Homebrew_PCBs

what is the best way to produce a PCB out of a layout on the PC at
home ?? i tried a lot and failed a lot

--- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
<salamgobran@h...> wrote:

> what is the best way to produce a PCB out of a layout on the PC at
> home ?? i tried a lot and failed a lot

Sal:

Steve tells me HE has given up trying to post in the PHOTOS section,
and suggests I put the photo of my Home Brew CNC PCB Drill in the
FILES section, so I looked there, and I see I had posted a copy of my
photo of that item there months back!

So, open the "Homebrew PCB Equipment" file, and then click on
DSCN0329. I do not have a better copy of that photo.

Jan Rowland

What led to the failures?

I'm a novice at home PCB etching but had very good success with
photo-transfer.

I purchased pre-sensitized PCB's then printed my PCB designs on an
Epson inkjet printer and high quality transparency film. The quality
was superb. Doing this I was able to make double sided boards
without too much hassle. The pre-sensitized boards were about $25
per square foot, I think.

I compared this to printing the designs on a laser printers (I tried
two different lasers) and neither of the lasers had accurate
reproductions. The material didn't feed consistently and the
magnification wasn't exactly 100%. The inkjet on the other hand was
super accurate, beyond my capacity to measure.

The main thing I had to do was get high quality inkjet transparency
film and print in highest quality mode.

The film I used was Pictorico premium OHP transparency film. The
quality is absolutely perfect on this film, much better than the 3m
and Apolo films I tried which don't seem to take the ink very well.

The other thing that was important was to print the images mirrored,
so that I could put the printed side of the material in direct
contact with the board. If you print normally, then the light has to
go through the transparency material after striking the printed
pattern, and then it gets blurry by the time it reaches the board.
This is key for sharp lines. Plus of course the glass on top to keep
things flat.

good luck.
-Ted

--- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
<salamgobran@h...> wrote:

> what is the best way to produce a PCB out of a layout on the PC at
> home ?? i tried a lot and failed a lot

can you share more information about where to purchase these photo boards.

do you have to keep the boards in the dark same as photography?

do you have to expose, develop, stop, fix, then etch?

what are the steps to processing?

thanks.

mkl

----- Original Message -----
From: <ted@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, December 14, 2002 7:17 AM
Subject: [Homebrew_PCBs] Re: How to make a PCB at home


> What led to the failures?
>
> I'm a novice at home PCB etching but had very good success with
> photo-transfer.
>
> I purchased pre-sensitized PCB's then printed my PCB designs on an
> Epson inkjet printer and high quality transparency film. The quality
> was superb. Doing this I was able to make double sided boards
> without too much hassle. The pre-sensitized boards were about $25
> per square foot, I think.
>
> I compared this to printing the designs on a laser printers (I tried
> two different lasers) and neither of the lasers had accurate
> reproductions. The material didn't feed consistently and the
> magnification wasn't exactly 100%. The inkjet on the other hand was
> super accurate, beyond my capacity to measure.
>
> The main thing I had to do was get high quality inkjet transparency
> film and print in highest quality mode.
>
> The film I used was Pictorico premium OHP transparency film. The
> quality is absolutely perfect on this film, much better than the 3m
> and Apolo films I tried which don't seem to take the ink very well.
>
> The other thing that was important was to print the images mirrored,
> so that I could put the printed side of the material in direct
> contact with the board. If you print normally, then the light has to
> go through the transparency material after striking the printed
> pattern, and then it gets blurry by the time it reaches the board.
> This is key for sharp lines. Plus of course the glass on top to keep
> things flat.
>
> good luck.
> -Ted
>
> --- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
> <salamgobran@h...> wrote:
> > what is the best way to produce a PCB out of a layout on the PC at
> > home ?? i tried a lot and failed a lot
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> 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/
>
>

I can help anyone interested in blank boards with dryfilm
photoresist. I have a laminator and plenty of dryfilm resist on hand.

Also have a photoplotter that makes positive or negative films from
Gerber photoplot data. Contact me off list if there is any interest.

Tom twb8899@...


--- In Homebrew_PCBs@yahoogroups.com, Matt Lorenz <mklorenz@c...>
wrote:

> can you share more information about where to purchase these photo

boards.

