Homebrew_PCBs

Been following all this about perf. boards and milling etc.

I like the idea of milling but it seems the prep. work is tremendous.

Doing pref. boards then PCB seems like hard labor.

I'd like to have comments as to why pre-sensitzed PCB and etching is not
mentioned and what you consider is so bad with it ?

Best Regards
Hans W

Hi Hans,
I have no problem with etching. I will even say that Proto
board then Perf onto etched PCBoard. Right now the boards I sell
are milled. If sales get higher I will have a run of boards
etched. I don't like the acid method because I have had some
accidents in the past. I feel all methods of making circuit
boards should be discussed. Going from schematic to PCBoard
has several routes also.

John

--- In Homebrew_PCBs@y..., hans@c... wrote:
> Been following all this about perf. boards and milling etc.
>
> I like the idea of milling but it seems the prep. work is
tremendous.
>
> Doing pref. boards then PCB seems like hard labor.
>
> I'd like to have comments as to why pre-sensitzed PCB and etching
is not
> mentioned and what you consider is so bad with it ?
>
> Best Regards
> Hans W

Etching works great for me as well. I have etched many boards by
printing with a bubble jet onto overhead projector transparencies and
using them as a mask to expose the pre-sensitized boards to UV light.
It is somewhat time consuming, but doesn't require as much accuracy
as milling the traces. One drawback is that it seems like if you get
a tiny drop of copper sulphate anywhere and it somehow rehydrates,
you have the stuff all over the place.

I converted to CNC milling the boards because it was a cool project
to build and it is fun to watch. The acid isn't all that fun to watch.

Dave

--- In Homebrew_PCBs@y..., hans@c... wrote:
> Been following all this about perf. boards and milling etc.
>
> I like the idea of milling but it seems the prep. work is
tremendous.
>
> Doing pref. boards then PCB seems like hard labor.
>
> I'd like to have comments as to why pre-sensitzed PCB and etching
is not
> mentioned and what you consider is so bad with it ?
>
> Best Regards
> Hans W

John,
OK just wanted to know.
Time is important, it's the main reason I don't have a board shop make
two side prototypes unless they are very densely packed.
I have a reasonable setup and now expose both sides at once, which cuts
down on development and etching.
I timed a session for a small board, that needed about 120 holes, from
the time I print transparencies on my laserjet until it's drilled
which also includes silver plating both side, about 1 hour.
The most time consuming issue is still via connections. I use eyelet's
and Mill-Max pins as well as Harwin via pins. For most DIP I use "high"
machined sockets and solder top and bottom, for really tight via's I
drill 16 mil and rivet stretched 22 swg wire in place, until recently
that was my standard way to do via's.
Many people I know tend to throw away the ferric chloride and lye
developer far to soon. My ferric chloride is over 5-7 years old and
still completes etching in 9-11 minute (temperature influences the time)
Lye developer is cheap and can be purchased at the grocery store I mix
it and once I have a good solution I use it for months.
All Transparencies material for laser jets are not equal, and I have
tried every on I could buy in small packets.
The best for my HP LJ1100 at 600 dpi is Apollo CG7060 it will do 5 mill
every day. Then next is 3M CG3300 which is good for 8-10 mil. What I
found with many others is they tend to have bare spots on smaller
traces.
I do not work in darkrooms, there is far too much hype about how
sensitive the pre-sensitized material is, I work in a north facing rom
and close the venetian blinds and have a 120 Watt bulb as light source
for room lighting. I use Datek material.
Exposure bulbs are GE 500W EBW 282 which has the wording average life 6
hours on it.... I have been using them for years... ! They get VERY hot
and the bulb holder should be ceramic.
For exposure of the board I align the transparencies and staple them
together, then slip the PCB between them, then sandwich the lot between
two sheets of 8"X10" glass (Home Depot) clamped together using four
small Binder Clips, and position the sandwich between the two bulbs at
distance 6 inches from bulb to glass. I expose for 110 seconds for new
board, and if I know some older bits ( I save all small bits) are older
I may increase the time to 120-130 seconds.
Actual development time in Lye is about 60-90 seconds. Wear thin rubber
gloves or the lye will eat at your skin, and do NOT get lye in your eyes
it will blind you. If contact is made between lye and skin flush with
LOTS of water.
Once developed, I dry off with a paper towel, there is another myth, the
green coating is not as delicate as many people hype on about.... It is
more brittle and of course can be scratched, but it can be swiped dry
and handle directly.
Once dry, I inspect and make sure the development went OK, if not I
simply put it back in the Lye and continue, what I'm looking for it a
super thin layer of the green coating that may still be on some area's,
and this indicates more development is needed. I touch up anything I
need to using a Laundry marker pen, the kind that people pay $$$ for
that are called etch resistant ! Marks-A-Lot works fine for large areas
and Sharpie markers #13601 for mid width and Sharpie #37000 for fine
work.
I drill using carbide drills and a Dremel in a drill press stand...
Silver plating I use Cool-Amp powder, it's expensive but far easier to
use than the Tin-It crap... Cool-Amp costs about $40 for 4 oz. however I
have been using it for a long long time and have over half left... I
reuse the same rag pad and sometimes simply wet the pad and use the
residual from the last session.

