Homebrew PCBs

Jan and the group,

I'll be glad to do a write up on making plated through holes. How 
much detail does everyone want?  There are about 60 steps to the 
whole process if you break it down. 

I could give an overview of the entire process and then in future 
posts give more details on each step. The hard part of the process is 
knowing what to do when something goes wrong. So another part could 
be a discussion on problem solving.

BTW, the activated solution mentioned is actually a super activated 
palladium chloride catalyst. My shop was the first one in North 
America to install this process in 1990. It was invented by Eric 
Harnden who owns a company called Solution Technology in California. 
I worked with Eric in the early days right after he received his 
patent for this process. We ran his solutions along side our 
electroless copper tanks and found them to be superior. At that point 
we junked the electroless system and converted everything to the new 
process by early 1991. 

At first there was much resistance to using this new method because 
the MIL SPEC at the time only allowed electroless copper. This kept 
the new process out of the big shops but one by one they caught on 
and now Eric has licensed the technology to all the big chemical 
suppliers. The magic ingredient was lignin vanillin extract!! The 
catalyst tank smelled like a milk shake! I'm sure that Eric Harnden 
has made a fortune from his invention.

The idea behind this catalyst was to get such a low resistance 
between the two board layers that the electrolytic copper would plate 
right over the catalyst layer. This eliminated the electroless copper 
part of the process and about thirty minutes of time per load.

I'll write up the basics stating at the beginning and post them over 
the next few days. 

Tom

Tom thanks for sharing this with the group. That is a fascinating
story. I just blows me away when I hear how a common ingredient used
in every day life can be so significant in a high tech processes like
printed circuits, heck, lignin vanillin extract !!! It just shows how
little the scientists understand electrochemistry and surface
chemistry. Its true when people say its in an art not a science.

During my research into the carbon black method of making holes
conductive I never came across Eric Harnden's invention. As far as I'm
aware of there are four main (non-electroless) commercial processes
for plating holes. This article gives a quick overview;

http://nr.stic.gov.tw/ejournal/ProceedingA/v23n3/365-368.pdf

I suspect Eric Harnden's super activate palladium chloride catalyst
puts a very large amount of palladium inside the holes, so much so
that copper can electroplate directly across the surface. I believe
the palladium acts as a catalyst and dramatically speeds up
electroposition of copper. The surface resistivity due to the
palladium alone does not need to be low. The article above mentions
Radovsky in 1969 discovering palladium inside holes being directly
electroplated even with initial resistance of 80 Mohms. The carbon
black process I am using reaches surface resistance of around 10 Kohms
for a unit square. This too uses an essential ingredient found in most
home  kitchens, and that's eatable Gelatin derived from beef skin.
There is already a patent on using Gelatin with carbon black
dispersions. The trick with using carbon black is to modifying the
carbon surface chemistry so it improves electrodeposition of copper.
Many soluble organic dyes can adsorb on the carbon surface and also
act as a catalyst in helping electrodeposition of copper. Palladium
can also be loaded into the carbon to dramatically improve the
plating, and I think that's what done with Blackhole(tm).

At the moment I'm working on trying to improve the Gelatin / carbon
dispersion process. I've got holes plating, but there are too many
variables and it takes long dwell times (30+ minutes) in the solutions
to achieve reliable results. Its all just fun experimenting and
discovery for me. I know that no money will be made from it because
the ideas are already patented and I don't really want to get into the
PCB manufacturing business.


--- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
<twb8899@y...> wrote:
> Jan and the group,
> 
> I'll be glad to do a write up on making plated through holes. How 
> much detail does everyone want?  There are about 60 steps to the 
> whole process if you break it down. 
> 
> I could give an overview of the entire process and then in future 
> posts give more details on each step. The hard part of the process
is 
> knowing what to do when something goes wrong. So another part could 
> be a discussion on problem solving.
> 
> BTW, the activated solution mentioned is actually a super activated 
> palladium chloride catalyst. My shop was the first one in North 
> America to install this process in 1990. It was invented by Eric 
> Harnden who owns a company called Solution Technology in
California. 
> I worked with Eric in the early days right after he received his 
> patent for this process. We ran his solutions along side our 
> electroless copper tanks and found them to be superior. At that
point 
> we junked the electroless system and converted everything to the
new 
> process by early 1991. 
> 
> At first there was much resistance to using this new method because 
> the MIL SPEC at the time only allowed electroless copper. This kept 
> the new process out of the big shops but one by one they caught on 
> and now Eric has licensed the technology to all the big chemical 
> suppliers. The magic ingredient was lignin vanillin extract!! The 
> catalyst tank smelled like a milk shake! I'm sure that Eric Harnden 
> has made a fortune from his invention.
> 
> The idea behind this catalyst was to get such a low resistance 
> between the two board layers that the electrolytic copper would
plate 
> right over the catalyst layer. This eliminated the electroless
copper 
> part of the process and about thirty minutes of time per load.
> 
> I'll write up the basics stating at the beginning and post them
over 

> the next few days. 
> 
> Tom

Adam,

Wow, you are quite a researcher and experimenter. I never did try out 
the blackhole process. They had some trouble in the early days with 
innerlayer voids on multilayers and we couldn't take a chance. On two 
layer boards the blackhole process has always been excellent. It 
could possibly be the way to go for home experimenters. If I remember 
right, you needed an agitation pump to keep the carbon dispersed in 
the solution and an oven to bake the panels after processing. After 
drying the panel you must sand the carbon off of the copper leaving 
just the holes coated. If thats the case, then this could be the way 
to go. Just fire it up and run it when you need boards. 

You can use a five gallon bucket for the electroplating part. The 
copper anodes must have some phosphorus in the alloy or it won't work 
properly. You will find these anodes marked "cu-phos". Plain copper 
anodes are used in a cyanide bath but the high pH of that chemistry 
will strip off your photoresist so it's no good for pc boards. When 
the solution is adjusted properly the plated boards will look like a 
copper mirror. Acid copper plating baths must be air agitated for 
proper plating. The solder plating tank can be set up the same way 
but doesn't require the air agitation.

