Even the earliest automobiles were assembled using a production line, sometimes known as an assembly line, because this is an efficient and quick way to produce a finished product while lowering overall costs. The car production line involves several stations at which workers or machines will perform various steps in the assembly process. The car-in-production will then move along a motorized conveyor system that will bring the car to the next work station, where a worker will perform yet another task. The specific parts of a car production line can vary by manufacturer, as some manufacturers will create more than one type of car on a single line or in a single factory.
In many factories, the car production line starts with the set-up, in which the frame of the car is mounted to the conveyor system. The frame is essentially the skeleton of the vehicle, and all other parts will be secured to this frame or supported by it. Once the frame is secured to the line, various components such as the engine, transmission, drive axles, and even the body can be secured to it at various stations along the car production line. The order of these component installations can vary by factory.
Sometimes the body of the car is assembled on a separate line, then brought to the main production line for installation on the frame. In other instances, body panels are installed onto the car on the main car production line as necessary. Panels do not necessarily need to be installed all at once, either; in most cases, it is easiest to install panels one at a time, thereby allowing internal components to be installed even after some body panels have been installed. The trunk, for example, may be installed early on in the process, but the hood and quarter panels, as well as the door panels, may be left off until internal components can be installed.
On modern car production line models, robotic machinery will often install components that humans used to be responsible for installing. This is done to improve safety, but also to improve efficiency, as robots can make the same motion over and over again within the same tolerances and with fewer mistakes. Humans are still required to install many other components, however, as installation may require certain skills and adaptability that a computer cannot accommodate. Once the car has been inspected — usually by a human — the car will be finished and ready for use.