Information about different types of glass with a list of glass manufacturers
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Glass is a foundational component of structural and architectural projects. The many types of glass provide protection, stability, and aesthetic features, due to glass’ appearance, strength, and durability. Engineers and designers rely on glass as a key component in a wide range of industrial and commercial buildings. Over the centuries, since its first discovery, glass has been adapted, adjusted, changed, and configured to meet the requirements of a long list of protective and aesthetic requirements.
In many cases, the term glass is used to refer to flat sheets of clear material that allows for visibility and the passage of light. In reality, the many forms of glass are used for conditions that far exceed its simple definition. To achieve glass’ many properties and characteristics, the raw materials are changed and configured to precisely meet the demands of an application. Glass of the 21st century far exceeds its initial uses and has made it a key component for a wide range of industrial applications.
The strength of glass is determined by the rate at which it is allowed to cool. The main methods for cooling glass are annealing, heat strengthening, and tempering. The differentiation between the methods is the amount of time allowed for the cooling and the addition of heat. Each method is designed to enhance and improve the properties and characteristics of glass. In addition, once the glass has cooled, it may be coated to increase its strength and toughness.
The scientific term for glass is an amorphous solid, the state of a material that places it between two states of matter. Glass is referred to as an amorphous solid because it does not have the ordered molecular structure that is found in a true solid. This irregular structure is too hard and rigid to be classified as a liquid, which places it between two states of matter. The absence of a defined crystalline structure means that glass does not have a specific melting point but gradually softens as it is heated.
The base material for the manufacture of glass is silica sand, which is 75% of its composition. The other 25% of the mixture includes sodium carbonate, limestone, clarifying agents, colorings, and recycled glass or cullet. One of the keys to the quality of glass is the purity of the sand. Although ordinary beach sand can be used for manufacturing glass, silica sand is chosen due to its chemical purity. The glass that is produced is of the highest quality in regard to appearance and function.
Silica sand, also known as industrial sand, white sand, and quartz sand, is made up of oxygen and silica. For a silica to qualify for use in the manufacture of glass, it must have a 99% SiO₂ (Silicon Dioxide) content with less than 0.2% iron oxide (Fe₂O₃) content. Unlike silica sand, regular sand is labelled as brown sand, feldspathic sand, and construction sand. It can have a silica content up to 80% and contain potassium, carbonate, iron, and other minerals. The additional elements in regular sand make it more reactive than silica sand. One of the factors that distinguishes silica sand from regular sand is its very light color. By comparison, regular sand comes in several colors depending on where it is in the world.
The choice of silica sand for glass making is due to its high percentage of silicon dioxide, which is an essential material for glass making. The durability, strength, and transparency of glass is due to the purity of silica sand. Every year, 50 billion tons of sand are extracted but less than 1% qualifies for the glass manufacturing process.
Batching involves carefully mixing the raw materials for making glass in the proper proportion to achieve the necessary thickness and quality. The primary ingredients of silica sand, soda, and limestone form the base of the mixture. Depending on the requirements for the glass, other ingredients may be added to color the glass or adjust its properties to meet the needs of an application.
During the batching process, the ingredients are melted together in a vessel or furnace, referred to as a day tank, at temperatures as high as 1600°C (2912°F) until they form a molten mass. To ensure the purity of the molten glass, it is stirred to make its thickness consistent and remove air bubbles trapped in the mass. In effort to assist with the stirring process, sodium sulfate may be added.
Batching is used as a manufacturing process due to its scalability in regard to customer demands. Multiple formulations can be used, which helps avoid cross contamination between glass compositions. The adjustability of batching makes it an ideal process for short runs and short lead times with production volumes of a quarter ton up to a ton.
The differences in melting practices are dependent on the scale and scope of the manufacturing, the composition of the glass, downstream processes, and product quality. Although batching is a common first step in the glass manufacturing process, the continuous melting process is also used. The choice of process is dependent on volume, speed, flexibility in design and cost.
Continuous glass melting is a different glass manufacturing process that uses a different mixing process. In the batching process, the measured ingredients are mixed and melted in a large day tank. In the continuous process, the mixture of ingredients is continuously added at one end of the furnace and removed, continuously, as glass at the other end of the furnace. It is a high throughput, high volume production method that produces 100 to 500 tons of glass per day.
The furnace is charged at the melting side. After charging, the ingredients travel through several heat zones that fine out the mixture before it enters the working zone. Finished glass is pulled from the working side. The melting, refining, and homogenization of the molten glass takes place in different zones, which is driven by the high temperatures of the furnace. The melting process can last as long as 50 hours and deliver glass at 1100°C (2012°F) that is free from inclusions and bubbles. In both batch and continuous glass melting, the melting process is the key to the quality of the final product.
