1. Material selection: Because underwear is in direct contact with the skin, it is usually considered from the aspects of whether there are harmful components, hygroscopicity, antistatic property, touch to the skin, perspiration fastness and washing fastness of dyes, elasticity and strength of fabrics, etc.

2. Sticking cloth: Sticking cloth means sticking cloth and sponge together with adhesive. The surface of the cloth after pasting must be smooth, and the adhesives and solvents harmful to human body, such as those containing formaldehyde and acetone, cannot be used in the process of pasting the cloth, otherwise these components will affect human health if they remain in the cloth.

3. Cutting: Generally, typesetting first and then cutting. Pay attention to the grain of the fabric when typesetting, and arrange it reasonably according to its performance. If the grain direction of the left and right pieces is different, the elasticity of the left and right back pieces of the finished product will be different, and the tightness of both sides will be different when wearing; In the process of sewing, there will also be different sizes, which will affect the appearance. Generally, a long shoulder strap is cut to a certain length as required, then the shoulder strap buckle is put on and sewn with a single needle zigzag sewing machine. Or sewing with a binding machine; In the use of the invisible shoulder strap, we must ensure that it has considerable elasticity and sufficient strength to prevent it from breaking and falling off. At the same time, pay attention to the selection of appropriate needles in the sewing process to prevent the glue line from sticking out.