Homebrew PCBs

I'm thinking about making a photo-plotter attachment for my router / 
mill.
Do any of you know of a small UV light source that would be suitable?
I've found some violet LEDs, but I'm not sure they emit enough in the
UV range.

I'll probably include a small stepper and aperture wheel, which I'll set
up as the A axis in TurboCNC. I could set it up so that A1 would
turn the wheel to aperture 1, A2 would turn to aperture 2, etc.

I suppose if it's an incandescent / fluorescent source, I'll also need 
some sort of
shutter affair too. I could probably spin the aperture wheel around to 
a closed
position.

Any help greatly appreciated!

Regards,
   JJ

On Wed, 14 Apr 2004 13:57:08 -0400, John Johnson <johnatl@...> wrote:

> I'm thinking about making a photo-plotter attachment for my router /
> mill.
> Do any of you know of a small UV light source that would be suitable?
> I've found some violet LEDs, but I'm not sure they emit enough in the
> UV range.
>
> I'll probably include a small stepper and aperture wheel, which I'll set
> up as the A axis in TurboCNC. I could set it up so that A1 would
> turn the wheel to aperture 1, A2 would turn to aperture 2, etc.
>
> I suppose if it's an incandescent / fluorescent source, I'll also need
> some sort of
> shutter affair too. I could probably spin the aperture wheel around to
> a closed
> position.
>
> Any help greatly appreciated!
>
> Regards,
>    JJ


maybe a lcd could be used as a shutter?

maybe some sort of fiberoptic could be used to connect the (bigger) 
lightsource to a small head.
must look out for the damping of course...

maybe mirrors would be another option..

aern't there uv lasers? maybe ebay?

ST

--- In Homebrew_PCBs@yahoogroups.com, John Johnson <johnatl@m...> wrote:
> I'm thinking about making a photo-plotter attachment for my router / 
> mill.
> Do any of you know of a small UV light source that would be suitable?
> I've found some violet LEDs, but I'm not sure they emit enough in the
> UV range.
> 
> I'll probably include a small stepper and aperture wheel, which I'll set
> up as the A axis in TurboCNC. I could set it up so that A1 would
> turn the wheel to aperture 1, A2 would turn to aperture 2, etc.
> 
> I suppose if it's an incandescent / fluorescent source, I'll also need 
> some sort of
> shutter affair too. I could probably spin the aperture wheel around to 
> a closed
> position.

There are UV LEDs. The question will be how long an exposure.

You'll naturally need to focus it down to a point, which will also
increase the density of light tremendously. A longer focal length will
mean it is less sensitive to changes in distance. But perhaps there's
a way to autofocus? It could only be active while the UV LED is on,
but perhaps the LED could be on only 10% or so all the time for
constant focusing.

Steve

>
> > I'm thinking about making a photo-plotter attachment for my router /
> > mill.
> > Do any of you know of a small UV light source that would be suitable?


Owing a Bungard CNC, I'm also interested.
Visit Maplin UK at www.maplin.co.uk, looking for N76AJ, 'High Power UV LED 
Narrow Directivity' or N75AJ 'Wide.....
Cristian

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

This idea of CNC photoploting has got my wheels turning.

Does anyone know what wavelength the laser emitters in laser printers 
are?

I'm thinking that it might be passible to photoplot directly onto 
sensitised boards.

There's several rather large issues to address. (wavelength, exposure 
time, feeding the board- just to name a few)

-Denny

On Friday 16 April 2004 04:40 pm, dkesterline wrote:
> This idea of CNC photoploting has got my wheels turning.
>
> Does anyone know what wavelength the laser emitters in laser printers
> are?

I don't know offhand,  but you can find a *lot* of info on those (as well as 
the lasers in cdroms,  and other lasers) at repairfaq.org,  if I'm 
remembering right.

> I'm thinking that it might be passible to photoplot directly onto
> sensitised boards.

I thought those required UV?  The lasers AFAIK are all IR...

Hello,

Is this to be used for exposing the pcb directly? Or a photofilm?

Bacause there are photofilms which can work with a standard red hene 
wavelength diode. (600-675nm)

You'll need opticcs to focus the beam, and good parallelism between 
axes and table, to keep the spot size consistent.

