Homebrew_PCBs

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

> Do any of the sensitized boards or materials react to INFRA-RED light?
> I have an infra-red laser diode on a cnc machine, its not powerful
> enough to cut stuff with but will smolder black foams. I was wondering
> if its possible to use that to rastorize the image, but I dont know
> about all the different types of sensitizer or what types of lights
> they react to. I know in screen printing, they make types which react
> to a 4k watt metal halide bulb, and newbie stuff that works with a 150
> watt lightbulb.

I don't know about any of the board materials being sensitive to IR.
As far as I know, the silkscreen materials are sensitive to UV,
depending on the material, with a peak sensitivity at either 360nm or
420nm. That is why a MH lamp works so well for exposure. I just did
a screen using Chromaline ProCap film and the exposure was 40 min 32
inches from a 400 watt metal halide.

Kevin

Ok, well I can buy a UV laser diode too just as easily as I bought a IR
diode.

Can I handle the emulsion or film in regular room light with the high-
intensity stuff?

--- In Homebrew_PCBs@yahoogroups.com, "docstein99" <docstein99@...> wrote:

>
> Ok, well I can buy a UV laser diode too just as easily as I bought a IR
> diode.
>
> Can I handle the emulsion or film in regular room light with the high-
> intensity stuff?
>

No, yellow bug light is required. Most of the diazo or dual cure
emulsions require long exposure. There is one, indirect capillary
film, Chromaline's product is called Reflex, that is exposed prior to
being put on the material, developed, and then applied. It comes on a
plastic backing sheet. I think the exposure speed is about one third
of the the diazo products. There is one in between, photopolymer,
that is about twice as expensive. Reflex suggests a 25-40 second
exposure from a 5000 watt!! Metal Halide at one meter.

Kevin

On Thursday 01 March 2007 12:28, docstein99 wrote:

> I was wondering if anyone can give me some advice, looking at the
> threads recently it looks like lots of people here have tried
> sensitized boards.
>
> This material appears to be the same stuff as silkscreen printers use
> on silkscreens, where the exposed areas to intense light are hardened
> and the unexposed areas are washed away with water.
>
> Do any of the sensitized boards or materials react to INFRA-RED light?
> I have an infra-red laser diode on a cnc machine, its not powerful
> enough to cut stuff with but will smolder black foams. I was wondering
> if its possible to use that to rastorize the image, but I dont know
> about all the different types of sensitizer or what types of lights
> they react to. I know in screen printing, they make types which react
> to a 4k watt metal halide bulb, and newbie stuff that works with a 150
> watt lightbulb.

Phillipe Terrone, the editor of makezine.com, had some luck using a CO2 laser
to do this:
http://www.makezine.com/blog/archive/2007/01/how_to_use_a_la.html
What he did was spray the copper board with black spray paint, and then he
used the CNC laser to selectively burn off the paint, exposing bare copper.
He then chemically etched the board in the usual manner..

-Sebastien Bailard
RepRap.org - self-replicating 3D printer project.

I thought co2 lasers were powerful enough to obliterate the copper
itself??? Why bother spraying and etching, when it could simply be set
to burn drill-holes, and burn the copper all on the same machine.

On Fri, 02 Mar 2007 15:45:37 +0100, docstein99 <docstein99@...>
wrote:

> I thought co2 lasers were powerful enough to obliterate the copper
> itself??? Why bother spraying and etching, when it could simply be set
> to burn drill-holes, and burn the copper all on the same machine.

because once the copper is gone, it's hard to stop and the fr4 will go too.
It's like cutting a piece of wood sitting on a chunk of styrofoam, using
an axe.

It has been done commercially, but it's not something one can cobble
together on a weekend.

ST

Any practical idea/results/cost here?
Cristian


At 16:45 02.03.2007, you wrote:

>I thought co2 lasers were powerful enough to obliterate the copper

> Any practical idea/results/cost here?
> Cristian

I have used a cheap infra-red, I can use to melt most any thin black
material, lines so thin you need a 10x lens to see them. With a cnc, I
can rasotize an image with it. A co-2 laser is LOTS more powerful and
really expensive, not something someone can buy to toy around with
(unless you have $300 - $1,200 ebay prices to throw around).

