Eaton Evaluates Foundry Lab Process as Die Cast Alternative: Aids Prototyping and Supply Chain

In a recent evaluation of Foundry Lab’s 3D-printing-enabled process for digital casting, Eaton successfully cast three electronics industry components the company currently produces through die casting. The parts were made in the same aluminum and zinc alloys as the die-cast versions, and — also like the die-cast versions — two of the parts featured cast-in-place stainless steel pins that were inserted prior to casting. In a conversation with Cameron Peahl, Eaton’s additive manufacturing manager and leader of the company’s Additive Manufacturing Center of Excellence, he described his observations of this test and what it potentially means for Eaton.

One of his observations is this: Parts made through the digital casting process are arguably superior to die-cast parts. Specifically, the density is better. This is good and bad, he notes. Better density is obviously better, but the dissimilarity influences Eaton’s view of the process as a potential die casting replacement. Finding a low-lead-time alternative to traditional die casting, yet one that can deliver parts much nearer to die-cast properties and performance than metal 3D printing, is the main promise Eaton sees in the Foundry Lab process.

Digital Casting and Eaton’s Four Pillars

Foundry Lab’s casting process uses 3D printing to get to a metal part which is not 3D printed. The additive process it uses is binder jetting. A temporary ceramic tool (negative of the cast part) is made this way. Then, within a microwave furnace developed by Foundry Lab, this ceramic tool conducts heat to melt a slug of raw material. A cast part is the result, and it can be obtained, including 3D printing the tool, within a lead time of less than a day. Here is a video with more detail on the Foundry Lab process.

So, while the process is casting, it is also additive manufacturing — and it fits within the long, careful journey Eaton is traveling to pursue the promise of AM technologies and develop additive manufacturing for production. There are various, specific reasons for this exploration.

Peahl says, “Eaton thinks about additive in four pillars: prototyping, tooling, supply chain resiliency and [getting a] superior product.” Any meaningful success with AM must entail success in one of these four areas. Digital casting offers the greatest potential within two of the pillars, he says.

One is prototyping. Die casting, with its need for tooling, is a challenging process to apply to making rapid, low-volume prototypes. Metal 3D printing is more responsive and less costly for prototyping, but it produces prototypes that do not match cast properties. Digital casting potentially offers the best of both options: a means to rapidly obtain low-volume parts with properties near to the ultimate casting that will be made in production. The chance to quickly and cheaply make low-volume castings can speed the development and engineering of new die-cast products. He says, “You can go through your product qualification and certifications with the digital process, and even use it for gap production as you build up your tooling.” A prototyping process delivering production-like parts makes this possible.

The other important pillar for digital casting is supply chain resiliency. Peahl says, “It’s no secret die casting is struggling to keep up with demand. Plus, tools are old and they wear out and break, and they are expensive so we generally don’t make spares, meaning we are not ready when something happens. We need to be able to respond to hiccups in our supply chains. That’s where this comes into play.” Further, he says, digital casting provides a potential solution for “the legacy and low-volume production” that casting suppliers are not well equipped to serve.

Digital Casting Vs. Die Casting

How much like die casting is the Foundry Lab process? It is much closer than metal 3D printing processes such as binder jetting and powder bed fusion. The steel pin insertion in the cast parts brings this home. This is a step that is straightforward for casting, including for digital casting, but would be problematic or impossible for the 3D printing processes. 

However, the two casting processes are not a perfect match. Eaton’s evaluation showed a coarser grain structure for the digital casting parts versus production parts made through die casting. Also higher density, meaning more consistent filling of the mold for a fully solid part. Peahl says, “The Foundry Lab process heats the entire mold, so there is very good metal flow. It fills the nooks and crannies before cooling begins.” The microwave furnace operating under vacuum also aids in this filling. The resulting improvement plays into Eaton’s understanding and characterization of the process as a potential die casting replacement.

“The superior densities we’re seeing raise a question like, ‘Is this even die casting anymore?’” he says. To serve as a die casting substitute, “Does this part perform too well? I don’t know. But these are the kinds of questions we are asking.” One implication: Perhaps digital casting plays into the “superior product” pillar as well.