The Model S will be produced at the new Tesla Factory in Fremont, California, The former New United Motors Manufacturing Inc. (NUMMI) plant. Everything from body panel stamping to final quality testing will take place at the Tesla Factory.
The Model S will begin as sheets of aluminum. The sheets will be placed in a hydraulic press machine and stamped into 3-dimensional fenders, hood panels, doors, and roofs. Stamped aluminum saves about half the weight of steel and the decrease in weight enables them to increase overall vehicle efficiency.
Even before they finalized the factory location, Tesla secured machinery and items needed to quickly bring the facility online. The hydraulic press line is of the finest quality and they expect to use it for decades. The press line will produce body panels you can see and structural features you can’t. The remaining body stampings, castings, and extrusions will be produced at outside facilities and shipped to the factory for assembly.
Sub-Assembly
The workers in the Body Sub-Assembly Shop will be responsible for joining the stamped pieces together at stations. It is far more efficient to compile groups of components into assemblies instead of building a car piece by piece on a single production line. The outer panels will be welded to the inner structures.
Framing
Next, the prepared sub-assemblies are moved to the Body Framing Shop. Robotic arms pick up sub-assemblies from nearby racks while other arms move in with glue, weld, and rivet guns to seal and join the parts. The doors, hood, and trunk lid are hung on the main frame. The roof frame that will hold the panoramic glass panels is then attached.
At this stage, precision is paramount. Once framed, the welds, holes, and gaps are checked for imperfections. The structure that leaves the Body Framing Shop is referred to as a “body-in-white.” The body-in-white represents the primary structure of the car and is critical to driving dynamics and occupant safety. Telsa hope to achieve a 5-Star Safety Rating from government crash tests.
Final Assembly
Once the final coat of paint is polished, the car moves to the final assembly area. Here, it transforms from a shell of sculpted, painted aluminum to a sedan. The movable pieces of the car (the doors and trunk lid) are removed and delivered to separate assembly stations for further work. At a door assembly station, for example, wiring is fed between the outer panel and the inner frame, the handles are attached, and the leather pieces are fastened. Other assembly stations work on the dashboard, trunk lining, and other pieces. The parts deepest within the main frame of the car are attached.
Next, the interior sub-assemblies are installed: carpet, headliner, console, dashboard, seats, and the steering wheel. Airbags are installed. The doors, once appointed, are reattached and adjusted for fit.
But, what would the Model S be without the state-of-the-art powertrain and battery systems? With far fewer moving parts than an internal combustion engine, the motor, transaxle, inverter, and rear suspension system will be contained within one sub-assembly that can be bolted into the Model S in one step. The liquid-cooled battery pack, with quick release fluid connections will be installed in a matter of seconds. The battery pack provides the final structural element to the body. With this engineering feat, you’ll be able to quickly swap an empty battery for a full one, should the need arise on long road trips.
Quality Testing
Before delivery, the car must go through quality testing. Typical quality tests consist of a ‘rolling road’, a water test to check for leaks, and an inspection station that ensures all components are installed to standard.