Clothes Iron (How Products are Made)
A clothes iron is a household appliance used to press the wrinkles out of and creases into clothes. When the iron is turned on, the consumer moves it over an item of clothing on an ironing board. The combination of heat and pressure removes wrinkles.
Irons have evolved over hundreds of years from simple objects made of metal (though they were sometimes made of glass or other materials) that were often heavy and hard to use. Before heated dryers were invented, irons served another purpose as well. Hot irons killed parasites and bacteria in clothing, and eliminated mildew. Most modern irons are made of metal and plastic, and have many features such as steam, temperature controls, and automatic shutoff. Steam provides an additional means for removing wrinkles from clothing.
Though objects have been used for thousands of years to remove wrinkles and/or press clothing, for much of that time only the wealthy had their clothes so treated. Because the use of such implements was hard and laborious, only the rich could afford to employ people (usually slaves or servants) to do the work. In about 400 B.C., Greeks used a goffering iron to create pleats on linen robes. The goffering iron was a rolling pin-like round bar that was heated before use.
Empire-era Romans had several tools similar to the modern iron. One was a hand mangle. This flat metal paddle or mallet was used to hit clothes. The wrinkles were removed by the beating. Another implement was a prelum. This was made of wood and not unlike a wine press. Two flat heavy boards were put between a turnscrew, also made of wood. Linen was placed between the boards and the increasing pressure applied by the turmscrew created pressure to press the fabric.
The ancient Chinese also had several primitive types of irons, including the pan iron. The pan iron looked rather like a large ice cream scoop. This iron had an open compartment with a flat bottom and a handle. The compartment held hot coal or sand, which heated the bottom of the pan iron. It was moved across clothing to remove wrinkles.
By about the tenth century A.D., Vikings from Scandinavia had early irons made of glass. The Vikings used what was called a linen smoother to iron pleats. The mushroom-shaped smoother was held near steam to warm up, and was rubbed across fabric.
What contemporary consumers would recognize as an iron first appeared in Europe by the 1300s. The flatiron was comprised of a flat piece of iron with a metal handle attached. To heat the iron, it was held over or in a fire until it was hot. When a garment was pressed with the flatiron, it was picked up with a padded holder. A thin cloth was placed between the garment and the iron so that soot would not be transferred from implement to the finished garment. The flatiron was used until it was too cool to do its job. Many people owned several flatirons so they could heat one or more while one was being used.
In approximately the fifteenth century, an improvement over the flatiron was introduced. The hot box (also known as the box iron or slug iron) was made of a hollow
Many innovations in iron technology came in the nineteenth century. When cast iron was invented in the early part of the nineteenth century, some of the problems with flatirons were solved. With the advent of cast iron stoves, flatirons could be heated on top of them, which was much cleaner than a fire. By the 1820s, cast iron was also used to make flatirons. These irons were called sad irons because they were heavy, weighing about 15 lb (5.6 kg), and hard to move.
Like flatirons, sad irons were heated on the stovetop, but they sometimes heated unevenly. The handle also heated up, which posed problems for users. American Mary Potts solved these predicaments in 1870. She made a cardboard base and filled it with plaster of Paris. This was placed around the iron's body and kept it cooler for more even heating. Potts also devised a detachable wooden handle that was spring loaded for the sad iron. Because wood does not hold heat in the same way that iron does, the person using the iron would not be burned.
After gas became available in American homes in the late 1800s, gas irons came into existence. The earliest were patented in 1874. Homes had individual gas lines into them, and the gas iron was hooked up to the gas line by a pipe. The iron contained a burner to which the gas flowed. When the burner was lit with a match, the iron heated up. The iron was very hot and gas sometimes leaked, but the gas irons were lighter than sad irons. Other fueled irons soon followed. These irons were heated with oil, gasoline, paraffin, and other fuels.
The electric iron was invented in the 1880s when electricity became widely available in homes. The first electric iron was patented by Henry W. Seeley in 1882. His iron was hooked up to an electrical source by detachable wires. The electricity stimulated the iron's internal coils. But Seeley's iron, like many early electric irons, did not have electric cords. The irons were heated on a stand. One big problem with Seeley's iron was that it heated very slowly on the stand, and cooled quickly while in use. This iron had to be reheated frequently.
By the turn of the century, iron technology had progressed considerably and irons became more common in American house-holds. In 1903, irons with electric cords directly attached to the iron were being sold. Earl Richardson invented a sole plate (the bottom part of the iron that is made of metal and does the actual pressing) that improved how and where sole plates were heated for better ironing. His iron had more heat in the tip than in the center and was known as the Hotpoint.
In the 1920s, Joseph Myers improved the iron and cord by adding an automatic heat control made of pure silver. Thermostats soon became a standard feature. The first cordless irons were introduced in 1922, though they did not catch on. (The first successful cordless irons were sold in 1984).