Be aware that either way, using the cnc/plotter in this xy way is 
SLOOooowwww.... (And you've got to maintain "safe" lighting condition 
during this time.)

My cheap machines can easily accomodate this usage, but I'm looking 
into offering a cheap drum type photoplotter as well.

Along that thought, would an 8x10 or 12x12 film size be adequate? Or 
do you guys need 12x18?  Or?

Ballendo


--- In Homebrew_PCBs@yahoogroups.com, Cristian <bip@f...> wrote:
> 
> >
> > > I'm thinking about making a photo-plotter attachment for my 
router /
> > > mill.
> > > Do any of you know of a small UV light source that would be 
suitable?
> 
> 
> Owing a Bungard CNC, I'm also interested.
> Visit Maplin UK at www.maplin.co.uk, looking for N76AJ, 'High Power 
UV LED 

> Narrow Directivity' or N75AJ 'Wide.....
> Cristian
> 
> [Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "Roy J. Tellason" 
<rtellason@b...> wrote:
> On Friday 16 April 2004 04:40 pm, dkesterline wrote:
> > This idea of CNC photoploting has got my wheels turning.
> >
> > Does anyone know what wavelength the laser emitters in laser 
printers
> > are?
> 
> I don't know offhand,  but you can find a *lot* of info on those 
(as well as 
> the lasers in cdroms,  and other lasers) at repairfaq.org,  if I'm 
> remembering right.
> 
> > I'm thinking that it might be passible to photoplot directly onto
> > sensitised boards.
> 
> I thought those required UV?  The lasers AFAIK are all IR...

The concept of a multi facted mirror that reflected the laser in time 
with the angle of the mirror would be a simple enought undertaking.

Obtaining a laser with enough power and the correct wavelength is 
just time spent (and luck) on E-bay.

My concerns would be the optics for laser focus on a board and the 
time to do the photo plot.

Since a board could potentailly be aligned on a fixture so you can 
rotate the board and get perfect second side alignment the idea is 
pretty neat.

I think I would look at those new lasers that will cut the near 
copper side, then change power and cut the substrate, but NOT the 
second copper.  

Laser cutting the copper side is cool enough, but imagine plated vias 
with a hole on only one side of the board....  cool !

Dave

>
>Along that thought, would an 8x10 or 12x12 film size be adequate? Or
>do you guys need 12x18?  Or?
>
>Ballendo

12x12 for me will suffice.
Cristian

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

>
>Is this to be used for exposing the pcb directly? Or a photofilm?
Sensitive pcb directly.


>My cheap machines can easily accomodate this usage,
>
>
>Ballendo


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

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

From: "dkesterline" <desterline@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, April 16, 2004 9:40 PM
Subject: [Homebrew_PCBs] Re: CNC photoplotting (was Small UV source)


> This idea of CNC photoploting has got my wheels turning.
>
> Does anyone know what wavelength the laser emitters in laser printers
> are?
>
> I'm thinking that it might be passible to photoplot directly onto
> sensitised boards.
>
> There's several rather large issues to address. (wavelength, exposure
> time, feeding the board- just to name a few)

It won't work - you need UV, not IR. You also need a *lot* of UV power at
the correct wavelength to do it 'on the fly'. It isn't really feasible with
the available technology, AFAIK. Think of how much power you need for, say,
a 5 minute exposure using ordinary UV exposure techniques.

Leon

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon_heller@h...>
wrote:
> 
> ----- Original Message ----- 
> From: "dkesterline" <desterline@t...>

> > This idea of CNC photoploting has got my wheels turning.
> >
> > Does anyone know what wavelength the laser emitters in laser printers
> > are?

Red or IR.

> > I'm thinking that it might be passible to photoplot directly onto
> > sensitised boards.
> >
> > There's several rather large issues to address. (wavelength, exposure
> > time, feeding the board- just to name a few)
> 
> It won't work - you need UV, not IR. You also need a *lot* of UV
power at
> the correct wavelength to do it 'on the fly'. It isn't really
feasible with
> the available technology, AFAIK. Think of how much power you need
for, say,
> a 5 minute exposure using ordinary UV exposure techniques.

