Homebrew PCBs

Exerpt from an article in Electronic Design - maybe the epoxy is 
available without the other paraphanelia.  I haven't looked into it - 
just got the e-mail article this morning.  (the foil mentioned appears 
to be just a mask to keep the epoxy restricted to the desired holes).
For the complete article:

www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=9984


Norm

PLATED THROUGH HOLES
The ProConduct system is designed to create plated through holes without 
resorting to electroplating. The approach starts by applying an adhesive 
foil to both sides of a board and then drilling the holes that will be 
plated /(Fig. 4 
<http://www.elecdesign.com/Articles/9984/Figure_04.gif>)/. Application 
of a conductive epoxy paste follows in a method of placing the board on 
a vacuum table, applying the paste, and pressing it through the holes 
/(Fig. 5 <http://www.elecdesign.com/Articles/9984/Figure_05.jpg>)/. This 
occurs for both sides of the board. After that, the foil on both sides 
is removed /(Fig. 6 
<http://www.elecdesign.com/Articles/9984/Figure_06.jpg>). /

Next, the board is placed in an oven for about half an hour /(Fig. 7 
<http://www.elecdesign.com/Articles/9984/Figure_07.jpg>)/. At this 
point, the board can be populated. The conductivity of hole plating is 
nearly as good as the electroplated approach, and ProConduct is 
significantly cleaner and easier to use. Typical resistance is 20 to 60 
m(omega). The minimum size hole is 0.3 mm.

Plated through holes for multilayer boards are done in the same fashion 
as double-layer boards. However, the layers are stacked before the 
adhesive foil is applied.

LPKF Laser and Electronics
/*www.lpkfusa.com*/


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