A rectifier can be made from a car battery charger and a variac 
(variable transformer) on the 120 volt input. When plating with acid 
copper, the tank voltage will only be around 1.5 volts and solder 
plating is about 0.5 volts. Many shops have dumped the lead and just 
plate tin only. 

After the solder plating is completed, the photoresist is stripped 
from the panel with a 1% caustic (lye) bath and then etched. The 
solder or tin plating is the etch resist. The background copper will 
be etched and the tin or solder on the surface and in the holes will 
not be etched thus leaving your desired pattern. Ferric chloride 
can't be used for this type of etching unless your plated metal is 
gold. The best etchant would be ammonium or sodium persulfate since 
they are cheap and work good. We used a sulfuric acid - hydrogen 
peroxide etchant that was easily recycled but the fumes were hard to 
handle.

After etching the board is "reflowed" if it is solder plated. When 
solder is plated it goes onto the board as tin and lead but not as 
the original alloy. The reflow process melts the tin and lead back 
into a solder alloy as well as fusing it to the copper traces. The 
reflowing process can be done with a solder pot full of water soluble 
soldering oil. We used a modified donut fryer at 475 degrees F. The 
reflowed board is then cleaned with a soap solution, dried and cut or 
routed to size.

That is the basics of electroplating circuit boards. I'll post some 
more information on the sensitizing and electroless part later.

Tom


--- In Homebrew_PCBs@yahoogroups.com, "adam_seychell 
<adam_seychell@y...>" <adam_seychell@y...> wrote:
> Tom thanks for sharing this with the group. That is a fascinating
> story. I just blows me away when I hear how a common ingredient used
> in every day life can be so significant in a high tech processes 
like
> printed circuits, heck, lignin vanillin extract !!! It just shows 
how
> little the scientists understand electrochemistry and surface
> chemistry. Its true when people say its in an art not a science.
> 
> During my research into the carbon black method of making holes
> conductive I never came across Eric Harnden's invention. As far as 
I'm
> aware of there are four main (non-electroless) commercial processes
> for plating holes. This article gives a quick overview;
> 
> http://nr.stic.gov.tw/ejournal/ProceedingA/v23n3/365-368.pdf
> 
> I suspect Eric Harnden's super activate palladium chloride catalyst
> puts a very large amount of palladium inside the holes, so much so
> that copper can electroplate directly across the surface. I believe
> the palladium acts as a catalyst and dramatically speeds up
> electroposition of copper. The surface resistivity due to the
> palladium alone does not need to be low. The article above mentions
> Radovsky in 1969 discovering palladium inside holes being directly
> electroplated even with initial resistance of 80 Mohms. The carbon
> black process I am using reaches surface resistance of around 10 
Kohms
> for a unit square. This too uses an essential ingredient found in 
most
> home  kitchens, and that's eatable Gelatin derived from beef skin.
> There is already a patent on using Gelatin with carbon black
> dispersions. The trick with using carbon black is to modifying the
> carbon surface chemistry so it improves electrodeposition of copper.
> Many soluble organic dyes can adsorb on the carbon surface and also
> act as a catalyst in helping electrodeposition of copper. Palladium
> can also be loaded into the carbon to dramatically improve the
> plating, and I think that's what done with Blackhole(tm).
> 
> At the moment I'm working on trying to improve the Gelatin / carbon
> dispersion process. I've got holes plating, but there are too many
> variables and it takes long dwell times (30+ minutes) in the 
solutions
> to achieve reliable results. Its all just fun experimenting and
> discovery for me. I know that no money will be made from it because
> the ideas are already patented and I don't really want to get into 
the
> PCB manufacturing business.
>

In a message dated 12/10/2002 3:50:14 PM Central Standard Time, 
twb8899@... writes:


> I'll write up the basics stating at the beginning and post them over 
> the next few days. 
> 

Right ON!  Looking forward to that!  

But ya know, somehow, it seems that plating over the "activator", once that's 
"in the holes", would be much faster if electrolytic!  I understand Nickel 
plates well without DC current, but copper???  News to me!  Hmmm...   

So, word from an experienced person would be very welcome and interesting!

Jan Rowland


[Non-text portions of this message have been removed]

Jan,

Let me clarify the plating issue. Everything past the activator stage 
is "electrolytic". In the acid copper plating tank it takes about 30 
minutes to plate .001" of copper at 25 to 30 amps per square foot.

The solder plating takes about 15 minutes and is only plated to 
about .0003" inches thickness. Current is about 20 amps per square 
foot.

More information is on the way in future posts. If anyone has 
specific questions I'll do my best to answer them. 

Tom 


--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 12/10/2002 3:50:14 PM Central Standard Time, 
> twb8899@y... writes:
> 
> 
> > I'll write up the basics stating at the beginning and post them 
over 
> > the next few days. 
> > 
> 
> Right ON!  Looking forward to that!  
> 
> But ya know, somehow, it seems that plating over the "activator", 
once that's 
> "in the holes", would be much faster if electrolytic!  I understand 
Nickel 
> plates well without DC current, but copper???  News to me!  
Hmmm...   
> 
> So, word from an experienced person would be very welcome and 
interesting!

> 
> Jan Rowland
> 
> 
> [Non-text portions of this message have been removed]

In a message dated 12/11/2002 12:01:08 AM Central Standard Time, 
twb8899@... writes:


> Let me clarify the plating issue. Everything past the activator stage 
> is "electrolytic". In the acid copper plating tank it takes about 30 
> minutes to plate .001" of copper at 25 to 30 amps per square foot.
> 

Gotcha!  Thanks for clarification.  I HAD originally realized he "activation" 
was electroless, so it was easy to read confusion into all that.     

Yeah, it'd take some TIME to electroless plate even only 0.001" of Cu, now, 
wouldn't it!  AND, I suspect that wouldn't even be very "nice", if it'd work 
at all!

I wonder how the "solder plating" can look as thick as if it had been 
"dipped", if it is only 3 tenths thick as you say???  Hmmm...


[Non-text portions of this message have been removed]

Jan,

The solder plating really is about .0003" thick. Not much is needed 
and everyone kind of cheats on that. We rarely measured the final 
thickness of the solder which reminds me of a story.