In 1926, the steam iron was introduced by the Eldec Company. Steam made it easier to smooth dry stiff fabrics. Previously the user sprinkled water on dry clothing, or clothing had to be ironed when damp. The steam irons employ a water tank that allows heated water vapor to be created and applied through small holes on the sole plate. Steam irons did not become popular until the 1940s.
Edward Schreyer conquered the problem of rusting sole plates in 1938. He developed an aluminum alloy that would not rust or leak. Irons that could vary between steam or dry were introduced in the 1950s. The first iron with automatic shut off was introduced in 1984.
Contemporary irons have nonstick coating on the sole plate, an innovation that was introduced in 1995. Most featured bodies made of plastic and more holes on the sole plate to allow steam to come through. A whip holds the cord out of the way during use. In 1996, about 13-14 million irons with a variety of features were sold in the United States.
Irons are made primarily of plastic and metal (aluminum and steel). The materials often come to the factory in the form of plastic resins, aluminum ingots, and steel sheets. The metal is used to make the sole plate, thermostat and other internal mechanisms. Plastics are used to make the exterior and handle, as well as the water tank. Certain components, like the spring for the thermostat, cord, plug, and related connections are usually outsourced by iron companies.
The Manufacturing Process
First, each sub-assembly of the iron is produced, most often on separate, automated production lines. Then the iron is assembled.
- 1 The sole plate is cast of molten aluminum. Part of the mold creates the holes that are essential in a steam iron. Heated metal is inserted into a mold under pressure, cooled, and released.
- 2 The cooled sole plate is treated in one of three ways. It is polished, coated with a non-stick PTFE material, or covered with another metal. Such metals include stainless steel.
- To complete one or more of these processes, the sole plates are put on a large automated carousel, which rotates through each step.
- 3 To polish the plate, an automated belt sander uses bands of abrasive to polish and buff the plate. The finish required determines which grade of abrasive is used.
- 4 An automated spray-painting machine applies non-stick coating. After application, the sole plate is baked in an automated industrial process.
- 5 To coat with another metal, the external metal cover is created by an automated stamp press. The resulting cover is either pressed or riveted onto the sole plate, through a smaller machine press.
- 6 In an injection mold, a small metal post is cast.
- 7 A spring is mounted onto the metal post. This spring is a bimetallic switch made of two different metals with divergent linear thermal coefficients bonded together. The spring actually controls the iron's temperature.
- 8 Power contacts are attached to the end of the spring, which let the electricity through so the iron can be heated. This whole process is generally automated.
- 9 In a two-part injection mold, heated plastic is inserted to make upper and lower sections of the tank. Several openings on the tank are created as part of the mold.
- 10 The mold is put under pressure, cooled, and released as a one-part tank.
- 11 Other parts for the tank (pump, internal chamber, piston, buttons, and other parts) are created by similar injection molding processes.
- 12 On an automated assembly line, the parts are put together, with each of the other parts put onto the water tank.
- 13 In an injection mold, heated plastic is inserted into a mold under pressure, cooled, and released.
- 14 In an injection mold, heated plastic is inserted into a mold under pressure, cooled, and released.
When all the parts are manufactured, the iron is assembled on an automated assembly line.
- 15 The sole plate is the first part on the assembly line. The thermostat is either screwed onto the plate, or welded to the plate by a robot.
- 16 To the sole plate-thermostat subassembly, the water tank is put in place. It is secured on an automated line with screws or other industrial fasteners.
- 17 The handle and body are attached over the sole plate, thermostat and water tank, and fixed by screws. Sometimes this process is automated, but it also can be done manually.
- 18 The electrical cord is the last piece to be added. Sometimes this process is automated, but it also can be done manually.
- 19 After an automated testing process, the irons are inspected by hand.
- 20 Completed irons are packed into indidual boxes with instructions and other documents by hand. (For some companies, this is an automated process.)
- 21 The individual boxes are placed in shipping cartons or master packs for distribution to warehouses.
Before the manufacturing process begins, all the raw materials are sample checked for consistency. As each subassembly of the iron is manufactured, the pieces are checked for correct functionality.
During the assembly process, an iron is removed from the production line and taken apart by an independent department to look for errors. Any mistakes result in the whole batch of irons being checked and corrected if necessary. After the product is assembled, a worker also checks the iron for electrical functionality and water integrity.
Any excess metal or plastic from the molding process is reused in the process, if possible. Anything that is unable to be used is recycled.
The most obvious improvements on the iron probably will be to the sole plate. Better coatings will probably be invented that are more resistant to damage from zippers or other protrusions on garments and reduce drag over fabric. These improvements might be in the form of better alloys or better nonstick coatings. Internal mechanisms that better control heat and steam also will continue to evolve.
Where to Learn More
Alpine, Elaine Marie. Irons. Minneapolis, MN: Carolrhoda Books, 1998.
Walkley, Christina, and Vanda Foster. Crinolines and Crimping Irons: Victorian Clothes: How They Were Cleaned and Cared For. London: Peter Owen, 1978.