The electric car company revealed last week that it manufactured 260 Model 3s in the third quarter--far less than the 1,500 Musk predicted in July.
On Friday, the Wall Street Journal reported that Tesla was still making major components of the car by hand. Car manufacturing experts told the Journal that it's uncommon to be manufacturing vehicles this way, especially as a car maker prepares to move into mass production.
On Sunday, Musk responded by posting a video to Instagram of the Model 3 being assembled by four robotic arms.
Tesla issued a statement to Forbes in which it called the Journal's reporting "fundamentally flawed and misleading."
"Every vehicle manufacturing line in the world has both manual and automated processes, including the Model S and Model X line today," the company wrote. "As we've always acknowledged, it will take time to fine-tune the line for higher volumes, but as we have also said, there are no fundamental issues with Model 3 production or its supply chain, and we are confident in addressing the manufacturing bottleneck issues in the near-term."
Tesla has said that it wants to deliver all 400,000 preordered Model 3s within a 12-month time frame. The first of the $35,000 electric vehicles rolled off the lot in late July.
So far, Tesla has focused on delivering vehicles to company employees and investors. It wants to begin shipping to customers by the end of the year. Musk has also said he hopes to be producing 5,000 Models 3s per week by that time.