For production, board shop is the only answer... 4pcb.com are still
doing two prototype boards for $35 each upto 64 sq. ins. not other cost
involved, but they have a 5-10 days wait.... That's why I still make my
own board when I can.

I called the CA outfit (the link you posted a few days back) and talked
with the owner that makes the PCB milling system, I think he has a good
product, but it's out of my price range...

I can't see me milling boards, if you only get about 600 inches per bit,
and the reduced resolution simply limits it usefulness.

Anyway that's how I do my boards, just wish I could fine a very simple
through hole plating system.

Hans W
PS here is a picture of a silver plated PCB I made some time ago...
http://hans-w.com/9909-01A_1.jpg






crankorgan wrote:

> Hi Hans,
> I have no problem with etching. I will even say that Proto
> board then Perf onto etched PCBoard. Right now the boards I sell
> are milled. If sales get higher I will have a run of boards
> etched. I don't like the acid method because I have had some
> accidents in the past. I feel all methods of making circuit
> boards should be discussed. Going from schematic to PCBoard
> has several routes also.
>
> John
>
>
>
> --- In Homebrew_PCBs@y..., hans@c... wrote:
> > Been following all this about perf. boards and milling etc.
> >
> > I like the idea of milling but it seems the prep. work is
> tremendous.
> >
> > Doing pref. boards then PCB seems like hard labor.
> >
> > I'd like to have comments as to why pre-sensitzed PCB and etching
> is not
> > mentioned and what you consider is so bad with it ?
> >
> > Best Regards
> > Hans W
>
>
> Yahoo! Groups Sponsor

ADVERTISEMENT

>
> To unsubscribe from this group, send an email to:
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[Non-text portions of this message have been removed]

I currently etch all the boards I've made so far. I've used
photoetching, manually applied rub-on transfers and drafting tape,
and even cut the pattern on a vinyl sign cutter and used the vinyl
as a directly applied etch resist. I used to make transparencies
for photoetching manually using paint, markers, drafting tape,
rub-on transfers, and a copy machine. I sprayed boards with the
photosensitive spray rather than buying pre-sensitive ones. This
was long, long ago, like 20 years. At that time, I recall the
Positive pre-sensitive boards I could get were a pain to use for a
variety of reasons. That has changed.

I also liked being able to cut the boards to size and shape before
coating them, otherwise I had to be so dainty not to ruin the
pre-sensitized ones.

I want to build a mill/engraver because I have other uses for it,
too.

I've drilled out a pen for my HP plotter and superglued a carbide
scratching tip into it. I'm going to try the method brainstormed by
members here of spraying the board with blue metal marking fluid
and scratching off the path to be etched.

In my manual tests I discovered that thickness of the coat seemed
to be less important to success than making sure you allow the coat
to dry completely. After a few hours of drying, scratching across
the coat would pull up a scraggly wide path. After a day it was a
nice neat thin line.

John came up with the idea, someone else tested it manually with
Dykem marking fluid. Has anyone tested it in a plotter yet? When I
do, I'll write something up and add it to the Files section.

Hey, you can get that marking fluid in a bottle, I mean not just as
a spray coat. Might it work in a drafting pen? May be too thick for
a felt tipped pen like the HP plotter uses. I'm just thinking that
it is cheaper and easier to find than Staedler 313 refill ink.

But I really like the idea of scratching isolation paths, saves -a-
-lot- on acid.

Remember, everyone, to check the Bookmarks section and feel free to
add to it. I went to some trouble to set up Folders so please use
them. There are links there to all kinds of methods, software,
suppliers, etc.

Steve Greenfield

--- ph4appl <ph4appl@...> wrote:

> Etching works great for me as well. I have etched many boards by
> printing with a bubble jet onto overhead projector transparencies
> and
> using them as a mask to expose the pre-sensitized boards to UV
> light.
> It is somewhat time consuming, but doesn't require as much
> accuracy
> as milling the traces. One drawback is that it seems like if you
> get
> a tiny drop of copper sulphate anywhere and it somehow
> rehydrates,
> you have the stuff all over the place.
>
> I converted to CNC milling the boards because it was a cool
> project
> to build and it is fun to watch. The acid isn't all that fun to
> watch.
>
> Dave

__________________________________________________
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I was going to add Cool-Amp's website to the Bookmarks, but it
seems to be gone.

http://www.cool-amp.com/

Says No DNS entry found.

Does anyone know if they are still in business?

Yep, those $1.29 laundry markers are exactly the same as the $5.29
"etch resist" pens. The Staedler 313 red ink works much better,
though.

Steve Greenfield

--- hans@... wrote:

> I touch up
> anything I
> need to using a Laundry marker pen, the kind that people pay $$$
> for
> that are called etch resistant ! Marks-A-Lot works fine for
> large areas
> and Sharpie markers #13601 for mid width and Sharpie #37000 for
> fine
> work.

