The Light Bulb

        One of the most important inventions of recent history is the light bulb.  Ever since its invention in 1879 by Thomas Edison, the light bulb has become a staple of modern life.  The light bulb was also a chief catalyst of the Industrial Revolution in the United States.  This marvel of a common consumer product is manufactured by multiple materials and processes.

        To begin with, light bulbs are made of many different materials.  Two specific materials that are used because of their unique properties and advantages are glass and tungsten.  First, glass is used for the main structure of the light bulb because of the advantages that a few of its properties yield toward the overall design of the light bulb.  Obviously, the first advantage is the clarity of the substance.  This allows for the emitted light to easily go through the bulb and into the desired area.  Another advantageous property of glass is its ability to withstand high temperatures without breaking or changing shape.  Furthermore, a vacuum can be kept in glass.  This allows nitrogen and argon to be pumped in a vacuum within the bulb to keep a perfect environment for the filament to have a long life.  Along with glass, tungsten’s unique properties make it a proficient material for the filament of a light bulb.  Tungsten has the highest melting point of all metals, at 3000 degrees Celsius.  This property allows it to be used in a filament of a light bulb and undergo very high temperatures for extended periods of time.  Another advantage of using tungsten is its low cost.  Since so many light bulbs are manufactured, price has become increasingly important.  

        In addition to the materials being important in the manufacturing of light bulbs, the processes are important as well.  One process that is described in Integrated Manufacturing and Design is blow molding.  This process is used to make the bulb of glass.  This process involves heating the glass to a temperature where its shape can be changed, and blowing air in a ribbon of glass to get the desired shape.  This process is suitable for light bulbs because blow molding allows many products to be made at a time.  A machine conducting this process is capable of creating 50,000 bulbs per hour.  However, this process may have possible limitations such as the inability to make bulbs of custom shapes and sizes.

        Many other processes are used to create light bulbs, including a couple that were not described in Integrated Manufacturing and Design.  One process is the drawing of wire.  This process creates the wire used for the filament of the light bulb.   The tungsten is mixed with a binder material and then pulled through a die to create a threadlike wire.  This wire then goes through more processes in order to become a filament, ready to be put into a light bulb.  The drawing process is further illustrated below by Figure 1.[pic 2][pic 1]

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