1. Not sure what you mean. I use overhead foils that I print onto using
an Epson Stylus C62. The PCB's are laminated using dryfilm fotoresist
(in my case Ordyl Alpha 950)
2. The datasheet is now uploaded in the project directory (
Homemade_PCB_equipment -> UV LED exposure unig)
3. I could, but it's realy dead simple. Since I use 5 LEDs in series,
~20V are requiered. I used a transformer that I took out of an el cheapo
battery charger (a 4 amp part with a center tab actually rated for 12V
but by not using the center I can draw 24V @ 2amps). That goes through a
rectifier and then a traditional LM317T is used to regulate the voltage
to 20V. Just downlaod the datasheet from national and look at the
standard cirquitry. I think if you build such a unit you may want to
change things or use some parts you have laying around. Well, if you
really want I can upload the eagle schematics and board layout.
4. I so far only did boards with it for customers where I first would
have to ask for the Ok to publish their board here. My boards are
probably a bit special in that they are mostly 4 layers with solder stop
mask etc. pp. So they look pretty much like any other profesionally made
board you may have laying around anyways. However, what in particular do
you want to see/know? I may can upload a part of a board only?
Markus
javaguy11111 schrieb:
>
> Very nice. A few questions
> 1. What are you using for the mask
> 2. Can you upload the datasheet for the LED's you are using.
> 3. Can you post parts lists and schematics for the driver board.
> 4. Do you have any pictures of boards you have done with it.
>
> Again very nice. Congratulations.
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Markus Zingg <homebrew-pcb@...>
> wrote:
> >
> > Hi group
> >
> > Last summer I created a UV LED based exposure unit with which I had
> IMHO
> > very good results. I uploaded a description and pictures to the
> > following place in the files section:
> >
> > Files </group/Homebrew_PCBs/files/> > Homemade_PCB_equipment
> > </group/Homebrew_PCBs/files/Homemade_PCB_equipment/> > UV LED
> exposure unit
> >
> > Below you find the descriptive text for your quick reference - enjoy!
> >
> > Markus
> >
> > <------- cut here --------->
> >
> > UV LED exposer unit
> > -------------------
> >
> > In this folder you can see pics of my homebrew, UV LED based double
> side exposure unit. The folowing features are maybe "special" enough
> to be noted:
> >
> > - It generates very PARALELL light. This is important if you want to
> make small traces. Using this unit, I already sucessfully created
> boards with 5 mil traces using dry film fotoresist.
> >
> > - There are two holes in each glass allowing the positioning shafts
> I use to allign the films against the PCB to remain. This allows me to
> leave the protection foil on the dryfilm resist, resulting in almost
> no wear out on the films.
> >
> > - Obviousely this unit allows to expose both sides of a PCB at the
> same time. To do this, the upper box is simply placed on top of the
> lower. The glass is intentionally NOT mounted to the boxes. This
> allows me to fimrly press the two glasses together thereby makeing
> sure there are no air bubbles.
> >
> > - The LED distance is 20mm square, distance from the LEDs to the PCB
> is ~65mm
> >
> > The exposure time is longer than what's normal with tube oriented
> units. I'm almost exclusively working with dryfilm resist due to it's
> several advantages. There the time is exactly one minute.
> >
> > Feel free to ask questions, otherwiese enjoy :-)
> >
> > Markus
> >
>
>