That power is going all over the place, though. Think of this: you can
look directly at a 100W bulb (ie, about a 20W fluorescent) and at
worst have spots in your vision. But a 2mW laser diode is not eye safe.

The question then becomes how tightly can you focus an IR LED, and how
much power output is available at the focus point?

Steve

Thanks to everyone who replied and discussed this. I went to an  
electronics supply house yesterday, but all they had was positive  
boards and developer.

Lasers in CDs, DVDs, etc. are toward the red end of the spectrum. They  
are currently developing CDs and DVDs that use blue lasers, and will  
have much higher density than is available now.

Regards,
   JJ

On Friday, Apr 16, 2004, at 16:53 US/Eastern, Roy J. Tellason wrote:

> On Friday 16 April 2004 04:40 pm, dkesterline wrote:
>> This idea of CNC photoploting has got my wheels turning.
>>
>> Does anyone know what wavelength the laser emitters in laser printers
>> are?
>
> I don't know offhand,  but you can find a *lot* of info on those (as  
> well as
> the lasers in cdroms,  and other lasers) at repairfaq.org,  if I'm
> remembering right.
>
>> I'm thinking that it might be passible to photoplot directly onto
>> sensitised boards.
>
> I thought those required UV?  The lasers AFAIK are all IR...
>
>
>
>
>
>
>
>
>
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>

I was thinking of plotting right on the PCB. I found the violet LEDs  
again (Mouser), and in reading the data sheet, it caution of UV  
exposure. The wave length is fairly short ranging from 383nm to 410nm.  
I believe one of the PCB sites said there UV tubes were 410nm, so I  
think this would work. The LEDS emit a minimum of 2.6mw, typically 6mw  
for an SMD up to 18mw min, 100mw typical for a T13/4.

So all I have to figure out now is how many milli-watt seconds  
(milli-Joules?)  it takes to harden the resist layer. Aperture size  
will affect exposure times too. It's possible I'll have to move lenses  
around when changing aperture size too (i.e. autofocus). It Might be  
easier to locate some negative board and do trial runs at different  
feed rates and aperture sizes.

Come to think of it, I have some positive board I could experiment  
with. Just need to order some of the LEDs.

BTW, currently I use 4x6 boards. This is closely related to my using  
the free version of Eagle. Keeps me thinking, and humble :-)

Thanks!

Regards,
   JJ

On Friday, Apr 16, 2004, at 18:32 US/Eastern, ballendo wrote:

> Hello,
>
> Is this to be used for exposing the pcb directly? Or a photofilm?
>
> Bacause there are photofilms which can work with a standard red hene
> wavelength diode. (600-675nm)
>
> You'll need opticcs to focus the beam, and good parallelism between
> axes and table, to keep the spot size consistent.
>
> Be aware that either way, using the cnc/plotter in this xy way is
> SLOOooowwww.... (And you've got to maintain "safe" lighting condition
> during this time.)
>
> My cheap machines can easily accomodate this usage, but I'm looking
> into offering a cheap drum type photoplotter as well.
>
> Along that thought, would an 8x10 or 12x12 film size be adequate? Or
> do you guys need 12x18?  Or?
>
> Ballendo
>
>
> --- In Homebrew_PCBs@yahoogroups.com, Cristian <bip@f...> wrote:
>>
>>>
>>>> I'm thinking about making a photo-plotter attachment for my
> router /
>>>> mill.
>>>> Do any of you know of a small UV light source that would be
> suitable?
>>
>>
>> Owing a Bungard CNC, I'm also interested.
>> Visit Maplin UK at www.maplin.co.uk, looking for N76AJ, 'High Power
> UV LED
>> Narrow Directivity' or N75AJ 'Wide.....
>> Cristian
>>
>> [Non-text portions of this message have been removed]
>
>
>
> ------------------------ Yahoo! Groups Sponsor  
> ---------------------~-->
> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark
> Printer at MyInks.com.  Free s/h on orders $50 or more to the US &  
> Canada.
> http://www.c1tracking.com/l.asp?cid=5511
> http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/bGYolB/TM
> --------------------------------------------------------------------- 
> ~->
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>