My plant was visited once by a customer who was a military 
contractor. He brought along two Navy big shots who wanted to see 
what we were doing. They were in full uniform and  watching one of my 
guys pulling boards from the solder plating tank. When asked about 
checking thickness my plating guy said "ask the boss". 

They made some comment about mil spec thickness requirements and 
before I could say something to cover my ass my customer said "We've 
been dealing with these guys for years... they know what they're 
doing and refuse to lower their standards by meeting that MIL SPEC  
BULLSHIT". 

Well, I was somewhat shocked by this guys comments but he was going 
to retire in several months and could care less what anyone thought.
Then one Navy guy said "How do we know that this gentleman is even 
the boss"  My customer asked them "How many circuit board plants have 
you guys visited?". Both Big Brass Navy guys said this was their fist 
time. My customer said "Well, look at this knuckleheads pants... the 
boss at every circuit board plant has the least amount of acid holes 
in his britches" I was shocked and speechless but the Big Navy guys 
were laughing their asses off. We all started laughing at that point 
and I said lets go to lunch. 

While having lunch they told me all kinds of stories "off the record" 
some of which were almost unbelieveable. I asked the Big Shots how 
their planes were ever able to fly. They're response: "Each one of 
those planes is it's own miracle" !!!

Military contracting... lots of paper and mostly BS!!!!

Now thats a true story and it lets you know what really goes on in 
some of these high tech companies!  

Tom

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 12/11/2002 12:01:08 AM Central Standard Time, 
> twb8899@y... writes:
> 
> 
> > Let me clarify the plating issue. Everything past the activator 
stage 
> > is "electrolytic". In the acid copper plating tank it takes about 
30 
> > minutes to plate .001" of copper at 25 to 30 amps per square foot.
> > 
> 
> Gotcha!  Thanks for clarification.  I HAD originally realized 
he "activation" 
> was electroless, so it was easy to read confusion into all 
that.     
> 
> Yeah, it'd take some TIME to electroless plate even only 0.001" of 
Cu, now, 
> wouldn't it!  AND, I suspect that wouldn't even be very "nice", if 
it'd work 
> at all!
> 
> I wonder how the "solder plating" can look as thick as if it had 
been 

> "dipped", if it is only 3 tenths thick as you say???  Hmmm...
> 
> 
> [Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
<twb8899@y...> wrote:
> Adam,
> 
> Wow, you are quite a researcher and experimenter. I never did try out 
> the blackhole process. They had some trouble in the early days with 
> innerlayer voids on multilayers and we couldn't take a chance. On two 
> layer boards the blackhole process has always been excellent. It 
> could possibly be the way to go for home experimenters. If I remember 
> right, you needed an agitation pump to keep the carbon dispersed in 
> the solution and an oven to bake the panels after processing. After 
> drying the panel you must sand the carbon off of the copper leaving 
> just the holes coated. If thats the case, then this could be the way 
> to go. Just fire it up and run it when you need boards. 
> 

That's kind of correct. The boards are drilled and then immersed in to
a conditioner solution A monolayer of long chain molecules are
adsorbed to the surface of the epoxy surface and act to improve the
adsorption of the following stage, the carbon black dispersion. The
boards are immersed into a suspension of carbon black particles and
coagulate or adsorb tn the surface of the holes (and the copper foil).
The board is removed from the dispersion and put through a an air
knifed to remove excess liquid from the holes. The panels are then
baked at about 60 to 80°C to completely dry the carbon. The carbon is
now firmly packed and adhered to the surface. The carbon on the copper
is then removed by immersion in ammonium persulfate to lightly etch
the copper and at the same time take with it any carbon. The panels
are finished with rinsing and drying. As far as I am aware the
Blackhole SP is Macdermids latest process which I think began around
1996. It is frequency used to in manufacture of 16 or more layers
boards. The carbon bath does coagulate over time, but I've heard the
bath is maintained with regular additions of dispersion concentrate,
and the entire bath is replaced every 1 to 2 years. Carbon aggregates
will simply settle to the bottom of the tank. There is no continuos
pump in Blackhole, you might be thinking of a competing process call
Shadow by Electrochemicals Co, which run the bath through a high shear
pump to keep the graphite dispersed. Graphite particles have much
lower surface are to volume ratio that carbon black and so do not
normally behave as stable colloids.




> You can use a five gallon bucket for the electroplating part. The 
> copper anodes must have some phosphorus in the alloy or it won't work 
> properly. You will find these anodes marked "cu-phos". Plain copper 
> anodes are used in a cyanide bath but the high pH of that chemistry 
> will strip off your photoresist so it's no good for pc boards. When 
> the solution is adjusted properly the plated boards will look like a 
> copper mirror. Acid copper plating baths must be air agitated for 
> proper plating. The solder plating tank can be set up the same way 
> but doesn't require the air agitation.
> 

Its interesting you mentioned solder plate. Is that how most people do
it ? I am using tin plate mainly because a stannous sulfate/sulfuric
acid bath is less toxic than the fluroboric acid/fluroborate tin/lead
bath commonly used to plate solder. One big advantage of solder plate
is the ease of selectively etching the copper. With tin metal resist,
I'm forced to use alkaline ammonical etching solution, which need a
special tank in order to contain the ammonia gas. I'm now wondering if
solder plate is the better way to go. Is a solder plating bath very
difficult to control and too toxic to setup in ones home workshop ?

Adam

For some time I have given thought to a method of plating through holes 
with out going to the expensive process that a comercial house uses.
I recently tried an experiment using a conductive ink pen from Radio 
Shack, I drilled the hole, then injected the conductive ink into the 
hole until it was well coated, then made sure there was a donut of the 
conductive ink around the copper on both sides. I then baked the board 
and checked for resistance. The hole had been sucessfully "plated", 
resistance was as close to 0 ohms as I could measure with the equipment 
I have available.

The Radio Shack Pen conductive ink pen is essentually silver particles 
suspended in a carrier that evaporates leaving the silver.

Radio Shack states that you can solder on to this conductive ink after 
baking, so my next experiment will be to plate a hole, and see if it 
will fill with solder.

