MELTING
The raw materials, which consist mainly of silica sand, limestone, kaolin, and dolomite, undergo precise weighing and thorough mixing to create a consistent ‘batch’ before being introduced into the furnace.
The manufacture of glass is carried out in a special furnace at about 1550°C/2822°F (E-Glass) using finely ground raw materials from carefully selected quarries. The glass leaves the furnace at a very high temperature and is used to feed bushings (blocks pierced with hundreds of holes) of platinum alloy. Most Vetrotex products are based on E-Glass continuous fibers, we also produce C-Glass staple fibers.
FORMING/ BUSHING
The basic glass strand is made by forming. Forming is achieved by drawing the molten glass flowing from the holes of the bushing at high speed. This forms between fifty and several hundred filaments. These filaments are defined by their diameters: from 5 to 13 microns (1µm = 1/1000 mm).
Assembled, they make up the basic strand defined by its linear mass expressed in tex (g/km).
SIZING
Following the cooling process through water spray, the individual filaments of Vetrotex reinforcements are coated with a specialized substance called 'sizing', using an applicator roll, immediately after they leave the bushing.
This size, made up of organic products dispersed in water, is designed to give the glass strand certain characteristics necessary for the end application. For textile applications, sizes are generally starch/oil based. For some applications, special sizes may contain film formers other than starch, as well as a silane-type chemical “coupling agent,” which enhances the mechanical and ageing properties of the end product. Vetrotex products are either manufactured immediately after they leave the bushing (direct roving) or made up of basic strands subjected to finishing operations (twisting for yarns, plying, texturizing, assembly of rovings, chopping of strands and warping).
WINDING
Fiberglass production involves winding continuous strands of fiberglass around a collet in a specific pattern to create the desired shape and structure of primary spin cake.
Vetrotex products are either manufactured immediately after they leave the bushing (Direct Roving or Zerotwist) or made up of basic strands subjected to next operations (twisting for yarns, plying, texturizing, assembling of rovings, chopping of strands and warping).
TWISTING
Twisting is a process used to create twisted yarn, to form a cohesive and stronger yarn. The degree of twist and the number of plies (individual strands) used can determine the properties of the resulting yarn.
The prepared strands are fed into a twisting machine, and through the twisting mechanism, they are twisted together in the opposite direction of their original twist. This is important to prevent the yarn from unraveling.
Yarn can be twisted in different directions: "S-twist" or "Z-twist." In an S-twist, the fibers are twisted to the left, creating a diagonal line that resembles the letter "S." In a Z-twist, the fibers are twisted to the right, forming a diagonal line resembling the letter "Z."
Twisted yarn is then used as a durable component in a wide range of applications. The number of twists contribute to the final characteristics of the yarn, such as its strength, appearance, and suitability for specific applications.
