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With the exception of the very simplest structures, it is too time consuming to represent warp knitted fabric using stitch or loop diagrams. For this reason two methods of fabric representation are commonly used a. Lapping diagrams, b. Numerical representation.
Warp knitting is the sequential formation and interlinking of loops in an axial direction on a lateral array of needles with at least one separate thread being supplied to each needle. The loops are joined together in a width-wise direction by moving the threads back and forth between adjacent needles.
Cellulosic chemical fibers of all lengths and degrees of refinement and with clearly different properties are at the disposal of the industry of nonwoven bonded fabrics. They are all characterized by the ability to absorb a fairly high amount of moisture. That recommends their use wherever this property is useful for the production of nonwoven bonded fabrics and/or the use of nonwoven bonded fabrics is even a precondition.
Nonwovens do not depend on the interlacing of yarn for internal cohesion. Intrinsically they have neither an organized geometrical structure. They are essentially the result of the relationship between one single fiber and another. This provides nonwoven fabrics with characteristics of their own, with new or better properties (absorption, filtration) and therefore opens them up to other applications.
Fabrics to be used as raincoats, umbrellas, and tarpaulins have to be treated with chemicals to give them a property which makes them water resistant. The finish is called waterproofing and it is a durable finish. Water repellant finish is different from the waterproof finish. It means water, if showered on the fabric briefly, cannot make the fabric wet.
Pre-shirking is needed almost on all fabrics because most textile materials shrink when washed. However preshrinking can only reduce the residual shrinkage to a lower percentage, but cannot completely eliminate it. On cotton fabrics, usually take away 8-10%shrinkage by preshrinking, leaving about 5-6% in them.
Fabrics which are woven or knitted, freshly coming off the machine are called grey goods which must be treated in different ways to give them the important finishing touch. We call this finishing touch “finish”. This finishes we apply to fabrics are either for practical reasons or appearances. There is a wide range of finish we use on fabrics.
Fabric direct from the loom is unattractive. To make the fabric attractive and acceptable to the consumer several finishing processes are applied. Sometimes special finishes are also applied to the fabric to make it serviceable for particular end use.
In the simplest weaving arrangement, alternate warp yarns are over or under the shuttle as it moves in one direction and the warp yarn positions are reversed for the return stroke of the shuttle. This weave can be made on a loom with only two harnesses. In other arrangements, several warp yarns may be moved upward or downward together, or several filling picks may take place before the warp yarns change position.
characteristics of blended yarns like – shrink or not, water absorbent, has creases or not, has the luster or not, soft/hard. Each kind of fiber has its own characteristics when mixing them, one should consider their characteristics to create a hybrid with the characteristics needed.