The molten glass from the melter flows over the surface of molten tin, where it begins at 1100°C (2012°F) and exits at 600°C (1112°F). The float bath gives the glass varying thicknesses depending on the requirements of an application. As the molten glass flows over the molten tin, it achieves a smooth, even surface that is devoid of waves and distortions. The viscous molten glass and fluid tin do not mix but make contact forming a perfectly flat connection, which gives the formation the term flat glass for the final product.
Chemical vapor deposition (CVD) is used to lay a variety of coatings that are less than a micron thick. The types of coatings take different forms depending on the requirements of the glass being formed. The coating deposition process takes a few seconds as the glass flows beneath the coaters. The coating material fuses with the hot glass allowing the two materials to bond at a molecular level that creates a hard coated surface that is mechanically and chemically durable.
During the cooling process, the float glass experiences a high amount of stresses, which can cause the glass to break when being cut. To relieve the stress, the glass undergoes a heat treatment in a furnace known as the lehr, a long temperature controlled kiln that has an adjustable gradient through which glass passes. This aspect of the process is precision controlled and includes technology that feeds back the level of stress experienced during the process.
The final step in the glass manufacturing process is the cutting of the cooled glass to a desired size. Diamond cutters with electromagnets for pressure control and accurate cutting are used to remove selvedge that is stressed edges. The long sheets of glass are cut to the desired size guided by a computer program. Since glass is sold in square meters, computers take customer orders and cut the glass in the desired patterns to minimize waste. The use of various electronic systems streamlines the manufacturing process and helps avoid waste.
The shipping process for the finished glass sheets takes different forms depending on the manufacturer and the end use of the glass. Clients work with manufacturers to decide on the size and shapes of the sheets to be shipped. Wooden crates with foam placed between the wood and the glass are commonly used, especially in instances when glass is being shipped long distances. Paper interleaving placed between the glass sheets prevents the pieces from rugging and scratching each other. Crates come in sizes that accommodate the size of the glass.
The key to understanding the different types of glass is understanding their manufacturing processes. The batch method and continuous method are two of the most used processes for transforming sand, soda, and limestone into glass but are the tip of the iceberg in regard to the manufacture of the different types of glass, which vary in accordance with additional methods that coat, toughen, and improve the durability of glass. The glass manufacturing process is used to adjust and change the physical properties of glass to meet unique and different requirements.
The general question regarding the types of glass normally gets a varied set of responses depending on the manufacturer providing the information. This difference between types of glass is due to the specialization by manufacturers since producing all forms of glass can be counter productive and unprofitable. As can be easily understood, the type of glass that is used for windows varies greatly from the type of glass used for aircraft and vehicles. To make an informed decision regarding the type of glass for a project, it is essential to have a basic understanding of the many types of glass manufacturers offer.
Although buying glass for windows is rather straightforward, it is very intelligent to consult with an expert regarding the type of glass that would be preferred. The term window glass covers a wide spectrum of glass types, each of which can provide protection and aesthetic appearance.
The annealing process for glass is designed to relieve the stress on glass that accumulates during the manufacturing process. It is a precision controlled process that improves the durability of glass by reducing stress that could lead to breakage. The term annealing or annealed may be confusing if viewed from the perspective of metal work where annealing refers to heating a metal to a point that it can be worked.
In glass manufacturing, annealing refers to a cooling process where sheets of glass are slowly cooled to remove stress. At the end of annealing, sheets or ribbons of glass are sufficiently cooled to be cut, polished, edged, and drilled. Viewed from a general perspective, proper annealing gives glass strength and prevents it from shattering.
The properties of annealed glass include clarity, versatility, and affordability. Annealed glass is exceptionally clear and allows for unobstructed light passage. After the completion of the annealing process, annealed glass can be cut, drilled, shaped, polished, and formed to meet the needs of any project. It is a cost effective, easy to fabricate, clear glass that is used for a wide range of applications. An important factor to consider when examining annealed glass is its lack of strength for use as safety glass due to annealed glass’ low breaking strength and tendency to shatter into large shards.
Laminated glass consists of two or more plies of glass that are bonded together with interlayers to form a permanent bond. It is an ideal alternative to normal glass in that laminated glass has a tough robust structure, which makes it hard to break. The interlayer can consist of ethylene vinyl acetate (EVA) or polyvinyl butyral (PVB). Pressure rollers are used to mechanically and chemically secure the bond between the layers. When laminated glass endures impact, its interlayers hold the various glass plies together and prevents structural breakage.
