In the lingerie market, people’s demand for seamless comfort is gradually rising, and the emergence of seamless bra, with its easy to match and comfortable features, is loved by the majority of consumers, and quickly become one of the mainstream products. This article will lead you to understand how seamless bra is made? Explore the process behind seamless bras.

What is a seamless bra？

Seamless bras are mainly made of one-piece technology, that is, the cup, underband, side wings and other parts are made of one piece of fabric through advanced weaving technology. Basically, no metal decorations are used. This design reduces friction and discomfort.

Seamless bra production process

1.Yarn Selection

The first step is to choose the right yarn, which is related to the comfort of seamless bras. Choosing the right yarn can make the product fit better, more elastic, and better support. The most commonly used materials are nylon and spandex, or a blend of the two.

When choosing yarn, you need to pay attention to the following core requirements:

1.To keep the finished product from deforming easily, it is necessary to maintain good elasticity. It is recommended that it must contain spandex. The spandex content is usually between 15%-30% to ensure that the fabric has a transverse stretch rate of 40%-60% and a longitudinal rebound rate of ≥90%.

2.There are also requirements for the fineness and strength of the yarn. When using high-speed weaving equipment, it can avoid yarn breakage caused by insufficient tension.

For example: Santoni models usually use yarn fineness of 18-50tex (corresponding to British count 32s-12s). Finer yarns (such as 32s cotton yarn) can weave more delicate fabrics, but they need to be matched with spandex to enhance toughness.

3.Heat resistance and pressure resistance. The hot pressing shaping process used in the production of seamless bras usually reaches a high temperature environment of 160-200 degrees. The yarn must be able to withstand high temperature environments without deformation or fading.

2.Weaving technology

The heat pressing process used in seamless bras is different from the sewing process used in traditional bras in that there is no need to sew multiple pieces of fabric together because seamless bras are made using whole-piece knitting techniques.

The entire cup, underband, and side wings are knitted by the machine at one time. Different knitting methods can be added to different areas according to functionality. For example, if better support is needed, dense knitting can be used.

3.Laser cutting

Laser cutting allows fabric segmentation through zero contact. It is based on the principle that by irradiating the fabric with a laser beam of high energy density, the fabric surface absorbs the laser energy and melts or vaporizes to form the cut. Such a process ensures that the cut edges are not easily stripped.

4.Hot press molding

Hot pressing is the process of placing a piece of fabric in a suitable mold and using high temperature and pressure to make the fabric take shape in the mold.

Specific Steps:

After the fabric is cut, the edges are sealed by heat (not sewn).

Subsequently, the fabric piece is placed in the mold with the sponge pad, softened by heat, and pressure is applied in the mold, causing the fabric to be shaped in the abrasive tool, after which it is cooled and shaped while maintaining the pressure.

5.Bonding technology

The shoulder straps and back buckles are bonded by ultrasonic technology, replacing traditional sewing, reducing thread ends and making the appearance more concise.

Its working principle is to generate heat through high-frequency vibration friction, so that the fabrics are partially fused and bonded together.

6.Quality inspection

After production is completed, focus on checking whether there are broken lines and indentations on the surface, whether the overall elasticity meets expectations, whether the size is accurate, and whether the hot pressing molding is symmetrical. If everything is intact, it can be packaged and shipped to the target customer.

Core advantages of the seamless bra production process

High production efficiency

Seamless bras use a hot pressing process, which requires fewer steps than traditional sewing, greatly saving labor costs and production cycles. At the same time, the one-piece process can reduce fabric waste.

High comfort value

There is no traditional sewing process of stitching line, reducing the friction on the skin, which is friendly to people with sensitive skin.

Invisible

It doesn’t leave any traces on the body. This style is perfect for tight clothes and fulfills the modern girl’s need for an “invisible styling”.

Functionality

Through a special process, encrypted knitting at the lower circumference and side flanks to enhance support, enabling better support for the chest.

Conclusion:

The craftsmanship of seamless bras has been recognized by many buyers, which not only demonstrates the level of modern underwear manufacturing, but also meets the market’s multiple demands for comfort, invisibility, and functionality. We have multiple seamless machines and 20 years of underwear production experience, supporting ODM and OEM customization. Whether you need a basic style, sports style, or a seamless bra with functionality, contact us now to get underwear customization services and start your business.