Homebrew_PCBs

Well,

I can't say as it was bad or good, certainly nothing like the
commercially produced boards I have worked with in kits.

The transfer process went good - I used that Pulsar brand Toner
Transfer System paper. I printed out the schematics (.012" wide
traces which was part of my problem) on the paper. Using an iron set
at about 3/4 the way to MAX and pressed down hard for about a minute.

I then let the board cool for a couple of minutes, placed it in water
for about a minute and the paper came right off leaving the toner.

I used the circuit boards and etchant that comes with the Radio Shack
starter kit. I simply placed the bottle in some Tap-hot water for
about 10 minutes to warm it. Poured it into the tray that came with
the kit, put in the circuit board, and placed a small piece of wood
under the tray so I could rock it back and forth (wave action).

In about 10 minutes, the copper was gone. I then used the solvent
that came in the kit to remove the toner and all was done.

The traces are a bit "pitted" in areas. Some of the spaces between
the traces didn't etch away completly. I should be able to scrap away
a small groove with a sharp hobby knife to create the gap needed.

It does appear as though they are good enough to be used (provided I
can scrape away the material where needed).

Now, the next part I am unsure of. I suspect I can solder it up as I
would with any other board. I suppose there my be some problems as
the copper isn't tinned, but I hope to get past that okay. After
soldering and cleaning, do I need to do anything else?

TIA

Chris

On Sun, 03 Jul 2005 00:23:32 +0200, lcdpublishing
<lcdpublishing@...> wrote:

>
> Now, the next part I am unsure of. I suspect I can solder it up as I
> would with any other board. I suppose there my be some problems as
> the copper isn't tinned, but I hope to get past that okay. After
> soldering and cleaning, do I need to do anything else?
> TIA
> Chris

Yes, just like normal boards. tinning doesn't make a difference with
flux-core solder.

I like to spray the board with spray flux (can be made as brush-on from
colophony resin and alcohol) before soldering, it also prevents corrosion
later on. I usually don't clean boards after soldering, using resin core
solder. If you remove all the resin you should put some clear laquer on to
prevent tarnishing.

ST

"The traces are a bit "pitted" in areas. Some of the spaces between
the traces didn't etch away completly. I should be able to scrap away
a small groove with a sharp hobby knife to create the gap needed."

Any chance of a close-up on your results? A pic on the group perhaps? I'd
love to see what results you got. I'm switching from ferric chloride to
sodium persulphate. Which one did you use?

I received my Pulsar stuff, but I haven't used it yet. I'm concentrating on
getting my drilling station up to speed.

Robert
:)

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
Yahoo! Groups Links

Cool,

If I can find some small drill bits tomorrow, I will try to drill
the holes and solder them up tomorrow. The smallest drill bit I
have on hand is .062" (2mm), and that is too big for these two
circuit boards.

I also thought about another way to clear out the copper between
traces that make work better for me than a hobby knife. In mold
making and other forms of metal working, we use riffler files that
are great for small detail work. I know I have some around so I will
give that a try first before the knife.

Chris

> > Now, the next part I am unsure of. I suspect I can solder it up

as I

> > would with any other board. I suppose there my be some problems

as

> > the copper isn't tinned, but I hope to get past that okay. After
> > soldering and cleaning, do I need to do anything else?
> > TIA
> > Chris
>
>
> Yes, just like normal boards. tinning doesn't make a difference

with

> flux-core solder.
>
> I like to spray the board with spray flux (can be made as brush-on

from

> colophony resin and alcohol) before soldering, it also prevents

corrosion

> later on. I usually don't clean boards after soldering, using

resin core

> solder. If you remove all the resin you should put some clear

laquer on to

> prevent tarnishing.
>
> ST

Hi Robert,
Look in FILES-LCDPUB-CircuitBoard001.jpg


Chris



--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan
<robert.hedan@v...> wrote:

> "The traces are a bit "pitted" in areas. Some of the spaces

between

> the traces didn't etch away completly. I should be able to scrap

away

> a small groove with a sharp hobby knife to create the gap needed."
>
> Any chance of a close-up on your results? A pic on the group

perhaps? I'd

> love to see what results you got. I'm switching from ferric

chloride to

> sodium persulphate. Which one did you use?
>
> I received my Pulsar stuff, but I haven't used it yet. I'm

concentrating on

> getting my drilling station up to speed.
>
> Robert
> :)
>
> Be sure to visit the group home and check for new Links, Files,

and Photos:

> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links

I guess it might help too to know the sizes...

