The mass production of automobiles

The traditional example of mass production is the automobile industry, which has continued to refine the basic principles originally laid down by Henry Ford and other pioneers of mass production techniques. Today's automobile is the result of a large number of mass production lines established in a multitude of manufacturing and assembly facilities throughout the world. The assembly plant from which the finished automobile emerges is only the final element of a mass production operation that, for many companies, includes plants in several different countries. Into the final assembly plant flow large subassemblies such as the automobile chassis, the engine, major body components such as doors, panels, upholstered seats, and many electronic, electrical, and hydraulic systems such as brakes, lighting systems, and sound systems. Each of these, in turn, is usually the product of a mass production line in another factory. Stamping plants specialize in producing the formed metal parts that constitute the body of the automobile. Radio assembly plants, in turn, depend upon other assembly plants for components such as transistors and integrated circuits. There are glass plants for windows, transmission plants, tire plants, and many others, each specializing in the mass production of its own product, which is, in turn, fed into the final assembly plant. The control of the flow of material into and out of final assembly plants, including the scheduling of production from feeder plants and the timing of rail and truck shipments, is among the major engineering tasks that make the total mass production system for automobiles work.

In the final assembly line one can see clearly how machinery and human effort in assembly are divided into many specialized skills. The special tooling and machinery developed to handle assembly parts and to aid operators in their tasks can also be observed. At a given point on the line a robot welder—unaided by a human operator—may weld body parts together. At another position the motor is mounted on the chassis by a large machine guided by an operator. In other places body panels and doors are assembled to the chassis, and dashboard instruments and wiring are added by hand with simple tools. Each operator learns his task in detail and uses tools specialized for that task. The total operation is paced by the speed of movement of the conveyor that carries the partially assembled automobiles. The number of operators, machine stations, and flow of materials to the conveyor have all been planned so that the conveyor can maintain an essentially constant speed with each operator and machine functioning near optimum effectiveness.

In Ford's early lines, parts and product were precisely standardized. Only one car model was manufactured, and each unit was identical to every other unit in all aspects, including colour—black. Today's automotive manufacturing engineers have learned to mass produce a highly customized product. The same assembly line may turn out a variety of models with many colours and options. This is achieved by continued insistence on standardization of critical elements such as the methods by which parts are held together internally. Thus, the operator who specializes in assembling doors can handle a variety of models and colours equally well. In addition, the flow of materials to the various line positions is carefully scheduled and controlled so that the specific part required for a given model, colour, oroption list arrives at the line at the precise moment that the partially assembled unit requiring the part has arrived along the conveyor. The exquisitely designed production-control systems operating in the automotive and other industries make it possible for the consumer to obtain a greatly enhanced variety of product without sacrificing the cost advantages of mass production techniques.

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