Homebrew PCBs

>The workflow for both the top vs. bottom (or bottom vs. top) are 
>identical.

So if you had to do 5 boards you would have to do the following steps 
5 times, once for each board;


----------------------------------------------
-- Combine in Photoshop the artwork for top, bottom, and silkscreen. 
Printthis centered onto ordinary bond paper. Trim and tape a piece of 
transferpaper over the artwork, and run it through the printer again, 
this time printing onto the just-right sized piece of transfer paper. 
Separate the three images.

-- Print the drill guide and legend. Stick it to the board with spray 
mount adhesive.

-- Drill and debur the board. There are three unconnected vias in the 
board corners for alignment pins.

-- Pierce the alignment vias on the top artwork; place the pins in the
board; place the top artwork over the pins. Visually confirm 
alignment, and tape in place. Black toner should occlude all holes.
------------------------------------------------

Do you know how double sided boards are done using photoetching?














--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> 
wrote:
>
> ----- Original Message ----- 
> From: "derekhawkins" <derekhawkins@y...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, November 16, 2005 3:18 PM
> Subject: [Homebrew_PCBs] Re: A $500.00 "UV" non-trivial exposure 
box.....
> 
> 
> > >For production runs of one or very few, the case for
> >>100% of "HOMEBREW PCBs", you'll have to explain as though to a 
young
> >>child the advantages that offset the cost and complexity of photo
> >>exposure.
> >
> > We'll get into the quality of the finished product later. Have 
you ever
> > done a double sided board using TT? If yes then explain the TT 
process.
> 
> The workflow for both the top vs. bottom (or bottom vs. top) are 
identical.
> 
> -- Combine in Photoshop the artwork for top, bottom, and 
silkscreen. Print 
> this centered onto ordinary bond paper. Trim and tape a piece of 
transfer 
> paper over the artwork, and run it through the printer again, this 
time 
> printing onto the just-right sized piece of transfer paper. 
Separate the 
> three images.
> 
> -- Print the drill guide and legend. Stick it to the board with 
spray mount 
> adhesive.
> 
> -- Drill and debur the board. There are three unconnected vias in 
the board 
> corners for alignment pins.
> 
> -- Pierce the alignment vias on the top artwork; place the pins in 
the 
> board; place the top artwork over the pins. Visually confirm 
alignment, and 
> tape in place. Black toner should occlude all holes.
> 
> -- Remove the pins. Tear off a suitable size scrap of bond paper to 
use as 
> slip sheet. Fold in half; place the board with top artwork in the 
crease. 
> Run it through the laminator.
> 
> -- Soak off the transfer paper. Pulsar's paper comes off cleanly in 
a few 
> seconds. Dry the board. Examine for alignment errors and incomplete 
traces.
> 
> -- Cut a piece of green sealer paper to size; laminate to the 
exposed toner.
> 
> -- Repeat for the bottom. The sealer prevents the completed top 
artwork from 
> sticking to the slip sheet.
> 
> -- Etch.
> 
> With one success for one try with the alignment pins, I'm ready to 
try both 
> sides at once. Pulsar's paper releases completely when wet and 
makes it 
> brain dead simple with a clean and deburred board. Slight hole 
misalignments 
> are entirely attributable to imprecise manual drilling. Since the 
drill 
> guide is printed on the same printer as the transferred artwork, 
I'm not at 
> all surprised to not find any systematic errors.
> 
> Quality differences? It's difficult to see where the TT process can 
be 
> improved.
>