Tesmanian, a blog specializing in Tesla news, said on Monday the company's new plant in Brandenburg, near Berlin, would be supplied with eight "Gigapress" machines.
Car bodies have traditionally been made by assembling multiple stamped metal panels, which has helped automakers to design crumple zones to absorb energy during a crash, but Musk is charting a new course at the Brandenburg plant.
"He wants the car's body to be made from modules, as few of them as possible," the source explained. "He sees casting as the new way forward. Like casting a toy car out of metal."
The Gigapress, which is the size of a small house, will be supplied by Italy's IDRA Srl, and forms a key part of Musk's drive to reinvent "the machine that builds the machine," the source added.
IDRA declined to comment. IDRA has previously said it has supplied its first ever Gigapress to a North American auto manufacturer, without naming it.
Musk's push to reduce manufacturing complexity comes as German automakers BMW, Mercedes and Audi face pressure from their workers to preserve domestic assembly jobs which are under threat as regulators push electric cars that have fewer components than combustion-engined ones.
Aluminum has proven cumbersome to use in large components because it is difficult to stamp into complex shapes. To get intricate ridges and other shapes, aluminum pieces have needed to be glued or riveted, since welding deforms the metal.
Injecting molten aluminum into a cast and having robots pull out the molded metal allows Tesla to combine several manufacturing steps.
Sandy Munro, CEO of manufacturing consulting firm Munro & Associates and a previous critic of some of Tesla's manufacturing processes, lauded its improvements.
"We were very critical of Tesla when we first started on their vehicles. The gaps were horrific, the weld spatter was everywhere. Nothing fit," Munro said during a recent presentation with consultants Frost & Sullivan. But the switch from the Model 3 to a larger vehicle, the Model Y, resulted in a step change in manufacturing improvements, he said.
Tesla has already reduced the rear underbody to two parts, forming the largest piece of aluminum that Munro has seen in 30 years of analyzing components. "This is the biggest casting we have seen in a car company. This is just spectacular," he said.