The glass and interlayers of laminated glass are available in several colors and thicknesses to meet the requirements of any application. The process for producing laminated glass begins with float glass, which is enhanced by the lamination process adding to the appearance and performance of float glass. The benefits of laminated glass include UV protection, noise pollution control, and an endless list of aesthetic benefits.
Mirror glass has a reflective metal coating that is applied on one side of clear glass. The coating can be made of various metals including silver, aluminum, gold or chrome. Simple mirrors involve the application of the reflective material, which is sealed with a protective layer. The types of mirrors are divided into categories in accordance with the type of material used for the mirror finish.
There are five primary types of mirror glass that are widely used. They include silver, aluminum, tinted, safety, and decorative. Specific applications include the use of convex, concave, anti-fog, and two-way mirrors. In accordance with the variations of mirror types, the glass for mirrors also varies in regard to how the mirror will be used, which varies between mirrors serving as décor to mirrors for industrial use.
The creation of mirror glass begins with a pane of glass that is scrubbed, washed, and cleaned to remove contaminates and other residue. Demineralized water is used in the cleaning process to avoid potential damage to the metals when they are applied. The first metal to be applied is tin, which will become the back of the mirror. The tin allows the second metal, normally silver, to adhere to the mirror since silver does not stick to glass. The application of the silver transforms the glass into a mirror. Once the silver is applied, it is sealed with coats of paint, and the mirror is passed through a curing oven.
Tinted glass is normal float glass that has colorants added for tinting and solar radiation absorption properties. The functions of tinted glass are to reduce heat in a building and serve as an architectural tool for exterior appearance. Tinted glass follows the same manufacturing process as that used to produce float glass with the variation in the process being the addition of colorants that are included in the initial mixture of the ingredients. The colorants, which are metal oxides, take different forms that include various chemicals such as chromium oxide to produce lime green, manganese dioxide for purple, or cadmium sulfide for yellow.
Although factory tinted glass described above is most common, tinted window film is an aftermarket method for creating tinted glass. Most tinted film is made from polyethylene terephthalate (PET) and is applied to clear glass using an adhesive. The film comes in rolls and can be applied by anyone with the right tools.
Aside from its aesthetic value, tinted glass has other benefits. It is used for cars, offices, and glass doors to allow for more privacy and security. Tinted glass is commonly used for UV protection and energy efficiency since it absorbs the sun’s rays. It is shatter resistant, easy to maintain, and has a pleasing appearance.
Toughened glass, also known as tempered glass, can be formed using various processes. During annealing, float glass can be toughened using the chemical reaction and ion exchange created when the glass is immersed in a potassium salt bath at 300°C (572°F). Chemically toughened or tempered glass lacks the strength and stability of heat toughened glass, which is produced by heating annealed float glass to 620°C (1148°F), a point just before the glass softens. The glass is then rapidly cooled such that the outer glass hardens before the center of the glass. This process creates a compressive stress where the center is held under tensile stress by the compressive stress of the outer layers.
The combination of stress and tension is what creates the strength of toughened glass. Prior to enduring the toughening process, toughened glass is cut to size since it cannot be cut after the process. Toughened glass does not shatter but breaks into tiny granular pieces upon impact. It is for this reason that it is used for car side and rear windows. The weakest part of toughened glass is at its edges where the tensile stress is greatest. It is thermal resistant, waterproof, and is ideal for conditions that experience high temperatures.
Insulated glass, also known as double glazed glass, consists of two panes of glass that are sealed together with an air space in between them. The space is filled with air, argon, or krypton gas and is designed to differentiate the temperatures between the exterior of a structure and the interior. The exterior pane has a space bar around its perimeter, a seal, and a desiccant material to absorb moisture. The space bar creates a consistent gap between the panes of glass and space for an inert gas. Although two panes are common, insulated glass can have three or four panes with gas in the space between each set of panes.
The types of insulated glass or double glazed glass are divided in accordance with the number of panes of glass and the types of gas placed between the panes. The most common of the various types is double pane insulated glass that has two panes and an insulating gas. Double pane insulated glass is the least expensive and most widely used. Triple pane insulated glass has an exterior pane, interior pane, and a pane placed between them. The unique structure of triple pane insulated glass creates two spaces for gas or air, providing a more efficient insulated glass structure.
Although air is commonly used for insulated glass, the other types of gas are krypton and argon. Of the two, krypton is the most efficient and most expensive. It is used with triple and double insulated glass. Argon gas is more affordable and most used for insulated gas. It is more efficient than air and less expensive than krypton. The use of insulated glass covers the full spectrum of glass uses from entry doors and French doors to exterior windows and other openings. The effectiveness of insulated glass is further enhanced by using tempered or toughened glass for the panes of glass.