>
> do you have to keep the boards in the dark same as photography?
>
> do you have to expose, develop, stop, fix, then etch?
>
> what are the steps to processing?
>
> thanks.
>
> mkl
>
>
> ----- Original Message -----
> From: <ted@s...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Saturday, December 14, 2002 7:17 AM
> Subject: [Homebrew_PCBs] Re: How to make a PCB at home
>
>
> > What led to the failures?
> >
> > I'm a novice at home PCB etching but had very good success with
> > photo-transfer.
> >
> > I purchased pre-sensitized PCB's then printed my PCB designs on an
> > Epson inkjet printer and high quality transparency film. The

quality

> > was superb. Doing this I was able to make double sided boards
> > without too much hassle. The pre-sensitized boards were about $25
> > per square foot, I think.
> >
> > I compared this to printing the designs on a laser printers (I

tried

> > two different lasers) and neither of the lasers had accurate
> > reproductions. The material didn't feed consistently and the
> > magnification wasn't exactly 100%. The inkjet on the other hand

was

> > super accurate, beyond my capacity to measure.
> >
> > The main thing I had to do was get high quality inkjet

transparency

> > film and print in highest quality mode.
> >
> > The film I used was Pictorico premium OHP transparency film. The
> > quality is absolutely perfect on this film, much better than the

3m

> > and Apolo films I tried which don't seem to take the ink very

well.

> >
> > The other thing that was important was to print the images

mirrored,

> > so that I could put the printed side of the material in direct
> > contact with the board. If you print normally, then the light has

to

> > go through the transparency material after striking the printed
> > pattern, and then it gets blurry by the time it reaches the board.
> > This is key for sharp lines. Plus of course the glass on top to

keep

> > things flat.
> >
> > good luck.
> > -Ted
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
> > <salamgobran@h...> wrote:
> > > what is the best way to produce a PCB out of a layout on the PC

at

> > > home ?? i tried a lot and failed a lot
> >
> >
> > Be sure to visit the group home and check for new Bookmarks and

files:

> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > 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/

> >
> >

What is the technique with dryfilm resist? It sounds like it is
laminated to the boards with heat? I just bought a dry mount press so
I'm interested. I assume this is better than spraying boads? Is this
one of those products where it is not sold in small qty?
thks
Bob

--- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
<twb8899@y...> wrote:

> I can help anyone interested in blank boards with dryfilm
> photoresist. I have a laminator and plenty of dryfilm resist on

hand.

>
> Also have a photoplotter that makes positive or negative films from
> Gerber photoplot data. Contact me off list if there is any

interest.

>
> Tom twb8899@y...
>

The boards I use are branded: Ever-Muse. I believe that I bought
them from this web site:
http://www.web-tronics.com
http://www.web-tronics.com/printed-circuit-board-supplies.html
Their prices seem good and I liked dealing with them.
The particular boards I got came in a metallic bag. No special
handling or storage required other than that. They also have an
opaque plastic coating that you peel off before use. I've cut them
in subdued light and done everything in a normal room, just keeping
the light level low.

For exposure, I have a fluorescent ring-lamp that I place about 6-8"
from the surface and expose about 10 minutes. It took a little
experimentation to get the exposure down.

Once you've exposed, it's just a developer stage then rinse and
etch.

Making double sided boards was a little tricky. I would develop one
side then drill through a few index marks. Then I'd align the second
side very carefully using those index holes.

One important thing I learned was that it's best to drill after
developing but before etching. Unless you've got really big pads, it
seemed that the drilling would rip things up if done after etching.


-Ted


--- In Homebrew_PCBs@yahoogroups.com, Matt Lorenz <mklorenz@c...>
wrote:

> can you share more information about where to purchase these photo

boards.

