How Light Bulbs Are Made (Jun, 1933)

How Light Bulbs Are Made

1 Pictures on this page show the steps in the process of making electric light bulbs. First, the tungsten wire filament is drawn through diamond dies. So fine is this wire, one-quarter the diameter of a hair, that it is extremely difficult to see it

2 Here is the mechanical spider that takes the fine tungsten wire and winds it around a steel wire form to shape the filament. An attendant watches the process through a microscope to be sure the spacing is accurate

3 Tungsten coil and steel core then are cut into accurate lengths and the pieces placed in an acid bath which dissolves the core and cleans the filament. Afterward, the coils go to the projector, right, and their enlarged images are inspected in a search for imperfect coils

4 This elaborate machine puts the glass mounting stem in the bulb, while mechanical fingers insert the lead wires, put the filament-supporting grill in place, and hook the filament coil in the exact position necessary to give the best and longest lasting service

5 At right, the last step of all. This machine draws air from the bulb, seals the top, and solders the screw base in place, thus finishing the lamp for packing

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