Homebrew PCBs

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/

(bottom part of this page for really thin copper sheet)
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

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
>
>

Hi Markus,

--- In Homebrew_PCBs@yahoogroups.com, Markus Zingg <homebrew-pcb@...>
wrote:
>
> Hi,
> 
> Why not simply use solder stop laminate?
> 
> Laminate, expose, develop, done - > I can't imagine something faster
and 
> simpler than that...
> 
> Markus

I've avoided these for two reasons:

1.  I don't have a UV exposure system setup
2.  It seems like the developer needed for the soldermask laminate
requires some caustic solutions.

Can you describe the materials you use?  Can you obtain small pieces
of the dry laminate material cheaply?

Thanks!

There is no way a vinyl cutter could cut such small pads, at least the one I
have (Roland CAMM, the same as in the first link) will not do anything
smaller than 4 mm(0.15") square without ripping the vinyl/copper. Also
corners tend to be rounded by the blade. I tried this method for making self
adhesive copper tracks with the same material used in link 1 and same
settings and it doesn't work for tracks thinner than 0.10/0.15".
Additionally the self adhesive copper foil I used was very expensive.

   _____  

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of iluvpcbs
Sent: 20 January 2008 22:16
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Two ideas for home made soldermask



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

HYPERLINK
"http://fab.cba.mit.edu/content/tools/machines/roland_vinyl_cutter/"http://f
ab.cba.-mit.edu/content/-tools/machines/-roland_vinyl_-cutter/

(bottom part of this page for really thin copper sheet)
HYPERLINK
"http://www.whimsie.com/coppersheetwire.html#anchor45391"http://www.whimsie.
-com/coppersheetw-ire.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



 


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

Also, all this weeding can't be good for you.
I mean, the idea is _not_ to have to do everything manually, right?

ST

On Jan 21, 2008 12:22 PM, Jerome Decock <jerome@...> wrote:
> There is no way a vinyl cutter could cut such small pads, at least the one I
> have (Roland CAMM, the same as in the first link) will not do anything
> smaller than 4 mm(0.15") square without ripping the vinyl/copper. Also
> corners tend to be rounded by the blade. I tried this method for making self
> adhesive copper tracks with the same material used in link 1 and same
> settings and it doesn't work for tracks thinner than 0.10/0.15".
> Additionally the self adhesive copper foil I used was very expensive.
>
>   _____

You are right, you need an exposure setup. For developement washing soda 
is sufficient, and that's really nothing dangerous.

I bought a roll of 25 meters from Bungard. As such it was more expensive 
than the dry film laminate, but I also use a lot less stopmask than dry 
film lamnate. Here too, one person could order one and cut it in smaller 
pieces. If the need arises, I could do that. I don't currently know 
another source but I figure this one or a similar product from one of 
those manufactures which make these kind of photosentivie foils must be 
available at other places.

Apart from this you really only need to:
- produce a film (for the expouser, I use an Epson Stylus C62 and print 
on avery over head foils)
- laminate the material onto the PCB (I use a cheap office laminator for 
all my lamination needs)
- expose
- develop
- harden the result by yet again expose it, this time just longer, or 
bake it in an oven

I realize that a big (meanwhile looked at the poll) part of the list 
users use the TT method and as such may don't have an UV exposer unit. 
They then would have to use a different method, or get one. However, if 
I look at the mess involved with "spraying the conformal coating" 
compared to just laminate a foil, me thinks that getting or building an 
UV exposer seems to be the smaller of the two problems.

Just my 2\ufffd of course

Markus

iluvpcbs schrieb:

>
> Hi Markus,
>
> --- In Homebrew_PCBs@yahoogroups.com 
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Markus Zingg <homebrew-pcb@...>
> wrote:
> >
> > Hi,
> >
> > Why not simply use solder stop laminate?
> >
> > Laminate, expose, develop, done - > I can't imagine something faster
> and
> > simpler than that...
> >
> > Markus
>
> I've avoided these for two reasons:
>
> 1. I don't have a UV exposure system setup
> 2. It seems like the developer needed for the soldermask laminate
> requires some caustic solutions.
>
> Can you describe the materials you use? Can you obtain small pieces
> of the dry laminate material cheaply?
>
> Thanks!
>
>

I used a Graphtec vinyl cutter and about the best I could do was
standard 0.1" spacing DIP ICs in a psuedo-SMT way. No holes, leads
trimmed flush and soldered onto the copper side.

I also made some boards that I did drill, but without a guide hole
etched it was difficult to drill accurately.

No way could I have had a lead pass between pins or done narrow traces
with standard solder pads.

But very possibly accurate enough to make a solder paste stencil.