>
> do you have to keep the boards in the dark same as photography?
>
> do you have to expose, develop, stop, fix, then etch?
>
> what are the steps to processing?
>
> thanks.
>
> mkl
>
>
> ----- Original Message -----
> From: <ted@s...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Saturday, December 14, 2002 7:17 AM
> Subject: [Homebrew_PCBs] Re: How to make a PCB at home
>
>
> > What led to the failures?
> >
> > I'm a novice at home PCB etching but had very good success with
> > photo-transfer.
> >
> > I purchased pre-sensitized PCB's then printed my PCB designs on

an

> > Epson inkjet printer and high quality transparency film. The

quality

> > was superb. Doing this I was able to make double sided boards
> > without too much hassle. The pre-sensitized boards were about $25
> > per square foot, I think.
> >
> > I compared this to printing the designs on a laser printers (I

tried

> > two different lasers) and neither of the lasers had accurate
> > reproductions. The material didn't feed consistently and the
> > magnification wasn't exactly 100%. The inkjet on the other hand

was

> > super accurate, beyond my capacity to measure.
> >
> > The main thing I had to do was get high quality inkjet

transparency

> > film and print in highest quality mode.
> >
> > The film I used was Pictorico premium OHP transparency film. The
> > quality is absolutely perfect on this film, much better than the

3m

> > and Apolo films I tried which don't seem to take the ink very

well.

> >
> > The other thing that was important was to print the images

mirrored,

> > so that I could put the printed side of the material in direct
> > contact with the board. If you print normally, then the light

has to

> > go through the transparency material after striking the printed
> > pattern, and then it gets blurry by the time it reaches the

board.

> > This is key for sharp lines. Plus of course the glass on top to

keep

> > things flat.
> >
> > good luck.
> > -Ted
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
> > <salamgobran@h...> wrote:
> > > what is the best way to produce a PCB out of a layout on the

PC at

> > > home ?? i tried a lot and failed a lot
> >
> >
> > Be sure to visit the group home and check for new Bookmarks and

files:

> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > 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/

> >
> >

Bob,

Dry film photo resist is laminated to the panel using a hot roll
laminator. The dry film resist that I use is .0015" thick and is
developed in a 1% sodium carbonate (soda ash) solution. These films
are negative acting and exposed with a UV light source. My light
source uses a mercury vapor lamp which exposes the film in about 17
seconds. If you expose the film using a negative you will have the
traces and pads left behind on the copper panel for etching. After
etching the photoresist is stripped from the board using a weak
sodium hydroxide or lye solution.

Tom


--- In Homebrew_PCBs@yahoogroups.com, "Bob Fitzgerald <newaag@y...>"
<newaag@y...> wrote:

> What is the technique with dryfilm resist? It sounds like it is
> laminated to the boards with heat? I just bought a dry mount press

so

> I'm interested. I assume this is better than spraying boads? Is

this

> one of those products where it is not sold in small qty?
> thks
> Bob
>
> --- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
> <twb8899@y...> wrote:
> > I can help anyone interested in blank boards with dryfilm
> > photoresist. I have a laminator and plenty of dryfilm resist on
> hand.
> >
> > Also have a photoplotter that makes positive or negative films

from

> > Gerber photoplot data. Contact me off list if there is any
> interest.
> >
> > Tom twb8899@y...
> >

Tom -
Thanks. As you can see, I'm not to savvy about how the pros do it. I
would imagine this process needs a very good negative. Do you use a
laser or inkjet printer? I really marvel at the quality boards one
can buy for relatively cheap these days, like computer motherboard
fully stuffed sans processor for 60-90.
Bob

--- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
<twb8899@y...> wrote:

> Bob,
>
> Dry film photo resist is laminated to the panel using a hot roll
> laminator. The dry film resist that I use is .0015" thick and is
> developed in a 1% sodium carbonate (soda ash) solution. These films
> are negative acting and exposed with a UV light source. My light
> source uses a mercury vapor lamp which exposes the film in about 17
> seconds. If you expose the film using a negative you will have the
> traces and pads left behind on the copper panel for etching. After
> etching the photoresist is stripped from the board using a weak
> sodium hydroxide or lye solution.
>
> Tom
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Bob Fitzgerald

<newaag@y...>"

