In a garment production, stitch length can appear to be a minute, specialized setting, but it may have significant impacts on seam strength, look, manufacturing time, and the theme of the thread used. The selection of the appropriate stitch length benefits in improving garment quality, balancing strength with manufacturing costs, and ensuring uniform quality across garments by manufacturers.
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Understanding Stitch Length
The distance between each of the stitches of a sewn seam is its stitch length. Usually it is measured in millimeters or stitches per inch (SPI). Longer stitches are fewer in number per seam length, and shorter stitches are more in number per seam length.
Several factors will determine the correct stitch length, namely the type of fabric, the kind of garment, the size of thread, the type of seam, and how the seam will be used.
Stitch Length and Seam Strength
The length of the stitch will directly impact the way the forces are spread out over a seam. A shorter stitch will result in more points of thread engagement that may be helpful in spreading tension across the seam. This may be beneficial to locations that are subjected to a lot of changing or tension.
A short stitch will result in the length of the needle creating more perforations in the fabric. In light or fine fabrics, care needs to be taken to not over-dye to weaken the fabric and generate a risk of tearing.
Longer stitches have fewer needle penetrations and can help to maintain the integrity of the fabric. If the stitches are too spaced apart, however, then there is less of a “lock” on the seams, which can lead to less seam security.
As a result, it’s not a matter of increasing or decreasing the density of stitches, but rather trying to find the optimum amount of stitches.
Impact on Thread Consumption
The feed rate also directly impacts thread consumption. The shorter the stitches, the more stitches are needed to obtain any given length of seam, and thus the more thread will be used.
If the manufacturer changed the stitch length from 3 mm to 2 mm, for example, the machine will produce four times as many stitches covering the same length. Thus, the needle and bobbin thread can be used in more quantity.
The longer the stitch, the less thread will be used due to fewer stitches being made along the seam. A few drops in thread per garment can be impactful for large quantities of garments.
But it is important to not sacrifice seam quality for thread reductions. Too much stitch will have poor seam integrity, aesthetics, or durability.
Stitch Length and Garment Appearance
Another visual factor to take into account is stitch length. The uniform spacing of stitches leads to an elegant and professional look, especially visible seams like collars, cuffs, pockets, waistbands, and decorative sewing (trilobal polyester thread).
Finer stitches can create a finer look and can be used on lighter fabrics or intricate designs. Sometimes longer stitches might create a more dramatic look and be suitable for thicker textiles or overalls.
When the length of the stitches in a seam is inconsistent, it can give the garment a poor start even if it still achieves acceptable strength.
Fabric Type Matters
Adjust the length of the stitches according to fabric. Lightweight fabrics might need careful handling to avoid puckering, perforated control, and hole damage. More massive materials may allow for longer and stronger stitches, contingent on the structure.
Some fabrics will need to be specially considered for the stretch, like fabric, as it requires some attention, since the seam must be able to move, not simply tear a piece of fabric or break the thread.
The stitch length should always be determined in conjunction with the thread, size of needle, tension set on the machine, and the tension of the thread used in the machine assembly.
Balancing Quality and Cost
Garment manufacturers, on the other hand, are not solely paying attention to maximizing seam strength or lowering thread usage. Instead, the goal is to achieve the required performance using an efficient amount of thread.
The more practical approach is to test various stitch lengths and assess:
- Seam strength and seam slippage
- Thread consumption per garment
- Fabric damage and needle penetration
- Seam appearance and consistency
- Puckering and distortion
- Sewing speed and machine performance
- Resistance to washing and repeated wear
These tests are used to determine suitable sewing specifications for every garment style by the manufacturers.
The Role of Thread Selection
As well, the stitch length behaves differently in production, depending upon how it is constructed. Other strengths, elongation, and resistance to abrasion, heat (flame-resistant sewing thread) and sewing characteristics can occur among spun, filament, and core-spun threads.
By using a high-performance thread and a suitable stitch length, manufacturers can get long-lasting seams with the least thread possible. Correct threads can also help to minimize breaks, rework, and production stoppages.
Finding the Right Balance
The final decision on the stitch length is a combination of seam strength, seam appearance, durability, and evaluation of thread use efficiency. Shorter stitches can lead to more stitches and more thread used; too long of stitches can decrease the security of the seam or the look of the garment.
Different kinds of stitches offer various quality benefits and costs for specific end-use applications and can be customized for a variety of fabrics, seams, threads, and garment configurations. What appears to be a simple machine setting can therefore have a significant impact on both the performance and economics of garment production.
