Some person accused me of reinventing the wheel, but what I'm really saying is this if we could use a mixture of carbon powder and copper powder (or silver but that costs more) suspended in a water alcohol solution with a cheap natural binding agent and there is where I am stuck because I dunno chemistry that much we could print the tracks and traces with a printhead ( there is that piezo electric one) maybe with an adjustable mixture (hey we could determine the resistance of the tracks and save on resistors) and then with a syringe we could bond the chips to our tracks with our own printing solution. No need for solder could use several layers printed (cool function for the water alcohol mixture to evoporate) print next layer could have multilayer tracks enclosed in plastic this way and the only thing exposed would be the chips which are put into place manually and then use a syringe of the copper mixture to bond the legs (yes you'd need steady hands and a magnifying glass) simple traces are already being printed on paper it would just be us taking it a step further the vias would consist of multiple layers of this stuff deposited in holes of our board material.
Requirements: bonding agent would have to desolve readily in a water alcohol solution (and I dun mean the drinking stuff would be too expensive isopropyl (rubbing alcohol or simular) should do.
B. the bonding agent would have to have reducing properties (I hope I got this right (chem was ten years ago to keep the copper from corroding)
C. the printhead must be able to extrude a paste like substance (copper and copper carbon mixture content will exceed 90% of the final dried mixture in order to ensure it will be sufficently conductive)
D most parts need to be printable
E. the bonding agent must not only be preferably non toxic but most importantly readily availible and dirt cheap.
Also a note here on chips like the allegro stepper drivers the copper mixture could be extruded under neath for several layers if not all the way through to create a decent heatsink. then take syringe one drop in the center of the copper solution place chip in way a few minutes and it shouldn't even move basically a natural homemade copper glue and is almost as conductive as pure copper when needed but less conductive when needed as well.
Just would like some input on what could be done