Tesla is working with multiple 3D printed sand casting companies
Breakthrough centers on how giant molds are designed and tested for mass production
Remember when, in 2020, we were the first media to show you the massive generatively designed cast part created by Tesla for the Model Y? There were no clear indications that the part was produced using 3D printed sand casting but it was very likely since it enabled the company to reduce 70 components into a single one. Now, according to an article from Reuters, Tesla’s casting innovations do center on sand 3D printing (such as the technologies described in VoxelMatter’s Traditional Ceramic and Sand AM Market Report 2023).
The leading news portal cites five different persons from design and casting specialists in Britain, Germany, Japan and the United States. All spoke to Reuters on condition of anonymity because they are not authorized to speak to the media. The breakthrough Tesla has made centers on how the giant molds for such a large part are designed and tested for mass production, and how casts can incorporate hollow subframes with internal ribs to cut weight and boost crashworthiness.
According to the detailed Reuters article, so far, automakers have shied away from casting ever-bigger structures because of the “gigacast dilemma”: creating molds to make parts of 1.5 meters squared or more boosts efficiency but is expensive and comes with myriad risks.
Once a large metal test mold has been made, machining tweaks during the design process could cost $100,000 a go, or redoing the mold altogether might come to $1.5 million, according to one casting specialist. Another said the whole design process for a large metal mold would typically cost about $4 million.
That has been deemed prohibitive by automakers – especially as a design might need half a dozen tweaks or more to achieve a perfect die from the perspective of noise and vibration, fit and finish, ergonomics and crashworthiness, the sources said.
But Musk’s vision from the start was to find a way to cast the underbody in one piece, despite the risks, the sources said.
To overcome the obstacles, Tesla turned to firms that make test molds out of industrial sand with 3D printers. The complete list of these companies is available on VoxelMatters’ Directory and in the market report mentioned above. Using a digital design file, printers known as binder jets deposit a liquid binding agent onto a thin layer of sand and gradually build a mold, layer by layer, that can die-cast molten alloys.
According to one Reuters’ source, the cost of the design validation process with sand casting, even with multiple versions, is minimal – just 3% of doing the same with a metal prototype. The value proposition of 3D printed sand casting is also described in detail in VoxelMatter’s report.
That means Tesla can tweak prototypes as many times as needed, reprinting a new one in a matter of hours using machines from companies such as Desktop Metal (DM.N) and its unit ExOne, or German company voxeljet and several other Chinese companies operating in the Chinese market.
The design validation cycle using sand casting only takes to two to three months, two of the Reuters’ sources said, compared with anywhere from six months to a year for metal mold prototypes.
