Manufacturing Process

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 of Insulated Water Bottles

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.

Vacuum Insulated Stainless Steel Bottle Tumbler 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:

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

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.

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.

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.

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

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

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.

4. Bottle Bottom Assembly
Assemble the bottom to the bottle by pressing machine.

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.

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.

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.

To read more about stainless steel drink bottle powder coating process, please check another article: Insulated Stainless Steel Bottle Manufacturing – Powder Coating Process

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 Manufacturing

Unlike vacuum flasks, most of the caps of vacuum insulated stainless steel drink 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. Anhui YOTO 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.

Anhui YOTO is a professional vacuum insulated water bottle manufacturer. We focus on developing and manufacturing high quality custom vacuum insulated water bottles, wholesale vacuum flasks, bulk tumblers, coffee mugs, thermos coffee cups, blank coffee jugs, beer pints, growlers, food jars, wholesale lunch boxes, dog bowls, and other insulated containers that aim at keeping liquids hot or cold for long hours. Anhui YOTO offers one-stop custom stainless steel container vessel / private label drinkware manufacturing service from product idea, design, prototype, molding, to mass production. Have questions or need help? Just contact us at any time, we would like to send you our latest full catalogue offer you prefessional help.