Scans in Files:
<http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/Sign_Cutter_to_make_PCBs/>

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "Jerome Decock" <jerome@...> wrote:
>
> There is no way a vinyl cutter could cut such small pads, at least
the one I
> have (Roland CAMM, the same as in the first link) will not do anything
> smaller than 4 mm(0.15") square without ripping the vinyl/copper. Also
> corners tend to be rounded by the blade. I tried this method for
making self

> adhesive copper tracks with the same material used in link 1 and same
> settings and it doesn't work for tracks thinner than 0.10/0.15".
> Additionally the self adhesive copper foil I used was very expensive.
>

Steve,

Could you try and make a solder paste stencil using your vinyl cutter
sometime to see if my idea might have any merit?

I agree that spraying coatings and stuff is a lot of work, but the UV
setup has, well setup time too.

My other idea was to use toner as a soldermask block and then remove
that later with acetone, but I don't know if the under cutting on that
would work.

I have yet to hear from any of the direct-inkjet-print guys if they
ever got a soldermask printed.

Thanks!


--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@...> wrote:
>
> I used a Graphtec vinyl cutter and about the best I could do was
> standard 0.1" spacing DIP ICs in a psuedo-SMT way. No holes, leads
> trimmed flush and soldered onto the copper side.
> 
> I also made some boards that I did drill, but without a guide hole
> etched it was difficult to drill accurately.
> 
> No way could I have had a lead pass between pins or done narrow traces
> with standard solder pads.
> 
> But very possibly accurate enough to make a solder paste stencil.
> 
> Scans in Files:
>
<http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/Sign_Cutter_to_make_PCBs/>

> 
> Steve Greenfield
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Jerome Decock" <jerome@> wrote:
> >
> > There is no way a vinyl cutter could cut such small pads, at least
> the one I
> > have (Roland CAMM, the same as in the first link) will not do anything
> > smaller than 4 mm(0.15") square without ripping the vinyl/copper. Also
> > corners tend to be rounded by the blade. I tried this method for
> making self
> > adhesive copper tracks with the same material used in link 1 and same
> > settings and it doesn't work for tracks thinner than 0.10/0.15".
> > Additionally the self adhesive copper foil I used was very expensive.
> >
>

Hello,
 
For SolderMask with Inkjet printer, you can see form Printar 
http://www.all4-pcb.us/printar.htm
 
The ink for solder mask is appromatevely the same for nomenclature 
just the color green or white.
 
But the viscosity is so so so hight, you can turn the pot and the ink 
not go out, very big marmelade, i think no possibility to put in 
inkjet cartridje
 
Special ink for solderMask, is necessacery go to 250° centigrade, for 
resist solder and automatik solder machine, reflow.
 
Also, special ink for solder mask by "LACKWERK PETERS"
http://www.peters.de/index_e.htm
 
ELPEMER photoimageable is a nice system 2467 pack, but in 2 component.
Developement in sodic soap.
 
For dry film solder mask: CONFORMASK by  SHIPLEY
http://www.pcb-pool.com/download/spezifikation/eng_ConforMask_2500_
(englisch).pdf
Developement in sodic soap.
 
Very nice process, vacum system not necesary for amateur application, 
just laminate, UV insolation and develop.
 
For copy film, also from SHIPLEY, "DIAZO-FILM", just copy transparent 
film from for lazer printed and copy with UV contact  chassi.
Developpement in amonia vapor soap the same from architechture copy 
plant.
 
You have a orange transparency film, you can place and see your pad 
to adjust position film and make UV exposur; very strong film.
 
Patrick

Hello,   For SolderMask with Inkjet printer, you can see form Printar 
http://www.all4-pcb.us/printar.htm <http://www.all4-pcb.us/printar.htm>
The ink for solder mask is appromatevely the same for nomenclature just
the color green or white.   But the viscosity is so so so hight, you can
turn the pot and the ink not go out, very big marmelade, i think no
possibility to put in inkjet cartridje   Special ink for solderMask, is
necessacery go to 250° centigrade, for resist solder and automatik
solder machine, reflow.   Also, special ink for solder mask by "LACKWERK
PETERS" http://www.peters.de/index_e.htm
<http://www.peters.de/index_e.htm>    ELPEMER photoimageable is a nice
system 2467 pack, but in component. Developement in sodic soap.   For
dry film solder mask: CONFORMASK by  SHIPLEY
http://www.pcb-pool.com/download/spezifikation/eng_ConforMask_2500_(engl\
isch).pdf
<http://www.pcb-pool.com/download/spezifikation/eng_ConforMask_2500_(eng\
lisch).pdf>  Developement in sodic soap.   Very nice process, vacum
system not necesary for amateur application, just laminate, UV
insolation and develop.   For copy film, also from SHIPLEY,
"DIAZO-FILM", just copy transparent film from for lazer printed and copy
with UV contact  chassi. Developpement in amonia vapor soap the same
from architechture copy plant.   You have a orange transparency film,
you can place and see your pad to adjust position film and make UV
exposur; very strong film.   Patrick
--- In Homebrew_PCBs@yahoogroups.com, "iluvpcbs" <iluvpcbs@...> wrote:
>
> Steve,
>
> Could you try and make a solder paste stencil using your vinyl cutter
> sometime to see if my idea might have any merit?
>
> I agree that spraying coatings and stuff is a lot of work, but the UV
> setup has, well setup time too.
>
> My other idea was to use toner as a soldermask block and then remove
> that later with acetone, but I don't know if the under cutting on that
> would work.
>
> I have yet to hear from any of the direct-inkjet-print guys if they
> ever got a soldermask printed.
>
> Thanks!
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Steve" alienrelics@ wrote:
> >
> > I used a Graphtec vinyl cutter and about the best I could do was
> > standard 0.1" spacing DIP ICs in a psuedo-SMT way. No holes, leads
> > trimmed flush and soldered onto the copper side.
> >
> > I also made some boards that I did drill, but without a guide hole
> > etched it was difficult to drill accurately.
> >
> > No way could I have had a lead pass between pins or done narrow
traces
> > with standard solder pads.
> >
> > But very possibly accurate enough to make a solder paste stencil.
> >
> > Scans in Files:
> >
>
<http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/Sign_Cutter_to_m\
ake_PCBs/>
> >
> > Steve Greenfield
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "Jerome Decock" <jerome@>
wrote:
> > >
> > > There is no way a vinyl cutter could cut such small pads, at least
> > the one I
> > > have (Roland CAMM, the same as in the first link) will not do
anything
> > > smaller than 4 mm(0.15") square without ripping the vinyl/copper.
Also
> > > corners tend to be rounded by the blade. I tried this method for
> > making self
> > > adhesive copper tracks with the same material used in link 1 and
same
> > > settings and it doesn't work for tracks thinner than 0.10/0.15".
> > > Additionally the self adhesive copper foil I used was very
expensive.
> > >
> >
>



