Synth-DIY Yahoo! Groups Archives

Thread

Novel way to expose photo resist??

2012-02-23 by drsage2007

Perhaps you all can comment on whether you think this flash from the past will work.

Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.

All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.

It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.

I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.

Any comments on if this would work?

Sage

Re: [Homebrew_PCBs] Novel way to expose photo resist??

2012-02-23 by Harvey White

On Thu, 23 Feb 2012 18:12:03 -0000, you wrote:

>Perhaps you all can comment on whether you think this flash from the past will work.
>
>Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
>
>All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.

Possible, but....
>
>It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
>The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
>

CD burners have IR leds, not UV.  You'd need a UV diode/laser diode.
Even then, The exposure is likely too small to affect the board when
run at any reasonable pen speed.

Harvey

Show quoted textHide quoted text

>I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
>
>Any comments on if this would work?
>
>Sage
>
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

Re: Novel way to expose photo resist??

2012-02-23 by drsage2007

Hmm. I guess the IR vs UV would be a problem. I've seen some pretty hot blue LEDS demonstrated. I don't suppose they'd hsve any UV component to the light. Then there's the speed issue. The plotter cannot be slowed down (easily). I could use my CNC mill to hold the light source. The Roland plot commands are easily converted to Gcode. Then I could slow the speed down as much as required
So; where do I get a UV point source?

Sage


--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:

Show quoted textHide quoted text

>
> On Thu, 23 Feb 2012 18:12:03 -0000, you wrote:
> 
> >Perhaps you all can comment on whether you think this flash from the past will work.
> >
> >Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> >
> >All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> 
> Possible, but....
> >
> >It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> >The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> >
> 
> CD burners have IR leds, not UV.  You'd need a UV diode/laser diode.
> Even then, The exposure is likely too small to affect the board when
> run at any reasonable pen speed.
> 
> Harvey
> 
> >I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> >
> >Any comments on if this would work?
> >
> >Sage
> >
> >
> >
> >------------------------------------
> >
> >Be sure to visit the group home and check for new Links, Files, and Photos:
> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>

Re: Novel way to expose photo resist??

2012-02-23 by Leslie Schwartz

I am sure many other people have had this idea before since I have as of
years ago and one of my reasons for joining this group, but I have not been
able to act on it. Given that you have the Roland Plotter you might be able
to conduct some trials. In any case I believe we really need more practical
ways to do homebrew pcb production, (just my opinion) so this potentially
might be one of them.

Show quoted textHide quoted text

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of drsage2007
Sent: Thursday, February 23, 2012 4:44 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??

Hmm. I guess the IR vs UV would be a problem. I've seen some pretty hot blue
LEDS demonstrated. I don't suppose they'd hsve any UV component to the
light. Then there's the speed issue. The plotter cannot be slowed down
(easily). I could use my CNC mill to hold the light source. The Roland plot
commands are easily converted to Gcode. Then I could slow the speed down as
much as required
So; where do I get a UV point source?

Sage


--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>
> On Thu, 23 Feb 2012 18:12:03 -0000, you wrote:
> 
> >Perhaps you all can comment on whether you think this flash from the past
will work.
> >
> >Back in the day I used to plot PCB's using an old flat bed plotter with
water proof ink in the pen. Getting the pens to work reliably and cleaning
them was always a headache.
> >
> >All this talk about UV resist got me thinking - what if I were to mount a
UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on
a board on the table and put it in the plotters pen hoder. I then coat the
board with UV resist and let the plotter expose it. I might even be able to
use the pre-sensitized boards.
> 
> Possible, but....
> >
> >It plots really fast so I'm not sure how much time is required to expose
the resist. But some of the LEDS from CD burners can apparently burn paper
so given that the exposure is an intensity vs. time sort of thing it might
work.
> >The pen-down signal could easily be used to activate the LED and not much
modification would be necessary to the plotter.
> >
> 
> CD burners have IR leds, not UV.  You'd need a UV diode/laser diode.
> Even then, The exposure is likely too small to affect the board when
> run at any reasonable pen speed.
> 
> Harvey
> 
> >I have an old Roland DXY800 plotter which for some strange reason is
still supported by Eagle 5.xx so it creates files ready to go to the
plotter.
> >
> >Any comments on if this would work?
> >
> >Sage
> >
> >
> >
> >------------------------------------
> >
> >Be sure to visit the group home and check for new Links, Files, and
Photos:
> >http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
>




------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links

Re: [Homebrew_PCBs] Novel way to expose photo resist??