> Silver plating I use Cool-Amp powder, it's expensive but far
> easier to
> use than the Tin-It crap... Cool-Amp costs about $40 for 4 oz.
> however I
> have been using it for a long long time and have over half
> left... I
> reuse the same rag pad and sometimes simply wet the pad and use
> the
> residual from the last session.

__________________________________________________
Do You Yahoo!?
Yahoo! Health - your guide to health and wellness
http://health.yahoo.com

At 08:02 AM 5/3/02 -0500, hans@... wrote:

>Been following all this about perf. boards and milling etc.
>
>I like the idea of milling but it seems the prep. work is tremendous.
>
>Doing pref. boards then PCB seems like hard labor.
>
>I'd like to have comments as to why pre-sensitzed PCB and etching is not
>mentioned and what you consider is so bad with it ?

We do both.

The photo process uses DuPont Riston 4215 laminate film, a much modified
Ibico laminator supplied by Kepro, developer is Soda Ash (Potassium
Carbonate), etch is Ammonium Persulphate, stripper is Caustic Soda (Sodium
Hydroxide), drilling is by Gordon Robineau's PCB drill. This is a very
mature process - we have made thousands of boards with the process over the
past 18 years or so.

The downside is the prep time. The raw board has to go through a 5 step
cleaning process before being laminated. The negative has to be done at a
local print shop - someone takes over a floppy and comes back with a
negative. Drilling used to be done by hand but is now with Gordon
Robineau's seriously cool PC drill - I simply feed it the drill file from
my CAD program. The bottom line is that it is a half day process from
start to finish - 1 board or 20 boards takes about the same amount of
time. The boards turn out perfect - it is a great process. But it ties up
somebody for that half day.

One of my techs purchased a dead engraving machine from the local repair
outfit. The computer part of it was completely dead but the mechanical
stuff was just fine. He cut the stepper motor drive section off of the CPU
card - he now had a stepper controlled X-Y-Z mill, complete with stepper
drivers. I wrote a simple PIC stepper controller (12c508) that takes in
step and direction commands and generates the step sequences for the
stepper drivers.

Ryan spent a couple of months in his spare time learning how make the
system work. He now uses a somewhat modified version of Kevin Carroll's
Stepster as the G-code interpreter - its what drives the stepper controllers.

It takes Ryan about 40 minutes to process the plot file from my CAD package
into G-code suitable for feeding to Stepster. I don't know the exact steps
involved: I do know that he uses Corel Draw, Adobe Photoshop, and Desk-NC
in the process. I'll document the procedure sometime soon and post it.

The milling bits are standard high speed steel engraving machine bits. For
milling PC boards, Ryan has the bits ground to what the re-grinder calls a
.005" flat. That means the tapered bit does not come to a point but
instead has a .005" wide flat surface at the very tip of the
bit. Apparently any finer than that results in a tip that is too fragile.

Milling a board takes anywhere from 20 minutes to an hour, depending upon
the size of the board and how much copper has to be removed. The boards
turn out OK - Ryan can get a trace between 2 IC pads reliably. The sides
of the traces are somewhat jagged - not perfectly smooth like the photo
process. The isolation path is probably about 0.015" or so - it means you
have to take a little care when soldering to make sure you do not bridge
the gap.

The boards are drilled after the isolation paths have been milled. Ryan
simply changes the milling bit to a drill bit, loads the (edited) .NCD
file, hits GO, and walks away. When all the holes for that size have been
milled, he changes the bit to the next size and the machine drills
those. The PC board is not moved between any of those steps so
registration remains perfect.

We now rarely use the photo process! The milled boards don't look quite as
nice as the photo etched boards but it takes less time to get a board made
and the milled board takes only about 1/4 of the total man-hours of actual
labor.

I've been planning on doing a bit of a write-up on the whole process - lack
of time has stopped me. But I'll try to get some pictures of actual boards
made on the machine - soon.

dwayne

PS - Ryan has done one hell of a great job in turning a dead engraver into
a wonderfully useful CNC tool. He was the driving force behind this - I
assisted him with some things but Ryan deserves all the credit. I want to
be clear on this - it was his idea, he found and purchased the dead
engraving machine, he figured out how to make the software available to him
do the job he needed.

dwayne


Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 18 years of Engineering Innovation (1984 - 2002)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

Hi Hans,
Milling circuit boards is actually called Mechanical Etching.
I call it milling because that's what it actually is. When I post
sites to look at. They have software that is first for making PCBoards
but they also have milling as a second step.
The milling cost for a single sided board 4 x 6". The board is
$2 the bit is $8 and the drill bit is $.79. So even with shipping I
can make a board for under $12. Your method has to be way cheaper.
Up until now I am still doing the holes on a Dremel drill press. I
could let the mill do it!
The advantage to milling is you can walk away during the
milling process. Every board is useable. The most important part is if
you use GCode to run the machine you overlap into CNC. This along
with using TurboCad for the DXF files teaches you drafting. I have
be drafting for years. Comes in handy! The hobby gets more interesting
while staying very cheap! That's if you build your own stuff!

