Re: Homemade PCBs!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Eastern Voltage Research Corporation" <dhmccauley-at-easternvoltageresearch-dot-com> 

 >From experience, these are generally very poor.  We have a variety of these
LPKF type machines
but we never use them anymore.  Instead, we primarily use ExpressPCB which
offers attractive pricing
with up to 4-layer boards with soldermask and silkscreen.  We could use
other PCB houses, but due to
union agreements within the company, we are only allowed to use such
software, as the ExpressPCB
free software to do our own engineering type boards.

Dan


 > 5) A very attractive alternative for a lot of prototyping is the computer
 > controlled router approach.  It will do the traces, and do the holes.
Won't
 > do the plated through, but it's definitely a hot ticket for RF
prototyping.
 > A tad pricey (again, if someone knows of a decent (assembled) system for
 > under $1000 (exclusive of PC), I'd love to hear about it).
 >
 > 6) There are some interesting approaches I've seen commercially, but I
 > haven't seen in hobby applictions, although I think they'd be appropriate.
 > Things like the "multiwire" where it essentially "plots" a special
insulated
 > wire onto the substrate, or various stereolithographic schemes (like the
 > computer controlled glue gun things).  I've also seen systems (based on
the
 > same scheme they use for making custom vinyl signs) that cut copper foil
on
 > a backing, which is then "glued" to a substrate.  Peeling the unused
copper
 > away doesn't strike me as a lot of fun (like peeling rubylith!) but might
 > give good results.
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Saturday, April 24, 2004 6:55 PM
 > Subject: Re: Homemade PCBs!
 >
 >
 >  > Original poster: "Jim Mitchell" <Electrontube-at-sbcglobal-dot-net>
 >  >
 >  > Or for about the same price it costs to get all the materials and
things
 > to
 >  > do photo etching,  you can have 10, 3X5 soldermask and silkscreened
boards
 >  > for 65$....
 >  >
 >  > Regards - Jim Mitchell
 >  > ----- Original Message -----
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > To: <tesla-at-pupman-dot-com>
 >  > Sent: Saturday, April 24, 2004 8:53 PM
 >  > Subject: Re: Homemade PCBs!
 >  >
 >  >
 >  >  > Original poster: Matthew Smith <matt-at-kbc-dot-net.au>
 >  >  >
 >  >  > Eric ("Hydrogen18") writes:
 >  >  > >I'm looking to make some homemade PCB's for a voltage multiplier,
 > whats
 >  >  > >the best way to do this? I've seen those kits where you draw
 > everything,
 >  >  > >but that seems pretty tedious. Is their a better way to do it at
home?
 >  >  > >Also, what kind of circuit board do I want to buy? Thanks.
 >  >  >
 >  >  > Matthew replies:
 >  >  >
 >  >  > I use PCBs for all prototypes - they are NOT hard to make once you
get
 > the
 >  >  > hang of it. I use a simple photolithographic process with all
home-made
 >  >  > equipment.
 >  >  >
 >  >  > Note that a PCB will be more reliable and easier to trouble-shoot
than
 >  >  > prototypes using solderless breadboard or ratsnesting.
 >  >  >
 >  >  > Now that I've got my technique down to pat and have got the optimum
 >  >  > exposure times, etc., I can throw a board together in very little
 >  >  > time.  I'm even starting to use some SMD components now.
 >  >  >
 >  >  > Abbreviated steps are:
 >  >  > 1) Produce artwork on a transparency.  This could be hand-drawn or
 >  > produced
 >  >  > by CAD software such as Eagle <http://www.cadsoft.de>.
 >  >  > 2) Acquire PCB stock coated with positive photoresist.
 >  >  > 3) Cut stock to size if required.
 >  >  > 4) Contact print artwork onto PCB stock with UV source
 >  >  > 5) Develop board with sodium metasilicate solution (easier to use
than
 >  > NaOH).
 >  >  > 6) Wash board
 >  >  > 7) Etch with ammonium persulphate solution.  This is far nicer to
work
 >  > with
 >  >  > than ferric chloride.
 >  >  > 8) Wash board
 >  >  > 9) Drill (unless SMD ;-)
 >  >  > 10) When ready to solder, remove remaining photoresist with acetone.
 > (It
 >  >  > protects the board in the meantime)
 >  >  > 11) - optional - flux and tin traces or use humungously expensive
 > tinning
 >  >  > compound ;-)
 >  >  > 12) Assemble and solder
 >  >  > 13) Clean off flux residues
 >  >  > 14) Step back and admire your work :)
 >  >  >
 >  >  > Exposure, developing and etching can easily be done in under half an
 > hour.
 >  >  >
 >  >  > One very important tip that I received from a member of this list
 > (think
 >  > it
 >  >  > was Dan Mccauley) is: remember to put plenty of test points on your
 >  >  > artwork, especially if this is a prototype!
 >  >  >
 >  >  > Contact me off-list if you want to know any specifics, like how to
make
 > a
 >  >  > UV exposure unit, etc.
 >  >  >
 >  >  > Cheers
 >  >  >
 >  >  > M
 >  >  >
 >  >  > --
 >  >  > Matthew Smith
 >  >  > Kadina Business Consultancy
 >  >  > South Australia
 >  >  > http://www.kbc-dot-net.au
 >  >  >
 >  >  >
 >  >  >
 >  >
 >  >
 >
 >
 >
 >
 >