Regardless of which fusible and machine are used, fusing is controlled by four processing components such as temperature,time, pressure and cooling.
What is a Fusing Process?
Regardless of which fusible and machine are used, fusing is controlled by four processing components:
There is a limited range of temperatures that are effective for each type of resin. Too high a temperature causes the resin to become too viscous, which could result in the resin being forced through to the right side of the cloth
Time is the only time element of any value during the fusing process is when the topcloth and fusible are under pressure in the heating zone of the machine .This timecycle for a particular fusible is determined by :
- Whether the fusible has a high –or low melt resin.
- If a high or heavy substrate is being used.
- The nature of the top cloth being used, thick or thin, dense or open.
When the resin is viscous ,pressure is applied to the top cloth and fusibleassembly to ensure that :
- Full contact is made between the top cloth and fusible.
- Heat transfer is at the optimum level.
- There is an even penetration of the viscous resin into the fibres of the top cloth.
Enforced cooling is used so that the fused assemblies can be handledimmediately after fusing. Cooling can be induced by various systems. Includingwater-cooled plates, compressed air circulation and vacuum.
The Requirements of Fusing
The laminate produced by fusing should show the aesthetic qualities required by the designer in the finished garment.
The strength of bond of the laminate must be sufficient to withstand handling duringsubsequent operations in the garment manufacturing process as well as the flexing which takes place in wear.
Fusing must takes place without either strike-through or strike back occurring. When the softened adhesive resin is pressed into the garment fabric, it is important that itdoes not go right through to the face side of that fabric, and that it does not go back tothe outside of the interlining base cloth.
The fusing process must not cause thermal shrinkage in the outer fabric. Fusing commonly takes place at around 150oc and at this temperature many fabrics may subject to thermal shrinkage.
A further possible effect of the heat of the fusing process is that of dye sublimation.Fabrics may change colour to a level which is unacceptable and in a way which causes a miss-match between the fused and unfused parts of the garment.
Since the fusing process involves pressure, there is a risk that pile fabrics may besubject to crushing during fusing.
Where shower proof fabrics are fused, there is a possibility that the presence of a fused interlining in the garment may wick water through the fabric in the fused areas while the unfused areas remain satisfactorily shower proofed. Water resistant interlinings have been developed for these situations.