The traditional shuttle weaving is still being used as conventional as well as modified and upgraded form in some specialised weaving machines for technical textiles, including special circular weaving machines.

• Nevertheless in most of the technical textiles, shuttleless weaving machines are used.
• Projectile weaving machines have become increasingly specialised in the production, If technical textiles. Insertion rates of 1000 to 1400 metres are being achieved over wider width fabrics. Today, machinery manufacturers offer weaving machines tailor-made for their products. This offers individual solutions for demanding technical textiles.
• Recently novel leno formation technique has been developed on projectile weaving machines in which lenosystem works with a guide bar and an eye-let reed. Shedding is accomplished by opposing upward and downward movements of the eye-let and the guide bar. An additional guide bar movement of the guide bar results in twisting of the warp. Today, projectile weaving machines are available upto a width of 12 m.
• Rapier weaving machines are flexible in terms of ease and speed set-up and switching article types and styles. They are particularly suitable for air bags.
• Water jet and air-jet systems can also be used for: technical fabrics, recently air-jet weaving machines are developed to produce leno fabrics at a very high speed.
• Extra widths ranging between 6 and 30 mare available for weaving papermaking felts, filtration cloth and dryer fabrics. Weft insertion methods used include shuttle, gripper shuttle.

Braided structure

A braid structure is formed by the diagonal intersection of yarns. There are no warp and weft in the sense of a woven fabric. Braiding does not require beat-up and shedding, yarns do not have to go through healds and reed. Braiding is more significant to technical textiles than consumer textiles as it is one of the major fabrication methods for composite reinforcement structures. Traditional examples of the braided structures for industrial applications are electrical wires and cables, harnesses, hoses, industrial belts and surgical sutures.

Coating and laminating

In coating process, a polymeric material such as vinyl, polyurethane, rubber, etc is directly applied to one or both surfaces of the fabric. The thickness of the viscous polymer is controlled by means of a blade or similar aperture controls. The coated fabric is heated and polymer is cured. Where a thick coating is required, the same is obtained by successive passages to coat layer on layer. Interlayer adhesion must therefore be very high.

Traditionally coating has been applied to woven fabrics only, today warp knitted fabrics, weft knitted fabrics and nonwovens are coated to a large extent. Nowadays coating machines are integrated to fabric manufacturing machine such as weaving or knitting to produce technical fabrics like georgrids, insect nets, bill boards, scrim fabrics. Online coating prevents disintegration of yarns during use or subsequently.

• In the lamination process, two or more layers, one of which is a textile fabric, bonded together by means of an adhesive, or by the adhesive properties of one or more of the component layers. Conventional laminated technical textiles normally consist of one or more textile substrates that are combined using a pre-prepared polymer film or membrane by using adhesives or by using heat and pressure. In some metalised fabrics, the metal is laminated using an adhesive or by use of an electric arc.

About the Author:

The author is the Secretary of the Textile Machinery Manufacturers' Association (TMMA).