Elon Musk says first Model 3 will exit the factory Friday

Tesla's affordable mid-size electric sedan, the Model 3, is ready for production, and the first car (Musk calls it SN1 which likely means serial number 1) will be completed on Friday.

That's according to Elon Musk, who shared the news on Twitter, explaining the Model 3 passed "all regulatory requirements for production two weeks ahead of schedule."

Musk also tweeted that he plans to throw a "handover party" for the first 30 Model 3s to be handed to customers on July 28. He says that production will grow "exponentially," meaning the company should be producing 100 cars in August, more than 1,500 in September, and 20,000 in December.

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This is very good news for Tesla, which historically wasn't always able to deliver on its ambitious promises on time. The Model 3 was slated to enter production in July, and that's exactly what will happen, but July has just begun. It's comforting to know that Tesla is ahead, and not behind the schedule on this one.

Tesla started taking reservations for Model 3 cars in March 2016, reaching several hundred thousand pre-orders within days.

The Model 3 starts at $35,000 before tax incentives, and comes with the same Autopilot hardware that's present on the more expensive Model S and Model X cars. Musk made it clear, however, that it is below both those models in the hierarchy of the company's car lineup.

For Tesla, the Model 3 is an incredibly important milestone. It is the affordable car that should sell at much larger volumes than luxury models and thus power the next steps in Musk's ambitious master plan. It also marks the company's transition to a new production line, which Musk claims is several times more automated than the production line of Model S.