Chapter 3, Problem 4C

The Tesla Model S, one of the most sought-after luxury cars, is produced in Tesla’s Freemont factory in California. The production process can be broken up into the following subprocesses.

Stamping: In the stamping process, coils of aluminum are unwound, cut into level pieces of sheet metal, and then inserted into stamping presses that shape the metal according to the geometry of the Model S. The presses can shape a sheet of metal in roughly 6 seconds.

Subassembly: The various pieces of metal are put together using a combination of joining techniques, including welding and adhesion. This creates the body of the vehicle.

Paint: The body of the vehicle is then moved to the paint shop. After painting is completed, the body moves through a 350° oven to cure the paint, followed by a sanding operation that ensures a clean surface.

General assembly: After painting, the vehicle body is moved to the final assembly area. Here, assembly workers and assembly robots insert the various subassemblies, such as the wiring, the dash board, the power train and the motor, the battery pack, and the seats.

Quality testing: Before being shipped to the customer, the now-assembled car is tested for its quality. It is driven on a rolling road, a test station that is basically a treadmill for cars that mimics driving on real streets.

Overall, the process is equipped with 160 robots and 3000 employees. The process produces some 500 vehicles each week. It takes a car about 3–5 days to move from the beginning of the process to the end.

Imagine you could take a tour of the Tesla plant. To prepare for this tour, draw a simple process flow diagram of the operation.

How many cars are you likely to encounter as work in progress inventory?