Glass, with its glossy shine, attracts many. It has been put into many uses from being made into utensils, mirrors, windows, doors to furniture and artworks.
too could not resist itself from the fatal attraction of glass. Although, hard and rigid by nature, glass can very well be made into fine, shiny and translucent fibers which more or less look and feel like silk fibers. These glass fibers
are commonly known as fiberglass
Prerequisite for Glass Fibers
Although there are two methods for making glass yarns
but certain processes have to be done before going on to any
of the manufacturing methods. Batches of silica, sand, limestone, soda ash, borax and any other ingredient required
for specific purpose have to be made. All these contents are in requisite proportion. These batches are formulated in
an electric furnace from where the molten glass at a temperature of approx. 2500o
F flows to marble forming machines
that produce tiny glass marbles of about 15 mm in diameter. Visual inspection of these marbles are carried on so as
to eliminate any of the impurities. The marbles are then again melted in small electric furnaces and extruded through
spinnerets. In yet another method, the molten glass is directly extruded from the furnace through spinnerets without
converting it into marbles.
Glass Fiber Manufacturing Processes
After the initial process of melting glass and passing it through spinnerets, continuous filaments or staple fibers
of glass are manufactured by two different methods.
Continuous Filament Process
In this process, continuous filaments of indefinite length is produced. The molten glass passes through spinnerets
having hundreds of small openings. These strands of multiple filaments are carried to winder revolving at very high
speed of more than 2 miles per km. This process draws out the fibers in parallel filaments of the diameter of the
openings. A sizing or a binder is applied to facilitate the twisting and winding process and to prevent breakage
during yarn formation. After winding, filaments are further twisted and plied to make yarns by methods similar to those for making other continuous filament yarns. The sizing is removed through volatizing in an oven. These yarns are used for making such items as curtains and drapes.
Staple Fiber Process
Fibers with long-staple qualities are
manufactured through staple fiber process. There are many methods for producing such fibers.
In one of such methods, the molten glass flows through the small holes of bushing, where jets of compressed air shake the thin streams of molten glass into fine fibers. These fibers vary in length ranging from 8 to 15 inches. The fibers fall through a spray of lubricant and a drying flame onto e revolving drum where they form into a thin web. These fibers in the form of web are gathered from the drum into a sliver. Yarn is then made from this sliver by similar methods that are adopted for making cotton or wool yarns. These yarns are used for fabrics for industrial purposes where insulation is required.
In yet another method, the ends of the glass rods are melted from which drops of glass fall away drawing off glass filaments after them onto a speedily revolving cylinder where they are wound parallel to each other. A web of sliver is formed if the cylinder moves sideways. Sometimes, the staple may be thrown off the cylinder onto a stationary sieve where it forms a sliver. In either conditions, the sliver is then converted into spun yarn.
The staple fiber, if subjected to oven, is compressed to the desired thickness and the binder which was earlier applied, is cured. This permanently binds the fibers.
Uses of Glass Yarns
Glass fiber is manufactured in a wide range of fine diameters. Some of them are so fine that they can be seen only through a microscope. This quality of fineness contributes greatly to the flexibility of glass fibers. Various manufacturers produce different types of glass fibers for different end uses. Glass fibers them are used for various purpose.
- For making home furnishings fabrics;
- For making apparels and garments; and
- For the purpose tires and reinforced plastics.
There are certain glass fibers that can resist heat upto 7200o
C and can withstand forces having speed of 15,000 miles per hour. These types of glass fibers are used as
- Filament windings around rocket cases;
- Nose cones;
- Exhaust nozzles; and
- Heat shields for aeronautical equipment
Some other types of glass fibers are embedded into various plastics for strength. These are used in
- Boat hulls and seats;
- Fishing rods; and
- Wall paneling
Some other types of glass fibers are used for reinforcing electrical insulation. Yet other types are used as batting for heat insulation in refrigerators and stoves.