I am curious to see if this will hold up to repeated thermal cycles as 
the "real" plated through holes do.

idaho_huckleberry wrote:
> The Radio Shack Pen conductive ink pen is essentually silver particles 
> suspended in a carrier that evaporates leaving the silver.

http://www.eecoswitch.com/Catalog%20Files/cat_sth.htm


-- 
uhmgawa@...        www.gnu.org

Uhmgawa,  did you forget to post comments concerning DIY plating?  Or are
you just taking the opportunity to spam a site?

Thanks Idaho, I'm going to look into that.  I'm also trying to find a
'simple' alternative to plated thru-holes.  It would be ideal if we could
get our hands on the supplier of this 'conductive ink' for larger volume
containers (unless a pen lasts for quite a while).

Oh yeah, what size hole are you using, and what size pads?  I'd like to
avoid doing the same testing you've already done.

Robert
:)



-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de uhmgawa
Envoyé : mai 25 2005 13:07
À : Homebrew_PCBs@yahoogroups.com
Objet : Re: [Homebrew_PCBs] Plated through holes


idaho_huckleberry wrote:
> The Radio Shack Pen conductive ink pen is essentually silver particles
> suspended in a carrier that evaporates leaving the silver.

http://www.eecoswitch.com/Catalog%20Files/cat_sth.htm


-- 
uhmgawa@...        www.gnu.org



Be sure to visit the group home and check for new Bookmarks and files:
http://groups.yahoo.com/group/Homebrew_PCBs 
Yahoo! Groups Links

If you want to get into nitty-gritty details and not want to flood the board
with your minute-to-minute observations,  :D  please feel free to email me
directly.  I'm really interested in this process and want to know everything
you learn about it.

I wonder if other 'silver' pens get the same results.  I'm sure I bought a
metallic silver marker from Staples.  I'm going to dig it out and see if
that thing works.

Robert
:)




For some time I have given thought to a method of plating through holes 
with out going to the expensive process that a comercial house uses. I
recently tried an experiment using a conductive ink pen from Radio 
Shack, I drilled the hole, then injected the conductive ink into the 
hole until it was well coated, then made sure there was a donut of the 
conductive ink around the copper on both sides. I then baked the board 
and checked for resistance. The hole had been sucessfully "plated", 
resistance was as close to 0 ohms as I could measure with the equipment 
I have available.

The Radio Shack Pen conductive ink pen is essentually silver particles 
suspended in a carrier that evaporates leaving the silver.

Radio Shack states that you can solder on to this conductive ink after 
baking, so my next experiment will be to plate a hole, and see if it 
will fill with solder.

I am curious to see if this will hold up to repeated thermal cycles as 
the "real" plated through holes do.

On Wed, 25 May 2005 22:19:45 +0200, Robert Hedan  
<robert.hedan@...> wrote:

> If you want to get into nitty-gritty details and not want to flood the  
> board
> with your minute-to-minute observations,    please feel free to email me
> directly.  I'm really interested in this process and want to know  
> everything
> you learn about it.
> I wonder if other 'silver' pens get the same results.  I'm sure I bought  
> a
> metallic silver marker from Staples.  I'm going to dig it out and see if
> that thing works.
> Robert
>

The silver markers will not work, much to cheap compared to the ink ;-)

Please let the list know the details, as long as the subject is proper  
nobody will object minute-to-minute observations.
While i am not sure this method is reliable (without further  
soldering/plating) i am still interested.

ST

Robert Hedan wrote:
> Uhmgawa,  did you forget to post comments concerning DIY plating?

I expected it to be self-explanatory.

> Or are
> you just taking the opportunity to spam a site?

That was a site I'd happened on a day or so ago.
I actually had to spend some time to dig it up again.
The intent of the mail was to illustrate there
are commercial vendors using this technique
thus it is viable.

Why would you think this would be spam?  If you
notice the name of this group, it is unlikely to
get any commercial attention from a group of
folks trying to fabricate PCBs at home.

> Thanks Idaho, I'm going to look into that.  I'm also trying to find a
> 'simple' alternative to plated thru-holes.  It would be ideal if we could
> get our hands on the supplier of this 'conductive ink' for larger volume
> containers (unless a pen lasts for quite a while).
> 
> Oh yeah, what size hole are you using, and what size pads?  I'd like to
> avoid doing the same testing you've already done.

You can find answers to your questions by referring
the the alleged "spam" in the previous post.

And you're welcome.

-- 
uhmgawa@...        www.gnu.org

Stefan Trethan wrote:
> The silver markers will not work, much to cheap compared to the ink ;-)
> 
> Please let the list know the details, as long as the subject is proper  
> nobody will object minute-to-minute observations.
> While i am not sure this method is reliable (without further  
> soldering/plating) i am still interested.

I recall a recent (within the last 3 months or so) issue
of Popular Science magazine (hey! it was a free subscription)
had an article extolling the virtues of ink jet printer
technology.

Mentioned were at least two companies in Japan who are using
a conductive silver particle ink to actually lay traces on
a bare board.  I'd assume there is some non-conductive coating
printed over the conductive trace.  This seems reminiscent
of multiwire PCB fabrication.  Anyway the ink should become
more available if this technique takes off.

The use of inkjet technology to fab PCBs was actually
one of the more mundane topics of the article.  The
part about using living cells as ink and "printing up"
tissue for surgical repairs was the interesting part.
Apparently this was the original use for which the
inkjet mechanism was invented by HP back in the late
70's.  Only later did someone at HP think to press this
technology into service for printing.


-- 
uhmgawa@...        www.gnu.org

"I expected it to be self-explanatory."

See, that was your first mistake, people like me need big banners.  :D
Bright neons with arrows help.  Seriously, it's common for people to either
forget attachments, or forget to include a comment with a URL.  Look at my
2nd post was directed solely at Idaho, but I forgot to change the
distribution list, d'uh...


"The intent of the mail was to illustrate there are commercial vendors using
this technique thus it is viable."

I know manufacturers use this, the question is can we get access to the same
supplies at a reasonable cost.


"If you notice the name of this group, it is unlikely to get any commercial
attention from a group of folks trying to fabricate PCBs at home."

You'd be surprised how many forums I'm in and how many people keep throwing
in URLs without any comments.  Spam pays, the financial forums are the worst
examples.


"You can find answers to your questions by referring the the alleged "spam"
in the previous post."