The term obscured glass covers a wide range of glass that has been treated in such a way that anything that is viewed through the glass is distorted or unclear. It isn’t a single form or type of glass but is a category used to describe different types of glass. One of methods of identifying obscured glass is determining the level of the obscurity, which can range from mildly obscured to completely opaque. When making the decision to purchase obscured glass, it is essential to determine the level of obscurity that will be required.
A common category of obscure glass is frosted glass, which has been acid etched to create a pitted surface that permits light through but prevents the ability to distinguish shapes or silhouettes. The wide use of frosted glass is due to its versatility and the ability to embed designs, patterns, and logos in the glass, a factor that makes it popular for commercial applications. Although frosted glass is obscure glass, not all obscure glass is frosted glass due to the countless different methods used to produce obscured glass.
The distortions that are prevalent in obscure glass are created using a variety of methods, including coloring, textures, and creative and pleasing patterns. Satin obscure glass has gained a great deal of popularity in recent years as a design feature and aesthetic architectural highlight. It has a smooth tough surface that has the appearance of etched frosted glass that provides privacy and allows light through.
Included in the processes to create obscured glass are texturing and sandblasting. Textured glass, also known as patterned glass and decorative glass, has a textured surface on one or both sides of the glass. The type of texture is dependent on the desired style and pattern required by an application. With sandblasted obscure glass, an abrasive material, under great pressure, etches the glass, which reduces transparency. The amount of reduction is dependent on the amount of pressure used to apply the abrasive.
Wired glass is plain glass with wire mesh embedded in the glass. It is designed to prevent glass from shattering during emergencies and critical situations. The implantation of wire prevents the glass from breaking and increases the durability and fire resistance of the glass. The purpose is to lower the potentiality of people being injured when glass breaks. The placement of the wire in the glass holds broken shards of glass and prevents them from being projected.
Referred to as shatter proof glass, wired glass is made using a calendaring process where rolled metal wire mesh is unfolded into molten glass. The embedding of the wire mesh creates square or hexagonal shapes in the glass, which can be patterned or smooth. The different types of wired glass are annealed, tempered, laminated, fire rated, tinted, and patterned, which are normal types of glass that have had wire mesh added. The differentiation between the different types is in relation to their strength and cost with tempered, laminated, and fire rated being the most expensive. All versions of wire glass, except for fire rated, do not have a fire rating.
In some instances, there is confusion related to wire glass with the main assumption being that wired glass has superior strength. Actually, wired glass has limited impact resistance, is without shatterproof properties, and is difficult to clean and maintain. Designers and builders use wired glass for specific applications in construction projects. In many cases, tempered glass is preferred for certain projects due its superior strength but is more expensive than wired glass.
Stained glass is an ancient artistic tradition that has evolved over the centuries into a significant art form. The manufacturing process for stained glass is the same as it is for all other forms of glass but includes adding coloring to the glass. Designs are carefully planned in advance to guide craftsmen as to how to cut the glass to fit the pattern. Unlike colored glass, stained glass is a central part of a performative art form that uses glass as the media to produce a design, image, pattern, or vision. Colored glass, on the other hand, is a broad spectrum of glass that is colored with pigments.
Although stained glass was an essential part of cathedrals and churches for centuries, during the reformation, it fell out of favor and was seldom used for decoration. Over the centuries, it regained importance as an art form and has survived into the 21st century. The different creations involving modern stain glass include a full array of designs, visions, and characterizations.
The basic techniques and methods used to produce stained glass designs have remained basically the same. As can be assumed, modern methods create works of art that are more substantial and longer lasting than those from ancient times. The basic pieces that produce a design are held together by narrow strips of lead, which is referred to as lead came. The lead is sufficiently flexible, durable, and adaptable to fit around the shapes, forms, and configurations of a stain glass design. To securely hold the pieces in place, the came is joined by solder, that is an alloy of lead and tin, melts easily, and sets quickly. This final step for preserving a design is the application of a coating of semi-liquid cement for a final secure hold.
Low-E glass minimizes the amount of infrared and ultraviolet light that enters a room without diminishing the total amount of light. It has a microscopically thin coating that is between 15 and 30 micrometers (µm) thick, which is thinner than a human hair that is about 75 µm. Low-E coatings help maintain the temperature of a home by reflecting interior temperatures back inside. The term emissivity is a measure of a surface's ability to emit thermal radiation, which is quantified by comparing it to a perfect emitter referred to as a blackbody.