Both boards are 1.6" X 3.6"

The traces are about .020" wide.

You will notice a "Grid" pattern in the copper, this was the texture
of the copper from the start. It wasn't very smooth to begin with
which may have caused poor results.

Chris

good job!

Not bad for your first attempt.

Looks like a little too much pressure with the iron, causing the
traces to flatten and widen.

Myc




--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> Hi Robert,
> Look in FILES-LCDPUB-CircuitBoard001.jpg
>
>
> Chris
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, Robert Hedan
> <robert.hedan@v...> wrote:
> > "The traces are a bit "pitted" in areas. Some of the spaces
> between
> > the traces didn't etch away completly. I should be able to

scrap

> away
> > a small groove with a sharp hobby knife to create the gap

needed."

> >
> > Any chance of a close-up on your results? A pic on the group
> perhaps? I'd
> > love to see what results you got. I'm switching from ferric
> chloride to
> > sodium persulphate. Which one did you use?
> >
> > I received my Pulsar stuff, but I haven't used it yet. I'm
> concentrating on
> > getting my drilling station up to speed.
> >
> > Robert
> > :)
> >
> > Be sure to visit the group home and check for new Links, Files,
> and Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > If Files or Photos are running short of space, post them here:
> > http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> > Yahoo! Groups Links

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> Hi Robert,
> Look in FILES-LCDPUB-CircuitBoard001.jpg
>
>
> Chris
>
>
>

Pretty good for a first attempt. I'll agree it looks like you have
used a bit too much pressure or the paper you used was not quite
right. Try some other papers (matte ink jet papers work well).

Also, for your next attempt I would set your board program to show
drill holes, so you pads come out as doughnuts rather than solid
circles. The advantage is that when you come to drill (by hand ?)
the center of the pad has a dip to stop the drill bit dancing across
the surface of the pad.

Mike

With my first board now drilled, and "Detailed", I am quickly
gaining the appreciation for alternative methods.

I used a riffler file to clean between the traces - worked pretty
good. It was easier to use than a hobby knife.

I used a #60 high speed steel drill for the holes. Chucked up real
short in the drill press chuck (yes I know, your not suppose to
chuck on the flutes - but it works great). Drilling went real easy
and the bit did not walk around as I suspected it would.

There are a number of problems I don't like about the process
already...

1) Chemicals - nasty stuff
2) Toner transfer & detail - maybe a hit or miss process. Although,
it it looks bad, you can remove it and try again with no real loss
at this point
3) Chemical etching appears to be a bit tricky, especially in the
areas where the traces are tight together. It is hard to see if you
etched away those areas until you get the board out and cleaned.
4) Drilling lot's of tiny holes is very hard on the eyes. I used a
large magnifier light device to help, but my eyes must be getting
older than the rest of me :-(
5) Detailing - cleaning up touching traces. Again, the process is a
pretty basic mechanical process using: picks, files, and hobby
knife. Would be pretty easy if I could only see this stuff without
so much eye strain.
6) Rather slow - step-by-step process. I am sure would get faster
with time and practice.

I think my focus is going to shift to mechanical engraving and
drilling. I already have a CNC machine with a 20,000 RPM spindle.
Fixturing a circuit board should be pretty easy. I will need to
make some adpaters to hold 1/8" shank tools (I am setup for 1/2" and
1/4" shank tools).

Tooling should not be too much of a problem to deal with, from what
I can tell, pointed end mills seem to be the "Choice" tool - cheap
and easy to get through industrial suppliers.

I think a part of the appeal for CNC drilling and routing is getting
around the hand work that requires careful attention - just too
difficult these days with bad eyes. It would (should) also yield a
better looking trace, no pits etc. I also have a hunch that the
trace width could be more narrow than what I have suspect with
chemicals.