John

--- In Homebrew_PCBs@y..., hans@c... wrote:
> John,
> OK just wanted to know.
> Time is important, it's the main reason I don't have a board shop
make
> two side prototypes unless they are very densely packed.
> I have a reasonable setup and now expose both sides at once, which
cuts
> down on development and etching.
> I timed a session for a small board, that needed about 120 holes,
from
> the time I print transparencies on my laserjet until it's drilled
> which also includes silver plating both side, about 1 hour.
> The most time consuming issue is still via connections. I use
eyelet's
> and Mill-Max pins as well as Harwin via pins. For most DIP I
use "high"
> machined sockets and solder top and bottom, for really tight via's I
> drill 16 mil and rivet stretched 22 swg wire in place, until
recently
> that was my standard way to do via's.
> Many people I know tend to throw away the ferric chloride and lye
> developer far to soon. My ferric chloride is over 5-7 years old and
> still completes etching in 9-11 minute (temperature influences the
time)
> Lye developer is cheap and can be purchased at the grocery store I
mix
> it and once I have a good solution I use it for months.
> All Transparencies material for laser jets are not equal, and I have
> tried every on I could buy in small packets.
> The best for my HP LJ1100 at 600 dpi is Apollo CG7060 it will do 5
mill
> every day. Then next is 3M CG3300 which is good for 8-10 mil. What I
> found with many others is they tend to have bare spots on smaller
> traces.
> I do not work in darkrooms, there is far too much hype about how
> sensitive the pre-sensitized material is, I work in a north facing
rom
> and close the venetian blinds and have a 120 Watt bulb as light
source
> for room lighting. I use Datek material.
> Exposure bulbs are GE 500W EBW 282 which has the wording average
life 6
> hours on it.... I have been using them for years... ! They get VERY
hot
> and the bulb holder should be ceramic.
> For exposure of the board I align the transparencies and staple them
> together, then slip the PCB between them, then sandwich the lot
between
> two sheets of 8"X10" glass (Home Depot) clamped together using four
> small Binder Clips, and position the sandwich between the two bulbs
at
> distance 6 inches from bulb to glass. I expose for 110 seconds for
new
> board, and if I know some older bits ( I save all small bits) are
older
> I may increase the time to 120-130 seconds.
> Actual development time in Lye is about 60-90 seconds. Wear thin
rubber
> gloves or the lye will eat at your skin, and do NOT get lye in your
eyes
> it will blind you. If contact is made between lye and skin flush
with
> LOTS of water.
> Once developed, I dry off with a paper towel, there is another
myth, the
> green coating is not as delicate as many people hype on about....
It is
> more brittle and of course can be scratched, but it can be swiped
dry
> and handle directly.
> Once dry, I inspect and make sure the development went OK, if not I
> simply put it back in the Lye and continue, what I'm looking for it
a
> super thin layer of the green coating that may still be on some
area's,
> and this indicates more development is needed. I touch up anything
I
> need to using a Laundry marker pen, the kind that people pay $$$ for
> that are called etch resistant ! Marks-A-Lot works fine for large
areas
> and Sharpie markers #13601 for mid width and Sharpie #37000 for
fine
> work.
> I drill using carbide drills and a Dremel in a drill press stand...
> Silver plating I use Cool-Amp powder, it's expensive but far easier
to
> use than the Tin-It crap... Cool-Amp costs about $40 for 4 oz.
however I
> have been using it for a long long time and have over half left... I
> reuse the same rag pad and sometimes simply wet the pad and use the
> residual from the last session.
>
> For production, board shop is the only answer... 4pcb.com are still
> doing two prototype boards for $35 each upto 64 sq. ins. not other
cost
> involved, but they have a 5-10 days wait.... That's why I still
make my
> own board when I can.
>
> I called the CA outfit (the link you posted a few days back) and
talked
> with the owner that makes the PCB milling system, I think he has a
good
> product, but it's out of my price range...
>
> I can't see me milling boards, if you only get about 600 inches per
bit,
> and the reduced resolution simply limits it usefulness.
>
> Anyway that's how I do my boards, just wish I could fine a very
simple
> through hole plating system.
>
> Hans W
> PS here is a picture of a silver plated PCB I made some time ago...
> http://hans-w.com/9909-01A_1.jpg
>
>
>
>
>
>
> crankorgan wrote:
>
> > Hi Hans,
> > I have no problem with etching. I will even say that Proto
> > board then Perf onto etched PCBoard. Right now the boards I sell
> > are milled. If sales get higher I will have a run of boards
> > etched. I don't like the acid method because I have had some
> > accidents in the past. I feel all methods of making circuit
> > boards should be discussed. Going from schematic to PCBoard
> > has several routes also.
> >
> > John
> >
> >
> >
> > --- In Homebrew_PCBs@y..., hans@c... wrote:
> > > Been following all this about perf. boards and milling etc.
> > >
> > > I like the idea of milling but it seems the prep. work is
> > tremendous.
> > >
> > > Doing pref. boards then PCB seems like hard labor.
> > >
> > > I'd like to have comments as to why pre-sensitzed PCB and
etching
> > is not
> > > mentioned and what you consider is so bad with it ?
> > >
> > > Best Regards
> > > Hans W
> >
> >
> > Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
> >
> > To unsubscribe from this group, send an email to:
> > Homebrew_PCBs-unsubscribe@y...
> >
> >
> >
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service.
>
>
> [Non-text portions of this message have been removed]

At 10:35 AM 5/3/02 -0700, Steve Greenfield wrote:

>I was going to add Cool-Amp's website to the Bookmarks, but it
>seems to be gone.
>
>http://www.cool-amp.com/
>
>Says No DNS entry found.
>
>Does anyone know if they are still in business?