> <newaag@y...> wrote:
> > What is the technique with dryfilm resist? It sounds like it is
> > laminated to the boards with heat? I just bought a dry mount

press

> so
> > I'm interested. I assume this is better than spraying boads? Is
> this
> > one of those products where it is not sold in small qty?
> > thks
> > Bob
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
> > <twb8899@y...> wrote:
> > > I can help anyone interested in blank boards with dryfilm
> > > photoresist. I have a laminator and plenty of dryfilm resist on
> > hand.
> > >
> > > Also have a photoplotter that makes positive or negative films
> from
> > > Gerber photoplot data. Contact me off list if there is any
> > interest.
> > >
> > > Tom twb8899@y...
> > >

Bob,

Most of my boards are rather simple and single sided. I use dry film
photo resist on FR-4 (glass epoxy) and CEM-1 (paper base)laminates.
These boards are what is called "print and etch" in the industry,
bare copper traces on the base laminate with no plating or solder
coating. Sometimes I do use a silk screen to print a soldermask which
is the green coating that covers everything except the pads that are
soldered.

A negative is used for exposing a print and etch board. The back
ground of this negative is opaque black and the traces are clear to
let the UV light through. The UV light will expose the traces through
the clear part of the film negative but not through the opaque areas.
The dry film areas on the board that didn't receive any light will
wash away during development thus leaving the traces which are now
covered with exposed resist and ready for etching. After etching a
weak lye solution will strip off the dry film resist from the traces.
The board can be scrubbed to clean the copper and drilled.

I make my films using a machine called a photoplotter. This machine
takes the data from a CAD system and "draws" the image on
photographic film for a perfect image in a positive or negative
format. These films are known as a "phototool" in the industry.

I have never used the laser or ink jet methods but know others that
have had excellent results with these methods. I believe they use
some type of translucent paper for printing which will allow UV light
to pass through.

Before photoplotters were popular we used large process cameras
similar to what a printing company uses. The artwork in those days
was made using narrow black tape and stick on pads. Most artwork was
made at 2:1 scale and some designs were 4:1 scale. These master
layouts were then reduced on the camera and a negative was shot. It
was a major job setting up multiple images on a larger panel making
sure that all layers were perfectly registered. Using a photoplotter
and a CAM system made this job much easier. In some cases we
could "tool up" a job in 30 minutes that would otherwise take all day
with hand taped artwork.

I still have a process camera but prefer the photoplotter because the
film is always perfect. If you look at a photoplotted film with a
microscope you will notice that it has excellent film density. There
are no gray areas. The film density goes from opaque black to clear
and back to black. It's difficult to get even the best cameras to
make films like this.

While the plotter is making the films, the drilling machine is
drilling the holes at the same time. Everything registers perfectly.
Because of all this automation the bare board prices have been
greatly reduced. Hope this answers some of your questions.

Tom





--- In Homebrew_PCBs@yahoogroups.com, "Bob Fitzgerald <newaag@y...>"
<newaag@y...> wrote:

> Tom -
> Thanks. As you can see, I'm not to savvy about how the pros do it.

I

> would imagine this process needs a very good negative. Do you use

a

> laser or inkjet printer? I really marvel at the quality boards one
> can buy for relatively cheap these days, like computer motherboard
> fully stuffed sans processor for 60-90.
> Bob
>
> --- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
> <twb8899@y...> wrote:
> > Bob,
> >
> > Dry film photo resist is laminated to the panel using a hot roll
> > laminator. The dry film resist that I use is .0015" thick and is
> > developed in a 1% sodium carbonate (soda ash) solution. These

films

> > are negative acting and exposed with a UV light source. My light
> > source uses a mercury vapor lamp which exposes the film in about

17

> > seconds. If you expose the film using a negative you will have

the

> > traces and pads left behind on the copper panel for etching.

After

> > etching the photoresist is stripped from the board using a weak
> > sodium hydroxide or lye solution.
> >
> > Tom
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "Bob Fitzgerald
> <newaag@y...>"
> > <newaag@y...> wrote:
> > > What is the technique with dryfilm resist? It sounds like it is
> > > laminated to the boards with heat? I just bought a dry mount
> press
> > so
> > > I'm interested. I assume this is better than spraying boads? Is
> > this
> > > one of those products where it is not sold in small qty?
> > > thks
> > > Bob
> > >
> > > --- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
> > > <twb8899@y...> wrote:
> > > > I can help anyone interested in blank boards with dryfilm
> > > > photoresist. I have a laminator and plenty of dryfilm resist

on

> > > hand.
> > > >
> > > > Also have a photoplotter that makes positive or negative

films

> > from
> > > > Gerber photoplot data. Contact me off list if there is any
> > > interest.
> > > >
> > > > Tom twb8899@y...
> > > >

