How is a washing machine made?
2008-08-25

Background Mechanical washing machines appeared in the early 1800s, although they were all hand-powered. Early models cleaned clothes by rubbing them, while later models cleaned clothes by moving them through water. Steam-powered commercial washers appeared in the 1850s, but home washing machines remained entirely hand-powered until the early 1900s, when several companies started making electric machines. The Automatic Electric Washer Company and Hurley Machine Corporation both began selling electric washers in 1907, while Maytag offered an electric wringer washer in 1911. In 1947, Bendix offered the first fully automatic washing machine, and by 1953 spin-dry machines overtook the wringer types in popularity. The last wringer washer manufactured in the United States was made in June of 1990 at Speed Queen's plant in Ripon, Wisconsin. The major U.S. manufacturers today are General Electric, Maytag (Montgomery Ward), Speed Queen (Amana and Montgomery Ward), Whirlpool (Kenmore), and White Consolidated (Frigidaire and Westinghouse). Many models with many varying features are now available; however, with a few exceptions, only the controls are different. The only difference between the washer in your home and the top-load washers in the laundromat is the ruggedness of construction. The washing machine operates by a motor, which is connected to the agitator through a unit called a transmission. The motor and transmission are near the bottom of the machine, while the agitator extends up through the middle of the machine. The transmission is similar to the transmission in your automobile in that it changes the speed and direction of the agitator. In one direction (agitate), the transmission changes the rotation of the agitator and spin tub—the inside tub with small holes in it—into a back-and-forth motion. When the motor is reversed by the controls (spin), the transmission locks up and the agitator, transmission, and spin tub all rotate as a unit. Without the transmission changing the speed or direction, the unit uses centrifugal force to remove as much water from the clothes as possible. The motor is also connected to a pump. When the motor is moving in the spin direction, the pump removes the water from the tub and discards it through the drain pipe. Models designed for use in other countries offer different features. One component required on all models sold in England (and possibly soon in the rest of Europe) is called the lid lock. Normally when the lid is raised the washer must stop for safety reasons. However, in England, when the washer is operating the lid must be locked closed. Raw Materials Many parts of a washing machine are manufactured from sheet steel, usually coated with zinc to improve rust resistance. The steel manufacturer supplies the metal in a coil, which allows the material to be cut to size with minimum waste or automatically fed into the forming process. On some models made by Speed Queen, the spin tub is made of stainless steel. All other models use a steel (called enameling iron) designed for a porcelain coating. For the wash tub, which isn't visible unless you open the machine cabinet, enameling iron with a porcelain coating is generally used. Whirlpool is the exception, using plastic instead of enameling iron for the outer wash tub. Many other parts are plastic as well. Manufacturers receive raw plastic from which they fabricate parts in pieces about the size of a small ant, using them for machine components that do not bear weight and/or require extremely good rust resistance. Such parts include the pump, the tub guards (which prevent your clothes from being thrown out of the spin tub into the wash tub or the cabinet area), and the agitator. The transmission is generally made from cast aluminum, which arrives from the manufacturer in ingots—20 pound slabs of aluminum. Scrap parts are usually remelted and reused. Hoses, controls (timers, switches, etc.), and motors are purchased in prefabricated form from other manufacturers.