Views: 0 Author: Site Editor Publish Time: 2021-04-30 Origin: Site
1. Serged or Stitched Seam
This is the standard method of stitching seams together for garments. The two fabric components are brought together and a simple overlock stitch holds them together.
This type leaves needle holes in the seam, through which liquids or dusts can penetrate. The holes will tend to open up under stress, so an ill fitting garment can result in more stress on seams and a greater likelihood of contamination.
Compare to 4 threads, 3 thread serged seams have a much longer stitch length and more likely to open up under stress. A 3 thread sewing machine is much cheaper, so lots of suppliers still adapt 3 thread overlock in garment production. Customers should pay attention to that while purchasing.
2. Bound Seam
An upgrade of a stitched seam. Still, suitable only for low hazard chemical protection.
ln this, an additional strip of fabric is wrapped around the"butt" join and stitched in place, which can add strength and reduce the tendency to allow penetration. Whilst an improvement on standard serged seams, it remains a stitched seam with needle holes, so it is not a sealed seam.
Usually, we do not recommend customers to choose this type, it costs more, but the protection level is much lower than taped seams.
3. Stitched & Taped Seam
Required for all garments for higher hazard chemical protection (Type 1 to 4).
The seam is first stitched and then an impervious tape is applied over the seam and sealed in place by an ultrasonic heat welding machine. It takes much more time and labor work, so the lead time and price are much higher than the common serged type.
This provides a fully sealed seam impervious to penetration as the tape seals all stitching holes. That’s why it is widely used in the COVID-19 epidemic prevention use protective clothing.
4. Ultrasonic Welded Seam
The fabric pieces are brought together, using ultrasonic (high-frequency sound) to generate heat so that the pieces are melt and welded together.
Provide a supposedly sealed seam using a single process (other sealed seams use a two step process). However, they may suffer from three problems:
1. The combination of heat, pressure and speed of welding has a narrow window to produce a weld. It can easily be over welded, the seams will become inflexible and brittle, then breaks the seal. It is difficult to identify and control, because it may not be visually apparent.
2. Whilst they can produce reasonable tensile strength across the seam they are often very weak along the seam and will tear very easily once damaged.
3.They can contain hairline cracks that are not visually apparent - especially if over welded. These could leak hazardous chemicals.
This type is more often to be seen in medical protective clothing, such as surgeon use gowns.