Can someone who know please explain the main difference between (apparently
older) G-10 and (apparently currently-used) FR-4? Thanks. Jan Rowland


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

Hi Tom

twb8899 wrote:

> Bob,
>
> Most of my boards are rather simple and single sided. I use dry film
> photo resist on FR-4 (glass epoxy) and CEM-1 (paper base)laminates.

I am wondering how you apply the dry film. I have a lot (30 meters x 16" roll) of dry film
at home for making PCB's. Its excellent to use once it has been applied to the board. I
made a rubber roller to apply the film on the board while cold. I then heat it in oven at
80°C for 10 minutes to get it sticking on really well. It's difficult to avoid wrinkles
and air bubbles without a proper laminator. I find applying the film the most difficult.

I once had a chance to buy a proper dry film laminator for fairly cheap at an auction, but
the machine stood 2 meters tall and weighed couple hundred kilograms. This machine is ok
if your laminating hundreds of panels in a single day, but for the hobbyist with limited
sotrage space and money there has to be a better way.

>
> I make my films using a machine called a photoplotter. This machine
> takes the data from a CAD system and "draws" the image on
> photographic film for a perfect image in a positive or negative
> format. These films are known as a "phototool" in the industry.

How does this photoplotter work ? I've heard that some use a red laser and scan across a
rotating drum with the film wrapped around. I priced photoplotter film and its very
expensive. I've remember you once mentioned that there is a lot of used PCB equipment on
the market, are there any fairly cheap photoplotters around ? Are these machines too big
for a home lab ?

>
> I have never used the laser or ink jet methods but know others that
> have had excellent results with these methods. I believe they use
> some type of translucent paper for printing which will allow UV light
> to pass through.


> I still have a process camera but prefer the photoplotter because the
> film is always perfect. If you look at a photoplotted film with a
> microscope you will notice that it has excellent film density. There
> are no gray areas. The film density goes from opaque black to clear
> and back to black. It's difficult to get even the best cameras to
> make films like this.

I've looked at inkjet printers transparencies under a microscope and the line edges are
very jagged. This is individual ink droplets scattered around the edges. There are no gray
areas however. After I expose and develop the dry film and then look under a microscope I
can clearly see the jagged edges reproduced from the inkjet prints. The film density of
black ink in inkjet printers is never any problem for UV exposure. The main thing to watch
out for is pin holes, but that depends entirly on what transparency and inkjet ink your
using. Epson brand stuff give the best prints I've seen.

Adam

How about using a "T" shirt press? you know the items used to apply
decorative heat transfers to t shirts.
Bill Higdon
Adam Seychell wrote:

> Hi Tom
>
> twb8899 wrote:
>
>>Bob,
>>
>>Most of my boards are rather simple and single sided. I use dry film
>>photo resist on FR-4 (glass epoxy) and CEM-1 (paper base)laminates.
>
>
>
> I am wondering how you apply the dry film. I have a lot (30 meters x 16" roll) of dry film
> at home for making PCB's. Its excellent to use once it has been applied to the board. I
> made a rubber roller to apply the film on the board while cold. I then heat it in oven at
> 80°C for 10 minutes to get it sticking on really well. It's difficult to avoid wrinkles
> and air bubbles without a proper laminator. I find applying the film the most difficult.
>
> I once had a chance to buy a proper dry film laminator for fairly cheap at an auction, but
> the machine stood 2 meters tall and weighed couple hundred kilograms. This machine is ok
> if your laminating hundreds of panels in a single day, but for the hobbyist with limited
> sotrage space and money there has to be a better way.
>
>
>
>>I make my films using a machine called a photoplotter. This machine
>>takes the data from a CAD system and "draws" the image on
>>photographic film for a perfect image in a positive or negative
>>format. These films are known as a "phototool" in the industry.
>
>
> How does this photoplotter work ? I've heard that some use a red laser and scan across a
> rotating drum with the film wrapped around. I priced photoplotter film and its very
> expensive. I've remember you once mentioned that there is a lot of used PCB equipment on
> the market, are there any fairly cheap photoplotters around ? Are these machines too big
> for a home lab ?
>
>
>>I have never used the laser or ink jet methods but know others that
>>have had excellent results with these methods. I believe they use
>>some type of translucent paper for printing which will allow UV light
>>to pass through.
>
>
>
>>I still have a process camera but prefer the photoplotter because the
>>film is always perfect. If you look at a photoplotted film with a
>>microscope you will notice that it has excellent film density. There
>>are no gray areas. The film density goes from opaque black to clear
>>and back to black. It's difficult to get even the best cameras to
>>make films like this.
>
>
> I've looked at inkjet printers transparencies under a microscope and the line edges are
> very jagged. This is individual ink droplets scattered around the edges. There are no gray
> areas however. After I expose and develop the dry film and then look under a microscope I
> can clearly see the jagged edges reproduced from the inkjet prints. The film density of
> black ink in inkjet printers is never any problem for UV exposure. The main thing to watch
> out for is pin holes, but that depends entirly on what transparency and inkjet ink your
> using. Epson brand stuff give the best prints I've seen.
>
> Adam

Jan,

The difference between G-10 and FR-4 is minimal and has to do with
flammability. G-10 is not self extinguishing in a vertical flame test
while FR-4 is. A strip of laminate is held vertically in a flame
until it ignites. When the source of ignition (flame) is removed the
G-10 will keep burning and the FR-4 will self extinguish. Check out
the Underwriter Laboratories test specifications. If I remember
correctly, this test is called the "UL 796 Vertical Flame Test".

I believe there are some slight differences in the velocity factor at
very high frequencies between the two types. This may also depend on
the specific vendor. G-10 laminate always has a white or grayish
water mark and FR-4 always has a red water mark. G-10 laminate is
kind of rare these days with most boards being made from FR-4. Hope
this information helps.

Tom

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> Can someone who know please explain the main difference between
(apparently
> older) G-10 and (apparently currently-used) FR-4? Thanks.
Jan Rowland
>
>
> [Non-text portions of this message have been removed]

Adam,

Bill's idea with the T shirt press is something to look into.
Anything that can apply heat and moderate pressure can be used for
dry film lamination.

I have applied the dry film by laying it on the clean copper surface
and then putting it in a nylon "turkey bag". Seal the edges with
masking tape and hook up a small diameter tube to a vacuum pump. The
pump will evacuate the air and force the dry film tightly against the
copper. Then you could just use a regular laundry iron to heat it
and "iron" it on. A small airbrush compressor hooked up backwards
will make plenty of vacuum for doing this. Try this method for hobby
boards because it really works good and isn't too hard to do.

I used a DuPont HRL-24 laminator in the past but as you mentioned,
they are big and expensive to operate. I sold that beast and got a
small table top laminator. The unit I use is made by the Steven
Daniels Company. It accepts 3" core rolls and has adjustable tension
and board thickness. The adjustable tension on the roll is what you
need to get rid of the wrinkles.

I used three different photoplotters over the years. My first one was
a Gerber Scientific 3244. This was a vector plotter with a mechanical
wheel that held up to 34 apertures. These apertures are a small piece
of negative film with the pad shape on it at 3:1 scale. The wheel
rotates to the proper aperture number by software control and exposes
the film via a lense and shutter. The table size was about 20" x 26".
This plotter would directly read a DOS diskette and plot the job. If
you only want to plot your own work then this plotter would be a good
one to have since you could match your CAD apertures to the
mechanical wheel and plot your films. This plotter will plot the
typical small hobby board in two or three minutes.

I sold this machine and stepped up to a Gerber Cresent raster laser
plotter for the big stuff. This was also a good plotter but required
green lights in the darkroom. This made it difficult because most of
our film was processed under red light. We had to have two darkrooms
which was a pain.

