This document provides an overview of glass manufacturing processes at the Centre for Development of Glass Industries (CDGI). It discusses: 1) The objectives of CDGI which include job creation, efficient resource use, technology development and environmental protection. 2) The departments within CDGI including laboratories, pollution control, product development and training. 3) The glass manufacturing process which involves mixing raw materials, melting in a furnace, shaping the glass through processes like blowing and annealing for controlled cooling. 4) Key aspects of melting, forming, and annealing glass as well as testing procedures to ensure quality.

1. HELLO EVERYONE 1

2. Glass Manufacturing
2
Prepared By:-
Harish Balout
Ceramic Engineering
Roll No. 12ECTCR020
Submitted To:-
Mr. Narayan Dutt Joshi
Training Project Coordinator

3. 3Introduction To CDGI
• Centre for the development of glass (CDGI) has been setup as a
joint venture
Project of Govt. of India, United Nation Development Program
(UNDP)/United Nation Industrial Development organization
(UNIDO), AND Govt. of Utter Pradesh as a register society on 06
1992 at Firozabad (U.P.)
• Objective of CDGI
1. Creation of new job opportunities and improvement of skill and working
condition for worker/artist engaged in small scale glass industries
2. Efficient utilization of country’s energy and resource
3. Development and adoption of new technologies and product
4. Protection of environment

4. Department In CDGI 4
1. Laboratory Service
• Physical Laboratory
• Chemical laboratory
1. Pollution control division
2. Combustion Engineering
3. Product and technology development unit
4. Pot development unit
5. Consultancy &Troubleshooting service
6. Design and decoration unit
7. Training

5. 5GLASS
• Glass is amorphous solid = non crystalline, lacking of periodic
atomic arrangement and long range order
• Glass is super cooled = Liquid cool to a stage where its
viscosity is so great that the molecule do not move free
enough to form a crystal
• Any material, inorganic, organic, metallic form by any
technique which exhibit time dependent glass transformation
behavior is glass

6. 6Raw material used for Glass
Manufacturing
• Network Former ( Glass making oxide)
1. 𝑆𝑖𝑂2
2. P2O5
• Network Modifier ( Flux)
1. Na2O
2. PbO
3. Li2O
Result in serious degradationin many properties
• Network Strengthening (Stabilizer)
1. Cao
2. Mgo
Degradation properties can be counter by addition of alkali earth or transition metal oxide
• Refining Agent
1. As2O5

7. 7
17280C
• SiO2 Glass ( High Quality)
• SiO2 + Flux Glass (Less Strength)
• SiO2 + Flux+ Strengthening Good Strength ( Not refined)
• SiO2 + Flux + Strengthening + Refining Glass ( Refined)

8. Glass Manufacturing Process 8

9. a
9
Flow Chart
Raw Materials
Cullet Silica Feldspar CalciteDolomite
Proportioning of Raw Materials
Mixture
Chamber
Silos
Dog House
Tank Furnace
Throat
Working end
Feeder
Shaping
MeltingCombustion

10. 10Melting Process
• Aim = Is to get defect free glass at working temperature
• Raw material in proper proportion is mixed along with the cullet. It is fine powder
and the mixture called Batch is fused in Furnace at high temperature results in
formation of homogeneous viscous fluid.
• CaCO3/Na2CO3/MgCO3 CO2 + Oxide
(source of air bubble)
• During melting, cullet will form high viscous layer on the surface of the carbonate
and flux
• Flux start react with the solid grain along with the formation of air bubble and liquid
melt.
• Practically all the reaction must be complete by 2/3 of furnace and then refining 1/3
furnace.
• The air bubble present in the melt comes on the surface and start bursting due to
the temperature and glass pressure

11. 11Individual Section Machine
• Melt from feeder is pushed by the plunger assembly which cut the melt into molten mass.
• Molten mass of glass called gob is transfer to the IS machine.
• IS machine forming process based on the Blow and Blow Process
• The machine consist of 19 mechanism to form a bottle by compressed air ( HP
=3.2 bar and LP =2.8 bar)
• IS machine part: Scoop, Trump, Deflector, Mold, Neck Ring, Take Out Arm.

12. 12
Blow and Blow Process
• Blow and Blow process take place in IS machine where a gob released during
plastic stage and move along to mould.
• The gob is forced into the blank mould using compressed air to push the gob into
place.
• The gob, now a parsion is then flipped into a corresponding final mould where it is
blow again to form interior container.

13. 13Annealing
• Annealing is process of controlled cooling of glass ware after shaping.
• In this process the hot glassware is transfer to annealing lehr where it is subjected
to prescribed cooling rate in different zone of the lehr. Combination of above
cooling rate is called ‘Annealing schedule’.
• Factor governing the cooling rate in different zone are:
1. Thickness of glass
2. Coefficient of linear expansion of glass
3. Tensile strength of glass.
• Most important factor to be kept in mind
1. Annealing schedule must be set according to the maximum thickness of any
portion of any ware to be annealed together.
2. Annealing temperature is an intrinsic property of glass and it has not at all related
to thickness of glass.
3. Even momentary slighter faster cooling rate in any zone result in self breaking of
ware, may be after very long time.
ZONE 1 – 550 degree centigrade
ZONE 2 – 400-450 degree centigrade
ZONE 3 – 300 TO RT
4. Cooling rate is inversely proportional to square of thickness of ware.

14. 14
Viscosity of Glass melt
•Viscosity of Glass melt should be uniform otherwise inhomogeneous melt result in chord and stone.
•Viscosity varies with change in temperature:
1. Strain point ( 10^14.6 p)– Temp(490Ċ). at which the internal stress is reduce and the glass become
rigid.
2. Annealing Point (10^13 p) – Temp (500-550Ċ) Above this point there is no stress.
3. Softening Point( 10^7.6 p) – Temp. (710-720Ċ) Glass will deform under its own weight.
4. Working point (10^4 p ) – Temp. (1250-1300Ċ)
Viscosity of glass at different part in glass melting
1. Melting – 10^2 poise
2. Feeder - 10^4 poise
3. Mold - 10^4.5 Poise
4. Remove from Mold – 10^7 Poise
5. Annealing - 10^13 Poise

15. Devices And Equipment Used In
Glass Industry
1. High temperature equipment
2. Pyrometer
3. Thermocouple
• Heat Saving Device
1. Regenerator ( matrix type)-
2. Recuperator
• Equipment
1. Cullet crusher
2. Magnetic separator
3. Vibrating sieve
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16. Testing
1 Impact Testing ( 90° suspend bob)
It is used to determine the impact resistance, strength and breakage resistance characteristic in order to ensure that they are
fit.
2 Thermal shock resistance
Glass article that may be subjected to significant difference in temperature during their normal used should be tested for TSR
to ensure the product is fit.
3 Physical inspection
4 Stress Testing by Polaroid glass
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17. Production Chart 17

18. 18
ANY QUESTIONS?

19. 19
Thank You