SOFTWARE - ARGHHH, I think this will be the problem. I am 95% sure
I could use regular CAD software to create the layout and convert
that to DXF. The CNC control software I use imports DXF very nicely
so I think my focus will be on streamlining the drafting process.
As I don't know if I will be making all that many circuit boards, I
don't think I can justify the cost of PCB CAD software for this
purpose. The free ones appear to have enough limits where I would
have to spend time playing "Work around" games and such.

If anyone cares to share their PCB milling experiences I am all
ears.

I guess what I would like to learn about is the tools used for
milling - anything you found that works great or good or not-so-good?

Any lubricants you found that may have helped the cutting process?

How about drills, any special tricks there, or just have a good
spindle, minimal run-out, and moderate feeds?

Thanks for listening and feel free to share your comments and
opinions.


Chris








--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> Hi Robert,
> Look in FILES-LCDPUB-CircuitBoard001.jpg

On Sun, 03 Jul 2005 19:45:50 +0200, lcdpublishing
<lcdpublishing@...> wrote:

>
> 1) Chemicals - nasty stuff

Yea, can't etch without ;-). A permanent setup makes it easier tho, and if
you make a clever board holder you don't need to come into contact with
the etchant or clean up much.

> 2) Toner transfer & detail - maybe a hit or miss process. Although,
> it it looks bad, you can remove it and try again with no real loss
> at this point

You will eventually get this to work reliably, well, almost always.

> 3) Chemical etching appears to be a bit tricky, especially in the
> areas where the traces are tight together. It is hard to see if you
> etched away those areas until you get the board out and cleaned.

Using a clear etchant (CuCl or persuphate) and tank helps a lot, with
light from the other side of the tank. Near traces etching is actually
faster - if you removed all the paper residue. ('cause over masked areas
the etchant is not used, so it eats the adjacent areas faster)

> 4) Drilling lot's of tiny holes is very hard on the eyes.

too true. better use your cnc.

> 5) Detailing - cleaning up touching traces. Again, the process is a
> pretty basic mechanical process using: picks, files, and hobby
> knife. Would be pretty easy if I could only see this stuff without
> so much eye strain.

will become redundant as you get better with the above steps.

> 6) Rather slow - step-by-step process. I am sure would get faster
> with time and practice.

right. will get MUCH more efficient over time. A small board is done in
half an hour, and you can use the time while one etches to prepare the
next or drill or...


Milling boards: has it's own set of problems. Do not expect it to solve
them all ;-)
Read the bungard file milling against etching, it is pretty clear as to
what the problems are.
EDM would solve many of those, but i admit not all.

ST

> Milling boards: has it's own set of problems. Do not expect it to

solve

> them all ;-)
> Read the bungard file milling against etching, it is pretty clear

as to

> what the problems are.

Stefan, don't know what the Bungard file is, can you direct me?

Yeah, I can see a whole host of problems with both CNC drilling and
milling. The good part is, I have extensive background and
understanding of machining processes and CNC. With that knowledge,
I hope to overcome many of the problems I foresee. Working with the
chemicals, toner transfer, etc., is a bit like "Voodoo" to me - you
can't really pinpoint the cause of some of the problems. In
machining, I can recognize many of the problems and correct them
based on past experiences.

On Sun, 03 Jul 2005 20:28:28 +0200, lcdpublishing
<lcdpublishing@...> wrote:

>
> Stefan, don't know what the Bungard file is, can you direct me?
> Yeah, I can see a whole host of problems with both CNC drilling and
> milling. The good part is, I have extensive background and
> understanding of machining processes and CNC. With that knowledge,
> I hope to overcome many of the problems I foresee. Working with the
> chemicals, toner transfer, etc., is a bit like "Voodoo" to me - you
> can't really pinpoint the cause of some of the problems. In
> machining, I can recognize many of the problems and correct them
> based on past experiences.

<http://www.bungard.com/downloads/anti_e.pdf>

I would consider that doecument controversial, but i agree in many points.
You need to keep in mind the company publishing this document makes both,
milling machines and chemical etching machines.

ST

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:

> With my first board now drilled, and "Detailed", I am quickly
> gaining the appreciation for alternative methods.
>
> I used a riffler file to clean between the traces - worked pretty
> good. It was easier to use than a hobby knife.