The best plotter we ever used was made by Lavenir Technology. It was
a model RPG-1622 and could process up to 16" x 22" films. The
exposure head has 100 special LED's that increment in the Y axis and
the whole exposure head travels back and forth in the X axis to
complete the plot. The model I have can handle about 250 different
aperture shapes and sizes. It is a desk top model. If you ever find
one of these cheap don't pass it by. I bought mine in 1989 and still
use it. They never break and are very accurate. You can plot positive
or negative films with this unit.

The film I use these days is Kodak AGX-7. This is a heavy .007" thick
film that is made for photoplotters. The cost is about $3.50 per 16"
x 20" sheet. Kodak also makes this in a .004" thickness which would
be less costly but not as stable as the thick stuff.

For the absolute finest detail you should use a vector plotter since
it plots point to point and the lines have a very sharp edge. The
raster plotters are more flexible to use but don't have the sharp
edge like a vector unit. You will almost need a microscope to see the
difference though and by the time the etching solution has done its
job everything is smoothed out anyway.

Bottom line: get a small table top laminator or turkey bag setup and
if you can ever find a Lavenir plotter grab it. You won't be sorry.
If it's working when you get it, chances are it will keep going for
many years.

Tom

--- In Homebrew_PCBs@yahoogroups.com, Bill Higdon <w.higdon@a...>
wrote:

> How about using a "T" shirt press? you know the items used to apply
> decorative heat transfers to t shirts.
> Bill Higdon
> Adam Seychell wrote:
> > Hi Tom
> >
> > twb8899 wrote:
> >
> >>Bob,
> >>
> >>Most of my boards are rather simple and single sided. I use dry

film

> >>photo resist on FR-4 (glass epoxy) and CEM-1 (paper base)

laminates.

> >
> >
> >
> > I am wondering how you apply the dry film. I have a lot (30

meters x 16" roll) of dry film

> > at home for making PCB's. Its excellent to use once it has been

applied to the board. I

> > made a rubber roller to apply the film on the board while cold. I

then heat it in oven at

> > 80°C for 10 minutes to get it sticking on really well. It's

difficult to avoid wrinkles

> > and air bubbles without a proper laminator. I find applying the

film the most difficult.

> >
> > I once had a chance to buy a proper dry film laminator for fairly

cheap at an auction, but

> > the machine stood 2 meters tall and weighed couple hundred

kilograms. This machine is ok

> > if your laminating hundreds of panels in a single day, but for

the hobbyist with limited

> > sotrage space and money there has to be a better way.
> >
> >
> >
> >>I make my films using a machine called a photoplotter. This

machine

> >>takes the data from a CAD system and "draws" the image on
> >>photographic film for a perfect image in a positive or negative
> >>format. These films are known as a "phototool" in the industry.
> >
> >
> > How does this photoplotter work ? I've heard that some use a red

laser and scan across a

> > rotating drum with the film wrapped around. I priced photoplotter

film and its very

> > expensive. I've remember you once mentioned that there is a lot

of used PCB equipment on

> > the market, are there any fairly cheap photoplotters around ? Are

these machines too big

> > for a home lab ?
> >
> >
> >>I have never used the laser or ink jet methods but know others

that

> >>have had excellent results with these methods. I believe they use
> >>some type of translucent paper for printing which will allow UV

light

> >>to pass through.
> >
> >
> >
> >>I still have a process camera but prefer the photoplotter because

the

> >>film is always perfect. If you look at a photoplotted film with a
> >>microscope you will notice that it has excellent film density.

There

> >>are no gray areas. The film density goes from opaque black to

clear

> >>and back to black. It's difficult to get even the best cameras to
> >>make films like this.
> >
> >
> > I've looked at inkjet printers transparencies under a microscope

and the line edges are

> > very jagged. This is individual ink droplets scattered around the

edges. There are no gray

> > areas however. After I expose and develop the dry film and then

look under a microscope I

> > can clearly see the jagged edges reproduced from the inkjet

prints. The film density of

> > black ink in inkjet printers is never any problem for UV

exposure. The main thing to watch

> > out for is pin holes, but that depends entirly on what

transparency and inkjet ink your

> > using. Epson brand stuff give the best prints I've seen.
> >
> > Adam

twb8899 wrote:

> Adam,
>
> Bill's idea with the T shirt press is something to look into.
> Anything that can apply heat and moderate pressure can be used for
> dry film lamination.

