Alternative methods of fabric joining – 1
Alternative Method of Joining:
The method /system/process which have been developed as alternative to sewing are known as alternative method of joining.
- Lower joining speed hence less production.
- Seam appearance is not so good.
- Seam performance is not satisfactory in some aspects compared to sewn seam
- Alternation of seam is quite difficult, also impossible in most of the cases.
- Comparatively less comfortable due to harsh feeling.
Welding & adhesive
- Most widely used system and mostly used in case of joining interlining.
- In this process, the resin / polymer coated side of the base fabric of interlining are spread on the underside of the garments fabric & joined by applying heat & pressure.
- Due to heating, the resin/polymer of interlining are melted & due to pressure, this melted resin/polymer penetrate inside the construction of fibre of garments fabric & of interlining base fabric. When they get cold, the melted polymer becomes hard & interlining is joined with fabric.
- Limitation is, it only can be used for joining interlining, not suitable for general joining of fabrics. Moreover this process cannot be used to join interlining to every kind of fabric
2. Welding & adhesive:
- To attach decorative motif on garments.
- Sealing the cut edge of fabric to prevent fraying.
- Temporary joining of garment parts, which are permanently joined by top stitching afterward.
- Used in water proofing seams.
- Limited use & Fabrics must contain at least 65% thermoplastic fibre to be joined by this method.
Principle of Ultrasonic Welding:
If two substances are rubbed/ vibrated against one another, then heat will be created in the area of rubbing. If these two or more plies of fabric are made from thermoplastic fibers, then the created het (because of rubbing/ vibration), if sufficient will cause the melting of thermoplastic fibers. By applying required pressure, the melted polymers are attached.
In welding machine, transducer is used to convert the electrical energy to vibrations. This transducer creates mechanical vibrations and produces heat. If this vibration is less than 18000/ sec, then the sound can be heard. For this reason, the vibration is kept 20000/ sec.
This vibrations produced by transducer is sent to a Horn. The vibrating horn against a fixed anvil will create heat in midst of them. By horn, pressure can also be produced. Horns may be rectangular or round. If the horn is rectangular, then its dimension can be up to 25 cm X 4 cm & if round, then diameter can be up to 90 cm.
Amount of heat generation depends on:
- Amplitude of frequency
- Time of frequency
- Completely water proof seam can be prepared.
- Produced seam is stiff & rough so cannot be used in the seam which stays closely with body
- Create discomfort feeling during wearing and used in cheap garments.
The fabrics containing less than 65% thermoplastic fibers can also be joined by this method. In that case, a thin polyethylene film should be used between two layers of fabric.