Elon Musk says Tesla relied on too many robots to build the Model 3, which is partly to blame for the delays in manufacturing the crucial mass-market electric car. In an interview with CBS Good Morning, Musk agreed with Tesla’s critics that there was over-reliance on automation and too few human assembly line workers building the Model 3.

Earlier this month, Tesla announced that it had officially missed its goal of making 2,500 Model 3 vehicles a week by the end of the first financial quarter of this year. It will start the second quarter making just 2,000 Model 3s per week, but the company says it still believes it can get to a rate of 5,000 Model 3s per week at the midway point of 2018.

“crazy, complex network of conveyor belts”

Previously, Tesla has blamed bottlenecks in the production of the Model 3’s batteries at the company’s Gigafactory for the delays. But in a wide-ranging (and largely positive) interview with CBS’s Gayle King, Musk also admits it was Tesla’s over-reliance on robots in the production.

Musk then said the company needs more people working in the factory and that automation slowed the Model 3 production process. He alluded to a “crazy, complex network of conveyor belts” the company had previously used and said the company eliminated it after it became clear it wasn’t working.

It’s a fairly stunning admission from the man who previously likened his company’s massive factory to an “alien dreadnought” thanks to the complex assemblage of advanced robotic arms building its line of electric cars. In an earnings call with investors last year, Musk spoke about the production speeds facilitated by Tesla’s robots. “It’s remarkable how much can be done by just beating up robots ... adding additional robots at choke points and just making lines go really, really fast,” he said. “Speed is the ultimate weapon.”

“Speed is the ultimate weapon”

Last year, Tesla acquired Perbix, a private machining firm that makes automated equipment for factories, allowing the carmaker to bring the production of more parts in-house. Tesla described the deal as a step further in its long-stated ambition to “build the machine that makes the machine.”

In fact, Musk was so confident that Tesla had gotten right the mix of robots and humans that its giant Gigafactory would become the company’s ultimate product. “The competitive strength of Tesla long-term is not going to be the car, it’s going to be the factory,” he said last February. “We’re going to productize the factory.”

Musk is also one of the foremost voices urging caution in the development of robotics and artificial intelligence. He has called for governments to regulate AI to prevent the technology from threatening human existence, and has warned for a coming “AI apocalypse.”

“We got complacent about some of the things we felt were our core technology”

Also in the interview, Musk said the Model 3’s technical complexities were additionally to blame for the company’s ongoing “production hell.” “We got complacent about some of the things we felt were our core technology, we put too much new technology into the Model 3 all at once,” Musk said.

A spokesperson for Tesla declined to clarify Musk’s comments. While aesthetically more minimal than the Model S or X, the Model 3 uses 2170 lithium-ion battery cells, which are more complex than the industry-standard 18650 battery cells used in the Model S and X. Musk previously confirmed that Tesla’s Gigafactory 1 in Nevada was the source for the production bottlenecks slowing Model 3 deliveries. Panasonic, Tesla’s battery cell manufacturing partner at the factory, has also confirmed this.

To be sure, Musk has used the “too much technology” excuse before. In 2016, he owned up to the problems with production of the Model X, telling an audience of Tesla shareholders, “This [Model X] program has been challenging. I particularly need to fault myself for a fair bit of hubris for putting too much technology all at once into a product.” The Model 3, he said, would not have as much technology as the Model S and X.

Now Musk said he has taken over production of the Model 3, sleeping at Tesla’s Fremont factory in an effort to keep tabs on the vehicle’s rollout. In the interview, he shows King the conference room where he sleeps. A pillow and sleeping bag can be seen in the shot. King calls the couch “not even [...] comfortable.”