Homebrew PCBs

Hi,
I've uploaded some pictures of my new spray etching machine. Its not 
finished yet, as I've still to work out the precise nozzle configuration 
on the spray arm.
This is a project which has gone through many revisions over the past 
few years, and has taken a lot more of my time than I originally 
anticipated :)   If people are interested I'll write up a web page with 
the details when I get free time.

http://members.optusnet.com.au/~eseychell/pictures/spraymachine

Adam

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@...>
wrote:
>
> 
> Hi,
> I've uploaded some pictures of my new spray etching machine. Its not 
> finished yet, as I've still to work out the precise nozzle
configuration 
> on the spray arm.
> This is a project which has gone through many revisions over the past 
> few years, and has taken a lot more of my time than I originally 
> anticipated :)   If people are interested I'll write up a web page with 
> the details when I get free time.
> 
> http://members.optusnet.com.au/~eseychell/pictures/spraymachine
> 
> Adam
>

Adam,

That etching machine looks great. You do nice work. 

I have always felt that spray etching is the way to go. My spray
etcher will etch 1 oz. copper in 3 minutes with fresh etchant and
about 5 minutes when it's almost used up. This is with ferric chloride
at 110 degrees F.

Keep us informed on your progress. Thanks for sharing the information. 

Tom

twb8899 wrote:
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com 
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Adam Seychell <a_seychell@...>
> wrote:
>  >
>  >
>  > Hi,
>  > I've uploaded some pictures of my new spray etching machine. Its not
>  > finished yet, as I've still to work out the precise nozzle
> configuration
>  > on the spray arm.
>  > This is a project which has gone through many revisions over the past
>  > few years, and has taken a lot more of my time than I originally
>  > anticipated :) If people are interested I'll write up a web page with
>  > the details when I get free time.
>  >
>  > http://members.optusnet.com.au/~eseychell/pictures/spraymachine 
> <http://members.optusnet.com.au/~eseychell/pictures/spraymachine>
>  >
>  > Adam
>  >
> 
> Adam,
> 
> That etching machine looks great. You do nice work.
> 
> I have always felt that spray etching is the way to go. My spray
> etcher will etch 1 oz. copper in 3 minutes with fresh etchant and
> about 5 minutes when it's almost used up. This is with ferric chloride
> at 110 degrees F.
> 
> Keep us informed on your progress. Thanks for sharing the information.
> 
> Tom

Tom, thanks for the reply. I agree spray etching gives the best results, 
but thats not the real reason for pursuing a project like this. At the 
end of the day its all just a hobby. Those pictures are of my new 
machine which is a total revamp of my previous machine. I was getting 
35um etches in about 7 minutes at 20\ufffdC (70\ufffdF) with good uniformity using 
air regenerated cupric chloride at ambient temperatures. It had some 
design issues with the lid, leaks and corrosion that made me build a new 
one.


Adam

On Wed, 01 Nov 2006 21:10:03 +0100, Adam Seychell  
<a_seychell@...> wrote:

>
> Tom, thanks for the reply. I agree spray etching gives the best results,
> but thats not the real reason for pursuing a project like this. At the
> end of the day its all just a hobby. Those pictures are of my new
> machine which is a total revamp of my previous machine. I was getting
> 35um etches in about 7 minutes at 20\ufffdC (70\ufffdF) with good uniformity using
> air regenerated cupric chloride at ambient temperatures. It had some
> design issues with the lid, leaks and corrosion that made me build a new
> one.
> Adam


Anyone know how the bungard splash works?
<http://www.bungard.com/seiten/p-splash.htm>

I believe it does not move the nozzles at all, which would greatly  
simplify construction.

ST

>Anyone know how the bungard splash works?
><http://www.bungard.com/seiten/p-splash.htm>
>
>I believe it does not move the nozzles at all, which would greatly  
>simplify construction.
>
>ST

The spray action is shown in their video (about 1:09 in).  Doesn't appear
to be very
complicated, at least in general mechanical layout .. just two stationary
heads
spraying the board.  Nothing moving, apparently.

No real detail visible in the AVI video, of course, but the general idea
can be seen
fairly well.  The video is so 70's euro-sterile-cool it's actually kind of
funny .. 
especially when she squeeges-off the water with a mangle at the end of the
video.
Somehow that made me giggle.

