Homebrew_PCBs

> Hi everyone, and thanks for the warm welcome Stefan. I poked around and
> saw the database and photos, and was darn impressed. I ran down to the
> WalMart in town here to find the cheapest glossy photo paper I have ever
> found, and am itching to try out the toner transfer method with it.
> I was especially impressed with the photos under the headed of "TT8mil".
> Who did them, and with what method? The board looks great.
> What seems to be the software of choice that people find the easiest to
> use for layout?
> I have an Eagle question too. I find that I'd like the holes on many
> parts that are in the Eagle libraries are just too small for me to drill
> by hand, and I'd like to make them bigger, but I don't want to modify
> every part file to update the hole size. Is there any way to do this
> easily? I've found kind of a crazy way that works is to actually place
> big vias over the pads. Eagle won't let you directly place a via over a
> pad, however, it will let you place one close to it, then scoot it over
> the pad after it's been placed. It's kinda corny, and takes a while.
> There's got to be a better way. :)
>
> Thanks in advance,
> Josh
>
>

> Note...Last night I happened to come across something that was a little
> like the discovery of penecillin to me...I was experimenting with
> different materials, and put an antistatic bag through our laser printer
> at work...the bag got stuck and created a paper jam.
> When I opened it up, I found that it hadn't been crinkled into a little
> ball, but had just quit moving...right after the toner transfer stage,
> but before the fuser. I had a nice, slipery surface, covered with toner
> that was clinging to the paper, but was still in it's unmelted, powdery
> form, and hadn't been fused yet. I immediately ironed it to a board, and
> with very little pressure it seemed to work very well. I'm wondering,
> why not try to trick a laser printer into thinking its fuser is present
> and up to temp when it's really been removed? That would give us toner
> that perhaps wasn't as hard to transfer. I'm still experimenting...
>
> -Josh
>
>

>>that was clinging to the paper, but was still in it's unmelted, powdery
>>form, and hadn't been fused yet. I immediately ironed it to a board, and
>>with very little pressure it seemed to work very well. I'm wondering,
>>why not try to trick a laser printer into thinking its fuser is present
>>and up to temp when it's really been removed? That would give us toner
>>that perhaps wasn't as hard to transfer. I'm still experimenting...

> You really want a new office laser do you?
> i mean sending plastic through it ;-) .
>
> a) you still fuse the toner to the surface you print on with your iron,
> so it still has to release it easy.
>
> b) it may be hard to keep the toner from moving while placing it on the
> board.
>
> I'm not very sure that it is easier, but please keep experimenting..
> I would like to read about more results.
>

> Hi everyone, and thanks for the warm welcome Stefan. I poked
>around and saw the database and photos, and was darn impressed. I
>ran down to the WalMart in town here to find the cheapest glossy
>photo paper I have ever found, and am itching to try out the toner
>transfer method with it.
> I was especially impressed with the photos under the headed
>of "TT8mil". Who did them, and with what method? The board looks
>great.
> What seems to be the software of choice that people find the
>easiest to use for layout?
> I have an Eagle question too. I find that I'd like the holes on
>many parts that are in the Eagle libraries are just too small for me
>to drill by hand, and I'd like to make them bigger, but I don't want
>to modify every part file to update the hole size. Is there any way
>to do this easily? I've found kind of a crazy way that works is to
>actually place big vias over the pads. Eagle won't let you directly
>place a via over a pad, however, it will let you place one close to
>it, then scoot it over the pad after it's been placed. It's kinda
>corny, and takes a while. There's got to be a better way. :)
>
>Thanks in advance,
>Josh

----- Original Message -----
From: "Alan King" <alan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, January 07, 2004 8:37 PM
Subject: Re: [Homebrew_PCBs] late night office experiment


>
> Yes you still have to get the toner up above the melt point, so
> really shouldn't be much difference.
>
> What really would make a difference is to have no sheet in between at
> all. As in a direct laser print to the board. I have looked at the
> idea, an insulation layer over the copper is all that's really needed,
> so it'll hold the electrostatic image. Something that can be etched,
> but that won't etch out too fast under the toner, or that the toner will
> melt through some in fusing with pressure but won't just melt off onto
> the fuser where there isn't toner. Plus it takes a straight through
> printer and mods for the board thickness, but that's minor enough. Also
> you have to be sure your edges and surface is smooth with no scratches
> or you'll scratch the drum. Quite a bit of trouble to get it going when
> the results from just ironing on are so good..

