How Are Light Bulbs Produced?

Structure

The structure of a light bulb is simple. It requires only a few materials to construct it. The filament of a light bulb is usually made of tungsten. Though tungsten is relatively fragile, it can withstand heat temperatures of 4,500 degrees Fahrenheit, which is why it's preferred.

The Process

When first invented, light bulbs were constructed by hand. Now with the invention of technology, the manufacturing of light bulbs is automated. Through a process called "drawing," the tungsten is pulled through a die (a small wire). The wire is then wound around a piece of metal bar (a mandrel). This creates a coil. It is then heated to soften the wire. The mandrel will then be dissolved in acid. The filament will be connected to two wires.

Creation of the Bulb

A ribbon machine creates the bulbs. Moving along a conveyor belt is a succession of glass ribbons. Once heated, they will move along this conveyor belt. Air is blown into the glass through holes, which creates casings for the bulbs. The bulbs are cooled and cut down. The inside of the bulb is then covered in silica. Once this is completed, a logo of the bulbs manufacturer will be stamped upon the bulb. A base with indentations will then be placed on the bottom of the bulb.

Construction

After the pieces of the bulb have been made, they are then assembled together with machines. The filament is placed on a mount to a stem assembly and clamped to the two wires. The air is removed from within the light bulb and replaced with an argon and nitrogen mixture. The base of the bulb is then sealed to the glass. Once this is done, the process is complete, and the bulbs will be tested, packaged and shipped.

Parts of the Bulb

Parts of the light bulb diagrammed: 1. Glass bulb 2. Inert gas 3. Tungsten filament 4. Contact wire (goes to foot) 5. Contact wire (goes to base) 6. Support wires 7. Glass mount/support 8. Base contact wire 9. Screw threads 10. Insulation 11. Electrical foot contact

Resources

• Light Bulbs
• How Light Bulbs Are Made