I just phoned them - they are having web site problems right now. But the
very nice young lady I spoke with gave me current pricing: 1/4 Lb: $46.00,
1/2 Lb: $75.00, 1 Lb: $140.00.

Cool Amp - Conducto Lube
15834 Upper Boones Ferry Road
Lake Oswego, Oregon 97035
Phone : 503-624-6426
Fax: 503-624-6436

dwayne


Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 18 years of Engineering Innovation (1984 - 2002)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

Greetings,

I have a question concerning the 'wet method' of making circuit boards. Since I am new to making circuit boards I did a search a while ago and found kepro circuit systems and purchased all the items to make circuit boards using the dry film method. After it was all said and done and everything was shipped I had quite a bit of money invested. Since I have been following this group I have heard people using 'lye' as a developer. My question is this: Are there any common chemical substitutions which could be used replace any of the development stuff kepro sells? Example: developer=lye, stripper=bleach??, tinplating = ?, acid= ? etc.

Thanks Much!

Randy Knutson

solarteam.mnsu.edu



---------------------------------
Do You Yahoo!?
Yahoo! Health - your guide to health and wellness

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

Dwayne,
Thanks for the interesting insight.
What if anything is your solution for via connections ?

BTW I think "stripper is Caustic Soda (Sodium Hydroxide)" is the same
as Red Devil Lye ! I buy it at Krogers, may be somewhat cheaper.

Best Regards
Hans Wedemeyer


Dwayne Reid wrote:

> At 08:02 AM 5/3/02 -0500, hans@... wrote:
> >Been following all this about perf. boards and milling etc.
> >
> >I like the idea of milling but it seems the prep. work is tremendous.
>
> >
> >Doing pref. boards then PCB seems like hard labor.
> >
> >I'd like to have comments as to why pre-sensitzed PCB and etching is
> not
> >mentioned and what you consider is so bad with it ?
>
> We do both.
>
> The photo process uses DuPont Riston 4215 laminate film, a much
> modified
> Ibico laminator supplied by Kepro, developer is Soda Ash (Potassium
> Carbonate), etch is Ammonium Persulphate, stripper is Caustic Soda
> (Sodium
> Hydroxide), drilling is by Gordon Robineau's PCB drill. This is a
> very
> mature process - we have made thousands of boards with the process
> over the
> past 18 years or so.
>
> The downside is the prep time. The raw board has to go through a 5
> step
> cleaning process before being laminated. The negative has to be done
> at a
> local print shop - someone takes over a floppy and comes back with a
> negative. Drilling used to be done by hand but is now with Gordon
> Robineau's seriously cool PC drill - I simply feed it the drill file
> from
> my CAD program. The bottom line is that it is a half day process from
>
> start to finish - 1 board or 20 boards takes about the same amount of
> time. The boards turn out perfect - it is a great process. But it
> ties up
> somebody for that half day.
>
> One of my techs purchased a dead engraving machine from the local
> repair
> outfit. The computer part of it was completely dead but the
> mechanical
> stuff was just fine. He cut the stepper motor drive section off of
> the CPU
> card - he now had a stepper controlled X-Y-Z mill, complete with
> stepper
> drivers. I wrote a simple PIC stepper controller (12c508) that takes
> in
> step and direction commands and generates the step sequences for the
> stepper drivers.
>
> Ryan spent a couple of months in his spare time learning how make the
> system work. He now uses a somewhat modified version of Kevin
> Carroll's
> Stepster as the G-code interpreter - its what drives the stepper
> controllers.
>
> It takes Ryan about 40 minutes to process the plot file from my CAD
> package
> into G-code suitable for feeding to Stepster. I don't know the exact
> steps
> involved: I do know that he uses Corel Draw, Adobe Photoshop, and
> Desk-NC
> in the process. I'll document the procedure sometime soon and post
> it.
>
> The milling bits are standard high speed steel engraving machine
> bits. For
> milling PC boards, Ryan has the bits ground to what the re-grinder
> calls a
> .005" flat. That means the tapered bit does not come to a point but
> instead has a .005" wide flat surface at the very tip of the
> bit. Apparently any finer than that results in a tip that is too
> fragile.
>
> Milling a board takes anywhere from 20 minutes to an hour, depending
> upon
> the size of the board and how much copper has to be removed. The
> boards
> turn out OK - Ryan can get a trace between 2 IC pads reliably. The
> sides
> of the traces are somewhat jagged - not perfectly smooth like the
> photo
> process. The isolation path is probably about 0.015" or so - it means
> you
> have to take a little care when soldering to make sure you do not
> bridge
> the gap.
>
> The boards are drilled after the isolation paths have been milled.
> Ryan
> simply changes the milling bit to a drill bit, loads the (edited) .NCD
>
> file, hits GO, and walks away. When all the holes for that size have
> been
> milled, he changes the bit to the next size and the machine drills
> those. The PC board is not moved between any of those steps so
> registration remains perfect.
>
> We now rarely use the photo process! The milled boards don't look
> quite as
> nice as the photo etched boards but it takes less time to get a board
> made
> and the milled board takes only about 1/4 of the total man-hours of
> actual
> labor.
>
> I've been planning on doing a bit of a write-up on the whole process -
> lack
> of time has stopped me. But I'll try to get some pictures of actual
> boards
> made on the machine - soon.
>
> dwayne
>
> PS - Ryan has done one hell of a great job in turning a dead engraver
> into
> a wonderfully useful CNC tool. He was the driving force behind this -
> I
> assisted him with some things but Ryan deserves all the credit. I
> want to
> be clear on this - it was his idea, he found and purchased the dead
> engraving machine, he figured out how to make the software available
> to him
> do the job he needed.
>
> dwayne
>
>
> Dwayne Reid <dwayner@...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 18 years of Engineering Innovation (1984 - 2002)
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[Non-text portions of this message have been removed]

