Homebrew PCBs

Inkjet printing is the latest "Holy Grail" for the
homebrew pcb maker. 

Inkjet print heads spit out the ink either through
small piezo pumps or by vaporizing a partion of the
ink solvent. The piezo pump is better.

The key is to find an "ink" that:

1. Flows through the filter screen in print head.
2. Does not clog the nozzles.
3. Dries slowly, preferably after the printing process
is completed.
4. Will 'wet out' and adhere to the copper.
5. Will give a thick enough coating to act as a
resist.
6. Can be post cured/dried for a durable resist during
the etching process.
7. Can be removed after etching.

Pigmented Ink is not suitible. The ink doesn't need to
be pigmented. Pigments are small particles that can
clog the screen. It's the binder in the inks that
holds it to the substrate. Speciality papers have  a
receptive binder on the surface of the paper.

Sublistatic inks. These are inks that transfer color
by vapor transfer, the ink is boiled off and the
substate accepts the color molecules. No binder is
involved.

Wax type inks need a high temp to lower the viscosity
to make it through the print heads. Heaters are built
into the delivery system.

UV cure inks are high solides, low solvent inks used
in industry to reduce air emmissions. That are cured
after printing, away from the printheads ;) These are
usually warmed up to lower the viscosity and make them
flow better.

The ideal ink is a water based (slow drying) clear or
transparent thin liquid, that can be "set" aftward by
heat or UV and can survive the etching process

Anything come to mind? 

How about the spray on photoresist? 

It can be thinned down with a suitible solvent. 
Dries slowly.
Post cured with UV. 
A thick coating is not needed to survive the exposing
and developing process.
A thin coating that is cured and directly etched is
all that is needed.

It's worth a try.

TANSTAAFL!

Myc


PS. Stefan, I'll send you my shipping address for the
printer. 






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