Adrian Bowyer's Instant 3D Printer

[ssashton]

Hi Everyone,

This very interesting video was released taking about a potential new 3D printing method passing electrical current through resin to cure it.

Adrian is a founder of the RepRap moment,  the idea of 3D printers being used to print nearly all the parts to replicate itself. He is certainly not a fool and I think that comes across in three interview.

https://youtu.be/aFjrZIqtLZM

I'd love to hear from those with knowledge in the field whether it is in some way possible to 'focus' a current in this manner?

In the field of acoustics where I am more comfortable, it is possible to used an array of transducers with various phase shifts to focus a sound by constructive and destructive interference. Can a similar method work for AC through a conductive medium?? Does AC acts as a wave at all in a conductor?

[thm_w]

https://reprapltd.com/electric-3d-printing/
https://reprapltd.com/the-electric-3d-printer-first-attempt-to-print-a-controlled-shape/

In its final form (shown in the diagram above), one would have a cylindrical bath containing the liquid monomer.  The walls of the bath would have a fine array of electrodes in a square grid over their entire area (the grid would be finer than in the diagram).  These would be addressed by a controlling computer to pass electric currents through the liquid monomer in such a way as to solidify it just where required to form the 3D solid defined by an STL file (as in conventional 3D printing).  The machine would have no moving parts, and the solid would be formed in (I hope) a few seconds.

The entire machine could, of course, be printed in a conventional two-filament RepRap if one filament were conducting.

Tangent:
Current resins require UV curing and IPA washing, just saw an ad for water washable resin:
https://filaments.ca/collections/3d-resin/products/polyjuice-water-washable-resin-grey
https://cdn.shopify.com/s/files/1/0376/9913/files/PolyJuice-MSDS-NonCasting.pdf?2255

It still looks like nasty stuff (per MSDS), but to me it sounds like a lot of innovation is possible.

[ssashton]

Reading those links I don't make the connection about how the current would be forced to take a specific path and be greater at a specific three dimensional location.

They simply say 'the current is programmed using the reverse of the spectra system', but in that system there is a physical object in the bath which has variable conductivity through it's body, hence it can be imaged.

If you ran multiple electrodes with various phase AC waveforms, would there be constructive / destructive interference of current flow throughout the body of conductive medium?

I mean we can do it 2D first, and it seems like their stimulation is doing just that - place electrodes around the perimiter of a conductive sheet like thin copper pcb, then can we create a modal patter of current in the sheet so that it only heats up at certain places?