The production line run by robot arms is a common image used to describe the spread of robotics in industry. Robots have long been deployed in the automotive sector because industrial robots consistently deliver the high quality demanded in car plants, and protect human workers from dirty, difficult and dangerous tasks.  The automotive sector automation can typically be:

CNC Machining: computer numerical control is the automated control of machining tools, without the need for a manual operator. The heavily routinised, repetitive production line tasks are where robots come into their own.
Welding: both Spot and Arc welding, with larger robots deployed to weld car body panels, smaller robots involved in more intricate work on brackets and mounts. The repetitive nature of the task is perfectly suited to the robotic solution.
Deburring and Material Removal: light trimming, cutting and polishing tasks are ideally suited for robots.
Assembly: think of the number of screws, nuts and bolts in a car. Additional tasks such as windshield installation and wheel mounting can efficiently and effectively be undertaken by robotic arms.
Spray: not just paint – robots are also used for spraying coatings such as sealants, primers and adhesives.