Homebrew PCBs

I read with much interest all the work that is going into the TT
method of creating artwork on copper. Has anyone experimented with
modifications to a Laser Printer to directly apply the artwork to the
copper? Seems this would solve a lot of the issues, if it were
possible. I remember a few years back I had a Laserjet 4L. It had a
straight through path and would accept some pretty thick card stock as
I recall. Now I wish I had not thrown it out in the late last century...

The toner is transferred to the paper from the drum via electrostatic  
charge.
This is not working with metal.

Some time ago when we talked about the silicone paper someone who has now  
left the list tried or planned to try using a silicone roller to  
statically take the toner from the drum, and directly transfer in on a  
heated PCB. An idea but a lot of work.


Short story, it's not that easy. Long story, look in the archives.

ST

On Mon, 13 Feb 2006 20:15:00 +0100, jam5411 <mardock@...> wrote:

> I read with much interest all the work that is going into the TT
>
> method of creating artwork on copper. Has anyone experimented with
>
> modifications to a Laser Printer to directly apply the artwork to the
>
> copper? Seems this would solve a lot of the issues, if it were
>
> possible. I remember a few years back I had a Laserjet 4L. It had a
>
> straight through path and would accept some pretty thick card stock as
>
> I recall. Now I wish I had not thrown it out in the late last century...
>
>

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

From: "jam5411" <mardock@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, February 13, 2006 7:15 PM
Subject: [Homebrew_PCBs] Laser Printers


>I read with much interest all the work that is going into the TT
> method of creating artwork on copper. Has anyone experimented with
> modifications to a Laser Printer to directly apply the artwork to the
> copper? Seems this would solve a lot of the issues, if it were
> possible. I remember a few years back I had a Laserjet 4L. It had a
> straight through path and would accept some pretty thick card stock as
> I recall. Now I wish I had not thrown it out in the late last century...

Xerox used to have a technique for transferring artwork to a PCB using the 
flat-bed copier (their first product, developed before the 914 automatic 
copier).  The toner pattern was transferred from the selenium plate to the 
PCB, then fused. When I worked for Rank-Xerox 40 years ago the UK training 
centre actually used the process a few times, and it worked quite well for 
the type of boards commonly used in those days. Drum-based copiers wouldn't 
work.

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller

Hi,

How much money are you willing to spend?  The opposite of your 
suggestion is already available (about $10K for a starter system).

It's a laser "printer" that has enough power to burn wood.  It's used 
to engrave things (like pens).  If you coated copper clad with an etch 
resist, you could use the "printer" to burn away the areas you don't 
want.

I thought about contacting them to find out if they had a laser that 
was powerful enough to burn the copper and holes.  But, that's more 
money than I could spend anyway...

Another option is a flat bed plotter with an appropiate ink for an 
etch resist.  When I worked at HP Labs in the late 70's, someone 
developed a flat bed plotter where the pen moved in on axis and the 
paper moved in another.  The ink came from a bottle with appropriate 
plumbing.  This plotter would have sold for hundreds of dollars.

If you had 10's of thousands, you could buy a huge flat bed plotter 
(like the Xynetics that was in use in the early 80's).  That plotter 
could be fit with cutting blades and the etch resist that would have 
been used in those days would have been "Ruby tape".  I've used that 
tape in various widths to create PCB's back in the 70's.  Back in 
those days there was no toner transfer because inexpensive, solid 
state lasers hadn't been invented/commercialized...  Back then, it 
took over 100mA to get a laser diode to lase and you had to decrease 
current when turning it off if you didn't want to destroy the diode.  
At low currents, they were just like LEDs.  Power output was irratic, 
so each diode had a beam splitter, detector, and driver to maintain 
constant output power.  My job was to find commercially viable 
applications for the stuff HP Labs was making (laser diodes, optical 
fibers, liquid crystals, SAW resonators, etc).  I was a technician 
back then, so I did mostly prototyping with minimal design...

Regards,
Dennis

--- In Homebrew_PCBs@...m, "jam5411" <mardock@...> wrote:
>
> I read with much interest all the work that is going into the TT
> method of creating artwork on copper. Has anyone experimented with
> modifications to a Laser Printer to directly apply the artwork to the
> copper? Seems this would solve a lot of the issues, if it were
> possible. I remember a few years back I had a Laserjet 4L. It had a
> straight through path and would accept some pretty thick card stock 
as
> I recall. Now I wish I had not thrown it out in the late last 
century...
>

On Mon, 13 Feb 2006 21:11:47 +0100, dl5012 <dl5012@...> wrote:

>
>
> It's a laser "printer" that has enough power to burn wood.  It's used
>
> to engrave things (like pens).  If you coated copper clad with an etch
>
> resist, you could use the "printer" to burn away the areas you don't
>
> want.
>
>
> I thought about contacting them to find out if they had a laser that
>
> was powerful enough to burn the copper and holes.  But, that's more
>
> money than I could spend anyway...
>


There are already machines that mill boards with a laser.

I think i could have one or two boards made commercially cheaper ;-)

ST

Sorry for the "What's the best laser printer" post but I need advice.

I am currrently using a Xerox DocuPrint 240A to produce positive PCB 
artwork which I then expose via UV to make my boards.  Unfortuantely 
the print quality is poor.

Firstly, the blacks aren't very black, they're all splotchy.  I 
wanted to use GCC Toner Density Spray, but according to GCC, the 
spray only works with carbon based toners - the Xerox uses something 
else - sorry I forget the details.

