Chain Stitch
Single chain stitch
Multi-thread chain stitch
The chain stitch, often referred to as a "single-thread chain stitch" in the professional field, is fundamentally different from the traditional lock stitch in its formation mechanism. It is formed by a single thread (needle thread) through the precise coordination of a needle and a looper (looper). When the needle, carrying the thread, penetrates the fabric to its lowest point and then rises, a loop is formed near the needle hole. Immediately thereafter, the looper precisely picks up this loop and, as the machine rotates, interlocks it with the next newly formed loop. The result is a chain-like stitch on the front of the sewing material, while on the back, without a dedicated thread-retracting device, it typically appears as a continuous straight line.
- Feature
I. High elasticity and ductility. Because the stitch itself is composed of a series of interlocking loops, it can stretch significantly under external force and return to its original shape when the force is removed. This makes it ideal for applications that require movement or the natural expansion and contraction of fabrics.
II. High efficiency and adaptability to high speeds. The single-thread system reduces thread changes and creates less resistance during stitch formation, allowing the sewing machine to run at extremely high speeds, significantly improving production efficiency.
III. Stitch fullness and decorative potential. Chain stitches are generally fuller and more three-dimensional than equivalent lock stitch, providing an excellent foundation for decorative sewing.
- Application
Joining knitwear and stretch fabrics: This is the most classic application of chain stitch. Fabric elasticity is crucial in knitwear like T-shirts, sportswear, underwear, and sweaters.
Hems and Cuffs: Chain stitch is often used to create stretch seams on hems and cuffs, achieving smooth coverage without restricting the fabric's natural elasticity, ensuring comfort.
Temporary Fixing and Basting: In custom haute couture or complex production processes, chain stitch is often used for basting or false seams to temporarily secure multiple layers of fabric or lining, facilitating subsequent finishing.
Decorative Stitches and Appliqués: Leveraging its rich, full-bodied nature, chain stitch can be used to create decorative stripes with a three-dimensional effect. In embroidery, particularly on fabrics like terry and terry, chain stitch creates rich, prominent patterns and is widely used on homewear, towels, and hats.
Product packaging and bag sewing: In some industrial packaging fields, such as the sealing of cement bags and grain bags, strong chain stitches are often used to achieve fast and reliable sealing.
Lock Stitch
Lock stitch
The lock stitch relies on the precise coordination of the sewing machine's bobbin and bobbin case. The upper thread passes through the needle, while the lower thread originates from the bobbin. Once the needle drives the upper thread through the material, the rotary or oscillating hook mechanism captures the upper thread and wraps it around the bobbin and bobbin case, creating a tight "locking" structure. This interwoven stitch creates a remarkably similar, almost indistinguishable seam on both sides of the material.
The most significant advantage of the lock stitch is its exceptional structural stability and security. Because each loop of needle and thread is securely locked, even if a partial thread breakage occurs, the entire seam will not unravel, greatly ensuring product durability. Furthermore, the lock stitch exhibits minimal stretch, effectively preventing wrinkling during sewing and ensuring smooth, aesthetically pleasing seams.
- Application
Garment sewing: This department handles routine processes such as seaming and overlocking, accounting for over 75% of total garment sewing output.
Specialized Equipment: Buttonhole machines create buttonholes using densely arranged lock stitch. This stitch is standard on lock stitch machines for conventional sewing.
Fabric Compatibility: Suitable for low-elasticity fabrics such as cotton and chemical fibers. Knitted fabrics require the use of elastic thread.