2012-02-24 by Kevin Impson

Hi Guys,

Just started to seriously look at the inkjet pcb idea, actually looking at a Artisan 50 and another on Ebay.

The plotter and UV laser can work. But, the downside is the cost of a UV 405nm laser head and controller.

Now the other option would be a 10mm diameter, 9,000 - 13,000mcd UV diode with a pin hole optical slit in front of it and some focusing optics behind the slit.

You can get UV laser diodes from Ebay.

http://www.ebay.com/itm/100-UV-10mm-LED-Ultra-Violet-15-Degree-Sharp-Angle-From-USA-/140678830209?pt=LH_DefaultDomain_0&hash=item20c11c9881

This guy sells them in 100 piece bags, but you get the idea.

Best Regards,

Kevin I.



________________________________

Show quoted textHide quoted text

 From: drsage2007 <davesage12@...>
To: Homebrew_PCBs@yahoogroups.com 
Sent: Thursday, February 23, 2012 10:12 AM
Subject: [Homebrew_PCBs] Novel way to expose photo resist??

Perhaps you all can comment on whether you think this flash from the past will work.

Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.

All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.

It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.

I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.

Any comments on if this would work?

Sage

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

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-24 by Slavko Kocjancic

I'm interested in that approach too.
But little extended. The old fashion PCB process have aperture wheel. 
and there was different shapes on it. So instead just thiny dot there 
can be bigger dot's too. And this can speed up process a lot. Now the 
light source. It's need to be UV period. And some laser's can do that 
but there is problem as we can't(easy) build that as is invisible and 
commercial UV laser (0.5 to 1W) isn't cheap. The scrap source is blueRAY 
disc. But managing the optic is near inposible. The other source is UV 
LED. But led light should be collimated too. But least the UV led has 
little visible light so we can manage to focus them. Another UV source 
is mercury light. It's just BIG but can be used.

We just need to know how long the dot must be developed and then we know 
if process is ussable or it's to slow.

Re: [Homebrew_PCBs] Novel way to expose photo resist??

2012-02-24 by Leon Heller

On 24/02/2012 07:01, Kevin Impson wrote:

>
> You can get UV laser diodes from Ebay.
>
> http://www.ebay.com/itm/100-UV-10mm-LED-Ultra-Violet-15-Degree-Sharp-Angle-From-USA-/140678830209?pt=LH_DefaultDomain_0&hash=item20c11c9881
> <http://www.ebay.com/itm/100-UV-10mm-LED-Ultra-Violet-15-Degree-Sharp-Angle-From-USA-/140678830209?pt=LH_DefaultDomain_0&hash=item20c11c9881>

Those are LEDs, not laser diodes!

Leon
-- 
Leon Heller
G1HSM

Re: Novel way to expose photo resist??

2012-02-24 by AlienRelics

Those are LEDs. I suspect you'd have to block a lot of the light to get it down to a spot. It is a limitation of the physical size of the LED die and the lens on the LED case. I've done a bit of fiddling with LEDs and lensing, and at best focus you can clearly see an image of the LED die including the bonding wire shadow.

You might think twice about the Artisan 50, I understand it has problems printing over the CD hole. Extreme Engineering has some info indicating you can install the R280 driver and ignore the error messages to print over the hole.

Or get a different printer. The R200-series seem to work.

Go to Inkjet_PCB_Construction, I just posted a message with a bunch of links addressing the problem of the CD hole.
http://tech.groups.yahoo.com/group/Inkjet_PCB_Construction/

Steve Greenfield AE7HD


--- In Homebrew_PCBs@yahoogroups.com, Kevin Impson <internetgiest@...> wrote:

Show quoted textHide quoted text

>
> Hi Guys,
> 
> Just started to seriously look at the inkjet pcb idea, actually looking at a Artisan 50 and another on Ebay.
> 
> The plotter and UV laser can work. But, the downside is the cost of a UV 405nm laser head and controller.
> 
> Now the other option would be a 10mm diameter, 9,000 - 13,000mcd UV diode with a pin hole optical slit in front of it and some focusing optics behind the slit.
> 
> You can get UV laser diodes from Ebay.
> 
> http://www.ebay.com/itm/100-UV-10mm-LED-Ultra-Violet-15-Degree-Sharp-Angle-From-USA-/140678830209?pt=LH_DefaultDomain_0&hash=item20c11c9881
> 
> This guy sells them in 100 piece bags, but you get the idea.
> 
> Best Regards,
> 
> Kevin I.
> 
> 
> 
> ________________________________
>  From: drsage2007 <davesage12@...>
> To: Homebrew_PCBs@yahoogroups.com 
> Sent: Thursday, February 23, 2012 10:12 AM
> Subject: [Homebrew_PCBs] Novel way to expose photo resist??
>  
> 
> Â  
> Perhaps you all can comment on whether you think this flash from the past will work.
> 
> Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> 
> All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> 
> It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> 
> I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> 
> Any comments on if this would work?
> 
> Sage
> 
> 
>  
> 
> [Non-text portions of this message have been removed]
>

Re: Novel way to expose photo resist??

