Pipe Picking: Rolls of stainless steel sheets are first selected according to the specific requirements of the thermos cup size. These sheets are then fed into a pipe-making machine.

Pipe Cutting: The formed stainless steel pipes are cut into appropriate lengths using precision cutting equipment. This step requires high accuracy to ensure that each section of the pipe is of the correct size for the subsequent manufacturing process.

Water Expansion: The cut pipes are subjected to water expansion. In this process, water is injected into the pipes under high pressure, causing the pipes to expand and take on the desired shape. This helps to form the basic shape of the outer shell of the thermos cup.

Segmentation: The expanded pipes are then segmented into individual parts, each of which will become an outer shell. Precise cutting ensures that each segment has a uniform size and shape.

Bulging: Using a press machine, the segmented parts are further shaped through a bulging process. This gives the outer shell its characteristic curved shape, enhancing both its aesthetics and functionality.

Rolling Middle Angle: A lathe is used to roll the two corners at the concave shape of the bulged shell. This operation is crucial for ensuring a proper fit when assembling the various parts of the thermos cup.

Bottom Shrinking: The circular arc bottom opening of the bulged shell is shrunk to meet the required size. This is done using a lathe and is carefully controlled to ensure that the bottom of the outer shell is of the correct shape and size.

Bottom Cutting: The bottom opening of the shell that has been shrunk is cut to the standard size using a lathe. The cutting process must result in a smooth, even edge without any notches or burrs.

Reinforcement: The welding joint at the shell opening is flattened on a small press. This step is important as it ensures that the welding process in the later stage is smooth and even, without any skipping.

Flat Upper Mouth: The upper mouth of the outer shell is flattened using a lathe to ensure a uniform and smooth edge, which is essential for a proper seal with the lid.

Bottom Flushing: The bottom of the outer shell is flushed to remove any impurities or rough edges.

Flat Bottom Mouth: The bottom mouth of the outer shell is also flattened to meet the required standards, ensuring stability when the thermos cup is placed on a surface.

Cleaning and Drying: The processed outer shells are thoroughly cleaned to remove any oil, dust, or debris from the manufacturing process. They are then dried to ensure that no moisture remains, which could affect the subsequent processes.

Inspection and Pit Knocking: Each outer shell is carefully inspected for any defects, such as pits or dents. If any are found, they are knocked out to ensure that the outer shell is of high quality. Only those outer shells that pass this inspection are considered qualified for further processing.

Inner Pipe Picking: Similar to the outer shell, suitable stainless steel pipes are selected for the inner shell. These pipes are chosen based on their thickness and quality to ensure optimal heat retention.

Pipe Cutting: The inner pipes are cut into appropriate lengths using a precise cutting method.

Flat Pipe: One end of the cut pipe is flattened using an instrument, ensuring a smooth and even surface.

Bulging: The inner pipe is also subjected to a bulging process to give it the desired shape for the inner shell of the thermos cup.

Rolling the Angle: The corners of the bulged inner shell are rolled to meet the specific size requirements, similar to the outer shell process.

Flat Upper Mouth: The upper mouth of the inner shell is flattened to ensure a proper fit with the lid and to prevent any leakage.

Flat Bottom Mouth: The bottom mouth of the inner shell is flattened to provide stability and a proper seal when assembled with the bottom part.

Thread Rolling: A thread is rolled onto the upper part of the inner shell using a specialized thread - rolling machine. This thread is crucial for screwing on the lid tightly.

Cleaning and Drying: The inner shells are thoroughly cleaned and dried to remove any contaminants that could affect the quality of the final product.

Inspection and Pit Knocking: Each inner shell is inspected for defects, and any pits or dents are removed to ensure high - quality standards.

Butt Welding: The inner shell is butt - welded to the inner bottom part. This welding process requires high precision to ensure a leak - proof and strong connection.

Water Test and Leakage Detection: After welding, the inner shell is subjected to a water test. It is filled with water and checked for any leaks. This is a crucial step to ensure the integrity of the inner shell and its ability to hold liquid without leakage.

Drying: Once the water test is passed, the inner shell is dried to prepare it for the next stage of assembly. Only those inner shells that pass all these tests are considered qualified for further processing.