Machine-made holes and DIY-made holes are not exactly the same quality.
Their inks are not necessarily the same viscosity nor have the same metallic
composition.  I prefer to follow the recommendations of someone that used a
similar ink that I will be using, and drills the holes in a similar fashion;
dremel-type on a small press usually.  I'm not saying their way is no good,
I'm saying DIY-people don't always have the quality of supplies and
equipment required.


"And you're welcome."

Any time.  :)


Robert
:)



Be sure to visit the group home and check for new Bookmarks and files:
http://groups.yahoo.com/group/Homebrew_PCBs 
Yahoo! Groups Links

> Machine-made holes and DIY-made holes are not exactly the same quality.
> Their inks are not necessarily the same viscosity nor have the same  
> metallic
> composition.  I prefer to follow the recommendations of someone that  
> used a
> similar ink that I will be using, and drills the holes in a similar  
> fashion;
> dremel-type on a small press usually.  I'm not saying their way is no  
> good,
> I'm saying DIY-people don't always have the quality of supplies and
> equipment required.
>

I have actually read the "spam", and found it quite interesting.
It says they can use cheap (phenolic) board, so hole quality seems not a  
big issue.

It is always VERY VALUABLE and HIGHLY INTERESTING to know of commercial  
examples, because it tells you something can be done, for sure.
If you have the means to do it is another story, but it is very nice to  
know it is at all possible in a reliable manner.

Thanks for spamming to the list, hehe ;-)

Man i wish someone would fight the tons of real spam instead i get each  
day...

ST

Stefan Trethan wrote:
> I have actually read the "spam", and found it quite interesting.
> It says they can use cheap (phenolic) board, so hole quality seems not a  
> big issue.

Moreover they are punching rather than drilling
the holes which does seem inexpensive if a bit
crude.  IIRC the polishing action of the bit in
a drilling operation leaves the hole wall relatively
smooth.  Likely the ink is more tolerant of the
punch/shearing operation leaving a more irregular
wall surface.

-- 
uhmgawa@...        www.gnu.org

What I'd like to know about this "silver ink pen" is, does the "donut" over  
the copper pads SOLDER-over?  Does the solder "wick" down-in, around the  
lead-wire?  That is, if a pad of a via with NO lead-wire that is, say,  under a 
0.6 in. wide IC, is it as metallurgically-bonded to the  "solder-accessible 
side" as a pad that is accessible/solderable "on top", as  well??????  Jan Rowland


[Non-text portions of this message have been removed]

JanRwl@... wrote:
> What I'd like to know about this "silver ink pen" is, does the "donut" over  
> the copper pads SOLDER-over?  Does the solder "wick" down-in, around the  
> lead-wire?  That is, if a pad of a via with NO lead-wire that is, say,  under a 
> 0.6 in. wide IC, is it as metallurgically-bonded to the  "solder-accessible 
> side" as a pad that is accessible/solderable "on top", as  well??????  Jan Rowland
> 

If you read the specs on the "EECO-Green\ufffd Silver-Through-Hole" datasheet
they state max resistance is 0.1 ohm/hole and is fixed to 0.5mm
diameter. This process is obviously only suitable for a 100% SMD design
  carrying signals < 1A. They also market their service as being lead
free, when standard plated through hole technology normally does not
involve any lead at all.

There is nothing wrong with wet chemistry if handled properly. I've been
plating holes at home and nothing compares to real copper inside the holes.

Adam.

> There is nothing wrong with wet chemistry if handled properly. I've been
> plating holes at home and nothing compares to real copper inside the
> holes.

So how exactly do you do this?  What chemicals, equipment are needed?

Ed

Adam Seychell wrote:
> If you read the specs on the "EECO-Green\ufffd Silver-Through-Hole" datasheet
> they state max resistance is 0.1 ohm/hole and is fixed to 0.5mm
> diameter. This process is obviously only suitable for a 100% SMD design
>   carrying signals < 1A.

For a single via per trace.  Multiple vias/trace for
higher current capacity is possible though admittedly
this is somewhat of a brute force approach.

> There is nothing wrong with wet chemistry if handled properly. I've been
> plating holes at home and nothing compares to real copper inside the holes.

I would agree it is preferable.  However from the little
I've researched it appears the required consumables are
somewhat difficult to obtain.  Would you care to share
your procedure?

-- 
uhmgawa@...        www.gnu.org

In a message dated 5/25/2005 8:22:11 P.M. Central Daylight Time,  
a_seychell@... writes:

There is  nothing wrong with wet chemistry if handled properly. I've been
plating  holes at home and nothing compares to real copper inside the  holes.



Oh, I agree 100%!  Only, ONE board every couple years with only ten  "MUST-be 
PTH" holes kinda makes all the "wet setup" a bit of a  drag!


[Non-text portions of this message have been removed]

On Thu, 26 May 2005 03:44:12 +0200, Ed Okerson <ed@...> wrote:

>> There is nothing wrong with wet chemistry if handled properly. I've been
>> plating holes at home and nothing compares to real copper inside the
>> holes.
> So how exactly do you do this?  What chemicals, equipment are needed?
> Ed


And more importantly, who is gonna pay for it?
The starting set of chemicals is so expensive i can have the boards done  
professionally.

ST

I was at a machine shop here in Jakarta several weeks ago and they do selective plating etc for Aircraft parts, they had also repaired an Engine Block in a camshaft bore using a Coloidal Copper solution (IIRC) applied with Electrolysis,
my first thought was to use this solution to plate via holes also, but of course the hole must be conductive for this to work so maybe the conductive silver pen will have to be used first to get the process working. I dont know about the price but looking at the amount they chew through 1liter would last me a long time if it worked ok.
http://www.brushplating.com/

Thomas

  ----- Original Message ----- 
  From: Stefan Trethan 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Thursday, May 26, 2005 1:33 PM
  Subject: Re: RE : [Homebrew_PCBs] Plated through holes


  On Thu, 26 May 2005 03:44:12 +0200, Ed Okerson <ed@...> wrote:

  >> There is nothing wrong with wet chemistry if handled properly. I've been
  >> plating holes at home and nothing compares to real copper inside the
  >> holes.
  > So how exactly do you do this?  What chemicals, equipment are needed?
  > Ed


  And more importantly, who is gonna pay for it?
  The starting set of chemicals is so expensive i can have the boards done  
  professionally.

