Inside the factory that builds the LG G4 smartphone (pictures)

LG's 640,000-square-meter Digital Park is home to 10,000 employees working on projects related to televisions, mobile and auto components. A small part of Digital Park is LG's mobile assembly facility, the largest of its five mobile assemblies found around the world.

Two main parts of the G4 drop in at the beginning of the assembly line -- the front of the phone and the "main board," which contains key components. The workers, who work in pairs at each station, scan the parts before assembling them.

An LG worker examines the back of the G4 to ensure everything is up to snuff. There's a lot of pressure to move quickly -- the target for G4 units assembled that day is nearly 15,000.

The G4 has to pass through several stations, including ones that test the various radio signals and another more basic video and audio check. Another station adds a SIM card and battery, while another automated system prints the LG logo at the bottom of the phone.

Once there are enough G4 units to fill a cardboard box, an Auto-Guided Vehicle comes around to pick up the box and ferry them away. It follows a track of gray duct tape on the floor to its next destination.