Second, the dimensions are wrong.  A 100mm x 100mm rectangle comes 
out at about 100.5 x 99.  I can scale it, but not accurately enough.  
My inkjet printer is much more precise but it sprays.

And finally, the paper handling is woeful.  The paper seems to jiggle 
around when being printed.  A line running down the left side of the 
page can be up to 2mm longer than the one on the right.  This makes 
the printer pretty useless for double sided boards.

All this is not a problem for small boards, 50mm x 50mm.  Up to 100mm 
it starts getting a bit tricky, vias can sometimes miss, but can be 
creatively soldered.  Larger than that and it is a waste of time 
trying.  I will go to my local printer and get them to print it for 
me.  They have a large table sized Xerox DocuCenter 1100 which prints 
amazing images on transparency - accurate, black, and no toner 
splatter.  Unfortunately, they are usually busy and I have to wait - 
hence this post; I won't get my print outs till tomorrow.

So, are there better printers around?  Affordable that is.  Am I 
expecting to much from a home laser?  Or do I just have a lemon?

Any advice will be appreciated.

Thanks,
Frank

--- Frank <frank@...> wrote:

> Sorry for the "What's the best laser printer" post
> but I need advice.
> 
> I am currrently using a Xerox DocuPrint 240A to
> produce positive PCB 
> artwork which I then expose via UV to make my
> boards.  Unfortuantely 
> the print quality is poor.
> 
> Firstly, the blacks aren't very black, they're all
> splotchy.  I 
> wanted to use GCC Toner Density Spray, but according

> And finally, the paper handling is woeful.  The
> paper seems to jiggle 
> around when being printed.  A line running down the
> left side of the 
> page can be up to 2mm longer than the one on the
> right.  This makes 
> the printer pretty useless for double sided boards.
> 
I think what you have is a printer that needs
servicing.

You don't want to print on transparency film.  Try to
find some polyester paper.  It will do wonders for
printing.  It's translucent, but not transparent, but
will expose with UV.


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> Frankwrote:
>
> They have a large table sized Xerox
> DocuCenter 1100 which prints amazing
> images on transparency - accurate,
> black, and no toner splatter.

I have one of the xerox monster
docucenters here.  They do produce the
best photo-tools of any printer I have
seen.  It is unfortunate they cost as
much as a small car.

At home I have a $2K-ish laserjet 4xxx
and I *used* to use that.

That was until someone here (Derek I
think) convinced me to give an inky a
go.

Now if I am only looking for 10/10 rules
I just use the inky on plain claycoat
paper.

It is not as good as the fuji-xerox but
it is better than the laser.

--- In Homebrew_PCBs@yahoogroups.com, KeepIt SimpleStupid
<keepitsimplestupid@...> wrote:
>
> 
> --- Frank <frank@...> wrote:
> 
> > Firstly, the blacks aren't very black, they're all
> > splotchy.  I 
> > wanted to use GCC Toner Density Spray, but according

> You don't want to print on transparency film.  Try to
> find some polyester paper.  It will do wonders for
> printing.  It's translucent, but not transparent, but
> will expose with UV.

Tshirt makers, when they print and expose their photosensitive
screens, use "vellum" as you describe, not transparencies. Either with
laser printers, or with inkjet printers.

Here is a good board on screenprinting and such where you may find
more info on these "vellums". I put that in quotes because real vellum
was something like the inside layer of animal hide, modern vellum is
cotton or polyester.

http://boards.screenprinters.net/

What looks the clearest is not always the best. I'm in EET training
right now and have to make blueprints. I bought some fancy very clear
vellum for drafting (pencil) and it -looks- like it would work better
than the stock 100% cotton vellum they wanted us to buy. Their vellum
is whiter and appears more opaque than what I bought. But the pencil
lines are a lot darker on their vellum, so their vellum works better
for blueprints.

Steve Greenfield

The white paper-like vellum also is what is used in the engraving 
industry for making the masks for sandblasting. At UV, it seems to be 
much more transparent than transparencies. Also, for a crisper image, 
put the printed side of the vellum closer to the reactive surface. It 
will create a much sharper transfer. Make sure you mirror your mask. :)

Chris

Steve wrote:

>
> --- In Homebrew_PCBs@yahoogroups.com 
> <mailto:Homebrew_PCBs%40yahoogroups.com>, KeepIt SimpleStupid
> <keepitsimplestupid@...> wrote:
> >
> >
> > --- Frank <frank@...> wrote:
> >
> > > Firstly, the blacks aren't very black, they're all
> > > splotchy. I
> > > wanted to use GCC Toner Density Spray, but according
>
> > You don't want to print on transparency film. Try to
> > find some polyester paper. It will do wonders for
> > printing. It's translucent, but not transparent, but
> > will expose with UV.
>
> Tshirt makers, when they print and expose their photosensitive
> screens, use "vellum" as you describe, not transparencies. Either with
> laser printers, or with inkjet printers.
>
> Here is a good board on screenprinting and such where you may find
> more info on these "vellums". I put that in quotes because real vellum
> was something like the inside layer of animal hide, modern vellum is
> cotton or polyester.
>
> http://boards.screenprinters.net/ <http://boards.screenprinters.net/>
>
> What looks the clearest is not always the best. I'm in EET training
> right now and have to make blueprints. I bought some fancy very clear
> vellum for drafting (pencil) and it -looks- like it would work better
> than the stock 100% cotton vellum they wanted us to buy. Their vellum
> is whiter and appears more opaque than what I bought. But the pencil
> lines are a lot darker on their vellum, so their vellum works better
> for blueprints.
>
> Steve Greenfield
>
>