2012-02-24 by Dave Sage

I presume a CD or DVD burner has all the optics required to focus the laser
diode to a very tiny spot. Maybe it's just a matter of swapping out the
diode for an ultra-violet version. Also concerning not being able to see it;
I know the coating inside fluorescent tubes converts a lot of ultra-violet
to visible light. Maybe a target made form a piece of coated glass could be
made to "see" the dot at least long enough to focus it if required.

 

Sage

 



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

RE: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-24 by Jeff Heiss

A DVD laser is IR and a CD laser is red.  Would the optics from the lasers
work for UV?

 

Jeff

 

  _____

Show quoted textHide quoted text

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Dave Sage
Sent: Friday, February 24, 2012 1:16 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??

I presume a CD or DVD burner has all the optics required to focus the laser
diode to a very tiny spot. Maybe it's just a matter of swapping out the
diode for an ultra-violet version. Also concerning not being able to see it;
I know the coating inside fluorescent tubes converts a lot of ultra-violet
to visible light. Maybe a target made form a piece of coated glass could be
made to "see" the dot at least long enough to focus it if required.

Sage

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

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

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-24 by John Anhalt

Depends on what wavelength of UV you are using.  If near UV (e.g., 405 nm), they will work fine. 

John

Show quoted textHide quoted text

  ----- Original Message ----- 
  From: Jeff Heiss 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Friday, February 24, 2012 1:21 PM
  Subject: RE: [Homebrew_PCBs] Re: Novel way to expose photo resist??

  A DVD laser is IR and a CD laser is red. Would the optics from the lasers
  work for UV?

  Jeff

  _____ 

  From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
  On Behalf Of Dave Sage
  Sent: Friday, February 24, 2012 1:16 PM
  To: Homebrew_PCBs@yahoogroups.com
  Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??

  I presume a CD or DVD burner has all the optics required to focus the laser
  diode to a very tiny spot. Maybe it's just a matter of swapping out the
  diode for an ultra-violet version. Also concerning not being able to see it;
  I know the coating inside fluorescent tubes converts a lot of ultra-violet
  to visible light. Maybe a target made form a piece of coated glass could be
  made to "see" the dot at least long enough to focus it if required.

  Sage

  [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]

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-24 by Leon Heller

On 24/02/2012 18:21, Jeff Heiss wrote:
> A DVD laser is IR and a CD laser is red. Would the optics from the lasers
> work for UV?

I don't think that UV lasers have the correct wavelength for most of the 
photo-resist available.

Leon
-- 
Leon Heller
G1HSM

Re: Novel way to expose photo resist??

2012-02-24 by designer_craig

Sage,
Go search the archives for Volkan, he did some great work on DLI using a blue ray laser diode mounted on a printer head shuttle.  The immages resolution was stunning.  The process was fairly slow because scanning was unidirectional.  I think the pixel resolution was aobut .002" I would guess a 3x5 card would take 15 to 20 minutes to scan.  He has also done a drum photo plotter in a similar manner.

Craig


--- In Homebrew_PCBs@yahoogroups.com, "drsage2007" <davesage12@...> wrote:

Show quoted textHide quoted text

>
> Perhaps you all can comment on whether you think this flash from the past will work.
> 
> Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> 
> All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> 
> It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> 
> I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> 
> Any comments on if this would work?
> 
> Sage
>

RE: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-25 by Tony Smith

>Perhaps you all can comment on whether you think this flash from the past
> will work.
>
>Back in the day I used to plot PCB's using an old flat bed plotter with
water
> proof ink in the pen. Getting the pens to work reliably and cleaning them
was
> always a headache.
>
>All this talk about UV resist got me thinking - what if I were to mount a
UV
> LED (laser diode?)with a lens or whatver it takes to focus a small dot on
a board
> on the table and put it in the plotters pen hoder. I then coat the board
with UV
> resist and let the plotter expose it. I might even be able to use the pre-
> sensitized boards.


