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Properties of Glass to be considered before Glass Fabrication

13/07/2021

Glass has always been one of the most critical materials for the development of today’s modern civilisation. It has a wide range of important applications in industry, science, home, work, play, art, and many other aspects of life.  Many items of regular use in our lives rely on glass components. These include micro ovens, labware, binoculars, watches, computers, kitchen appliances, fibre optics, automobiles, and much more.

Glass fabrication is a complex and broad industry that plays a significant role in our lifestyle. Most of the critical applications of glass can be attributed to this industry. However, unfortunately, many of us have very little idea about the unique properties of glass. Owing to its excellent insulation property, glass was first used as an integral component of the early-day electrical and telegraph industry. Over the years, the unique properties of glass have paved the way for numerous important uses.

Understanding the Unique Properties of Glass

Depending on their chemical composition and production methodology, different qualities are found in different types of glasses. Therefore, selection of the right glass type for a specific purpose requires thorough understanding of the properties of each type. The five major properties to be considered before glass fabrication are thermal, optical, chemical, electrical, and mechanical.

Thermal Properties:

Coefficient of Thermal Expansion (CTE) is one of the most important thermal properties of glass that measures its expansion with rising temperature. This is an important factor to take into account while making glass to metal and glass to glass seals. Thermal conductivity is another property while using glass for high infrared applications or as a high temperature exposed viewport.  These thermal properties of glass are changed when glass is altered by chemical strengthening, heat tempering, or heat strengthening.

 

Optical Properties: 

The amount of light passing through glass is determined by several important parameters. The refractive index is a measure of deviation light waves while entering or leaving the glass surface. Dispersion is another important parameter that helps determine the separation of light into its different colour components. The amount of light passing through any glass material is measured by the transmission property. Finally, the amount of light energy getting converted to heat within a glass material is referred to as absorption.

Chemical Properties:

As a result of their composition, sodium or alkali ions migrate to glass surface on prolonged exposure to liquids or vapour. This leaching of sodium or alkali causes haze or cloudiness on the glass surface. The potential for this occurrence must be considered in critical surface applications.  The amount of this reaction can be minimised by using barrier coatings like silicon dioxide.

Electrical Properties:

Several characteristics should be considered while choosing glass for electronic or electrical applications. The volume resistivity is a measure of resistance between opposite faces of a test glass’ centimetre cube. The dielectric constant, on the other hand, measures a glass material’s ability to store electrical energy. Surface resistivity is another key parameter that measures the conductivity of coated glass.

Mechanical Properties:

The amount of stress glass can withstand is determined by its mechanical properties. A glass material’s ability to withstand these stresses is its strength. The bending or flexural strength of glass is measured by Modulus of Rupture (MOR) test. Twisting or shearing forces that can be withstood by glass is measured by shear modulus. Finally, the hardness of glass is measured by the Knoop Hardness Number (KHN).

If you have any questions related to your upcoming glass fabrication project, please contact us at GM Fabrication. We have over 40 years of experience in glass, aluminium, and stainless steel fabrication.