There are four variables used to measure the effectiveness of Low-E coatings, which are solar heat gain coefficient (SHGC), U-value, visible light transmission (VLT), and light to solar gain.
Low-E coatings can be a hard passive coat or a soft solar control coating. Passive coatings are manufactured using a pyrolytic process, which is applied when the glass ribbon is on the float line causing the coating to fuse with the glass. Solar control coatings use magnetron sputtering vapor deposition, which is a coating applied to cut glass in a vacuum chamber at room temperature. This form of coating is applied to insulated and laminated glass and has lower emissivity and superior solar control.
Coated glass is treated with a thin layer of metallic or oxide material that is applied to the surface of the glass. It is designed to change the characteristics of the glass by giving it special properties, such as those found in Low-E glass. Coatings are applied during the manufacture of glass or afterward and are invisible to the naked eye. The use of coatings plays a crucial role in enhancing the performance and functionality of glass.
Aside from the Low-E coating, other forms of coatings include solar control coatings, reflective coatings, and self-cleaning coatings. The variations between the coatings are in regard to the properties they add to any form of glass. Solar control coated glass reduces heat gain while allowing high amounts of light through. The resulting effect is a cooler and more comfortable environment.
The other forms of coatings, self-cleaning and reflective, have unique special effects. Reflective coated glass has a metallic coating that reflects light and heat, which reduces glare and limits solar heat. It is used to control sunlight in large buildings and increase energy efficiency. In addition, reflective coated glass enhances privacy and makes it difficult to see inside a building.
Self-cleaning glass is coated with a hydrophilic and photocatalytic coating. The hydrophilic portion of the coating causes rainwater to spread evenly over a window, washing dirt and debris away. The photocatalytic aspect breaks down organic dirt under sunlight, which is washed away. As with reflective coated glass, self-cleaning glass is used on large structures as a means of reducing the amount of routine maintenance and cleaning.
In the modern era, coated glass plays an important role in reducing a building’s carbon footprint. Coatings reduce energy costs, minimize the need for heat and cooling, and make buildings eco-friendly. In addition, coatings are made of recyclable materials, a factor that further reduces environmental impact.
The general description of safety glass is a type of glass that is least likely to break and less prone to causing cuts or injuries when broken. It falls under the category of glass that has high strength and is classified as fire resistant. The two types of safety glass are heat strengthened and tempered, which differ in regard to the rate at which they are cooled.
All glass undergoes a cooling process during manufacturing. What distinguishes heat strengthened glass from annealed glass is the rate at which it is cooled. The glass is heated to a point just below its melting point and then cooled at a moderate rate. The cooling process alters the structure of the glass such that the outer surface compresses the inner layer in the same manner as toughened glass. The result is glass that is 2 to 4 times stronger than normal glass.
By comparison, tempered glass, known as toughened glass, is heated to the same level as heat strengthened glass but is cooled at a rate that far exceeds that used to cool heat strengthened glass. The result of the process is glass that is 4 to 5 times stronger than heat strengthened glass. The tempering process makes tempered glass better able to resist the effects of heat, wind, and impact.
Along with wire glass and laminated glass, heat strengthened glass and tempered glass are referred to as safety glass. Unlike regular annealed glass, when safety glass experiences force or pressure, it shatters into small fragments that have little chance of causing harm. Laminated glass is classified as safety glass due to its PVB film preventing glass particles from being projected outward.
Ballistic glass is a bullet-resistant glazing that is designed to absorb the impact of projectiles that are initiated by explosive force with high energy. It is errantly referred to as “bulletproof” glass, which is a misnomer. Ballistic glass is made of polycarbonate, acrylic, and glass clad polycarbonate. It is important to understand that no type of glass is bullet proof or capable of completely blocking the energy of projectiles. Regardless of the structure of a piece of glass, it will eventually succumb to persistent ballistic attacks. The real measure of glass’ strength and stability is its resistance to ballistic attacks.
Monolithic acrylic is the most common form of ballistic glass. It consists of optically clear acrylic of varying thicknesses that meets levels 1 and 2 of Underwriters Laboratory’s UL752 requirements. Acrylic glass is capable of stopping three shots from a 9 mm handgun and three shots from a .357 Magnum. The attraction of acrylic glass is due to its easy workability. It can be drilled, routed, cut, slotted, and custom formed.
Polycarbonate ballistic glass is made by laminating the polycarbonate between two sheets of acrylic to make a laminated polycarbonate. The resulting glass meets UL levels 1, 2, and 3. Unlike acrylic bullet-resistant glass, polycarbonate glass is less clear but still retains positive aesthetic properties.
