Hi,
Why not simply use solder stop laminate?
Laminate, expose, develop, done - > I can't imagine something faster and
simpler than that...
Markus
iluvpcbs schrieb:
>
> Hi,
>
> I have two ideas for home made soldermask, would like to hear
> comments. I have not tried any of these but they have promise.
>
> Idea A (Toner Transfer on to Pads):
>
> 1. Toner-Transfer image to PCB, etch PCB
> 2. Use acetone or something else, remove all toner
> 3. Do a second toner-transfer pass, this time transfer toner only
> onto ∗PADS∗ of component (i.e. solder paste layer)
> 4. Spray the conformal coating(soldermask material) over entire PCB
> and let it dry
> 5. Use acetone and gently rub to remove toner on the pads; even
> though there is a conformal coating, it is on top of the toner, so the
> toner could be undercut
>
> - One variation is instead of transferring onto the pads with toner,
> use inkjet ink or something that doesn't really stick but rests on the
> surface of the pad
> - A second variation is to Toner-Transfer the solder mask onto the PCB
> and use a laser transfer foil
>
> Idea B (Vinyl cut a solderpaste layer):
>
> 1. Toner-Transfer image to PCB, etch PCB
> 2. Use acetone or something else, remove all toner
> 3. Use a vinyl cutter and either with thin copper foil or heavy duty
> aluminum foil cut out pads for the design (i.e. solder paste layer)
>
> See links below for some background
>
> http://fab.cba.mit.edu/content/tools/machines/roland_vinyl_cutter/
> <http://fab.cba.mit.edu/content/tools/machines/roland_vinyl_cutter/>
>
> (bottom part of this page for really thin copper sheet)
> http://www.whimsie.com/coppersheetwire.html#anchor45391
> <http://www.whimsie.com/coppersheetwire.html#anchor45391>
>
> 5. Overlay copper foil on PCB
> 6. Spray some solution that can be easily removed on the pads, maybe
> latex or the Testors Solution ("temporary block")
> 7. Remove copper foil and spray actual conformal coating and let it dry
> 8. Rub the board and remove the "temporary block"
>
> ∗ Note, the same foil (or a new version) could be used to put solder
> paste on the pads for easy SMD assembly!
>
> What do you guys think?
>
> I'm also curious if anyone tried the Direct-PCB inkjet technique and
> was able to get a soldermask out of it.
>
> Thanks
>
>