Provided you can get the right laser & the right resist, it'll work fine.
I've seen UV lasers around 400nm, some resists would work with that.

Similar has been done before, the last one I remember was someone wrapping
film around a drum and exposing that with a laser.  I think he used the guts
of a laser printer, hence the drum.

Even that isn't new, many many years ago I work for a company making film
masters for bar codes, you'd put the film on a XY table, the computer (a BBC
micro of all things) would move the laser around plotter-style.  Develop the
film and off you went.

Of course you're trying to skip that step, but there's plenty of prior work.

You might be able to take a UV tube and use something like a magnifying
glass lens to focus it, exiting though a small hole to cut down on scattered
light ruining things.  A bit like a pinhole camera in reverse.  Might be
worthwhile looking at plano-convex lens (used in lasers, flat one side,
curved on the other), they're rather good at focussing to a small dot.  Use
both.

Tony

Re: Novel way to expose photo resist??

2012-02-25 by Dave Sage

SO, can anyone quote the required wavelength of light required for some UV
photo resists? The MG Chemicals exposure light is 375nm. I think it will do
both their pre-coated positive resist boards and their negative dry film
resist. Of course positive pre-sensitized boards are of no use to the laser
plotting technique proposed.

 

Sage



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

Re: Novel way to expose photo resist??

2012-02-25 by Dave Sage

Just looked at the MG chemicals site and it appears they no longer offer the
dry negative photo resist film. So where does one purchase small quantities
of NEGATIVE resist.

 

Sage



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

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-25 by John Anhalt

The positive resists I am aware of are all 375 nm or greater.  NB: incandescent lamps may put out to 350 nm.  I use Injectorall, and it recommends something around 390'ish nm. ±20nm is not going to make much difference.  Injectorall also allows exposure with ordinary incandescent lamps.

John

Show quoted textHide quoted text

  ----- Original Message ----- 
  From: Dave Sage 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Saturday, February 25, 2012 10:16 AM
  Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??

  SO, can anyone quote the required wavelength of light required for some UV
  photo resists? The MG Chemicals exposure light is 375nm. I think it will do
  both their pre-coated positive resist boards and their negative dry film
  resist. Of course positive pre-sensitized boards are of no use to the laser
  plotting technique proposed.

  Sage

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

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

Re: Novel way to expose photo resist??

2012-02-25 by boombox666

Hello Sage,

I have done some tryntific tests by exposing a photopositive PCB with the common 405nm laser diodes from HD-DVD and Blueray players.

Here are the results:
http://www.flickr.com/photos/98835706@N00/5234166236/in/set-72157625407033197

As you can see the results seem hopeful but still need to do some experiments, but I need a good test setup where you can vary laser scanning rate and power.

My first idea was to use a polygon mirror assembly from a laser printer or copier, change the laser to a 405nm one with collimating lens and scan the whole PCB via that method. The idea seems workable as seen on this youtube movie:

http://www.youtube.com/watch?v=G9h9tzfpaY8

I intend to do something similar later. My first plan is recycle a inkjet printer carriage and scan with a optical pickup unit from a blue-ray burner (much more powerful laser, around 80mw) instead of the ink cart. I have a set of those pickups ready for reuse.

At a later stage I am going to replace the carriage with the polygon assembly. This will require a lot more work but will increase the scanning speed.

Greetings,

Bart

--- In Homebrew_PCBs@yahoogroups.com, "drsage2007" <davesage12@...> wrote:

Show quoted textHide quoted text

>
> Perhaps you all can comment on whether you think this flash from the past will work.
> 
> Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> 
> All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> 
> It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> 
> I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> 
> Any comments on if this would work?
> 
> Sage
>

Re: Novel way to expose photo resist??

2012-02-25 by boombox666

A optical pickup unit from a blueray player or HD-DVD has a 405nm laser diode with the wavelength optimized optics inside like a collimator, focus actuator and a photodiode array for checking the focus.

One problem is a diffraction grating that is behind the lens that is there to create the tracking sidebeams. They might create optical leakage and inadvertently expose parts of the PCB.

Another problem is the spot focusing, the spot size for blueray is around 800nm, so you need a way to track while not completely in focus or just choose a fixed focus and hope for the best. 
The focusing actuator can be controlled by the actuator driver on the drive PCB, but you can use a high power opamp like the L2722. The datasheet contains some example schematics on bidirectional control of inductive loads. Best would be to use a TDA7073, unfortunatly that chip is obsolete but made for the task.