Laminated glass is the original form of bullet-resistant glass and has been crafted for many years as a protective glass. The manufacture of laminated glass includes many layers of glass and resin, which can be polycarbonate or acrylic. As with typical laminated glass, bullet- resistant glass has an interlayer that is a thin adhesive film. Once the layers and panes are completed, they are vacuum sealed and pressure heated in an autoclave, a process that binds the elements together.
Soda lime glass is the most common form of glass. It is known as soda lime silica glass, which are the ingredients used to manufacture soda lime glass. The three compounds are mixed in different proportions to manufacture soda lime glass with the proportions being 60% to 75% silica, 12% to 18% soda, and 5% to 12% lime. Alterations in the percentages of ingredients allow producers to manufacture different types of soda lime glass. Some forms have high strength and resistance to the effects of chemicals.
The list of uses for soda lime glass covers nearly every possible application from food and beverage packaging to an insulator for high voltage electronics. Although soda lime glass is normally clear, colors can be added for the manufacture of glasses, bottles, and other glass containers. Of the many forms of glass, soda lime glass is by far the least expensive and most readily available. It is not capable of enduring stress, impact, or extreme temperatures. In essence, soda lime glass is an every day glass that is the most widely used type of glass.
Acoustic glass is a thick heavy glass that has exceptionally high sound reduction efficiency. It is a laminated glass that consists of two or more layers of glass that are bonded by a polymer interlayer. The decoupling of the glass panes in the manufacturing process further insulates against sound and the vibrations that sound generates. The use of PVB as the interlayers further improves the sound dampening capabilities of acoustic glass.
The effectiveness of acoustic glass is determined by its acoustic rating. The acoustic rating is measured by the sound transmission class (STC) rating, which is the standards set by ASTM E90 and ASTM E413. The measurement process includes placing the glass to be tested between two rooms. Sound pressure is raised in both rooms and compared. The difference between the readings is used to calculate the transmission loss of the glass. The higher the STC rating of a glass indicates that it blocks more sound. A STC rating of 60 or higher means that a glass is good for soundproofing.
The two main types of acoustic glass are divided between outdoor and indoor. Outdoor ratings are in compliance with ASTM E 1332 and are measured as OITC or Outdoor-Indoor Transmission Class ratings that are similar to STC ratings, which are used for interior ratings. For a glass to be classified as acoustic glass, it has to meet the requirements stipulated by ASTM.
Chromatic glass has varying levels of transparency to protect against daylight. It can be photochromatic where the glass includes a light sensitive lamination. When chromatic glass is manufactured with electrochromic material, it has an electrical lamination, while the inclusion of a thermoschromatic material makes the glass heat sensitive. Photochromatic, electrochromic, and thermoschromatic are the designations of the three different forms of chromatic glass.
The purpose of chromatic glass is to control transparent efficiency in order to protect the interior of a structure from daylight. It is used in intensive care units (ICUs) and meeting rooms.
The strength of glass is determined by its cooling method, such as annealing, heat strengthening, or tempering, and can be further enhanced by special coatings to increase toughness and durability.
Annealed glass is slowly cooled to relieve internal stresses for clarity and workability, while toughened glass is rapidly cooled to create compressive stress, making it much stronger and causing it to break into small pieces.
Laminated glass has multiple glass plies bonded with interlayers like EVA or PVB, which hold the shards together upon impact, preventing structural breakage and reducing injury risks.
Silica sand is essential due to its high silicon dioxide content and purity, enabling the production of strong, durable, and transparent glass compared to regular sand, which contains more impurities and different minerals.
Insulated glass (double or triple glazed) enhances thermal efficiency, while acoustic glass uses laminated layers and polymer interlayers to reduce sound transmission, making them ideal for energy savings and noise control.
Obscured glass, such as frosted, textured, sandblasted, or satin glass, distorts visibility while allowing light through, making them popular choices for privacy in offices, residences, and commercial spaces.
There are hundreds of different varieties of glass that are produced by adjusting the materials that are used to manufacture glass. The element that is found in all types of glass is silicon, which is the second most prevalent element on earth. Although silicon is a common element, it is not found in its natural state but is part of several chemical compounds. Of the many compounds, silicon dioxide or silica is the most common and is found in sand. Over 70% of glass is made up of pure silica sand.
The primary raw materials for glass are found in all forms of glass and are the foundational ingredients. The percentage of each type of ingredient determines the strength, color, and type of glass
Silica sand, also known as quartz sand, white sand, and industrial sand, contains silica and oxygen. It is a chemically inert hard mineral that rates at 7 on the Mohs hardness scale, which makes it ideal for the manufacture of glass. Unlike regular sand that is chemically reactive due to the elements it contains, silica sand is unreactive, a factor that makes it easy to handle during glass production. Of the materials used to produce sand, 75% of all glass is silica sand.