  ST


[Non-text portions of this message have been removed]

On Thu, 26 May 2005 11:28:21 +0200, Thomas <teecee@...> wrote:

> I was at a machine shop here in Jakarta several weeks ago and they do  
> selective plating etc for Aircraft parts, they had also repaired
> an Engine Block in a camshaft bore using a Coloidal Copper solution  
> (IIRC) applied with Electrolysis,
> my first thought was to use this solution to plate via holes also, but  
> of course the hole must be conductive for this to work so maybe
> the conductive silver pen will have to be used first to get the process  
> working. I dont know about the price but looking at the amount
> they chew through 1liter would last me a long time if it worked ok.
> http://www.brushplating.com/
> Thomas


Well, hole wall activation is apparently the hardest part of it all.

Silver paint costs like 1eur/g, so it is relatively expensive. there is  
much cheaper conductive graphite paint, and ideas if that can be used for  
hole wall activation?

Even if that works i am not sure it is suitable for my style of making  
pcbs, which is quick and cheap.
Toner transfer is not really compatible with THP, because it can't tent  
the holes. What you'd have to do is transfer the negative (which raises a  
number of problems in itself), and then plate with tin, which in turn  
requires a change of etchant to sulphuric/H2O2 instead of CuCl.

Considering the work you need to add (2 plating baths, more complicated  
etchant, wall activation), and the costs, i will rather stay with using  
pieces of wire for vias. I mean, unless you do it for the advantage of  
having a PCB in an hour, financially it does not seem justifyable to make  
homebrew PTH boards. The prices for boards are incredibly low nowadays...

ST

Ed Okerson wrote:

>>There is nothing wrong with wet chemistry if handled properly. I've been
>>plating holes at home and nothing compares to real copper inside the
>>holes.
> 
> 
> So how exactly do you do this?  What chemicals, equipment are needed?
> 
> Ed



I happen to find chemistry fascinating, which I guess started since I 
was introduced to the subject back in high school. Because it this I was 
able to spent a *lot* of my time experimenting and learning about doing 
PTH for the end goal of being able to fabrication PCBs at home. Having 
spend the last 4 years or so fiddling with this I conclude PTH a time 
consuming and tedious task, even with all the equipment laid out in 
front of you. It is *not* possible to make a quick and simple PTH board 
but rather requires lots of patients combined with enthusiasm to make it 
work.

I've made probably a dozen PTH PCBs so far using my latest tank 
equipment. About the quickest time I've made a PTH board is 4.5 hours, 
counting from the time I begin drilling to the time I'm ready to solder 
parts on, and no board yet has come out perfect. I prefer to make single 
sided PCB whenever possible. When I've finally finished my setup I'm 
hoping to get it down to 3 hours or less, otherwise PTH is just too 
monotonous.

There are lots of steps, all of which have potential problems.
The processing tanks and the maintenance of the chemicals is important, 
as well as a good understanding of how the process behaves.

These are most of steps and chemicals I use to make a PTH PCB. I'm still 
refining the "Make holes conductive" step, as my current method needs 
much improvement.

**********************************************
1) Drill board

2) Cleaning

  dishwashing detergent
  60~80\ufffdC
  5 minutes immersion

3) immersion rinse

4) Make holes conductive

  high purity conductive carbon black aqueous dispersion
  using a cationic type dispersion agent.
  pH controlled to 9.0 with sodium bi-carbonate
  room temp
  5 minutes immersion


5) Absorb excess liquid with sponge.

6) Hot air dry

... repeat steps 4 to 6 ...

... repeat steps 4 to 6 again ...


7) Microstrip

  Ammonium persulfate
  room temp
  5~10 minutes immersion

8) Spray Rinse

9) electroplate the holes

  200g/L H2SO4
  75g/L CuS04.5H20
  Macdermid Macuspec copper plating additive
  30~60ppm chloride
  15~35 \ufffdC
  120 minutes, bubble agitation

10) immersion rinse

11) laminate dry film photoresist

12) Expose

13) Develop

  9g/L sodium carbonate
  25~35 \ufffdC
  2 minutes, paint brush agitation

14) immersion rinse

15) Etch

  CuCl2+O2
  room temp
  5 minutes spray

16) immersion rinse

17) strip resist

  50g/L NaOH
  20~55 \ufffdC
  10 minutes immersion


18) immersion rinse

Thanks Adam,

that tells me my guess it will not be worth the effort for me was correct.
In 3 hours i can via a lot of holes with wire, if need be, and 99.9% of  
the time i can do without them.
Not counting the time you put into setting it all up...

ST



On Thu, 26 May 2005 12:03:43 +0200, Adam Seychell  
<a_seychell@...> wrote:

> I've made probably a dozen PTH PCBs so far using my latest tank
> equipment. About the quickest time I've made a PTH board is 4.5 hours,
> counting from the time I begin drilling to the time I'm ready to solder
> parts on, and no board yet has come out perfect. I prefer to make single
> sided PCB whenever possible. When I've finally finished my setup I'm
> hoping to get it down to 3 hours or less, otherwise PTH is just too
> monotonous.

Thomas wrote:

> I was at a machine shop here in Jakarta several weeks ago and they do selective plating etc for Aircraft parts, they had also repaired an Engine Block in a camshaft bore using a Coloidal Copper solution (IIRC) applied with Electrolysis,
> my first thought was to use this solution to plate via holes also, but of course the hole must be conductive for this to work so maybe the conductive silver pen will have to be used first to get the process working. I dont know about the price but looking at the amount they chew through 1liter would last me a long time if it worked ok.
> http://www.brushplating.com/
> 

I would admit that getting holes conductive is probably the most 
problematic step the process, but I would say on a whole compared to all 
the other steps, it is not that big it stands out from the rest. You can 
easily have problems with any another step while you making hole walls 
conductive step is working perfectly. I've spent a good deal of time on 
getting steps of the process working, such as the electroplating and 
photoresists lamination and the least expected one, the developing step.