--- In Homebrew_PCBs@yahoogroups.com, "Jeff Heiss" <jeff.heiss@...> wrote:

Show quoted textHide quoted text

>
> A DVD laser is IR and a CD laser is red.  Would the optics from the lasers
> work for UV?
> 
>  
> 
> Jeff
> 
>  
> 
>   _____  
> 
> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Dave Sage
> Sent: Friday, February 24, 2012 1:16 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??
> 
>  
> 
>   
> 
> I presume a CD or DVD burner has all the optics required to focus the laser
> diode to a very tiny spot. Maybe it's just a matter of swapping out the
> diode for an ultra-violet version. Also concerning not being able to see it;
> I know the coating inside fluorescent tubes converts a lot of ultra-violet
> to visible light. Maybe a target made form a piece of coated glass could be
> made to "see" the dot at least long enough to focus it if required.
> 
> Sage
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-25 by Donald H Locker

<http://bucktownpolymers.com/ve200-uv.html> costs $60/quart, cures with 385nm UV. Could work.

Donald.
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----- Original Message -----

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> From: "Dave Sage" <davesage12@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Saturday, February 25, 2012 10:16:11 AM
> Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??
> SO, can anyone quote the required wavelength of light required for
> some UV
> photo resists? The MG Chemicals exposure light is 375nm. I think it
> will do
> both their pre-coated positive resist boards and their negative dry
> film
> resist. Of course positive pre-sensitized boards are of no use to the
> laser
> plotting technique proposed.
> 
> 
> 
> Sage
> 
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
> ------------------------------------
> 
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> 
> 
>

Re: [Homebrew_PCBs] Re: Novel way to expose photo resist??

2012-02-25 by Malcolm Parker-Lisberg

Make your own pulsed nitrogen UV laser with tow bits of bent aluminium and fresh air

For technical coverage of the UV Nitrogen laser, see:

<http://spt06.chez-alice.fr/00/air.htm>

Malcolm
 
I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.


________________________________

Show quoted textHide quoted text

 From: designer_craig <cs6061@...>
To: Homebrew_PCBs@yahoogroups.com 
Sent: Friday, February 24, 2012 7:10 PM
Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??

Sage,
Go search the archives for Volkan, he did some great work on DLI using a blue ray laser diode mounted on a printer head shuttle.  The immages resolution was stunning.  The process was fairly slow because scanning was unidirectional.  I think the pixel resolution was aobut .002" I would guess a 3x5 card would take 15 to 20 minutes to scan.  He has also done a drum photo plotter in a similar manner.

Craig

--- In Homebrew_PCBs@yahoogroups.com, "drsage2007" <davesage12@...> wrote:
>
> Perhaps you all can comment on whether you think this flash from the past will work.
> 
> Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> 
> All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> 
> It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> 
> I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> 
> Any comments on if this would work?
> 
> Sage
>

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

Re: Novel way to expose photo resist??

2012-02-26 by Robert

cool!

Robert

--- In Homebrew_PCBs@yahoogroups.com, Malcolm Parker-Lisberg <mparkerlisberg@...> wrote:

Show quoted textHide quoted text

>
> Make your own pulsed nitrogen UV laser with tow bits of bent aluminium and fresh air
> 
> For technical coverage of the UV Nitrogen laser, see:
> 
> <http://spt06.chez-alice.fr/00/air.htm>
> 
> Malcolm
> Â 
> I don't suffer from insanity I enjoy it!
> Mene, mene, tekel, upharsin
> The writing is on the wall.
> 
> 
> ________________________________
>  From: designer_craig <cs6061@...>
> To: Homebrew_PCBs@yahoogroups.com 
> Sent: Friday, February 24, 2012 7:10 PM
> Subject: [Homebrew_PCBs] Re: Novel way to expose photo resist??
>  
> 
> Â  
> Sage,
> Go search the archives for Volkan, he did some great work on DLI using a blue ray laser diode mounted on a printer head shuttle.  The immages resolution was stunning.  The process was fairly slow because scanning was unidirectional.  I think the pixel resolution was aobut .002" I would guess a 3x5 card would take 15 to 20 minutes to scan.  He has also done a drum photo plotter in a similar manner.
> 
> Craig
> 
> --- In Homebrew_PCBs@yahoogroups.com, "drsage2007" <davesage12@> wrote:
> >
> > Perhaps you all can comment on whether you think this flash from the past will work.
> > 
> > Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
> > 
> > All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
> > 
> > It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> > The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
> > 
> > I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
> > 
> > Any comments on if this would work?
> > 
> > Sage
> >
> 
> 
>  
> 
> [Non-text portions of this message have been removed]
>