The variations in silica sand are in accordance with the sand’s grain size, shape, color, structure, distribution, and refractoriness, which influences silica sand’s strength and stability. These characteristics fluctuate and change according to the mineral from which the sand is mined.
Pure silica sand, with a 99.5% silica oxide content with an iron content less than 0.02%, is used for the manufacture of glass. It is the primary standard ingredient in all glass products. The purity of silica sand determines the color, strength, and clarity of glass products. The durability of Silica crystals, which are hard and have a melting point of over 1600°C (2912°F), makes silica oxide ideal for glass production.
Soda ash or sodium carbonate is used in glass production due to its ability to reduce melting temperatures. Its alkali content makes glass easy to shape. Soda ash is a white, crystalline powder with a high alkaline content that is a primary content in glass due its ability to provide clarity, durability, and chemical stability. Soda ash makes up 12% to 15% of the glass mixture.
Limestone or calcium carbonate adds calcium oxide to the glass mixture, which improves the chemical resistance of glass and increases its durability. It makes up 5% to 10% of the glass mixture and is a basic ingredient in soda lime glass, which is the most common form of glass. Limestone reacts with all of the other substances found in the glass mixture to form a complex compound that determines the properties of glass.
Aside from the primary materials that are the foundation and necessary part of glass manfacturing, additional materials are included in the mixture to provide unique properties and characteristics to meet the requirements of an application. Each form of additional material enhances strength, durability, thermal stability, thermal resistance, and reduces thermal expansion.
Alumina or aluminum oxide is used in glass to provide hardness that is second only to diamond hardness. Its addition makes glass scratch resistant and highly durable. The thermal and chemical resistance provided by alumina enables glass to be used for spacecraft windows.
As with alumina, magnesium oxide is added to the glass mixture to improve durability and thermal stability. It is a material that is used in the production of specialty glass where melt viscosity is necessary for mold control and a reduction in breakage. Magnesium oxide is compatible with the base materials used to produce glass and enhances the performance of the overall mixture.
Boron oxide or boric oxide is a mixture of boron and oxygen and appears as a white solid. As with other compounds, boron oxide blends easily with the other ingredients in the glass mixture. It acts as a network former and helps build the framework of the glass. The inclusion of boron oxide leads to the forming of borosilicate bonds, a factor that enhances the mechanical strength, reduces thermal expansion, and adds flexibility to glass.
Different metal oxides are added to glass to give it various colors. Gold, red, blue, violet, and purple are all produced by adding gold chloride, magnesium dioxide, and cadmium sulfide. The addition, amount, and type of metal oxide that is added is determined by the use of the glass and its mixture.
Opacifiers, opacifying agents, and pacifying pigments are added to glass to increase its opacity and include a group of materials that have a high refractive index and resistance to high temperature. They include alumina and calcium carbonate. Opacifiers increase opacity by scattering light. It is a glaze additive that transforms glaze into an opaque material. Opacifiers do not dissolve into the glass mixture melt but become suspended in the material to reflect and scatter light.
Fluxes in glass production, like soda ash, lowers the melting point of silica to help the basic raw materials to fuse at a lower temperature. The uses of fluxes make the glass production process more efficient and increase elasticity, strength, and the hardness of glass. The list of fluxes includes lithia, boric oxide, lime, and zinc oxide. Lime decreases the viscosity of glass at high temperatures but increases the rate of setting and provides the highest tensile strength.
The above list of minor additives is a small sampling of the many compounds that manufactures use to improve and enhance their products. The glass industry is ever changing and innovating to produce glass products that can withstand the stress of modern day use.
Glass is found in every part of life. It is used to make windows, doors, and cookware and as a shield against the elements. Glass is one of those materials that has become so common that it is taken from granted and ignored. Artistic forms of glass are praised for their appearance and valued for their aesthetics. Windshields on cars, airplanes, and equipment serve as protection and provide safety. All of these aspects of glass emphasize the importance of glass and its role in society.
The uses of glass extend beyond windows, glassware, and doors to more critical functions where glass serves as protection and provides safe clean conditions. This wide and varied list of applications necessitates glass that is customized, specially designed and of the highest quality.
The two types of glass used for car windshields are tempered glass and laminated glass. The layers of laminated glass make it thicker and sturdier, which makes the glass difficult to break or shatter. The choice of laminated glass by manufacturers is due to the difficulty of breaking laminated glass, a factor that prevents car break ins. Laminated glass is commonly used for the front windshield due to its propensity to stay intact preventing the driver from being thrown from the car.
