Michael Black wrote in
xample.org:

I can't think of any. But a general construction practice (and flexible
circuit board qualifies) seems to have more value than some very expensive
method of making an antenna.


Isn't the real issue one of accuracy? For example, I once tried a cheap HP
plotter on eBay to draw some PCB tracks. It turned that getting the pens was
expensive! Then I had to empty them, wash them, dry them, refill with the
best ink I had learned of for doing this. Only to discover that a different
colour in that range worked better than the one I was told was best! And then
the accuracy killed the whole deal..... it was terrible. And to make it
cleaner I had to write code to parse and clean up the HPGL....

In short it was a disaster, makign up for all the shortcomings. An HP
Laserjet 5N turned out cheaper than the plotter, the new toner catridge
cheaper than the plotter pens, and the accuracy increased a HUNDREDFOLD.

As far as I know, the accuracy of a cheap 3D printer makes that plotter look
as accurate as the Laserjet.

I doubt that uses for 3D printers and flexible circuot boards and such will
come out of ham exploration first, but out of seeign what enthusiasts of 3D
printers and such extend themselves to. The first reach will almost certainly
come from those who habitually use the stuff in question, whatever it is.