Dwayne,
Sounds right, when I purchased it several years ago it was $40 even for
1/4 lb.
Have your ever used it ?
hansw

Dwayne Reid wrote:

> At 10:35 AM 5/3/02 -0700, Steve Greenfield wrote:
> >I was going to add Cool-Amp's website to the Bookmarks, but it
> >seems to be gone.
> >
> >http://www.cool-amp.com/
> >
> >Says No DNS entry found.
> >
> >Does anyone know if they are still in business?
>
> I just phoned them - they are having web site problems right now. But
> the
> very nice young lady I spoke with gave me current pricing: 1/4 Lb:
> $46.00,
> 1/2 Lb: $75.00, 1 Lb: $140.00.
>
> Cool Amp - Conducto Lube
> 15834 Upper Boones Ferry Road
> Lake Oswego, Oregon 97035
> Phone : 503-624-6426
> Fax: 503-624-6436
>
> dwayne
>
>
> Dwayne Reid <dwayner@...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 18 years of Engineering Innovation (1984 - 2002)
> .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
> `-' `-' `-' `-' `-' `-' `-' `-' `-'
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.
>
>
> Yahoo! Groups Sponsor

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

--- Dwayne Reid <dwayner@...> wrote:

> At 10:35 AM 5/3/02 -0700, Steve Greenfield wrote:
> >I was going to add Cool-Amp's website to the Bookmarks, but it
> >seems to be gone.
> >
> >http://www.cool-amp.com/
> >
> >Says No DNS entry found.
> >
> >Does anyone know if they are still in business?
>
> I just phoned them - they are having web site problems right now.
> But the
> very nice young lady I spoke with gave me current pricing: 1/4
> Lb: $46.00,
> 1/2 Lb: $75.00, 1 Lb: $140.00.
>
> Cool Amp - Conducto Lube
> 15834 Upper Boones Ferry Road
> Lake Oswego, Oregon 97035
> Phone : 503-624-6426
> Fax: 503-624-6436

Great! Glad to hear it.

I expect a 1/4 pound will last a long time for most of us.

Steve Greenfield

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At 03:05 PM 5/3/02 -0500, hans@... wrote:

>Dwayne,
>Thanks for the interesting insight.
>What if anything is your solution for via connections ?
>
>BTW I think "stripper is Caustic Soda (Sodium Hydroxide)" is the same
>as Red Devil Lye ! I buy it at Krogers, may be somewhat cheaper.

We haven't tried to mill any double sided boards - those are done with the
photo process or, more commonly these days, sent off to AP circuits. But I
try to avoid vias by routing top side traces to IC pins or any other
component with accessible pads (not covered by the component). Where I
can't avoid top side connections that are covered by the component's body,
I use the "Copperset" via repair system from Multicore. Vias that are
occur in traces (no component leads) generally use Harwin track pins.

Top side IC connections are no problem when soldering the chip directly to
the PCB or by using machined pin IC sockets (Augat, Asman, etc).

Thanks for the info on the Red Devil Lye - I'll keep it in mind. We bought
50 Lb bags of Potassium Carbonate and Sodium Hydroxide years ago from one
of the industrial chemical supply houses (it was cheap) and still have lots
left.

dwayne


Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 18 years of Engineering Innovation (1984 - 2002)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

At 12:54 PM 5/3/02 -0700, Randy Knutson wrote:

>Greetings,
>
>I have a question concerning the 'wet method' of making circuit boards.
>Since I am new to making circuit boards I did a search a while ago and
>found kepro circuit systems and purchased all the items to make circuit
>boards using the dry film method. After it was all said and done and
>everything was shipped I had quite a bit of money invested. Since I have
>been following this group I have heard people using 'lye' as a developer.
>My question is this: Are there any common chemical substitutions which
>could be used replace any of the development stuff kepro sells? Example:
>developer=lye, stripper=bleach??, tinplating = ?, acid= ? etc.

