Thank you for your information.
But I said several days before that is possible to apply the photoresist by using blank screen mesh and I though was better using the RC reference. Am I right ?.
By the way...
How do you do to match the trasnparencies for expossing a double sided PCB.. do you have any web site where It is explained using pictures or something ?
Thanks for your help
Sincerely
Ingeniero Andres F. Hernandez
Pontificia Universidad Javeriana
Celular (300)7825582
Casa (572) 5572655
________________________________
From: jcarlosmor <
jcarlosmor@...>
To:
Homebrew_PCBs@yahoogroups.comSent: Sat, October 24, 2009 6:22:13 PM
Subject: [Homebrew_PCBs] Re: pcb overlay ?
--- In Homebrew_PCBs@ yahoogroups. com, Andres Hernandez <afhernandez79@ ...> wrote:
>
> Hello
>
> Please can you tell me how many mj/cm2 does the Black Lights provide for exposure the PCB using the LPI inks as the AQ 3000 RC ?
>
> And What's the difference Between the AQ3000 RC (Roller coating) And AQ3000 DC (dip coating) for applications for double sided PCBs?
>
> Thanks for your Help.
>
> Ingeniero Andres F. Hernandez
> Pontificia Universidad Javeriana
The difference between RC and DC is the viscosity and the solids composition of the liquid. You just cannot use one for another. The most simple way is to use DC since you can build a dip coating machine with relative simplicity. However, you must control the release of the PCB out of the tank with a microcontroller to obtain the required thickness of the photoresist.
With respect to how to measure the uv energy the solutions are very expensive, but also you do not need to do any measure. With the help of a Stouffer guide you can calculate exactly your exposition time for any kind of LPI. If your question is about how many black light tubes are acceptable, I can tell you that I use 4 tubes (model F15T8BL, 15 watts, termination BL, not BLB) for exposing AQ3000 DC at a distance of 5 centimeters and the exposition time is only 58 seconds.
However, for final curing of LPI soldermask and legend ink 4 tubes have few effect and maybe you need a mercury-arc lamp.
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