Unlike laminated glass, tempered glass is chosen because it breaks easily. The tempering process produces glass that breaks into small fragments with round edges. This factor is the reason that tempered glass is referred to as safety glass. The characteristics of tempered glass makes it the normal choice for side and rear windows. Since it does not shatter when broken, it will not produce dangerous shards when impacted.
Airplanes use a stretched acrylic glass that is composed of acrylic that is physically stretched and molded. The glass includes a layer of normal glass that is placed over the acrylic panes. In special cases, a layer of urethane is placed between the acrylic and glass to enhance the strength of the glass. Most airplane glass is water repellent due to the application of a coating of hydrophobic material that is found in water repellent windows. The use of the acrylic material for the manufacture of airplane windows is the need for limiting the weight of materials placed on an aircraft.
Cleanrooms are divided into classifications in regard to the amount of particulate matter contained in the air in the room. The standards for cleanrooms have been established by the International Organization for Standardization (ISO). As the requirements for cleanrooms increase, the adherence to the standards requires the use of materials that help in maintaining those standards.
The materials used to produce cleanroom windows are restricted to a select set of glass and frame materials. The most common type of cleanroom windows are tempered windows that are disinfectant resistant, long lasting, and have superior visual clarity, a necessary requirement for cleanrooms. It is common for cleanrooms to have fire rated window panes that have been glazed and are multi-layer laminated. The approved materials for window frames are stainless steel and polypropylene, which are easy to clean, resistant to chemicals and biocides, and are long lasting.
A common use of glass is for the manufacture of optical lenses that can be flat, concave, or convex and are used for distributing natural or artificial light for illumination or magnification. Lenses can be made from any type of glass and come in a wide range of sizes, shapes, finishes, and tolerances. By bending light, optical lenses can converge it to a central point to form a focused image or spread the light to brighten an area. The ability to manipulate and change light makes lenses an essential part of eyeglasses, cameras, microscopes, telescopes, and lasers.
Optical lenses are made in a wide variety of ways in accordance with the application for which they are required. In addition, the materials for optical lenses take several different forms and include various forms of plastics.
Glass cutting is a method of weakening the structure of glass along a score line that can be broken by applying controlled force; this separates the glass into two sections along the score line or fissure. Regardless of the application, the cutting of glass is...
Quartz is one of the most abundant and widely distributed minerals in nature. Quartz is the only stable polymorph of crystalline silica on the Earth‘s surface. It is found in all forms of rocks: igneous, metamorphic and sedimentary. It becomes concentrated in...
Acid etching, also known as chemical etching or photo etching, is the process of cutting a hard surface like metal by means of a specially formulated acid for the process of etching in order to allow for the creation of a design onto the metal...
Alumina ceramic is an industrial ceramic that has high hardness, is long wearing, and can only be formed by diamond grinding. It is manufactured from bauxite and can be shaped using injection molding, die pressing, isostatic pressing, slip casting, and extrusion...
A ceramic insulator is a non-conductive insulator made from red, brown, or white porous clay that provides a bridge between electronic components and has high dielectric strength and constant and low electrical loss. They are easy to maintain and...
Ceramic machining refers to the manufacture of ceramic materials into finished usable products. Machining involves the continual removal of material from the workpiece, in this case, ceramic material...
Chemical milling is a subtractive machining process that removes material from a workpiece to achieve a desired shape. Unlike aggressive milling methods that depend on sharp tools to produce a design, chemical...
A graphite crucible is a container used for melting and casting non-ferrous, non-iron metals such as gold, silver, aluminum, and brass. The main reason graphite crucibles are popular as a manufacturing tool is their thermal conductivity...
Graphite machining is a method for shaping, forming, configuring, and cutting graphite material to produce a wide selection of parts and components for industrial applications. The success of graphite machining is dependent on the types of tools used...
Rods are thin, straight rods made of plastic, metal, ceramic, or organic substance. They are relatively simple to construct and can serve a variety of functions depending on their composition and size...
Metal etching is a metal removal process that uses various methods to configure complex, intricate, and highly accurate components and shapes. Its flexibility allows for instantaneous changes during processing...
Photochemical etching, also known as photochemical machining or metal etching, is a non-traditional, subtractive machining process in which photographic and chemical techniques are used to shape the metal workpiece...
Zirconia Ceramics, or zirconium dioxide ceramics, are exceptionally strong technical ceramic materials with excellent hardness, toughness, and corrosion resistance without the brittleness common to other ceramic materials...