Homebrew_PCBs

Hello to all!!!
I have asked this question on the picbasic list but no answers.
a couple of thought but !!!!
now I ask all of you on the homebrew board.
instead of transfers from laser printer to copper.
how about just buying a thin copper sheet say 3mil or so.
then run the copper through the laser printer and print your art work.
once that's done laminate the copper to a fiberglass board.
then etch as normal.
would this work????
does anyone see any problems with this?
or the question should be will the laser printer print to copper sheeting??
thank you
regards
Victor Faria

I would worry a lot about the drum getting scratched.
The copper would just have to get bent up very
slightly on an edge and you'd ruin the expensive drum.

A friend of mine used to use a laser printer to print
directly on PCB. It was some huge old thing that had a
board straight paper path. He very thoroughly deburred
the edges first.

How about those wax thermal/resin printers that print
right onto CDs? You'd only need a single color. You'd
have to either make your PCB the size and shape of a
CD or make a carrier.

Or maybe there is a market for a modified CD printer
like this. Make sure you get one that is not inkjet
and does not require special coatings. I found one for
about $2500 that is wax thermal ribbon and does not
require coated CDs. It is called the Primera Inscripta
and it is 610x305 dpi and does a CD in 5 to 10
seconds. I know, not 600dpi which is what common
wisdom says your laser printer should be for toner
transfer, but this way you don't have the transfer
step that causes lines to mush out.

It is only two colors (at once) but who cares? You
only need one color, and you can flip it over and
print the component layout.

Docs say you can take it out of the case and fit it in
a drive bay, so you could do PCB printing with zero
desktop space!

OK, who's gonna by me one to try this out? ;')

http://www.verbatim.com.au/Hardware/cdprinters/inscripta.html

http://shop.store.yahoo.com/cdrsavings/primin2colth.html

http://www.primeratechnology.com/inscripta/features.html

Here it is for only $2075!

http://www.cddimensions.com/accessories/pri-56200.asp

Y'know, you all missed my birthday, but Christmas is
coming up soon... :'>

Steve Greenfield

--- victor Faria <victorf@...> wrote:

> Hello to all!!!
> I have asked this question on the picbasic list but
> no answers.
> a couple of thought but !!!!
> now I ask all of you on the homebrew board.
> instead of transfers from laser printer to copper.
> how about just buying a thin copper sheet say 3mil
> or so.
> then run the copper through the laser printer and
> print your art work.
> once that's done laminate the copper to a fiberglass
> board.
> then etch as normal.
> would this work????
> does anyone see any problems with this?
> or the question should be will the laser printer
> print to copper sheeting??
> thank you
> regards
> Victor Faria

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In a message dated 06-Dec-01 17:55:59 Central Standard Time, victorf@... writes:

how about just buying a thin copper sheet say 3mil or so.
then run the copper through the laser printer and print your art work.
once that's done laminate the copper to a fiberglass board.
then etch as normal.
would this work????
does anyone see any problems with this?

Vic:  First question:  NO.  Second question:  YES!  This would be akin to training dolfins to fly.  Even if you could get the toner to stick to the copper, it ROLLS in there, and would crumble.  And, laminating it to FR-4 requires HEAT and PRESSURE, and there wouldn't even be consecutive CRUMBS of toner left on the Cu!  If this was a "good idea", it'd be "perfected" and DONE, by now! 

There are TWO ways to do homebrew PCB's:  Use "rub-off" ("impression") patterns (Radio Shack sells NICE ones that work very well, if you keep your nasty fingers away from the "good side"!).  Etch.  Drill.  OR, if you have a "CNC method" to drill on a 0.05" grid, drill the holes first, sand (deburr), and THEN do the "rub-off thing". 

Second method, OK for really-simple little PCB's:  Use FINGERNAIL polish, and PAINT the pattern on.  Use an Xacto-knife to scrape-off or shape the sloppy work, etc.  OR, press-on 3/4" wide Scotch "Magic Mending Tape" (the "frosty" Scotch-tape stuff), and then CUT the pattern with that knife, peeling-off the unwanted part.  Then etch.  If you worked neatly, and didn't get greasy fingers all over the stickum-side of the tape, this will make a FINE etch! 

