Factory
The Factory is one of the advanced Terran tech buildings that allows Terran to build Hellions, Hellbats, Widow Mines, Siege Tanks, and Thors. The Factory requires a Barracks before it can be built. The Factory can be lifted off and landed elsewhere after it has been constructed.
A Factory is also required before you are able to build a Starport, thus it is a key step in the Terran Tech Tree. It is also required to build a Nuke.
Usage
If you choose to go for a mechanical unit mix towards mid/endgame, then you’ll need to build a few Factories to churn out the mechanical units. With the addition of the Widow Mine and the Hellbat, Mech-Play is a lot more viable. One opener for Mech that has been seen is a push with Marines and Widow Mines to deny the natural. Another successful harassment-method with Mech is Hellbat drops in TvZ and TvT. Hellbats can also replace Marines in TvT, but you will be giving up air control. They are, however, a much better meat shield.
Alternatively, if you choose to go for a primarily Bio-based army the Factory can be used as a scout. The Starport is built as soon the Factory is finished and the Factory is Lifted from the ground and flown in the direction of the enemies base. Since the Starport tech has already started there is no downside to losing the Factory if you are not using its units for your composition. Also, the Factory has a large number of Hitpoints and 1 armor meaning it can withstand a large degree of punishment from enemy units while scouting. A side effect of using this Factory for scouting is that the Factory is landed inside the enemies base and Hellions can be produced and used for extras scouting or harassment. Again, due to the Factory’s hitpoints, in the early stages of the game it can get Hellions onto the field even if the Factory is being attacked. Dustin Browder in an interview with Team Liquid, mentioned that this was not an intended usage of the Factory.
The Factory is one of the key parts in the 1/1/1 build. Another successful build is a Factory opener with Hellion harass.
TERRANS – THE FEDERAL MARINE CORPS.
PRIDE. STRENGTH. DISCIPLINE
Outcasts, lawbreakers and rebels were once sent from Earth to establish the first human colony outside the solar system. Left to their own devices, a tight military organization gave them the adaptability and flexibility they needed to survive in the far reaches of the galaxy. Far away from their homeland, a multitude of more or less independent colonies gradually developed.
Terran Buildings
The nomadic-looking people owe their assertiveness, among other things, to the ability to build their tactical outposts quickly and effectively in the contested area. A special achievement of the Terrans is the ability to land finished buildings from a greater distance in more distant areas.