Seam grinning occurs when the fabric displays a gap or lift along a stitched seam due to stretch, pressing, or wearing the garment. Seam grinding is not just a cosmetic problem and can be connected to a mismatch between the thread, stitch, fabric, and/or sewing machine.
To avoid this, you must be careful in the selection of fabrics, threads, types of sewing machines, and their precisions, as well as in quality control.
What Causes Seam Grinning?
Sometimes the cloth and thread are not effective, and seam grinning results. The stitches may be pulled apart, becoming visible gaps between the points at which the needles went through the fabric when tension is applied across the seam.
Common causes include:
- Excessive thread tension
- Incorrect stitch length
- Inappropriate thread size
- Insufficient seam allowance
- Low fabric seam strength
- Poor stitch formation
- Incorrect needle selection
- Excessive fabric stretching during sewing
It’s crucial to know the exact cause, as rolling thread might not solve the problem if the problem is connected to fabric or machine setup.
Choose the Right Thread Size
The size of the thread will affect the quality of the widths and the way they will look and function. If the thread is too heavy for the quality of the knitting fabric, it can cause too much needle penetration and may affect the right stitch formation. On the other hand, a thin thread may not be strong enough for heavier cloths for seaming purposes.
When selecting a thread, remember to take into account:
- Fabric weight and construction
- Seam type
- Stitch density
- Garment end use
- Required seam strength
- Sewing machine capability
The goal is to have a balanced seam where the seam is performed properly without adding undue strain to the fabric.
Select the Appropriate Thread Construction
Depending on the thread construction, you may come to a different strength, flexibility, abrasion, heat resistance (meta-aramid sewing thread) and sewnability. If the clothes need to be moved often, then there is the possibility that if the elongation is suitable, it can provide room for linen flow and can minimize stress placed on the seam.
Thread should also work well and glide through the machine and needle with consistency when sewing at high speed for industrial sewing.
Control Thread Tension
One of the other significant factors responsible for seaming issues is incorrect threading. Too much tension may bunch up the fabric or create so much tension on the fabric that the stitch is too tight.
Balanced tension is created by the interlacing of the needle thread with the bobbin thread in such a way that all the threads meet in the center to provide an even stitching appearance.
Regular machine checks are to be done during the process to maintain the tension for production.
Optimize Stitch Length and Density
The length of a stitch will affect how a seam stretches when pulled. Very long stitches can cause larger openings between penetrations, and excessively short stitches can focus penetrations and cause weaker fabrics.
When sewing a seam, the correct length of stitch will vary by fabric, thread, method of stitching, and garment requirement. It is important to create appropriate stitch specifications for production teams by testing and not selecting a single setting for each and every material.
Match the Needle to the Fabric and Thread
Also, the quality of the seam might depend on the type of needles selected. It might cause either too many holes or may puncture the whole structure of the fabric if an improper needle size or point is used.
The choice of needle should be made so that the manufacturers know:
- Fabric type and weight
- Thread size
- Sewing operation
- Required stitch appearance
The right size needle facilitates clean penetrations and ensures quality and uniformity in stitch formation.
Maintain Consistent Sewing Conditions
Seam grinning may be caused by fabric handling during sewing. If the fabric is stretched or pulled through as it’s fed, the seam may be distorted, causing uneven stitch formation.
The feeding of the fabric should be kept constant, and operators should not place unnecessary strain on the fabric. Regular machine maintenance is also important to ensure that there are no issues with irregular stitching or worn and damaged components.
Test Before Production
Testing of garments before full-scale production is a useful method to determine potential seam-grinding issues that need to be addressed prior to going to production.
Testing should examine:
- Seam appearance under normal conditions
- Seam appearance when stretched
- Stitch formation
- Thread breakage
- Fabric damage
- Seam strength and recovery
It is more helpful to test just the fabric and the needle and not the different combinations alone.
Conclusion
The most important and key construction factors involved in the reduction of seam grinding are the selection of the threads, their compatibility with the fabrics, stitch construction, machine settings, and sewing technique. The right recycled sewing thread needs to have appropriate strength, bending, and sewing qualities without applying too much stress to the fabric.
Sewing machine manufacturers have achieved cleaner seams with reduced seam “grinding” by controlling the tension of the thread, selecting the appropriate needle size and type and thread size and length, and ensuring that the sewing conditions are standardized and using pre-production tests.