Metal 3D printing and classic foundry techniques: Friends or foes?

The question is: What impact will this technology have on traditional foundries, asks

The first question that is often asked when a new technology is introduced is: What of the old way of doing things? Sometimes the answer is that it fades into oblivion. Think fortran and floppy disks. Other times it falls out of use in mainstream society but becomes the domain of a small, especially devoted community, like calligraphy or pedal loom weaving. And in other cases, it simply shifts its focus and allows itself to flower as it removes extra ‘noise’ from the workflow. John Phillip Sousa wondered if the invention of the phonograph might cause human beings to lose their vocal chords as they would no longer have to sing any song they wished to hear, and an equally pessimistic (although slightly more realistic) group worried that the Kindle would eradicate books altogether.

What has happened is that humanity has access to more music than ever and book production may see a fall in the print of throwaway paperbacks, but there appears to be no reason to fear that beautiful books will be eliminated from publication. One new technology that is causing both concern and overinflated speculation is the introduction of metal 3D printing. The question is: What impact will this technology have on traditional foundries? Foundry work is not inherently antithetical to 3D printing as many have, in fact, been using 3D printing to create moulds for years now and have found the technology to be quite helpful in their production.

Casting metal in a 3D printed mould. Image: Olivier van Herpt

Beyond the printing of 3D moulds, metal 3D printing is demonstrating a capacity for directly creating metal objects that is improving with each passing project. Voxeljet, which recently produced a new design for aircraft doors using 3D metal printing, doesn’t think that this signals the end of the classic foundry, however. Instead, they see it as something akin to a separate track of printing. What made the doors they produced such a good candidate for 3D printing was the need for a precise internal geometry, something impossible to be produced in a foundry. So rather than stealing work from a foundry, they were doing work that otherwise would not have been performed at all. And there are other reasons not to see metal 3D printing as a threat to foundry work, as voxeljet explained in a statement.

“3D metal printing, such as direct metal laser sintering (DMLS), currently only competes with foundries in a relatively small segment. The build spaces of DMLS systems are ideally suited to smaller components. And 3D printed components for aerospace require time-consuming certification, which metal casting has had for decades already. Direct 3D metal printing is also relatively expensive. This is not only due to the high cost of metal powder, but also the high cost of 3D printers and the comparatively slow building speeds.”

In addition to these factors, the products of 3D printing in metal require hand finishing, which is labour intensive. All of these factors lead up to an average cost for 3D printed metal pieces that hovers around $160 per pound for aluminium ($352 per kilogram), and $215 per pound for stainless steel ($473 per kilogram), whereas pure cast steel has a price point of about $15 per pound ($33 per kilogram). However, with the introduction of less expensive machinery, greater build bed sizes, and a more experienced workforce, the input prices for 3D printed metal are bound to come down. And so the question arises: Will there be a change as the costs associated with metal 3D printing fall?

This uncertainty necessarily creates a degree of concern among those whose businesses and livelihoods depend upon a demand for foundry work. Rather than viewing the technology as an enemy to be shut out, perhaps the best solution is for foundries to get ahead of the game and embrace the tech, integrate it into their workflows and determine for themselves what makes sense to leave to a 3D printer and what can still only be produced at the hands of skilled foundry workers.

As Ingo Edere, CEO at voxeljet, stated: “3D sand and plastic printing are a perfect alternative for foundries, both in terms of cost, as well as the printable complexity. Foundries can manufacture equally complex components without having to change the process chain. Foundries do not have to purchase their own 3D printing systems as there are service providers worldwide supplying 3D sand or plastic printing.”

Clearly, a company such as voxeljet believes in the efficacy of this technology and its firm place as part of the landscape of future production. However, just because something can be 3D printed, doesn’t always mean that it should be, and discerning artisans and clients alike are the ones who will ultimately have to determine where that line lies.