inspection: Check that the shell is up to scratch and that any pits and dents are knocked flat until they meet the requirements.

Manufacture inner bottle

The production process is similar, with differences in the expansion process.

Pipe cutting: Cutting the raw stainless steel tube to the right length.

Press-welding seams: To prevent breakage of the bottle.

Expansion: Forming the stainless steel into the shape of a bottle. There are basically two different methods: water expansion and stretching.

Shaping: A large press is used to ensure that the outer bottle is pitted, sized and shaped as required.

Necking: Use a machine to squeeze the upside of the bottle into the neck.

Cleaning: Removing lubricants and dust during molding.

Inspection: check that the shell is up to scratch and that any pits and dents are knocked flat until they meet the requirements.

Assembly

Assembling (bottle mouth matching)

Assemble the inner and outer bottles together by means of a press.

Bottle bottom assembly

Assembling the bottom to the bottle by means of a press.

Assembly (bottle mouth welding)

Weld the inner and outer bottles together in preparation for vacuum insulation. Ensure flatness and no bumps or solder joints.

Assembly (bottle bottom welding)

Weld the outer bottle to the bottom of the bottle in preparation for vacuum insulation. Ensure flatness and no bumps or weld joints.

Spot welding of aspirator in the centre bottom 

Spot weld the absorbent inside the centre bottom. The spot welded absorbent must be de-vacuumed within 24 hours or it will be ineffective.

Vacuuming

Extraction of excess air between the two cup walls through the bottom.

Leak test

Check that the inner and outer bottles are well welded.

Temperature test / insulation test

Blow hot air into each bottle. If the outside of the bottle stays cool, it means that the heat from the hot air is not transferred and that the bottle is vacuum insulated. Conversely, if the bottle becomes hot, there is a problem with the vacuum insulation.

Electrolytic polishing

The interaction between the electric current and the electrolyte improves the microscopic geometry of the metal surface and reduces the surface roughness of the metal, resulting in a bright and smooth surface of the stainless steel bottle. The surface of the inner bottle is bright and even, without watermarks and yellow spots.

Mechanical polishing

Polish the surface of the outer bottle insure it is smooth and the mouth of the bottle is smooth and shiny. No obvious brushing, scratching, black wire and pockmark.

Cleaning

Clean and dry the bottle. Make the bottle ready for external coating/decoration.

External coating (painting)

Bottles can now be externally coated - powder coated or painted.

Pattern and logo printing

Print graphic designs and logos on bottles using a variety of techniques - screen printing, heat transfer, water transfer, laser etching, etc.

Packaging inspection

After checking each bottle, including a visual inspection and cap leak test, the bottles are placed in an individual bag for packaging.