Homebrew PCBs

Philip Pemberton <ygroups@...> writes:
> <http://pcbwiki.philpem.me.uk/tiki-download_wiki_attachment.php?attId=1>

I do not have permission to use that feature :-(

> Now I just need to get the masks aligned,

I don't have a double-sided exposure box, but...

For DS boards, what I do is include targets on my artwork.  I print a
paper copy of the artwork (in the same printer, just not film
quality), tape it down, and pre-drill the targets, usually 13 mil
holes.

When you place your film, you can see the holes through the film and
align the film to the target holes.  That gets both sides pretty well
aligned.

For my targets, I use four square pads, placed together in a square,
with about 1 mil between them.  Since I use negative film, this
results in a 1 mil crosshair inside a square hole in the ink, which is
really easy to align with those holes.

It looks kinda like this:

######## ########
######## ########
######## ########
######## ########
######## ########

######## ########
######## ########
######## ########
######## ########
######## ########

and prints like this:

###################
#        #        #
#        #        #
#        #        #
#        #        #
#        #        #
###################
#        #        #
#        #        #
#        #        #
#        #        #
#        #        #
###################