I worked for Rank-Xerox UK many years ago.

Xerox's first copier was a manually operated 'flat bed' copier, with a
photoreceptor plate. The plate
was charged, then exposed to the image. The image on the plate was then
developed
by cascading developer and toner over it, the toner image on the plate was
then transferred
onto paper and passed through a fuser (a simple radiant heater).

Even when automatic copiers like the 914 and 813 were developed the flat bed
machines were still popular for certain jobs, like making prototype PCBs.
Instead of transferring the toner image onto paper, the image on the plate
was transferred directly to the copper surface of a PCB. It was then passed
through the fuser and then etched. I saw some PCBs made using this technique
and they were quite good by the standards at the time. I kept meaning to try
it for myself, but never got round to it.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

> I worked for Rank-Xerox UK many years ago.
>
> Xerox's first copier was a manually operated 'flat bed' copier,

> photoreceptor plate. The plate
> was charged, then exposed to the image. The image on the plate was

> developed
> by cascading developer and toner over it, the toner image on the

> then transferred
> onto paper and passed through a fuser (a simple radiant heater).
>
> Even when automatic copiers like the 914 and 813 were developed

> machines were still popular for certain jobs, like making

> Instead of transferring the toner image onto paper, the image on

> was transferred directly to the copper surface of a PCB. It was

> through the fuser and then etched. I saw some PCBs made using this

> and they were quite good by the standards at the time. I kept

> it for myself, but never got round to it.
>
> Leon
> --
> Leon Heller, G1HSM
> Email: aqzf13@d...
> My low-cost Philips LPC210x ARM development system:
> http://www.geocities.com/leon_heller/lpc2104.html

----- Original Message -----
From: "joshdewinter" <joshdewinter@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, January 07, 2004 9:54 PM
Subject: [Homebrew_PCBs] Xerox printers?


>
> > I worked for Rank-Xerox UK many years ago.
> >
> > Xerox's first copier was a manually operated 'flat bed' copier,
> with a
> > photoreceptor plate. The plate
> > was charged, then exposed to the image. The image on the plate was
> then
> > developed
> > by cascading developer and toner over it, the toner image on the
> plate was
> > then transferred
> > onto paper and passed through a fuser (a simple radiant heater).
> >
> > Even when automatic copiers like the 914 and 813 were developed
> the flat bed
> > machines were still popular for certain jobs, like making
> prototype PCBs.
> > Instead of transferring the toner image onto paper, the image on
> the plate
> > was transferred directly to the copper surface of a PCB. It was
> then passed
> > through the fuser and then etched. I saw some PCBs made using this
> technique
> > and they were quite good by the standards at the time. I kept
> meaning to try
> > it for myself, but never got round to it.
> >
> > Leon
> > --
> > Leon Heller, G1HSM
> > Email: aqzf13@d...
> > My low-cost Philips LPC210x ARM development system:
> > http://www.geocities.com/leon_heller/lpc2104.html
>
> Hi Leon.
> This fascinates me. I too tried to run a PCB straight through the
> office laser printer (yes, trying to get them to buy a new one)... I
> found that the toner didn't stick to the copper...of course, no
> charge would mean the toner particles wouldn't cling to it.
>
> So are these older Xerox copiers still available? Do they require a
> bunch of now hard to find supplies to operate?