...

> Bottom line: get a small table top laminator or turkey bag setup and
> if you can ever find a Lavenir plotter grab it. You won't be sorry.
> If it's working when you get it, chances are it will keep going for
> many years.

I got a small (15cm cubed box) diaphram pump that would be ideal for
sucking bags. I got it for $10 at a sunday market. I know a junk shop
that has more...

Russell wrote:

> twb8899 wrote:
>
>>Adam,
>>
>>Bill's idea with the T shirt press is something to look into.
>>Anything that can apply heat and moderate pressure can be used for
>>dry film lamination.
>
> ...
>
>>Bottom line: get a small table top laminator or turkey bag setup and
>>if you can ever find a Lavenir plotter grab it. You won't be sorry.
>>If it's working when you get it, chances are it will keep going for
>>many years.
>
>
> I got a small (15cm cubed box) diaphram pump that would be ideal for
> sucking bags. I got it for $10 at a sunday market. I know a junk shop
> that has more...

Reversing the plunger in a bicycle bump might do suction too.

Russell wrote:

> twb8899 wrote:
>
>>Adam,
>>
>>Bill's idea with the T shirt press is something to look into.
>>Anything that can apply heat and moderate pressure can be used for
>>dry film lamination.
>
> ...
>
>>Bottom line: get a small table top laminator or turkey bag setup and
>>if you can ever find a Lavenir plotter grab it. You won't be sorry.
>>If it's working when you get it, chances are it will keep going for
>>many years.
>
>
> I got a small (15cm cubed box) diaphram pump that would be ideal for
> sucking bags. I got it for $10 at a sunday market. I know a junk shop
> that has more...

Reversing the plunger in a bicycle pump might do suction too.

--- In Homebrew_PCBs@yahoogroups.com, "twb8899 <twb8899@y...>"
<twb8899@y...> wrote:

> Bob,
>
> Most of my boards are rather simple and single sided.

Me too. Thanks for taking the time to go through the process and
explain the equipment, it is quite interesting to see how one does it
with the proper tools. I have had fair success so far using laser
prints to Avery label paper backing (as suggested here in one of the
links) and using the heat method to apply these to the bare copper
board. Then etch. My stuff is mostly for audio, with occasional
surface mount parts, but mostly thru hole. I just bought this item
a Seal Dry Mount press to see if it helps the process to be more
reliable.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1943039096

I'll let everyone know how it works once it is delivered.

Bob

This could be an interesting link for you:
http://www.techniks.com/
I personally don't use their method, I prefere a film printed by an
image setter and screen printing before etching the plates, but I
have a lot of experience in printing business and I don't suggest it
to anybody who starts. (Hard to catch two rabbits at once)

regards,
work

--- In Homebrew_PCBs@yahoogroups.com, "Salam <salamgobran@h...>"
<salamgobran@h...> wrote:

> what is the best way to produce a PCB out of a layout on the PC at
> home ?? i tried a lot and failed a lot

> I once had a chance to buy a proper dry film laminator for fairly cheap at

an auction, but

> the machine stood 2 meters tall and weighed couple hundred kilograms. This

machine is ok

> if your laminating hundreds of panels in a single day, but for the

hobbyist with limited

> sotrage space and money there has to be a better way.

I'm very sorry if I don't understand what a laminator is. But seeing
"Don Lancaster" articles, I think it comes closer to a fuser assembly from a
laser printer :o)

I use to do direct toner transfer using transparencies printed on laser
printer (I have a good old 600DPI HP Laserjet 4 Plus) with not-so-large
black areas. I use a household iron to transfer my prints, but I'm assembly
a "laminator" using the fusor assembly from an old Toshiba printer. If I can
do a good heat regulator, I think I'll do perfect transfers with it.

Of course, the fuser can be used unmodified! The lower roller (at least
on HP and the Toshiba fuser I have) has a set of coils to press the roller
against the paper, and so against the fuser roller. I tried to stuff a board
there, and it worked flawlessly. I just didn't lighted up the fuser yet. But
I'm sure it will work.

Maybe this is of some help for anyone...