Just as a note, you don't need a UV-LED based box for the resist. I used
it for years with an exposure box using UV tubes. The advantage of UV
LEDs over tubes IMHO are:
- LEDs have a 20 degree (or less, see below) viewing angle whereas tubes
radiate all around them. Alas you get more paralellized light
- UV tubes are MUCH stronger. Exposure time was here < 10 seconds. Thats
a problem if the tubes do not start all at the same time cause then not
all areas are evenly exposed.
I can say that since I'm using the LED box, I can do finer artwork. I
already did sucessfully a board with 5mil traces (GigE switch, the
signal pairs from the PHYs to the RJ45 transformers) Whereas I've not
been able to go that fine with the previous setup. Exposure time with
the LEDs is pretty much exactly one minute and obviousely the LEDs go on
and off all simultanousely. Exposure time of course varries a great deal
depending on the distance and quantity of LEDs used.
The disadvanteage of the UV-LED based aproach is that they are
relatively costly. I used 80pcs (20x20cm squares, Kingbright L-7113UVC
in my case). Make sure to get a datasheet and check that the peek
radiation is around 400nm. Also look at the viewing angle and use some
trigonometric calculations to find out how many LEDs you need at what
distance to cover the area your unit is suposed to work with.
It apears like the general distributors (Mouser, Digikey etc.) in the
meantime no longer carry UV LEDs due to the dangers involved with using
them. Ledtronics does. However they want you to sign a form where you
state to have read and understood the dangers involved and that you do
not hold them responsible. They have a fairly interesting LED (
http://www.ledtronics.com/ds/L200CUV395/ article L200CUV405-8D
<dsdc0304.pdf>) whoes viewing angle is only 8!! degrees. However, such a
narrow beam means even more LEDs. This one is $1.15/pp, minium oder
quantity 100. I'm tempted to try them :-)
HTH
Markus
javaguy11111 schrieb:
>
> Sorry, I forgot to mention that. It is 12 inches wide. I bought it
> from think tink, so you can go to their site for information on how to
> apply it. There are plenty of other sites as well. I am just getting
> started with this as well.
>
> For initial tests I will just use a flourescent light as my UV source.
> I will also need to get some washing soda(sodium carbonate) to develop
> the resist and sodium hydroxide to strip off the exposed resist.
>
> If you go to a pool supply, do not get sodium hydrogen carbonate,
> which is sodium bicarbonate. I did that on Friday, only to discover it
> is not what I want. I will still keep it because it is good to have to
> clean up acid spills or if I want to bake a cake. :)
>
> After the initial tests I will probably build a UV LED exposure box
> like Markus Zingg for my real board work. You can read his posts for
> more information.
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Bill Maxwell <wrmaxwell@...>
> wrote:
> >
> > Hi Damon
> >
> > 5feet long but how wide is it and , briefly, how is it applied please.
> >
> > Bill
> >
> >
> > javaguy11111 wrote:
> > > The photoresist is ready for shipping. It is 5 feet long and was cut
> > > off from a 100ft roll that I purchased from ThinkTink. I have 18 rolls
> > > available and 4 people have contacted me. So there is plenty left, if
> > > anyone wants to give it a try.
> > >
> > > If ordering inside the US, the cost is $20 and shipping is by USPS.
> > >
> > > If ordering outside the US, the cost is $25 and shipping is by USPS.
> > > You are responsible for any customs charges
> > >
> > > I am using PayPal.
> > >
> > > Everyone who has emailed already, I have sent a reply with payment
> > > information. If you did send me an email, but have not heard from me
> > > then send me another email.
> > >
> > > Damon
> > > --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "javaguy11111"
> > > <javaguy11111@> wrote:
> > >
> > >> Just an update. I have received the resist and shipping materials.
> > >>
> > >> I decided to use USPS instead of UPS because I have had more requests
> > >> for it. I will also be using paypal instead of google checkout. Again
> > >> more people were requesting that. I am trying to keep things simple.
> > >>
> > >> I should be ready to start shipping by Monday and should have payment
> > >> information posted before the weekend is up.
> > >>
> > >> Damon
> > >>
> > >> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "javaguy11111"
> > >> <javaguy11111@> wrote:
> > >>
> > >>> I am going to start doing some experimenting with dry film resist. I
> > >>> have just placed an order for a roll from Think Tink.
> > >>>
> > >>> Since it is way more than what I need, I am planning to sell the
> > >>> excess. I plan on selling in 5 foot lengths, which should be enough
> > >>> for people to experiment around with.
> > >>>
> > >>> Figuring out time, costs, shipping materials and shipping charges I
> > >>> expect to charge $20.
> > >>>
> > >>> The price includes UPS ground shipping within the continental US. If
> > >>> you want it sooner or live outside the continental US, contact me
> > >>> directly by email and we can try to make other arrangements.
> > >>>
> > >>> If you are interested, send me a private email and I will let
> you know
> > >>> when it is available. I plan on setting up payment through Google
> > >>> Checkout or personal check. If other payment methods are
> desired, let
> > >>> me know and I will try to accommodate you.
> > >>>
> > >>> Taking into account shipping time, I should be able to take
> orders in
> > >>> one to two weeks.
> > >>>
> > >>> BTW, I ran this by Steve ahead of time so I would not run afoul
> of any
> > >>> spamming rules.
> > >>>
> > >>> Damon
> > >>>
> > >>>
> > >
> > >
> > >
> > >
> > > Be sure to visit the group home and check for new Links, Files,
> and Photos:
> > > http://groups.yahoo.com/group/Homebrew_PCBs
> <http://groups.yahoo.com/group/Homebrew_PCBs>
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
>
>