Adam

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, May 26, 2005 10:45 AM
Subject: Re: RE : [Homebrew_PCBs] Plated through holes


> On Thu, 26 May 2005 11:28:21 +0200, Thomas <teecee@...> wrote:
>
>> I was at a machine shop here in Jakarta several weeks ago and they do
>> selective plating etc for Aircraft parts, they had also repaired
>> an Engine Block in a camshaft bore using a Coloidal Copper solution
>> (IIRC) applied with Electrolysis,
>> my first thought was to use this solution to plate via holes also, but
>> of course the hole must be conductive for this to work so maybe
>> the conductive silver pen will have to be used first to get the process
>> working. I dont know about the price but looking at the amount
>> they chew through 1liter would last me a long time if it worked ok.
>> http://www.brushplating.com/
>> Thomas
>
>
> Well, hole wall activation is apparently the hardest part of it all.
>
> Silver paint costs like 1eur/g, so it is relatively expensive. there is
> much cheaper conductive graphite paint, and ideas if that can be used for
> hole wall activation?
>
> Even if that works i am not sure it is suitable for my style of making
> pcbs, which is quick and cheap.
> Toner transfer is not really compatible with THP, because it can't tent
> the holes. What you'd have to do is transfer the negative (which raises a
> number of problems in itself), and then plate with tin, which in turn
> requires a change of etchant to sulphuric/H2O2 instead of CuCl.
>
> Considering the work you need to add (2 plating baths, more complicated
> etchant, wall activation), and the costs, i will rather stay with using
> pieces of wire for vias. I mean, unless you do it for the advantage of
> having a PCB in an hour, financially it does not seem justifyable to make
> homebrew PTH boards. The prices for boards are incredibly low nowadays...


A small PCB company I know who had just been making non-PTH PCBs decided to 
install the equipment for PTH. I think it took a couple of months before 
they got the process working reliably.

Leon

Stefan Trethan wrote:

> Thanks Adam,
> 
> that tells me my guess it will not be worth the effort for me was correct.
> In 3 hours i can via a lot of holes with wire, if need be, and 99.9% of  
> the time i can do without them.
> Not counting the time you put into setting it all up...
> 
> ST
> 

Once upon a time I believed PTH could be made simple, with minimal 
equipment and was just a matter of knowing the right things, but I have 
  learned first hand that this is not possible.

Adam

I drilled the hole with a regular through the board IC pin sized drill 
bit (sorry, I an away from home and don't have the drill size handy), 
then used the pen to squeeze some of the silver ink into the hole, 
making sure that it pushed through to the other side. The donut was 
just getting the silver ink on the surface pad to make sure there was a 
good connection from the pad to the silver in the hole, then on to the 
pad on the opposite side.

I have not been able to try soldering on it yet to see if it will take 
solder, though the instructions on the solder pen indicate that it can 
be soldered to if the board is baked to cure the silver in place.

I looked into the comercial plating through the holes once and decided 
that was not the way to go if one only needed to make a few boards now 
and then. The information I had indicated that there was some sort of 
Paladium coating that needed to be applied to the holes, then several 
other plating steps that I deamed were beyond the reach of my home brew 
budget/capability.

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> What I'd like to know about this "silver ink pen" is, does 
the "donut" over  
> the copper pads SOLDER-over?  Does the solder "wick" down-in, around 
the  
> lead-wire?  That is, if a pad of a via with NO lead-wire that is, 
say,  under a 
> 0.6 in. wide IC, is it as metallurgically-bonded to the  "solder-
accessible 
> side" as a pad that is accessible/solderable "on top", as  
well??????  Jan Rowland

> 
> 
> [Non-text portions of this message have been removed]

idaho_huckleberry wrote:

> I drilled the hole with a regular through the board IC pin sized drill 
> bit (sorry, I an away from home and don't have the drill size handy), 
> then used the pen to squeeze some of the silver ink into the hole, 
> making sure that it pushed through to the other side. The donut was 
> just getting the silver ink on the surface pad to make sure there was a 
> good connection from the pad to the silver in the hole, then on to the 
> pad on the opposite side.

   Still sounds like a bit of work though not too bad.

> 
> I have not been able to try soldering on it yet to see if it will take 
> solder, though the instructions on the solder pen indicate that it can 
> be soldered to if the board is baked to cure the silver in place.
> 
> I looked into the comercial plating through the holes once and decided 
> that was not the way to go if one only needed to make a few boards now 
> and then. The information I had indicated that there was some sort of 
> Paladium coating that needed to be applied to the holes, then several 
> other plating steps that I deamed were beyond the reach of my home brew 
> budget/capability.
> 

   It is a lot of hassle and work for light or medium work.

   Thinking about it again, I see that it isn't the soldering that is the 
problem, but the locating and cutting and crimping the wires.  Soldering both 
sides is easy enough after they're in place.

   And that part could easily be automated.  A small tube just above the board 
with a stepper feeding the wire through the tube.  Say 30 gauge wire wrap wire 
with no insulation.  Have the holes just barely larger than the wire, so they 
don't need much bent over to hold it in.  Locate the hole, feed just enough wire 
to go through with about 1/16th inch extra, move the board over slightly to the 
bending blocks to hold the wire in, cut the wire, move more to finish the 
bending, then repeat.  A stationary wire feed/bending system and moving the 
board X and Y and this would be a breeze for a CNC setup.  Put in a stationary 
vertical drill and you can do the holes too.  Thin wire and you can get by with 
very little knife power, which is good since it must be thin and right at the board.

   For doing vias and drilling it might be worth making, and much simpler for 
low volume than trying to do PTH..  Same aluminum angle I use for CNC support 
would work great for bending/guide pieces, and the wire feed and knife would be 
easy.

Alan

It appears much easier, IMO, to just buy a big spool of thin wire, and  
thread it through all vias in a board (in one piece). then solder, then  
cut the crisscross pieces away. I think the CNC would be more work.

Maybe it is practical to make small studs of copper, just a bit longer  
than the hole. Place the board on spacers to allow the studs to protrude  
maybe 0.5mm or less, above a steel plate. then take a hammer and hammer on  
the board, so that the studs are riveted in place.