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

I have thought about what might work. Perhaps a sheet of mylar stuck
onto some removable vinyl as a carrier. I had some around here, it's
relatively thick, not the thin overhead transparency stuff.

I seem to recall some others here saying they don't remove the toner
or ink, just solder right through it. So based on that, I'd think
neither would work as a soldermask.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "iluvpcbs" <iluvpcbs@...> wrote:

>
> Steve,1
> 
> Could you try and make a solder paste stencil using your vinyl cutter
> sometime to see if my idea might have any merit?
> 
> I agree that spraying coatings and stuff is a lot of work, but the UV
> setup has, well setup time too.
> 
> My other idea was to use toner as a soldermask block and then remove
> that later with acetone, but I don't know if the under cutting on that
> would work.
> 
> I have yet to hear from any of the direct-inkjet-print guys if they
> ever got a soldermask printed.
> 
> Thanks!
> 
>

Hi Steve,

Agreed, I don't think toner itself will work as a soldermask.  The
idea is if you vinyl cut a solder paste sheet, then one can spray some
kind of temporary solution (latex?), remove the solder paste sheet and
then spray the actual solder mask material.

Even though it might need an oven bake to cure, the temporary stuff
sprayed before the soldermask should lift off the pads, so voila
you're left with a soldermask on traces but nothing on pads.

Would you be willing to try something like this?  I don't have access
to a vinyl cutter at the moment.



--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@...> wrote:

>
> I have thought about what might work. Perhaps a sheet of mylar stuck
> onto some removable vinyl as a carrier. I had some around here, it's
> relatively thick, not the thin overhead transparency stuff.
> 
> I seem to recall some others here saying they don't remove the toner
> or ink, just solder right through it. So based on that, I'd think
> neither would work as a soldermask.
> 
> Steve Greenfield
> 
> --- In Homebrew_PCBs@yahoogroups.com, "iluvpcbs" <iluvpcbs@> wrote:
> >
> > Steve,1
> > 
> > Could you try and make a solder paste stencil using your vinyl cutter
> > sometime to see if my idea might have any merit?
> > 
> > I agree that spraying coatings and stuff is a lot of work, but the UV
> > setup has, well setup time too.
> > 
> > My other idea was to use toner as a soldermask block and then remove
> > that later with acetone, but I don't know if the under cutting on that
> > would work.
> > 
> > I have yet to hear from any of the direct-inkjet-print guys if they
> > ever got a soldermask printed.
> > 
> > Thanks!
> > 
> >
>

Have you folks tried to make a solder mask using a thin brass sheet just 
like how you would etch a PCB. It would last longer than a vinyl mask.

Kim


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

From: "iluvpcbs" <iluvpcbs@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, January 21, 2008 8:02 PM
Subject: [Homebrew_PCBs] Re: Two ideas for home made soldermask


> Hi Steve,
>
> Agreed, I don't think toner itself will work as a soldermask.  The
> idea is if you vinyl cut a solder paste sheet, then one can spray some
> kind of temporary solution (latex?), remove the solder paste sheet and
> then spray the actual solder mask material.
>
> Even though it might need an oven bake to cure, the temporary stuff
> sprayed before the soldermask should lift off the pads, so voila
> you're left with a soldermask on traces but nothing on pads.
>
> Would you be willing to try something like this?  I don't have access
> to a vinyl cutter at the moment.
>
>