Hello,
I am trying different methods of transfereing my artwork from printed positive to the plain copper board, Can any one suggest me the easy and cheap way to make fine tracks.
My PCB need to have 10 mil tracks and gaps.
Regards
Tayyab
----- Original Message -----
From: Mike Putnam
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, April 27, 2003 12:10 AM
Subject: Re: [Homebrew_PCBs] Re: Oh no, blank fibreglass again!
I have to differ with you, Tom. I used Tin Plate (Electrolysis) in my shop
for many years and not Gold. Gold plating was too expensive. I etched with
Ferric Chloride with no problems ever. Perhaps the trick is in how fast you
are able to etch the panel.
-Mike
----- Original Message -----
From: "twb8899" <twb8899@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, April 26, 2003 11:40 AM
Subject: [Homebrew_PCBs] Re: Oh no, blank fibreglass again!
> Max,
>
> We always used solder plating as a resist and it worked fine. After
> etching either reflow the solder or strip it off and apply one of the
> newer "white tin" coatings if you want tin plating. Are you using
> immersion tin or really electroplating it? Immersion tin is worthless
> as a metallic resist but some electroplated tins will work if they
> are plated heavy enough. By switching to solder plating you will
> eliminate the problem. The same plating bath can probably be used.
>
> Ferric chloride will not work unless gold is being used as the etch
> resist. Sulfuric/peroxide will work as an etchant for solder plated
> boards. After stripping the photoresist dip the panel in a 10%
> peroxide dip and then etch. This keeps the black crud from forming on
> the solder plated surface for a better reflow finish. After etching
> dip the panels in a 10% hydrochloric acid dip for about five minutes
> to brighten the solder plating for reflow. Skip the peroxide and
> hydrochloric dips if the solder is being stripped after etching. They
> are only required for solder reflow quality.
>
> Bake the boards for at least 30 minutes at 300 degrees F after
> etching and before reflowing. This is for outgassing any trapped
> moisture and will keep the plated through holes from blowing out when
> soldering.
>
> BTW, are you using the newer activated palladium cataylyst and
> skipping the electroless copper stage? Good luck on your new system!
>
> Tom
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Max Davies" <max.davies@b...>
> wrote:
> > Hi everyone.
> >
> > A newbie to this group, I am (perhaps over-ambitiously) attempting
> > to set up a micro through-hole plating line at home. It's a lot
> > more involved than I ever thought it would be, but I now have most
> > of it working fine. ...Except what should be the easy bit - the
> > final stage - the etching!
> >
> >
> > To give a brief description of what I do...
> >
> > STAGE 1: Starting with plain, copper-clad board, I do the drilling.
> > STAGE 2: Apply photopolymer laminate, then expose & develop. (This
> > is positive photopolymer, so the copper which will ultimately
> become
> > tracks is exposed to the air on developing the pattern)
> > STAGE 3: Go through a 6-stage process to electroless-plate the
> > entire thing (including the holes & edges). The copper cover it
> puts
> > on is pretty thin, but uniform at 1-2 microns.
> > STAGE 4: Electroplate the copper - this gives reasonable thickness
> > to the copper applied in stage 3 - I aim for 25 microns.
> > STAGE 5: Electroplate with tin to 10 microns. This
> > (theoretically!) protects the copper from etchant.
> > STAGE 6: Remove remaining resist. Then etch. This should leave
> > the tin-plated areas untouched, everything else should be zapped.
> >
> >
> > But alas no! Stage 6 fails, because both tin ∗and∗ copper are
> > etched, leaving me with a fine, blank piece of fibreglass! It
> > matters not whether I use Ferric Chloride or Sulphuric/Peroxide
> > etchant - they both destroy what has been so lovingly created!! So
> > I reckon there must be something awry with my tin plating.
> >
> > It's a total impasse, and nothing I do, from increasing/decreasing
> > current to re-formulating the tin plating bath according to
> > manufacturer's instructions seems to change things.
> >
> > Does anyone else use a similar process, or have any clue about what
> > might be the problem here?
> >
> > Max.
>
>
>
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