ST

On Thu, 26 May 2005 16:21:51 +0200, Alan King <alan@...> wrote:

>
>    It is a lot of hassle and work for light or medium work.
>   Thinking about it again, I see that it isn't the soldering that is the
> problem, but the locating and cutting and crimping the wires.  Soldering  
> both
> sides is easy enough after they're in place.
>   And that part could easily be automated.  A small tube just above the  
> board
> with a stepper feeding the wire through the tube.  Say 30 gauge wire  
> wrap wire
> with no insulation.  Have the holes just barely larger than the wire, so  
> they
> don't need much bent over to hold it in.  Locate the hole, feed just  
> enough wire
> to go through with about 1/16th inch extra, move the board over slightly  
> to the
> bending blocks to hold the wire in, cut the wire, move more to finish the
> bending, then repeat.  A stationary wire feed/bending system and moving  
> the
> board X and Y and this would be a breeze for a CNC setup.  Put in a  
> stationary
> vertical drill and you can do the holes too.  Thin wire and you can get  
> by with
> very little knife power, which is good since it must be thin and right  
> at the board.
>   For doing vias and drilling it might be worth making, and much simpler  
> for
> low volume than trying to do PTH..  Same aluminum angle I use for CNC  
> support
> would work great for bending/guide pieces, and the wire feed and knife  
> would be
> easy.
> Alan

Stefan Trethan wrote:

> It appears much easier, IMO, to just buy a big spool of thin wire, and  
> thread it through all vias in a board (in one piece). then solder, then  
> cut the crisscross pieces away. I think the CNC would be more work.

   Yeah for 1 or 2 maybe, but try doing about 10 or 20 per board.  Punch a 
button, go away, and come back and they're all done is way easier.  You'll 
easily make up the difference with a machine in no time.  Get it reliable and 
50+ via tight boards may not even be a problem..  Real work is locating the 
right holes in a dense board, that's why the CNC would be such a boon doing it 
by itself from the drill file.

> 
> Maybe it is practical to make small studs of copper, just a bit longer  
> than the hole. Place the board on spacers to allow the studs to protrude  
> maybe 0.5mm or less, above a steel plate. then take a hammer and hammer on  
> the board, so that the studs are riveted in place.
> 

   There are some like that, with more of a press than a hammer.  Still easier 
to not be there, I'd want to CNC even this method.  But thin wire needing only a 
slight bend and light cut would be easier still, doesn't even need the studs or 
press.  Especially good when you can drill the board with the same machine.  I 
rarely drill or via, doing SMT and wire jumpers on single sided for ease.  But a 
decent automated via machine would bring them back into play.  Still easier to 
not have 2 sides to align, but it'd be worth it sometimes.

   While I have a full gantry CNC system, a simple seperated XY slide 
arrangement for the PC board would be easier for most to build.  I'm going to 
play around a bit and see about the simplest design I can come up with, it may 
be very practical.

   But after a trip to the store for some Reynold's paper.  Should have thought 
of that myself, not like I haven't used it before and noticed how good it was at 
non-stick cooking.  But wasn't doing boards at that time so didn't put 2 and 2 
together.

Alan

BTW for whoever mentioned the ink jet circuitry, they are working on more 
than just the circuitry too.  Like print out a whole remote etc as one solid 
object, case, circuitry, and all.  Add battery and go.  Of course the printed 
transistor density is low compared to a manufactured IC but it's enough for many 
low to mid tech items.  Would be great for DIY credit card remotes.

Alan

On Thu, 26 May 2005 19:43:02 +0200, Alan King <alan@...> wrote:

>
>    BTW for whoever mentioned the ink jet circuitry, they are working on  
> more
> than just the circuitry too.  Like print out a whole remote etc as one  
> solid
> object, case, circuitry, and all.  Add battery and go.  Of course the  
> printed
> transistor density is low compared to a manufactured IC but it's enough  
> for many
> low to mid tech items.  Would be great for DIY credit card remotes.
> Alan
>


Why not print the battery too? With how long stuff is built to last  
nowadays the whole device is thrown out long before it is empty anyway ;-)

ST

Track pins are available from Harwin in PCB diameters of 0.84 and 1.0mm
suitable for a PCB thickness of 1.59mm.
They are available from Farnell In One at AU$43.52 + 10% per 1000 for the 0
84mm versions.

They are most likely available from Newark & Radio Spares among others.

Cheers
Brian

-------Original Message-------
 
From: Homebrew_PCBs@yahoogroups.com
Date: 05/27/05 00:33:50
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: RE : [Homebrew_PCBs] Plated through holes
 
It appears much easier, IMO, to just buy a big spool of thin wire, and
thread it through all vias in a board (in one piece). then solder, then
cut the crisscross pieces away. I think the CNC would be more work.
 
Maybe it is practical to make small studs of copper, just a bit longer
than the hole. Place the board on spacers to allow the studs to protrude
maybe 0.5mm or less, above a steel plate. then take a hammer and hammer on
the board, so that the studs are riveted in place.
 
ST
 
 
 
On Thu, 26 May 2005 16:21:51 +0200, Alan King <alan@...> wrote:
 
>
>    It is a lot of hassle and work for light or medium work.
>   Thinking about it again, I see that it isn't the soldering that is the
> problem, but the locating and cutting and crimping the wires.  Soldering
> both
> sides is easy enough after they're in place.
>   And that part could easily be automated.  A small tube just above the
> board
> with a stepper feeding the wire through the tube.  Say 30 gauge wire
> wrap wire
> with no insulation.  Have the holes just barely larger than the wire, so
> they
> don't need much bent over to hold it in.  Locate the hole, feed just
> enough wire
> to go through with about 1/16th inch extra, move the board over slightly
> to the
> bending blocks to hold the wire in, cut the wire, move more to finish the
> bending, then repeat.  A stationary wire feed/bending system and moving
> the
> board X and Y and this would be a breeze for a CNC setup.  Put in a
> stationary
> vertical drill and you can do the holes too.  Thin wire and you can get
> by with
> very little knife power, which is good since it must be thin and right
> at the board.
>   For doing vias and drilling it might be worth making, and much simpler
> for
> low volume than trying to do PTH..  Same aluminum angle I use for CNC
> support
> would work great for bending/guide pieces, and the wire feed and knife
> would be
> easy.
> Alan
 
 
 
 
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