There was another technique for making circuit boards in the 70s: a
programmed/automated machine moved over the initially bare board and laid down
a fine wire from a spool to form the circuits. I think the wire stuck to the
board initially and the board was later lacquered or coated with something to
seal/hold the wires better. I forgot how the wire traces were terminated
around IC pin locations, probably a pressure weld.
I think the economics were such that it was too slow for large production
runs, but was suitable for prototypes and small production runs of larger,
more-complex boards. Last example I saw was a disk-controller for a TI-990
mini circa 1980.
Anybody remember the name for the technique?