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Manufacturing Process of Vacuum Insulated Stainless Steel Bottles

Many people are curious and want to know how vacuum insulated water bottles are made. Here we will show you the manufacturing process of vacuum insulated stainless steel water bottles step by step in detail to help you understand.

Principle of Thermal Insulation

The vacuum insulated stainless steel bottle is generally a container made of stainless steel and a vacuum structure. The vacuum insulation structure can delay the heat dissipation of the liquid such as water inside to achieve the purpose of heat preservation. Most of the inner walls are made of stainless steel with silver or copper plated. The shiny wall can reflect the radiation of hot water. The vacuum structure can block the heat transfer, thus preventing heat convection and achieve the effect of insulation. This is why insulated water bottles can keep the beverage hot or cold for a long time.

Raw Material

The material used to make insulated water bottles is stainless steel, which forms the inner bottle and the outer bottle. SUS304 (18 / 8 food grade stainless steel) is the most widely used as stainless steel, and is used in food equipment, general chemical equipment, atomic energy industry, etc. SUS304 is corrosion resistance, heat resistance, low temperature strength and good mechanical properties. SUS304 using temperature: -196 to 800 °C.

Manufacturing Process

Brief description: Stainless steel arrives at the factory in the form of pines and sheets –> Produce outer bottle and inner bottle –> Assembly and welding –> Vacuuming –> Decorating.

Vacuum Insulated Stainless Steel Bottle Manufacturing Process Chart:

Vacuum Insulated Stainless Steel Bottle Manufacturing Process Chart

1. Manufacture Outer Bottle

1.1 Pipe cutting: Cut raw material – stainless steel pipe – to the appropriate length.

pipe cutting process video

1.2 Expansion
There are basically two different ways to make stainless steel into the shape of a bottle: water expansion and stretching.

Water Expansion: Stainless steel pipes are raw material for this method. First, stainless steel pipe is put on the water expansion machine. The pipe swells into a bottle shape under the huge pressure of the water. With this method, the bottle formed is with no bottom, so a round stainless steel plate will be welded onto it to form a complete bottle.

water expansion process video

Stretch: Stainless steel sheets are raw material for this method. First, the stainless steel sheets are cut into round plates at appropriate size, and then we use a punch press to stretch the stainless steel plate into a cylinder with a bottom.
The outer bottle can be formed by any of these two methods. Water expansion is more popular.

1.3 Separating: If using water expansion process to form outer bottle, then separating process is a must.

separating process video

1.4 Shaping: Use a large press and follow the “Bottle Shaping Guide” to ensure that the pits, size and shape of the outer bottle meet the requirements.

shaping process video

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

necking process video

1.6 Thread Rolling/Making: Threads are made with a special threading machine. Ensure that the thread meets requirements.

thread making process video

1.7 Cleaning: Removes lubricating oil and dust during molding.
1.8 Inspection

2. Manufacture Inner Bottle

2.1 Pipe cutting: Cut raw material – stainless steel pipe – to the appropriate length.
2.2 Expansion. Water expansion or stretch. The inner bottle can be formed by any of these two methods. Water expansion is more popular.
2.3 Separating
2.4 Shaping
2.5 Necking
2.6 Thread Rolling/Making (Normally if outer bottle is designed with thread, there’s no thread on inner bottle)
2.7 Cleaning
2.8 Inspection

3. Assembly (Bottle Mouth Matching)

Assemble the inner bottle and the outer bottle together by pressing machine.

inner bottle and outer bottle assembly process video

4. Bottle Bottom Assembly

Assemble the bottom to the bottle by pressing machine.

bottle bottom assembly process video

5. Assembly (Bottle Mouth Welding)

Weld the inner bottle and outer bottle together to prepare for vacuum insulation. Ensure smoothness, no bumps or solder joints.

bottle mouth welding process video

6. Assembly (Bottle Bottom Welding)

Weld the outer bottle and the bottle bottom to prepare for vacuum insulation. Ensure smoothness, no bumps or solder joints.

bottle bottom welding process video

7. Leaking Test

Check whether inner bottle and outer bottle were well welded.

8. Vacuuming

Vacuuming with a vacuum machine.

9. Temperature Test / Insulation Test

Blow hot air into each bottle. If the outside of the bottle is kept cool, it means that the heat from the hot air will not be diverted and the bottle is vacuum insulated. On the contrary, if the bottle gets hot, there is a problem with vacuum insulation.

10. Electrolysis Polishing

Through the interaction of current and electrolyte to improve the micro-geometry of the metal surface, reduce the surface roughness of the metal, so as to achieve the purpose of bright and smooth surface of the stainless steel bottle. Surface of inner bottle to be bright and even, no watermark, yellow dot.

11. Mechanical Polishing

Polish the surface of outer bottle to ensure it is smooth and bottle mouth is smooth and bright. There must be no obvious drawing, scratching, black wire and pits.

mechanical polishing process video

12. Cleaning

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

13. Temperature Test / Insulation Test

Blow hot air into each bottle. If the outside of the bottle is kept cool, it means that the heat from the hot air will not be diverted and the bottle is vacuum insulated. On the contrary, if the bottle gets hot, there is a problem with vacuum insulation.

14. External Coating

The bottle is now ready for external coating –powder coating or spray painting. KingStar is capable of doing both spray printing and powder coating process.

spray painting process video

powder coating process video

15. Pattern and Logo Printing

Print the pattern design and logo on the bottle with various techniques – screen printing, thermal transfer printing, water transfer printing, laser etching and so on.

16. Temperature Test / Insulation Test

Blow hot air into each bottle. If the outside of the bottle is kept cool, it means that the heat from the hot air will not be diverted and the bottle is vacuum insulated. On the contrary, if the bottle gets hot, there is a problem with vacuum insulation.

17. Packing

After inspect each bottle, including visual inspection and lid leak test, the bottle is place in a separate bag for packaging.

Bottle Cap / Lid

Unlike bottles, most of the caps of vacuum insulated stainless steel water bottles are usually made of plastic.

Sometimes the inside of the cap is made of plastic and the outside is wrapped in stainless steel. It is made by pressing a piece of stainless steel onto an injection molded plastic. KingStar has an all stainless steel cap option as well.

If you want to get more videos of vacuum insulated stainless steel container manufacturing, just contact us. We will be more than happy to share with you.

All the videos in this article were took in 2010. It is not good to show the latest product equipment on internet due to well-known reason. The equipment in the video were previous generation devices. You are welcome to visit our factory and our latest and most advanced production equipment and production process. Now our production line is more artificial intelligent, more automated, cleaner and better organized.

KingStar is a professional vacuum insulated water bottle manufacturer. We focus on developing and manufacturing high quality vacuum insulated water bottles, flaskstumblers, coffee mugs, coffee pots, coffee jugs, beer pints, growlers, food jars and other insulated containers that aim at keeping liquids hot or cold for long hours.