First, I strenuously object to the term "ACID" when talking about
etchant. Etchant MAY contain acid (I use Ammonium Persulphate catalyzed
with Sulphuric Acid) but Ferric Cloride is not strong enough to be called
acid. Neither is Ammonium Persulphate.

As far as the rest is concerned, it depends upon the photo chemistry. For
example, DuPont's Riston dry film laminate uses Potassium Carbonate as the
developer: this is also known as Soda Ash. Same with the stripper: Sodium
Hydroxide is more commonly known as Caustic Soda.

Hans uses Cool Amp for silver plating boards - I will soon be ordering some
and trying it since he has had such good results with it. The initial
price is a tad steep but it sounds like it lasts a LONG time. (Thanks, Hans!)

dwayne


Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax

Celebrating 18 years of Engineering Innovation (1984 - 2002)
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-
`-' `-' `-' `-' `-' `-' `-' `-' `-'
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

Dwayne,
I agree with your comments about acid... ferric chloride can make a
mess, and if anyone has a stainless steel sink, better be careful it
will eat holes in it...
I have my FC in a TupperWare breakfast cereal container, clearly marked,
and never pour the stuff, I simply fill the sink with hot water, stand
the container in it and remove the lid. Then I hang the pcb in the FC ,
that way there are less chances of an accident.

About "Caustic Soda" That is what's it's called in England, and when I
tried to find it here in Houston I asked for Caustic Soda and people
looked at me as if I came form mars or something similar.... Finally I
found Red Devil Lye and of course it is the same stuff... Norwegian use
it to make "Lute Fisk" that's nasty stuff...

The same story about denatured alcohol, I remember looking for
"methlylated spirits" until I found an Eckerds guy that had a
dictionary.... and we think we have a common language :-)

hansw



Dwayne Reid wrote:

> At 12:54 PM 5/3/02 -0700, Randy Knutson wrote:
>
> >Greetings,
> >
> >I have a question concerning the 'wet method' of making circuit
> boards.
> >Since I am new to making circuit boards I did a search a while ago
> and
> >found kepro circuit systems and purchased all the items to make
> circuit
> >boards using the dry film method. After it was all said and done and
> >everything was shipped I had quite a bit of money invested. Since I
> have
> >been following this group I have heard people using 'lye' as a
> developer.
> >My question is this: Are there any common chemical substitutions
> which
> >could be used replace any of the development stuff kepro sells?
> Example:
> >developer=lye, stripper=bleach??, tinplating = ?, acid= ? etc.
>
> First, I strenuously object to the term "ACID" when talking about
> etchant. Etchant MAY contain acid (I use Ammonium Persulphate
> catalyzed
> with Sulphuric Acid) but Ferric Cloride is not strong enough to be
> called
> acid. Neither is Ammonium Persulphate.
>
> As far as the rest is concerned, it depends upon the photo chemistry.
> For
> example, DuPont's Riston dry film laminate uses Potassium Carbonate as
> the
> developer: this is also known as Soda Ash. Same with the stripper:
> Sodium
> Hydroxide is more commonly known as Caustic Soda.
>
> Hans uses Cool Amp for silver plating boards - I will soon be ordering
> some
> and trying it since he has had such good results with it. The initial
>
> price is a tad steep but it sounds like it lasts a LONG time.
> (Thanks, Hans!)
>
> dwayne
>
>
> Dwayne Reid <dwayner@...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 18 years of Engineering Innovation (1984 - 2002)
> .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
> `-' `-' `-' `-' `-' `-' `-' `-' `-'
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.
>
>
> Yahoo! Groups Sponsor

ADVERTISEMENT

>
> To unsubscribe from this group, send an email to:
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>
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

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

When I ran a commercial shop we used a 1% solution of soda ash for
developing dry film. We ran out of soda ash once and used Tide
laundry soap. It worked good on DuPont 4715 dry film but we had to
use some defoaming agent. I think for small batches of boards this
would work fine. Don't worry about the suds unless you are running
larger volumes in a spay developer. Store bought lye works good for
stripping the resist from an etched panel.

When using a Kepro spray etcher as a developing unit for dry film,
make sure the soda ash solution is drained from the sump when
finished. Jim Keil who owns Kepro told me that this solution will
destroy the plastic pump bodies if they are exposed to soda ash for
long periods of time.

I have several of these Kepro etchers for sale if anyone would be
interested. I use one with ferric chloride and the etching time is 3
to 5 minutes depending on the copper weight.

Tom

Generally positive resists use 10g/L sodium hydroxide at a set temperature. Negative dry film resists are developed in 8 - 10 g/L sodium carbonate at 28 - 35°C. I'm not familiar with the Kepro dry film but I assume its standard 'negative' aqueous processing resist. I have never seen positive dry film. Visit the Dupont web site for all the dry film technical information you'll ever need.
The basic dry film stripper is 30 to 100g/L sodium hydroxide at 10 to 40°C.

