Which quality defects of molten glass have the greatest impact on wire drawing operations?

In the process of fiberglass forming, the glass strands with a diameter of millimeters are drawn at a very high drawing speed and cooled and solidified into micrometer-sized fiberglass. Obviously, the quality of the glass liquid is an important prerequisite for the continuous and stable fiber forming process.

The requirements of fiberglass drawing process for glass liquid quality include two aspects. First, the glass liquid should contain as few substances different from the base glass as possible. Such substances are mainly divided into three categories: bubbles (gas inclusions), stones (solid inclusions), and streaks or nodules (vitreous inclusions). Second, the glass composition should fluctuate less during continuous production, that is, the composition should be stable.

During the fiber forming process, small bubbles in the glass liquid are drawn into capillaries, which has little effect on fiber forming. However, if the bubbles are large or located near the fiber surface, they are likely to cause fiber breakage or reduce fiber strength. Of course, the elongated bubbles in the fiber will also become brittle, which is likely to cause hair or defects or breakage in subsequent textile processing, reducing the quality of yarn and fabric.

Stones are much more harmful to the wire drawing operation than bubbles. I will tell you later that most of the broken ends are caused by various stones. Even if some stones do not cause broken ends, they will greatly reduce the strength of fiberglass.