You probably didn't leave the board in the etchant long enough. from
looking at the pictures, even with trace spread, there seemed to be
some gap. I usually give my boards a few minutes past where I think
its done. I use AP to etch which is clear and with good lighting in
my vertical etch tank, I can see a lot of detail.

>
> I used a #60 high speed steel drill for the holes. Chucked up real
> short in the drill press chuck (yes I know, your not suppose to
> chuck on the flutes - but it works great). Drilling went real easy
> and the bit did not walk around as I suspected it would.

That's kind of a big bit. I use 64-69, depending on the leads.

>
> There are a number of problems I don't like about the process
> already...
>
> 1) Chemicals - nasty stuff

AP is a lot better than FeCl or CuCl on the nastiness scale. I've
used all 3 and like AP the best, even with the disposal problem.

> 2) Toner transfer & detail - maybe a hit or miss process. Although,
> it it looks bad, you can remove it and try again with no real loss
> at this point

I agree with ST, this will get a lot better with practice. I've
gotten pretty good at it - lots of little tricks to learn. I've been
batting 1000 for that last 5 or so boards.

> 3) Chemical etching appears to be a bit tricky, especially in the
> areas where the traces are tight together. It is hard to see if you
> etched away those areas until you get the board out and cleaned.

as I said above, give it more time. you might also get a loup, pull
the board out, rinse and carefully inspect it. If not done, put it
back into the brew.

> 4) Drilling lot's of tiny holes is very hard on the eyes. I used a
> large magnifier light device to help, but my eyes must be getting
> older than the rest of me :-(

yeah. a cnc driller can help but the best "holes" are the ones you
don't have to drill. I use SMDs where ever I can. My last board had
3 ICs, 30 various other parts and a number of connectors. 26 holes
all together. and my eyes are getting pretty old along with
"floaters" but I manage. good lighting helps there.

> 5) Detailing - cleaning up touching traces. Again, the process is a
> pretty basic mechanical process using: picks, files, and hobby
> knife. Would be pretty easy if I could only see this stuff without
> so much eye strain.

as said, this will diminish. you should plan on some testing time, no
matter what. buzz out your board to find those hidden shorts and
such. By the way, I picked up a stereo microscope at a local auction.
It really helps for this sort of thing.

> 6) Rather slow - step-by-step process. I am sure would get faster
> with time and practice.

Yes, you will/would. I've gotten to the point where I can do a board
in about 2.5 hrs of effort.


Have fun with the CNC approach. there are many advocates but its got
its own set of issues as others are sure to point out.

Hmm, read through it, I think it was written by the marketing
department ;-)

Chris


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

> On Sun, 03 Jul 2005 20:28:28 +0200, lcdpublishing
> <lcdpublishing@y...> wrote:
>
> >
> > Stefan, don't know what the Bungard file is, can you direct me?
> > Yeah, I can see a whole host of problems with both CNC drilling

and

> > milling. The good part is, I have extensive background and
> > understanding of machining processes and CNC. With that

knowledge,

> > I hope to overcome many of the problems I foresee. Working with

the

> > chemicals, toner transfer, etc., is a bit like "Voodoo" to me -

you

> > can't really pinpoint the cause of some of the problems. In
> > machining, I can recognize many of the problems and correct them
> > based on past experiences.
>
>
> <http://www.bungard.com/downloads/anti_e.pdf>
>
> I would consider that doecument controversial, but i agree in many

points.

> You need to keep in mind the company publishing this document

makes both,

> milling machines and chemical etching machines.
>
> ST

On Sun, 03 Jul 2005 21:18:23 +0200, lcdpublishing
<lcdpublishing@...> wrote:

> Hmm, read through it, I think it was written by the marketing
> department
> Chris

No i think it says pretty well what the problems are with milling.
It is a crude way to do things and will not have the same quality of
results.
I would not be surprised at all if this document was written by a guy that
signs with Bungard, the marketing department wouldn't allow negative words
about one of their products.

You will cut into the epoxy. You will need expensive cutters that dull
quickly.
The possible resolution is lower than what you can do with etching.
It is slow and noisy. Keeping the tool in the right height isn't easy.


I don't say it isn't possible or anything, but just don't expect it to be
the magical solution ;-)
As you already have the CNC there is really no reason why you shouldn't at
least try it out though.

ST