The IR laser diodes are strong enough to melt, smolder thin black
materials. I can etch a logo in black plastic within a square 1/4 inch!

I just cant figure out what to use to melt or solidify as a resist onto
a copper board. Spray paint is a new idea, if I can manage to find a
paint that is thin enough that will vaporize with the diode I am
using. And also thought about using printer toner (just the black
powder) - to somehow coat the entire board, the IR diode could also
melt and fuse the toner right to the copper, but that stuff is very
messy!

Can you provide a price info for the ir laser diode?
I'm thinking of converting my Epson printer to just a plotter.

regards -
Henry

www.ehydra.dyndns.info


-----Ursprüngliche Nachricht-----
Von: "docstein99" <docstein99@...>
An: <Homebrew_PCBs@yahoogroups.com>
Gesendet: Freitag, 2. März 2007 18:08
Betreff: [Homebrew_PCBs] Re: sensitized boards


| > Any practical idea/results/cost here?
| > Cristian
|
| I have used a cheap infra-red, I can use to melt most any thin black
| material, lines so thin you need a 10x lens to see them. With a cnc, I
| can rasotize an image with it. A co-2 laser is LOTS more powerful and
| really expensive, not something someone can buy to toy around with
| (unless you have $300 - $1,200 ebay prices to throw around).
|
| The IR laser diodes are strong enough to melt, smolder thin black
| materials. I can etch a logo in black plastic within a square 1/4 inch!
|
| I just cant figure out what to use to melt or solidify as a resist onto
| a copper board. Spray paint is a new idea, if I can manage to find a
| paint that is thin enough that will vaporize with the diode I am
| using. And also thought about using printer toner (just the black
| powder) - to somehow coat the entire board, the IR diode could also
| melt and fuse the toner right to the copper, but that stuff is very
| messy!
|
|
|
|
|
|
| Be sure to visit the group home and check for new Links, Files, and Photos:
| http://groups.yahoo.com/group/Homebrew_PCBs
|
| If Files or Photos are running short of space, post them here:
| http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
| Yahoo! Groups Links
|
|
|

> Can you provide a price info for the ir laser diode?
> I'm thinking of converting my Epson printer to just a plotter.
>

I bought this one from ebay (auction # 290087913046):

http://cgi.ebay.com/HIGH-POWER-BURNING-LASER-DIODE-IR-OPTICS-MODULE-
UNIT_W0QQitemZ290087913046QQihZ019QQcategoryZ4661QQssPageNameZWDVWQQrdZ1
QQcmdZViewItem

But paid alot less for it, actually. You will need a lens for it too
pulled from a cd rom player or a laser pointer, and a small 300 ma
power circuit.

-----
Convert epson printer to a plotter??? Sounds like lots of work.

Another problem is that when the copper melts it becomes highly reflective making it harder for
the laser. Plus it reflects all over the place potentially causing other problems. Cutting metal
is not as easy as it would seem because of the reflectivity.

On Friday 02 March 2007 15:10, William Nelson wrote:

> Another problem is that when the copper melts it becomes highly reflective
> making it harder for the laser. Plus it reflects all over the place
> potentially causing other problems. Cutting metal is not as easy as it
> would seem because of the reflectivity.

Also, copper in particular is a very good reflector of the infrared light CO2
lasers use. CO2 laser cutting/engraving is easier with other metals.

This is a good web resource on lasers:
http://www.repairfaq.org/sam/lasersam.htm

-Sebastien

I have had similar thoughts after seeing this website for hacking dvd
laser diodes.

http://www.felesmagus.com/pages/lasers-howto.html
<http://www.felesmagus.com/pages/lasers-howto.html>

The thing that is holding me back from experimenting is I do not know
enough about laser safety. It is hard enough to place components
without having my retinas burned out.

>
> I have used a cheap infra-red, I can use to melt most any thin black
> material, lines so thin you need a 10x lens to see them. With a cnc,

I

> can rasotize an image with it. A co-2 laser is LOTS more powerful and

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

> The thing that is holding me back from experimenting is I do not know
> enough about laser safety. It is hard enough to place components
> without having my retinas burned out.

I had to use a video camera to check to see if the diode was on or
off. Otherwise there is no way to tell whats going on because its
invisible. And when it turns a black piece of sponge into a pile of
smoldering rubble is another way to tell if its on.

