A factory is an automated terran structure which acts as the primary production center for vehicles, structures, and ammunition.
The factory maintains first-class housing for the elite crews of tanks, walkers and the other mechanical units it produces. The factory walls are made of reinforced neosteel, making the structure one of the most survivable in any terran base. The factory contains heavily reinforced fuel supply reservoirs, as well as interior construction cranes to aid in the lifting and assembly of machinery, and ventral thrusters allowing it to liftoff.
Protoss plasma shields have finally given us the ability to fit the tech lab and the reactor into a single structure add-on. This new add-on, known as the tech reactor, replaces the old tech lab and reactor add-ons, and allows us to train two of any unit type simultaneously.
All structures repair themselves to 50% life. All structure fires are automatically put out.
This all-in-one safety system automatically dispatches robotic drones to put out any fires and perform basic repairs on damaged structures. Although these drones are effective at doing basic repairs, they do not have a strong enough AI to perform the more delicate repairs needed to restore a structure past half life.
The balance between team color and metal was the focus of factory development in StarCraft II. During development, artist Phill Gonzales hid posters of "fat chicks" on the back wall of the factory. However, they were spotted during a Q&A session and he was forced to remove them.
As of April 2012, Blizzard was experimenting with a wide range of new terran units for Heart of the Swarm. Many of these originated from the factory, the structure being a "little light" on its unit options.