Also, for "one-off" double-sided boards, DRILLING first is necessary! 

See my PCB drill in FILES.

I do this so infrequently that I just use warmed Ferric Chloride (the nasty yellow-brown stuff).  I once got some Ammonium Persulfate from one of those mail-order places in the back of the magazines, but I could never get that to work right, and it left a ruined cabinet and carpet, where it "came through" the factory-container after a year! 

If you need more than three of "same board", get 'em done  PROFESSIONALLY!  Unless you are very, very poor, and on house-arrest, so "have the time".  NOTHING beats a plated-through board for soldering leads in place!  Wicking!  Strong!  Excellent!  Lotsa luck!   Jan Rowland

> instead of transfers from laser printer to copper.
> how about just buying a thin copper sheet say 3mil or so.
> then run the copper through the laser printer and print your art work.

just tested this and it dosent work so well

I used 'Slug & Snail' tape its an adhesive backed copper foil
sold in the garden dept at some stores (Seattle area)
placed a small strip on a sheet of regular paper and ran a
test page on an HP laserjet 1200 (nice printer for toner transfers BTW)

got some of the letters,but many dropouts and the toner lifted off onto
the rolls and re-deposited itself further down the page (smear)
a second test page without the tape came
out clean and sharp ,so no damage done :-)

Brian

--- Brian Pitt <bfp@...> wrote:

> > instead of transfers from laser printer to copper.
> > how about just buying a thin copper sheet say 3mil
> or so.
> > then run the copper through the laser printer and
> print your art work.
>
> just tested this and it dosent work so well
>
> I used 'Slug & Snail' tape its an adhesive backed
> copper foil
> sold in the garden dept at some stores (Seattle
> area)
> placed a small strip on a sheet of regular paper and
> ran a
> test page on an HP laserjet 1200 (nice printer for
> toner transfers BTW)
>
> got some of the letters,but many dropouts and the
> toner lifted off onto
> the rolls and re-deposited itself further down the
> page (smear)
> a second test page without the tape came
> out clean and sharp ,so no damage done :-)

Very brave, foolish, or got an old cheap laser
printer. ;')

Foreseeable, I suppose, as the fuser roller is only
sized to heat up at most a thick sheet of paper, and
paper has very little heat capacity so it doesn't take
much to heat it to 400F. Copper, on the other hand,
takes a lot to heat up. Think about how long you have
to hold the iron or heat press on the board, and some
recommend preheating the board. I can only send thin
boards through my non-modified laminator.

I suspect my friend's laser printer directly on PCB
worked because it was very old and likely overpowered.

Steve Greenfield

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This is a copy of an E-Mail I sent to CAD_CAM_EDM_DRO a while back. I
thought It might be usefull to someone so I am reposting here.

Chris


Much like others are describing. After a week or so of using Protel for
board layout, use the Protel CAM processor and export the gerbers then
convert them to eagle scripts to import into eagle then converting to
outlines and outputing G-codes and then post processing them. Also I
was taking the drill files and seperately processing them. And finally
taking a board outline and processing that.

And after all that I could not work with oval pads.

The whole process was very manual and a PAIN!

Thanks to some help from this list I can now generate outlines in
Protel. I also do all the CAD work for the board outline. Then I run
the Protel CAM processor to get gerbers for top layer outline, bottom
layer outline, board outline (including tool dimensions) and NC drill
file for the holes.

I then have a post processor (Basically a scripting program and script)
that takes the files and converts them to G-Code along with tool changes
and clearance heights.

Finally I just load the G-Code files into my MaxNC and run them in
order, getting a completed board out at the end.

This new version uses far less programs works with oval pads and is a
lot more automated. Plus I have more control in Protel as to what
happens.

Chris Coley.