--- In Homebrew_PCBs@yahoogroups.com, "docstein99" <docstein99@...> wrote:

>
> Ok, well I can buy a UV laser diode too just as easily as I bought a IR
> diode.
>
> Can I handle the emulsion or film in regular room light with the high-
> intensity stuff?
>

As far as I know the UV lasers are extremly expansive. Do you have a
cheap source for UV laser diodes ?

Daniel

On Saturday 03 March 2007 01:07, javaguy11111 wrote:

> I have had similar thoughts after seeing this website for hacking dvd
> laser diodes.
>
> http://www.felesmagus.com/pages/lasers-howto.html
> <http://www.felesmagus.com/pages/lasers-howto.html>
>
> The thing that is holding me back from experimenting is I do not know
> enough about laser safety. It is hard enough to place components
> without having my retinas burned out.
>

This might be a good starting point. I would suggest reading the entire
thing, rather than skimming, but they're your eyeballs. X)
http://www.repairfaq.org/sam/lasersaf.htm

“The goggles: they do nothing!"
http://www.visionarysupplies.com/includes/Laser.htm
http://www.safetyviz.com/laser-eyewear-polymer-eyewear/c_204_210.html
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1293&search=1

You'd want to get the right wavelength protective eyeware. I was going to
suggest a plexiglass enclosure, but I'm too tired / not sufficiently
interested to find information formally stating that plexiglass absorbs light
at the wavelength you'd be working at. Caveat Tinker, and all that.

If you do have a protective enclosure, than you can let other people in the
room without having to buy multiple sets of $125+ safety goggles.

Also, you may want to look here for general laser tips and such.
http://www.cnczone.com/forums/forumdisplay.php?f=79

I don't know what machine controller to suggest. emc2 (linuxcnc.org) can
probably do it?

I was going to say "Good Luck!" but I think we make our own luck in this
world, especially vis-a-vis safety. Luckily, it sounds like you're going
around this the right way.

Regards,
-Sebastien

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards


I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.





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

Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards


I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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





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

--- In Homebrew_PCBs@yahoogroups.com, "docstein99" <docstein99@...> wrote:

>
> Ok, well I can buy a UV laser diode too just as easily as I bought a IR
> diode.
>
> Can I handle the emulsion or film in regular room light with the high-
> intensity stuff?
>

As far as I know the UV lasers are extremly expansive. Did you found a
cheap source for such thing ?

250 watt 120 volt GE Infared Heat Lamp.
Spaced 11" from the pc board with an exposure time of 75 to 90 seconds. I generally do the 90 seconds.
I bought it at Walmart about 10 years ago and it's still going strong.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:11 AM
Subject: Re: [Homebrew_PCBs] sensitized boards


Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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

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





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

Thanks for the information, Richard.

That is interesting. In graduate school, we used "sun lamps" for near UV. The reactions we were studying were similar to what I understand is the basis for most positive-resist boards. I am surprised there is enough absorption of "infrared" to make the photochemical reaction go, or alternatively, enough near UV from an infrared lamp. Does the lamp have a reddish glow, or is it a brighter white? If you have the actual lamp number (which should be printed on the face of the lamp), I will check it out.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 5:52 PM
Subject: Re: [Homebrew_PCBs] sensitized boards


250 watt 120 volt GE Infared Heat Lamp.
Spaced 11" from the pc board with an exposure time of 75 to 90 seconds. I generally do the 90 seconds.
I bought it at Walmart about 10 years ago and it's still going strong.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:11 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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

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

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





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

John P. Anhalt:

Your point is well-taken.
Infrared (IR) is on one side of the visible spectrum, and
Ultraviolet (UV) is on the other side. Big differences in wavelength
between the two.

I think that most, if not all photoresist materials
polymerize when exposed to UV.

The mixup might come from the commercial names given to
various light sources (especially consumer reflector-type lamps)
commonly available.

Most "heat lamps" are Infrared (IR).
Most "sun lamps" are UV.
Physically, the reflector type lamps look alike.

High intensity reflector-type sun lamps (UV) are getting
more difficult to find, what with all the hoopla about
skin cancer, etc.

