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COMPOSITE MANUFACTURING
Generally, manufacturing using composites involves the processing of two main ingredient materials to make a final product. The ingredients involve the matrix and fiber materials.
CONSTITUENTS OF COMPOSITES
There are two main constituents making up advanced composites. These are fibers and matrix. The interface between the fiber and matrix is critical for the function of the composite material. The interface may be considered as a third constituent of the material.
FIBERS
Fibers provide strength and stiffness to the composite materials. Fiber materials are usually glass, carbon or Kevlar.
GLASS FIBER MANUFACTURING PROCESS
The raw materials for glass fibers are silica sand, boric acid and other minor ingredients (e.g., clay, coal, and fluorspar). These are dry mixed in a high temperature refractory furnace.
First the mixture of silica sand and ingredients is put in a batch silo. They are then mixed and weighed. The mixture is transported to a batch charging unit where the mixture is fed into the furnace. The temperature in the furnace vanes from 1540 degree Celsius at the melting stage to 1425 degree Celsius at the refining The molten glass flows to the fore-hearth stage where temperature is reduced to 1260 degree Celsius. At the bottom of the fore hearth station, there is a plate made of platinum contains many tiny holes. The molten glass flow through these tiny holes and forms filaments. These filaments are then pulled mechanically to make smaller filaments. The diameter filaments depends on the speed of drawing. A chemical sizing is applied on the surface of the fibers at this sizing is used to reduce the friction between the prevent breakage.
A finish can also be applied to the fiber. Finish is a type of chemical used to protect the surface of the fibers and to provide good bonding with the matrix material when the composite is made. Many filaments are bundled together to form tows or strands. These tows or strands are then wound onto a creel for shipping purpose, or they can be cut into short fibers.
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