It was about 35 years ago when I last saw any of these machines, so I doubt
if any are still around. The case was made of wood! I suppose you could make
your own from scratch, like Chester Carlson (the inventor of the Xerographic
process) did. The tricky thing is the selenium-coated plate, everything else
is standard optics and electrical stuff. If you look at Carlson's original
patents, you will see exactly how they worked. I think he used a rabbit fur
brush to remove the excess toner from the plate. The developer was 'Ottawa
sand' (uniform particle size) coated in a special resin that held a static
charge.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

>>
>> Hi Leon.
>> This fascinates me. I too tried to run a PCB straight through the
>> office laser printer (yes, trying to get them to buy a new one)... I
>> found that the toner didn't stick to the copper...of course, no
>> charge would mean the toner particles wouldn't cling to it.
>>
>> So are these older Xerox copiers still available? Do they require a
>> bunch of now hard to find supplies to operate?
>
> It was about 35 years ago when I last saw any of these machines, so I
> doubt
> if any are still around. The case was made of wood! I suppose you could
> make
> your own from scratch, like Chester Carlson (the inventor of the
> Xerographic
> process) did. The tricky thing is the selenium-coated plate, everything
> else
> is standard optics and electrical stuff. If you look at Carlson's
> original
> patents, you will see exactly how they worked. I think he used a rabbit
> fur
> brush to remove the excess toner from the plate. The developer was
> 'Ottawa
> sand' (uniform particle size) coated in a special resin that held a
> static
> charge.
>
> Leon

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <homebrew_pcbs@yahoogroups.com>
Sent: Wednesday, January 07, 2004 10:26 PM
Subject: Re: [Homebrew_PCBs] Xerox printers?


>
> >>
> >> Hi Leon.
> >> This fascinates me. I too tried to run a PCB straight through the
> >> office laser printer (yes, trying to get them to buy a new one)... I
> >> found that the toner didn't stick to the copper...of course, no
> >> charge would mean the toner particles wouldn't cling to it.
> >>
> >> So are these older Xerox copiers still available? Do they require a
> >> bunch of now hard to find supplies to operate?
> >
> > It was about 35 years ago when I last saw any of these machines, so I
> > doubt
> > if any are still around. The case was made of wood! I suppose you could
> > make
> > your own from scratch, like Chester Carlson (the inventor of the
> > Xerographic
> > process) did. The tricky thing is the selenium-coated plate, everything
> > else
> > is standard optics and electrical stuff. If you look at Carlson's
> > original
> > patents, you will see exactly how they worked. I think he used a rabbit
> > fur
> > brush to remove the excess toner from the plate. The developer was
> > 'Ottawa
> > sand' (uniform particle size) coated in a special resin that held a
> > static
> > charge.
> >
> > Leon
>
>
> couldn't you use mostly parts from a complete copier?
>
> Will the selenum coating break if you try to unroll a photodrum?

Yes, it's brittle stuff. It's actually a semiconductor - the Se is doped
with As, and other stuff, IIRC. It's quite toxic, like As. The Xerox drums
were made of cast aluminium and we had a lot of trouble with coating getting
chipped and scratched by operators when cleaning the machines.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

> Hi!
>
> MUCH more important are big enough copper rings around the hole.
> they are often designed for through-hole plated boards.
> there the top and bottom side is connected through a tiny copper
> pipe in the hole. obviously this holds quite good (like a rivet).
> it is hard to do that at home, and there is not often the need.
> but if you don't have through hole plating all that holds your
> copper pad on the board is the glue.
> Therefore it may be necessary to change the pads for your needs.
> (second set of libraries or so)
>

On Wednesday 07 January 2004 11:58 am, joshdewinter wrote:
> Hi guys.
> Thanks for the suggestion Marc. That drilcfg.udp utility is
> handy. I guess I should have gotten my terminology straight when I
> wrote that...I'm thinking more of enlarging the copper pad that I
> would solder to, rather than the drilling hole. You don't know of a
> way to do this effectively in Eagle by any chance do you? The pads
> it makes are just plain tiny. If you have a good drill, this is
> great, I'm using a Dremel by hand, which can be a little harder to
> eyeball than a nice drill press.

>
> There is a ULP in Eagle called change-pad-in-lbr.ulp
>
> You open a library, run the ULP and specify pad shape and size. The ULP
> will whip through your library making the changes for you.
> It seems to leave SMT devices alone.
>
> this is probably not reversible so copy ythe specific components into a
> special library first
>
> Pete
>
>