Sun lamps generally carry caveats regarding overexposure,
eye protection and the like.

The old Kepro system I used many years ago with Kodak KPR
photoresist material used an IR oven (heat) for drying the resist, and
UV for
photographic exposure.

The IR had no effect on the resist insofar as polymerization was
concerned.

Roland F. Harriston

John P. Anhalt wrote:

>
> Thanks for the information, Richard.
>
> That is interesting. In graduate school, we used "sun lamps" for near
> UV. The reactions we were studying were similar to what I understand
> is the basis for most positive-resist boards. I am surprised there is
> enough absorption of "infrared" to make the photochemical reaction go,
> or alternatively, enough near UV from an infrared lamp. Does the lamp
> have a reddish glow, or is it a brighter white? If you have the actual
> lamp number (which should be printed on the face of the lamp), I will
> check it out.
>
> John
>
> ----- Original Message -----
> From: Richard
> To: Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>
> Sent: Sunday, March 04, 2007 5:52 PM
> Subject: Re: [Homebrew_PCBs] sensitized boards
>
> 250 watt 120 volt GE Infared Heat Lamp.
> Spaced 11" from the pc board with an exposure time of 75 to 90
> seconds. I generally do the 90 seconds.
> I bought it at Walmart about 10 years ago and it's still going strong.
>
> Richard
>
> ----- Original Message -----
> From: John P. Anhalt
> To: Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>
> Sent: Sunday, March 04, 2007 9:11 AM
> Subject: Re: [Homebrew_PCBs] sensitized boards
>
> Richard,
>
> Can you give a little more detail about the heat lamp that you use,
> such as brand, wattage, and identifier number on it?
>
> Thanks.
>
> John
>
> ----- Original Message -----
> From: Richard
> To: Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>
> Sent: Sunday, March 04, 2007 9:40 AM
> Subject: Re: [Homebrew_PCBs] sensitized boards
>
> I use Infared Light to expose my positive sensitized boards because I
> can expose them in about 90 seconds using a IR heat lamp.
>
> Richard
>
> ----- Original Message -----
> From: docstein99
> To: Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>
> Sent: Thursday, March 01, 2007 11:28 AM
> Subject: [Homebrew_PCBs] sensitized boards
>
> I was wondering if anyone can give me some advice, looking at the
> threads recently it looks like lots of people here have tried
> sensitized boards.
>
> This material appears to be the same stuff as silkscreen printers use
> on silkscreens, where the exposed areas to intense light are hardened
> and the unexposed areas are washed away with water.
>
> Do any of the sensitized boards or materials react to INFRA-RED light?
> I have an infra-red laser diode on a cnc machine, its not powerful
> enough to cut stuff with but will smolder black foams. I was wondering
> if its possible to use that to rastorize the image, but I dont know
> about all the different types of sensitizer or what types of lights
> they react to. I know in screen printing, they make types which react
> to a 4k watt metal halide bulb, and newbie stuff that works with a 150
> watt lightbulb.
>
> [
>

There is no number on the lamp. It's bright white.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 6:02 PM
Subject: Re: [Homebrew_PCBs] sensitized boards


Thanks for the information, Richard.

That is interesting. In graduate school, we used "sun lamps" for near UV. The reactions we were studying were similar to what I understand is the basis for most positive-resist boards. I am surprised there is enough absorption of "infrared" to make the photochemical reaction go, or alternatively, enough near UV from an infrared lamp. Does the lamp have a reddish glow, or is it a brighter white? If you have the actual lamp number (which should be printed on the face of the lamp), I will check it out.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 5:52 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

250 watt 120 volt GE Infared Heat Lamp.
Spaced 11" from the pc board with an exposure time of 75 to 90 seconds. I generally do the 90 seconds.
I bought it at Walmart about 10 years ago and it's still going strong.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:11 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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

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

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

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





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

Oh, it is marked as "Reflective"

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 6:02 PM
Subject: Re: [Homebrew_PCBs] sensitized boards



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

Richard,

The bright white appearance of your lamp makes me think you actually have a "sun lamp" (that is, one that puts out a lot of near UV light) rather than an infrared lamp intended for surface heating of things. A sun lamp can cause sunburns to skin, if the exposure is long enough. As I recall, only a few minutes of exposure will cause redness (the change is not immediate) and 10 minutes exposure at a foot or two was certainly enough for a serious sunburn. The risk of sunburn for the same exposure time drops sharply as the distance to the lamp increases. The amount of skin heating was minimal compared to the amount of sunburn produced, so one would see bright-red students who had the excuse that they fell asleep under the sunlamp.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 11:07 PM
Subject: Re: [Homebrew_PCBs] sensitized boards


There is no number on the lamp. It's bright white.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 6:02 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

Thanks for the information, Richard.