What type of process is "tinplating =" and "acid =" ?



Randy Knutson wrote:

> Greetings,
>
> I have a question concerning the 'wet method' of making circuit boards. Since I am new to making circuit boards I did a search a while ago and found kepro circuit systems and purchased all the items to make circuit boards using the dry film method. After it was all said and done and everything was shipped I had quite a bit of money invested. Since I have been following this group I have heard people using 'lye' as a developer. My question is this: Are there any common chemical substitutions which could be used replace any of the development stuff kepro sells? Example: developer=lye, stripper=bleach??, tinplating = ?, acid= ? etc.
>
> Thanks Much!
>
> Randy Knutson
>
> solarteam.mnsu.edu
>
> ---------------------------------
> Do You Yahoo!?
> Yahoo! Health - your guide to health and wellness
>
> [Non-text portions of this message have been removed]
>
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

Hi Randy,

Here are a few links for you. It's not that trivial, but there are a few
rules of thumb that you can use. I have been involved with design switching
supplies for high power car stereos since 1982, so email me directly if you
can't find what your'e looking for.

http://www.powerdesigners.com/
http://www.ogradyeng.com/Pages/frameset2.html
http://www.powersimtech.com/download.html
http://www.geocities.com/genomeuk/
http://www.chipcenter.com/power/powparch.htm
http://www.national.com/appinfo/power/
http://www.ee.uts.edu.au/~venkat/pe_html/peintro.htm
http://www.sonic.net/~sjl/power.html
http://www.smpstech.com/tutorial/t02top.htm
http://www.powersupplies.net/
http://www.smpstech.com/websites.htm
http://www.fgl.com/pwrapps.htm
http://www.mag-inc.com/

Have fun......

Regards,
Lukas Louw
louw1@...

>
> Hi:
> I know this is off the pcb topic but I was wondering if anyone on this

list knew how to design transformers or where to look to find this
information out. I am trying to build a 500 watt 100khz switching power
supply that will bring 12volts to 60 volts. I understand the concept of
turns ratio but my question is how do I treat the primary of the
transformer? Do I treat it as merely an inductor whose value I would need to
calculate? I was also wondering about the magnetic selection of a core. How
much permeability can I have before I saturate the core using a given power
level?

> Thanks!
> -=Randy Knutson

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.371 / Virus Database: 206 - Release Date: 6/13/02

Hi:
I know this is off the pcb topic but I was wondering if anyone on this list knew how to design transformers or where to look to find this information out. I am trying to build a 500 watt 100khz switching power supply that will bring 12volts to 60 volts. I understand the concept of turns ratio but my question is how do I treat the primary of the transformer? Do I treat it as merely an inductor whose value I would need to calculate? I was also wondering about the magnetic selection of a core. How much permeability can I have before I saturate the core using a given power level?
Thanks!
-=Randy Knutson




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

And of course don't forget Unitrode's Seminar series at TI's web site

http://focus.ti.com/docs/analog/support/training/seminar.jhtml?templateId=2&navigationId=156&tfsection=Seminar_Materials

or more specific to your application

http://www-s.ti.com/sc/psheets/slup126/slup126.pdf

Other online teach-your-self sites are to visit ferrite and magnetic materiel
manufactures. Request all the catalogs you can.


Lukas Louw wrote:

> Hi Randy,
>
> Here are a few links for you. It's not that trivial, but there are a few
> rules of thumb that you can use. I have been involved with design switching
> supplies for high power car stereos since 1982, so email me directly if you
> can't find what your'e looking for.
>
> http://www.powerdesigners.com/
> http://www.ogradyeng.com/Pages/frameset2.html
> http://www.powersimtech.com/download.html
> http://www.geocities.com/genomeuk/
> http://www.chipcenter.com/power/powparch.htm
> http://www.national.com/appinfo/power/
> http://www.ee.uts.edu.au/~venkat/pe_html/peintro.htm
> http://www.sonic.net/~sjl/power.html
> http://www.smpstech.com/tutorial/t02top.htm
> http://www.powersupplies.net/
> http://www.smpstech.com/websites.htm
> http://www.fgl.com/pwrapps.htm
> http://www.mag-inc.com/
>
> Have fun......
>
> Regards,
> Lukas Louw
> louw1@...
>
> >
> > Hi:
> > I know this is off the pcb topic but I was wondering if anyone on this
> list knew how to design transformers or where to look to find this
> information out. I am trying to build a 500 watt 100khz switching power
> supply that will bring 12volts to 60 volts. I understand the concept of
> turns ratio but my question is how do I treat the primary of the
> transformer? Do I treat it as merely an inductor whose value I would need to
> calculate? I was also wondering about the magnetic selection of a core. How
> much permeability can I have before I saturate the core using a given power
> level?
> > Thanks!
> > -=Randy Knutson
>
> ---
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Randy K:

I wrote an article answering every question you have. Try this link:

<A HREF="http://members.tripod.com/~schematics/xform/xformer1.htm">Roll Your Own Power-Transformers!</A>

Jan Rowland


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