Ch 12 Glass working MC

4. Typical glass melting temperatures are in which of the following ranges: (a) 400°C to 500°C, (b) 900°C to 1000°C, (c) 1500°C to 1600°C, or (d) 2000°C to 2200°C?

1500°C to 1600c

A lehr is which of the following: (a) a lion's den, (b) a melting furnace, (c) a sintering furnace, (d) an annealing furnace, or (e) none of the above?

Annealing furnace

Casting is a glassworking process used for (a) high production, (b) low production, or (c) medium production?

Answer. (b). Casting is used in glassworking for large components like giant telescope lenses in small lot sizes. It is a slow process for these large products.

If a glass part with a wall thickness of 5 mm (0.20 in) takes 10 minutes to anneal, how much time would a glass part of similar geometry but with a wall thickness of 7.5 mm (0.30 in) take to anneal (choose the one closest answer): (a) 10 minutes, (b) 15 minutes, (c) 20 minutes, or (c) 30 minutes?

Answer. (c). The rule is that annealing time varies as the square of the wall thickness. That would indicate an annealing time of (0.30/0.20)2 = 2.25 times 10 minutes or 22.5 minutes. 20 minutes is closest.

Which one of the following processes or processing steps is not applicable in glassworking: (a) annealing, (b) pressing, (c) quenching, (d) sintering, and (e) spinning?

Answer. (d). Sintering is used to cause bonding of particulate materials such as metal and ceramic powders.

4. Which one of the following processes is used to produce glass tubing: (a) Danner process, (b) pressing, (c) rolling, or (d) spinning?

Danner process

4. The press-and-blow process is best suited to the production of (narrow-necked) beverage bottles, while the blow-and-blow process is more appropriate for producing (wide-mouthed) jars: (a) true, or (b) false?

False It's the reverse.

Besides helping to preserve the environment, the use of recycled glass as an ingredient of the starting material in glassmaking serves what other useful purpose (one answer): (a) adds coloring variations to the glass for aesthetic value, (b) makes the glass easier to melt, (c) makes the glass stronger, or (d) reduces odors in the plant?

Makes the glass easier to melt

The charge in glassworking is which one of the following: (a) the duration of the melting cycle, (b) the electric energy required to melt the glass, (c) the name given to the melting furnace, or (d) the starting materials in melting?

Starting materials in melting

Which one of the following terms refers to the glassy state of a material: (a) crystalline, (b) devitrified, (c) polycrystalline, (d) vitiated, or (e) vitreous?

Vitreous