Ron Yost

A little more on the Bungard Splash Center, from its downloadable 
instructions:

"The machine's body is made from grey, the front from transparent PVC.

There are two full cone nozzels mounted diagonally in the spray room.
Their position and spray angle allow to have a shadow free etching
of the hole useable surface." 

Ron Yost

On Thu, 02 Nov 2006 03:25:38 +0100, Ron Yost <musik42@...> wrote:

> A little more on the Bungard Splash Center, from its downloadable
> instructions:
> "The machine's body is made from grey, the front from transparent PVC.
> There are two full cone nozzels mounted diagonally in the spray room.
> Their position and spray angle allow to have a shadow free etching
> of the hole useable surface."
> Ron Yost


Shouldn't that be rather easy to make? I've used the spash center some  
years ago and it worked quite well.
Not having to move a nozzle seems a good thing to me?

ST

Spray Nozzle technology is big business.  It is amazing what can be 
done with a well designed nozzle.  The spray patterns and coverage can 
be very precise!

I suspect that they are just using very good nozzles, probably 
engineered by this company 

www.spray.com

Chris



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:

>
> On Wed, 01 Nov 2006 21:10:03 +0100, Adam Seychell  
> <a_seychell@...> wrote:
> 
> 
> Anyone know how the bungard splash works?
> <http://www.bungard.com/seiten/p-splash.htm>
> 
> I believe it does not move the nozzles at all, which would greatly  
> simplify construction.
> 
> ST
>

lcdpublishing wrote:
> 
> 
> Spray Nozzle technology is big business. It is amazing what can be
> done with a well designed nozzle. The spray patterns and coverage can
> be very precise!
> 
> I suspect that they are just using very good nozzles, probably
> engineered by this company
> 
> www.spray.com
> 

They made the nozzles used in my spray machine :) Very happy with them.
VeeJet series: Fan type, 65\ufffd angle, #8 flow rate, 1/4" BSP thread, kynar 
material, price AU$10/ea.

That's great work.  A spray etcher is on my todo list.  I currently 
just agitate in a plastic container with hot ammonium persulphate.

Where did you get the spray nozzles from?  And what pump are you 
using?

Frank wrote:
> 
> 
> That's great work. A spray etcher is on my todo list. I currently
> just agitate in a plastic container with hot ammonium persulphate.
> 
> Where did you get the spray nozzles from? And what pump are you
> using?
> 

The nozzles were from a company with the web site http://www.spray.com 
You should find a sales office somewhere in your country. They are setup 
for worldwide orders and they don't complain if buying just 1 nozzle.
I used 4 fan type nozzles. Let me know if you want part numbers.

I had to choose the right flow rates nozzles to maximize power usage of 
the pumps. This is estimated by looking at flow rate vs pressure graphs 
of both the pump and nozzle. I have the formulas somewhere. Operating 
pressure is about 2.3 bar which is just below pump limits before causing 
heating problems. Current drain is 6.5A at 12.5Volts per pump. The pumps 
are diaphragm type used for caravan water. These give good pressure, and 
cheap. They are made by Shurflo, but needed modifying internally to make 
them acid resistant. Unfortunately I bought them in the belief there 
were no metal-fluid contact, but I later found the hard way they used 
stainless screws to hold the "pistons". I replaced these with plastic 
coated screws and so far have survived over 1 year in cupric chloride. 
According to customer support at Flojet (competitor) their pumps no not 
have any metal-fluid contact so they should be ok in HCl.
Below are links to  their pumps, and it looks like Shurflo have brought 
out replacement models since. I would suspect they too have internal 
stainless steel screws.

http://www.shurflo.com/pages/RV/rv_categories/general_purpose/generalPurposePumps.html

http://www.flojet.com/prodInfoApp/servlet/DisplayProducts?typeId=FRQSP&page=0&catalogId=RV&categoryId=FRMPU&companyId=FLOJET

The exact pumps I used are here:
http://www.shurflo.com/pdf/rv/product_data_sheets/pds-2088-422-144.pdf

Because they are not terribly expensive I bought 2 pumps, and run them 
in parallel for double flow rate.

Adam

I posted wrong link to Shurflo web site. should be portable water pumps.

http://www.shurflo.com/pages/RV/rv_categories/potable_water/potableWaterPumps.html