This is my favorite part.
Lets start with Direct Metal Deposition. This video breaks it down:
This approach can create fully melted seamless structural elements out of stainless or tool steel. Incredible! I see using this for the structural elements such as the walls of the core.
For delicate welding there is electron beam welding. EMC used this to weld the toruses without damaging the the coils inside.
However this approach requires 1) a level work surface 2) high vacuum 3) covering the work surface with metal powder. Arcam’s current size limit is 200mm X 200mm X 350mm, so too small for the core. However the technology could possibly be adapted for a larger format. I image EBM could be used to fabricate superconductors in-situ (wild speculation, more later).
Finally, we have old fashioned robotic milling, as featured recently in Apple’s making of the macbook video:
Robotic milling and polishing allow you to achieve high tolerances and high finish even while using an additive process like Direct Metal Deposition.
What is so exciting about these fabrication technologies is that taken together they allow for a direct to metal workflow. A CAD file goes in one side and a finished product comes out the other (with hours of WTF in-between).