Question

The glass marbles are subjected to melting process at the temperature of __________ before feeding to spinneret for its spinning.

• A. $538^{\circ}C$
• B. $697^{\circ}C$
• C. $832^{\circ}C$
• D. $1371^{\circ}C$

Hint:

The melting temperature for glass fiber is nearly 5 times higher than the melting temperature of Polyester ($260^{\circ}C$).

Answer 1

The Correct Option is D

Concept: Glass fibers are inorganic synthetic fibers. Unlike organic polymers (like Nylon or Polyester), glass does not have a specific melting point but rather a softening range where its viscosity changes with temperature.

Step 1: The "Marble Melt" Process.
In this specific manufacturing method, high-quality glass is first formed into marbles to allow for easy inspection of impurities. These marbles are then fed into a furnace (often called a bushing) made of platinum and rhodium to prevent contamination at extreme temperatures.

Step 2: Thermal Requirements for Spinning.
For the glass to be drawn into incredibly fine filaments through the tiny holes of a spinneret, it must reach a state of very low viscosity. This requires an intense heat of approximately $1371^{\circ}C$. At this temperature, the molten glass flows consistently, allowing for high-speed attenuation (stretching) into fibers.