DESIGN CONSIDERATIONS FOR GLASS FABRIC SELECTION
There are five basic design variables to consider when choosing fabric for industrial use:
Glass fabrics are available in thicknesses ranging from ~0.0010” to ~0.060”.
The weight range begins at less than 1 ounce per square yard to over 50 ounces per square yard.
Yarn size determines the weight and thickness of the fabric. For specific applications, one yarn may be selected over another to the advantage of the fabric’s physical and mechnical performance characteristics.
This is determined by the number of warp yarns (machine direction) and fill yarns (cross-machine direction) per inch of the fabric and by the weave pattern.
Most industrial applications require that fabric be used with a coating material. For compatibility with resins coatings, an organic finish or after treatment is often applied to the fabric
This process serves to control the yarn strength,diameter, weight, and flexibility.Filaments are twisted to a predetermined specification,and the twisted threads are then combined or plied to balance and avoid any stresses in the yarn that may cause processing difficulties. Many glass fabrics are woven from single yarns as received from the yarn producers.
Warping, shown in the drawing, is essentially the laying of the yarns in parallel order. A specified number of threads per inch are drawn from a creel and wound on a warp beam. Several “section” beams are then combined to provide the designated number of threads per inch required in the fabric specification.
The combination of section beams occurs during the slashing process to create the warp, or loom, beam. This entire system of parallel threads is wound on one loom beam to become the “warp”, or lengthwise system of threads in the fabric.
Slashing is employed when non twisted yarn is used. Warp sizing is applied to the yarns to facilitate handling and to provide protection during the weaving process. This operation involves (1) sizing single-fiberglass warp yarns with a specially compounded chemical formulation, (2) drying the yarns, and (3) winding the desired number of ends on the loom beam through the combination of section beams.
The entering operation prepares warp yarn for weaving.In this process, the warp yarns are threaded from the loom beam through the headle eyes on the proper harnesses to achieve the desired pattern in the fabric. The warp yarn is then drawn through a reed to establish the warp thread count.The reed is also used to place the filling yarns in their proper position.