Module 4

Question 1

is an inorganic, noncrystalline, brittle solid that is formed by cooling from a liquid state

Answer 1

Glass

Question 2

It shows no discontinuous change in properties at any temperature, but becomes more rigid when its temperature decreases and less rigid when its temperature increases.

Answer 2

Glass

Question 3

occurs at a level of stress approximately equal to yield stress.

Answer 3

The proportional limit

Question 4

causes the material to be permanently deformed

Answer 4

Stress greater than the yield stress value

Question 5

When tiny crystals form in a repeating orderly fashion in a material, the material is said to be

Answer 5

crystalline or to have “crystalline regions”

Question 6

Is glass amorphous or crystalline?

Answer 6

Amorphous

Question 7

Glass is sometimes is reffered to as a

Answer 7

supercooled liquid

Question 8

heat from a volcano can melt sand to form a natural glass called

Answer 8

obsidian.

Question 9

lightning strikes onto a sand dune or beach can melt sand to form a natural glass called

Answer 9

fulgurite

Question 10

There are two such natural heat sources that occur in nature:

Answer 10

volcanoes and lightning

Question 11

wrote that the process of glass making was discovered when Phoenician mariners used pieces of natron to support cooking pots over a campfire on the beach.

Answer 11

Pliny, Roman historian

Question 12

a mixture of soda ash and sodium bicarbonate

Answer 12

Natron

Question 13

Glass beads were used in Syria in

Answer 13

12,000 BC

Question 14

The Egyptians had glass jewelry in

Answer 14

700 BC

Question 15

The Egyptians made glass bottles by winding strands of glass onto baked clay forms in

Answer 15

3000BC

Question 16

Blowpipes were first used around ______ to form glass objects

Answer 16

300 BC

Question 17

The _______ greatly improved the ability of artisans to produce glass objects.

Answer 17

blowpipe

Question 18

The Romans produced flat glass in

Answer 18

200 BC

Question 19

Glass manufacturing began at ____ in ____.

Answer 19

Jamestown, in the Virginia colony, in 1608

Question 20

Use of manual glass container manufacturing machines began in the

Answer 20

1800s

Question 21

worked for the Libby Company, invented the first automated bottle-making machine in 1903.

Answer 21

Michael Owens

Question 22

If a ______ is added to the mix, the glass will be colored.

Answer 22

colorant

Question 23

Three Selected Types of Glass

Answer 23

Glass Made from Pure Silica
Glass Made from Soda and Silica
Container (Packaging) Glass

Question 24

Characteristics of Pure Silica Glass

Answer 24

• Inexpensive raw material
• Excellent durability
• High energy requirements to melt the mix
• Hard to fine (remove bubbles)
• Hard to form
• Expensive to process

Question 25

The only significant application is for the manufacture of mirrors and lenses for telescopes and other optical equipment.

Answer 25

Glass Made from Pure Silica

Question 26

This type of glass is used in the chemical industry because it is resistant to attack by many chemicals.

Answer 26

Glass Made from Soda and Silica

Question 27

is made of a mixture of several materials, including silica, soda, calcium carbonate (calcia), aluminum oxide, and other materials

Answer 27

Container glass

Question 28

which are added to improve the durability of the glass, also increase the viscosity of the melt, making the container manufacturing process more difficult and more expensive.

Answer 28

Aluminum oxide and calcium carbonate

Question 29

The _________ is the part of the plant where the ingredients are mixed in the proper quantities to be added to the glass furnace

Answer 29

batch house

Question 30

The batch house is located at the

Answer 30

input end of the glass furnace

Question 31

The _____ are usually supported on heavy frames above a large conveyor that feeds the hopper.

Answer 31

silos

Question 32

The ingredients are thoroughly mixed together and then dumped into a _____, which dumps the mix into the furnace

Answer 32

hopper

Question 33

The glass furnace consists of a number of sections:

Answer 33

melter, bridgewall, throat, refiner, and one or more forehearths

Question 34

The _____ is the largest section of the glass furnace.

Answer 34

melter

Question 35

The _____ form the end of the melter opposite the input end.

Answer 35

bridgewall and throat

Question 36

floating mix of impurities is typically referred to as

Answer 36

slag

Question 37

The _____ is the section on the downstream side of the bridgewall

Answer 37

refiner

Question 38

The _____ is the section on the downstream side of the bridgewall

Answer 38

refiner

Question 39

Small bubbles float to the surface and are removed in a step known as

Answer 39

fining

Question 40

are ceramic-lined troughs like bathtubs that convey the glass from the refiner to the glass container forming machines

Answer 40

Forehearths

Question 41

are shaped to influence the quantity of glass that flows into different parts of the container

Answer 41

Gobs

Question 42

As the molten glass leaves the spout, a gob is cut off by the

Answer 42

gob shears

Question 43

Containers are formed in

Answer 43

IS (individual section) machines

Question 44

preliminary form of the container

Answer 44

Parison

Question 45

There are two basic approaches to manufacturing containers:

Answer 45

1) press and blow molding or 2) blow and blow molding

Question 46

to manufacture containers with wide necks, jars and cups.

Answer 46

Press and Blow Molding

Question 47

A wide-neck jar is usually defined as having a finish larger than

Answer 47

43 mm in diameter

Question 48

Annealing is done in a large oven called a

Answer 48

lehr

Question 49

is applied at the hot end (the front end) of the annealing lehr

Answer 49

A bonding agent (usually tin or titanium tetrachloride)

Question 50

At the cold end (the back end) of the lehr, what is applied?

Answer 50

a friction-reducing agent (or a coating) is applied. Coatings that are applied include polyethylene, waxes, and silicones.

Question 51

Following are some of the defects that can cause rejection of a container:

Answer 51

• Dimensions that are out of tolerance 1. Thread height 2. Finish diameter 3. Sealing ring at the top of the finish 4. Diameter of the body 5. Bottom • Chips or cracks • Birdswings (glass bridge across the interior of the container) • Bubbles • Color variation

Question 52

Containers that reach the end of the manufacturing process are packaged for delivery to the customer. There are two approaches that can be used:

Answer 52

(1) bulk handling, and (2) reshippers

Question 53

The glass manufacturing process includes two steps that are specifically intended to improve the strength of the containers:

Answer 53

annealing and coating.

Question 54

is the process of changing from a vitreous structure to a crystalline structure as the glass cools.

Answer 54

Devitrification

Question 55

The bridgewall extends partways down from the surface, leaving an open area, called the _____, under the wall.

Answer 55

throat

Question 56

Design and Manufacturing Factors That Affect Container Strength

Answer 56

• Distribution of glass throughout the container, including thickness at various points and the distribution pattern of the glass into specific areas, such as corners • Container shape, such as the sharpness of radii, and so on. • Surface condition, such as scratches on the surface of the glass. Tiny scratches act as stress concentrators, substantially reducing the strength of the glass. • The type of load. As discussed previously, glass is very strong in compression, but often fails under tension.

Question 57

Ways to Improve the Strength of Glass

Answer 57

• Anneal containers in a lehr to relieve internal stresses in the container. • Limit surface damage. • Build compressive stresses into the material (although this is not done much with packaging glasses and will not be discussed here). • Change the package design (change radii, take out corners, increase wall thickness, change the distribution of glass in the mold, etc).