Transcript
MANUFACTURE OF GLASS
SYNOPSIS
• INTRODUCTION
•TYPES
•METHODS
THE GLASS WAS DISCOVERED IN THE REGION OF SYRIA AROUND 5000BC
INTRODUCTION
INTRODUCTION
•The glass was first discovered in the region of
syria around 5000 BC
•It is an amorphous compound
•It is also known as super cooled liquid
•It has no melting point
•It has high viscosity which prevents from
crystallizing
TYPES OF GLASS MATERIAL
Variety of ophthalmic glass material
Crown glass >>>>> RI= 1.523
Barium crown glass >>>>> RI= 1.6
Borosilicate crown glass >>>>> RI= 1.53
Flint glass >>>>> RI= 1.75
COMPOSITION OF CROWN GLASS
70% of silica [si]
12% of calcium oxide (or) lime [cao]
15% of sodium oxide [Nao]
Small percentages of following compound acts as refining materials which improves the quality of glass
Potassium [Ka]
Borax [Na2B4O7.10H2O]
Antimony [sb]
Arsenic [As]
CROWN GLASS
COMPOSITION OF BARIUM
CROWN GLASS
35% of barium oxide[Bao]
30%of silica[Si]
Small percentage of following materials
Lime[Cao]
Zinc[Zn]
Alumina[Al]
Borax[Na2B4O7.10H2O]
NOTE:the effect of barium oxide is to increase the refractive index
BARIUM CROWN GLASS
BOROSILICATE CROWN GLASS
• Borosilicate crown glass is used for
windows,lenses and prisms
• Transmission ranges between 0.4µm to 1.4µm
BOROSILICATE CROWN GLASS
COMPOSITION OF FLINT GLASS
60% of lead oxide
30% of silica
8% of soda and potash
Small percentage of arsenic and antimony
NOTE:the effect of lead oxide is to increase the refractive index
FLINT GLASS
METHODS
There are two methods of manufacturing of glass
Individual batch method
Continuous flow method
• Six stages are common in both method
Mixing
Melting
Fining
Stirring
Forming
Annealing
THANK YOU
REFERENCE:
http://www.historyofglass.com/
http://www.pfg.co.za/all-about-glass.aspx
http://www.slideshare.net/Alizeeshansuhail/spectacle-lens-materials
http://www.janostech.com/knowledge-center/optical-materials-guide/borosilicate-crown-glass-bk-7.html
The principles of ophthalmic lenses- M.jalie
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