That is interesting. In graduate school, we used "sun lamps" for near UV. The reactions we were studying were similar to what I understand is the basis for most positive-resist boards. I am surprised there is enough absorption of "infrared" to make the photochemical reaction go, or alternatively, enough near UV from an infrared lamp. Does the lamp have a reddish glow, or is it a brighter white? If you have the actual lamp number (which should be printed on the face of the lamp), I will check it out.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 5:52 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

250 watt 120 volt GE Infared Heat Lamp.
Spaced 11" from the pc board with an exposure time of 75 to 90 seconds. I generally do the 90 seconds.
I bought it at Walmart about 10 years ago and it's still going strong.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:11 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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It surely may be although it actually states Reflective Infared Heat Lamp on the lense. I know it will blind you and hurt your eyes if you do not wear eye protection.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Monday, March 05, 2007 5:56 AM
Subject: Re: [Homebrew_PCBs] sensitized boards


Richard,

The bright white appearance of your lamp makes me think you actually have a "sun lamp" (that is, one that puts out a lot of near UV light) rather than an infrared lamp intended for surface heating of things. A sun lamp can cause sunburns to skin, if the exposure is long enough. As I recall, only a few minutes of exposure will cause redness (the change is not immediate) and 10 minutes exposure at a foot or two was certainly enough for a serious sunburn. The risk of sunburn for the same exposure time drops sharply as the distance to the lamp increases. The amount of skin heating was minimal compared to the amount of sunburn produced, so one would see bright-red students who had the excuse that they fell asleep under the sunlamp.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 11:07 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

There is no number on the lamp. It's bright white.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 6:02 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

Thanks for the information, Richard.

That is interesting. In graduate school, we used "sun lamps" for near UV. The reactions we were studying were similar to what I understand is the basis for most positive-resist boards. I am surprised there is enough absorption of "infrared" to make the photochemical reaction go, or alternatively, enough near UV from an infrared lamp. Does the lamp have a reddish glow, or is it a brighter white? If you have the actual lamp number (which should be printed on the face of the lamp), I will check it out.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 5:52 PM
Subject: Re: [Homebrew_PCBs] sensitized boards

250 watt 120 volt GE Infared Heat Lamp.
Spaced 11" from the pc board with an exposure time of 75 to 90 seconds. I generally do the 90 seconds.
I bought it at Walmart about 10 years ago and it's still going strong.

Richard

----- Original Message -----
From: John P. Anhalt
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:11 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

Richard,

Can you give a little more detail about the heat lamp that you use, such as brand, wattage, and identifier number on it?

Thanks.

John

----- Original Message -----
From: Richard
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, March 04, 2007 9:40 AM
Subject: Re: [Homebrew_PCBs] sensitized boards

I use Infared Light to expose my positive sensitized boards because I can expose them in about 90 seconds using a IR heat lamp.

Richard

----- Original Message -----
From: docstein99
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, March 01, 2007 11:28 AM
Subject: [Homebrew_PCBs] sensitized boards

I was wondering if anyone can give me some advice, looking at the
threads recently it looks like lots of people here have tried
sensitized boards.

This material appears to be the same stuff as silkscreen printers use
on silkscreens, where the exposed areas to intense light are hardened
and the unexposed areas are washed away with water.

Do any of the sensitized boards or materials react to INFRA-RED light?
I have an infra-red laser diode on a cnc machine, its not powerful
enough to cut stuff with but will smolder black foams. I was wondering
if its possible to use that to rastorize the image, but I dont know
about all the different types of sensitizer or what types of lights
they react to. I know in screen printing, they make types which react
to a 4k watt metal halide bulb, and newbie stuff that works with a 150
watt lightbulb.

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

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