The document outlines the processes involved in glass production, detailing techniques such as batch and continuous-flow processes, along with specific materials needed for different glass types. Additionally, it covers the characteristics and applications of thermoplastic and thermosetting materials used in polymerization and molding. Key stages of glass fabrication include batch preparation, refining, conditioning, and annealing, emphasizing the transformation of raw materials into finished products.

1. -PRATIKSHA PATIL
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2. METHODS
GLASS
(MINERAL)
BATCH PROCESS
CONTINUOUS-FLOW
PROCESS
PLASTIC
(ORGANIC)
INJECTION MOLDING
(THERMOPLASTIC)
POLYMERIZATION
(THERMOSETTING)
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3.  Often called as “supercooled” liquid
 Raw Materials
◦ Quartz sand (provides silica)
◦ Soda aka sodium carbonate (added as flux to assist
melting)
◦ Lime aka carbon oxide (added to increase chemical
stability & to decrease solubility of glass in water)
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4.  Prime ingredients
◦ For Crown glass
 Silica
 Soda or potash
 Lime
◦ For Flint glass
 Silica
 Lead oxide
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5.  It is used only for the production of relatively
small quantities of glass
 Special types of glass such as high-index
glass and many varieties of colored glass.
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6. MOLDING STAGE
ANNEALING
CONDITIONING STAGE
REFINING STAGE
HEATING OF BATCH MATERIALS
BATCH PREPARATION
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7.  BATCH PREPARATION
◦ The ingredients are put into a melting pot 36
inches in diameter and 32 inches high, capable of
making about 1000 pounds of glass.
◦ Ingredients depend on the type of glass being
made
◦ Principally oxides or salts of metals including
silica, sodium and potassium, calcium, and
aluminum.
◦ An additional ingredient, called cullet, is waste
glass from previous melts is added.
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8.  HEATING OF BATCH MATERIALS
 Before furnace operations are begun, the pot
is gradually raised to a temperature of 800°
to 1000°C and kept there for 3 to 5 days,
following which the pot is glazed by the use
of small pieces of cullet.
 The ingredients are then added, at intervals,
until the temperature of the pot is raised to
about 1400°C.
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9.  REFINING STAGE
 During the melting process, the batch is full
of bubbles of escaping gas
 The escaping of the gas is known as fining
 Toward the end of the melting and fining
process (which requires several hours), scum,
stones, and other materials rise to the top of
the batch and are skimmed off.
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10.  CONDITIONING STAGE
 After completion of the melting, fining, and
stirring processes, the molten glass has the
consistency of heavy syrup.
 Then the molten glass is cooled to a
temperature of 1200°C making it more
homogenous for molding
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11.  ANNEALING
 When cooled to a temperature of 1200°C, it is
poured and rolled into sheets of various
thicknesses, and each sheet of glass is placed
in a heated annealing oven where it is
gradually cooled to room temperature.
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12.  MOLDING STAGE
 After annealing, the glass is cut into small
pieces, is reheated, and is then either pressed
or molded into rough blanks.
 After inspection, the rough blanks are
blocked on grinding shells and the first
surface is ground and polished to the desired
curvature.
 The blanks are then reblocked, and ground
and polished on the second side.
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15.  An automated method
 Used for making large quantities of a
particular type of glass.
 This process differs from the batch process in
that the molten glass is not poured into
sheets but is extruded, by means of a
continuous process, and pressed into molds,
making the rough blanks.
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16.  Also known as resin/ hard resin
 Raw Materials
◦ Organic ingredients
◦ Inorganic materials
 carbon, hydrogen, oxygen, nitrogen, chlorine, and
sulfur.
◦ Some come directly from plant and animal sources
such as wood and cotton (cellulose) and milk
(casein).
◦ More commonly, are derivatives of fossil-formed
products including oil, coal, and natural gas.
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17. THERMOPLASTIC THERMOSETTING
 Soften when heated
 can be remolded
 Usually supplied in
pellet, granular, or
sheet form.
 Less dimensionally
stable(2-D)
 withstand less heat
without deformation.
 Eg. Polycarbonate
 once hardened cannot
be softened, even at
high temperatures
 usually supplied in
liquid monomer form
and cast in molds.
 molecules forms a 3-D,
cross-linked, lattice
pattern
 good dimensional
stability
 Eg. CR-39
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18.  Thermoplastic materials have their molecules
arranged in long chains
 They are usually supplied in pellet, granular,
or sheet form.
 The material softens when heated and can be
stretched, pressed, or molded into complex
shapes with no appreciable change in its
chemical structure.
 When cooled, the material hardens and
shrinks, having the same configuration as the
mold in which it was heated.
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19.  Since no chemical change transpires, the
softening and hardening cycle may be
repeated indefinitely.
 Thermoplastic materials are generally less
dimensionally stable than thermosetting
materials and they can withstand less heat
without deformation.
 Other ex. acrylates, cellulose acetate and
cellulose nitrate, polystyrene, the nylons, and
the vinyls
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21.  Thermosetting materials are usually supplied
in liquid monomer form and cast in molds.
 Plasticizers, filters, dyes, binding modifiers,
other monomers, and catalysts may be added
to the basic chemical compound and then
material is heated. After which polymerization
occurs.
 The molecules form a threedimensional,
cross-linked, lattice pattern rather than the
two-dimensional pattern of the thermoplastic
material.
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22.  This process transforms a liquid monomer
first into a syrup and then into a gel, and
finally into a solid.
 The relationship between the time and
temperature required in the hardening
process is known as the curing cycle.
 Once hardened, the material cannot be
softened (even at high temperature).
 If the thermosetting materials are subjected
to a high temperature, the material
decomposes without melting or substantially
softening.
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23.  https://www.sciencedirect.com/topics/engin
eering/glass-batch
 https://www.sciencedirect.com/topics/engin
eering/float-glass-process
 Injection molding video
https://youtu.be/AwWlmBka1Gs
 Clinical Optics- Troy.E.Fannin-chapter 1
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